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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(Mark One)

☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended September 30, 2025

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

Commission file number: 001-38492

Kiniksa Pharmaceuticals International, plc

(Exact Name of Registrant as Specified in Its Charter)

England and Wales		98-1795578
(State or Other Jurisdiction of		(I.R.S. Employer
Incorporation or Organization)		Identification No.)

23 Old Bond Street, Floor 3

London, W1S 4PZ

England, United Kingdom

(781) 431-9100

(Address, zip code and telephone number, including area code of principal executive offices)

Kiniksa Pharmaceuticals Corp.

100 Hayden Avenue

Lexington, MA, 02421

(781) 431-9100

(Address, zip code and telephone number, including area code of agent for service)

N/A

(Former name, former address and former fiscal year, if changed since last report)

N/A

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Class A Ordinary Shares

KNSA

The Nasdaq Stock Market LLC

(Nasdaq Global Select Market)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.



Large Accelerated Filer	◻	Accelerated Filer	☒

Non-accelerated Filer	☐	Smaller Reporting Company	☐

		Emerging Growth Company	☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ◻

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

As of October 24, 2025, there were 75,795,759 ordinary shares outstanding in aggregate, comprised of:

45,161,019 Class A ordinary shares, nominal value $0.000273235 per share

1,795,158 Class B ordinary shares, nominal value $0.000273235 per share

12,781,964 Class A1 ordinary shares, nominal value $0.000273235 per share

16,057,618 Class B1 ordinary shares, nominal value $0.000273235 per share

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Kiniksa Pharmaceuticals International, plc

FORM 10-Q

FOR THE THREE MONTHS ENDED SEPTEMBER 30, 2025

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	Page
PART I — FINANCIAL INFORMATION	7
Item 1. Financial Statements (unaudited)	7
Consolidated Balance Sheets as of September 30, 2025 and December 31, 2024	7
Consolidated Statements of Operations and Comprehensive Income (Loss) for the three and nine months ended September 30, 2025 and 2024	8
Consolidated Statements of Shareholders’ Equity for the three and nine months ended September 30, 2025 and 2024	9
Consolidated Statements of Cash Flows for the nine months ended September 30, 2025 and 2024	10
Notes to Consolidated Financial Statements	11
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations	31
Item 3. Quantitative and Qualitative Disclosures About Market Risk	44
Item 4. Controls and Procedures	44

PART II — OTHER INFORMATION	45
Item 1. Legal Proceedings	45
Item 1A. Risk Factors	45
Item 2. Unregistered Sales of Equity Securities, Use of Proceeds and Issuer Purchases of Equity Securities	105
Item 3. Defaults Upon Senior Securities	105
Item 4. Mine Safety Disclosures	105
Item 5. Other Information	106
Item 6. Exhibits	107

SIGNATURES	108

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Quarterly Report on Form 10-Q (this “Quarterly Report”), contains forward-looking statements. All statements other than statements of historical facts contained in this Quarterly Report including statements regarding our commercial strategy; potential value drivers; potential indications; potential market opportunities and competitive position; ongoing, planned and potential clinical trials and other studies; timing and potential impact of clinical data; future results of operations and financial position; expected timeline for our cash, cash equivalents and short-term investments; product development; prospective products and product candidates; supply of drug products at acceptable cost and quality; collaborators, license and other strategic arrangements; the expected timeline for achievement of our clinical milestones; potential marketing authorizations from the United States Food and Drug Administration (the “FDA”) or regulatory authorities in other jurisdictions; potential and ongoing coverage and reimbursement for our products and product candidates, if approved; clinical and commercial activities; research and development costs; timing of regulatory filings and feedback; timing and likelihood of success; and plans and objectives of management for future operations and funding requirements, are forward-looking statements.

These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

In some cases, you can identify forward-looking statements by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “goal,” “design,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these identifying words. The forward-looking statements in this Quarterly Report are only predictions. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our business, financial condition and results of operations. These forward-looking statements speak only as of the date of this Quarterly Report and are subject to a number of risks, uncertainties and assumptions described under the sections in this Quarterly Report entitled “Summary Risk Factors,” “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and elsewhere in this Quarterly Report. These forward-looking statements are subject to numerous risks and uncertainties, including, without limitation, the following:

●

our continued ability to commercialize ARCALYST® (rilonacept) and to develop and commercialize our current and future product candidates, if approved;

●

competitive and potentially competitive products and technologies;

●

our ability to source sufficient quantities of our products and product candidates to meet patient and partner demand at acceptable cost and quality specifications;

●

our ability to successfully complete the technology transfer of the manufacturing process for ARCALYST drug substance;

●

prescriber awareness and adoption of our products and product candidates, if approved;

●

the size of the market for our products and product candidates, if approved;

●

the decision of third party payors not to cover or maintain coverage of or to establish burdensome requirements prior to covering or maintaining coverage of ARCALYST or any of our current or future product candidates, if approved;

●

the lengthy and expensive clinical development process with its uncertain outcomes and potential for clinical failure or delay;

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●

the decision by any applicable regulatory authority to permit clinical development of, to grant regulatory exclusivity for and to approve marketing and sale of our current and future product candidates;

●

our ability to anticipate and prevent adverse events caused by our products and product candidates;

●

our ability to identify, in-license, acquire, discover or develop additional product candidates;

●

our ability to undertake and execute on business combinations, out-licensing activities, collaborations or other strategic transactions and our ability to realize value therefrom;

●

potential product liability claims;

●

changes to federal, state and foreign regulatory requirements applicable to our products and product candidates;

●

the impact of current and future healthcare reforms, including those affecting the delivery of, payment for, or marketing of healthcare products and services;

●

our ability to obtain, maintain, protect and enforce our intellectual property rights related to our products and product candidates;

●

incurring losses in the future, potentially requiring us to raise additional funds;

●

general economic, industry and market uncertainty, including due to tariff policy and geopolitical tensions; and

●

our ability to attract and retain skilled personnel.

Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond our control, you should not place undue reliance on our forward-looking statements. Except as required by applicable law, we do not assume and specifically disclaim any obligation to update any forward-looking statements, whether as a result of any new information, future events, changed circumstances or otherwise.

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SUMMARY RISK FACTORS

Our business is subject to numerous risks and uncertainties, including those described in Part II, Item 1A. “Risk Factors” in this Quarterly Report. You should carefully consider these risks and uncertainties when investing in our Class A ordinary shares. The principal risks and uncertainties affecting our business include the following:

●

we may not be able to continue to commercialize ARCALYST or be successful in commercializing any future products, potentially impacting the commercial potential for our current and future products and our ability to generate revenue;

●

successful commercialization of our products and product candidates, if approved, will depend in part on the extent to which third party payors, including governmental authorities and private health insurers, provide funding, establish and maintain favorable coverage and pricing policies and set adequate reimbursement levels;

●

current and future healthcare legislation or executive or administrative action may have a material adverse effect on our business and results of operations;

●

if we are unable to advance our product candidates in clinical development, obtain regulatory approval and pursue commercialization, or experience significant delays in doing so, our business may be significantly harmed;

●

the incidence and prevalence for target patient populations of our products and product candidates have not been established with precision; if the market opportunities for our products and product candidates are smaller than we estimate, or any approval that we obtain is based on a narrower definition of our targeted patient population, our revenue and ability to sustain profitability may be materially adversely affected;

●

clinical development of our product candidates is a lengthy and expensive process with uncertain timelines, costs and outcomes;

●

we may encounter substantial delays in our preclinical studies and/or clinical trials or we may fail to demonstrate safety and efficacy to the satisfaction of applicable regulatory authorities; we may therefore be unable to obtain required regulatory approvals and be unable to successfully commercialize our product candidates on a timely basis, if at all;

●

we contract with third parties, including independent contract development and manufacturing organizations (“CDMOs”) to manufacture our commercial supply of ARCALYST and clinical supply of our product candidates and for certain research and development, which is highly regulated and complex, and we expect that we will continue to do so in the future; this reliance on third parties increases the risk that we may not have sufficient quantities of ARCALYST or our product candidates or such quantities at an acceptable cost, which could delay, prevent or impair our research and development or commercialization efforts;

●

we are conducting a technology transfer of the manufacturing process for ARCALYST drug substance from Regeneron Pharmaceuticals, Inc. (“Regeneron”) to Samsung Biologics Co., Ltd. (“Samsung”), and the analytical testing methods of ARCALYST drug substance and drug product to new contract testing labs (“CTLs”), which will be subject to significant risks and uncertainties;

●

we rely, and expect to continue to rely, on third parties, including independent investigators and contract research organizations (“CROs”) to activate sites, conduct and otherwise support our research activities, preclinical studies, clinical trials and other trials for our product candidates; if these third parties do not successfully carry out their contractual duties, comply with regulatory requirements or meet expected deadlines, we may not be able to obtain regulatory approval or commercialize our product candidates, and our business could be substantially harmed;

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●

if we are unable to adequately protect our proprietary technology or obtain and maintain patent protection for our technology and patents, if the scope of the patent protection obtained is not sufficiently broad, or if the terms of our patents are insufficient to protect product candidates for an adequate amount of time, our competitors could develop and commercialize technology and products similar or identical to ours, and our ability to successfully commercialize our technology and products may be materially impaired;

●

we have a history of operating losses and may require substantial additional financing in the future, which we may be unable to obtain when needed or on acceptable terms;

●

we face significant competition, which may result in others discovering, developing or commercializing drugs before or more successfully than us;

●

we may not successfully execute our growth strategy to identify, discover, develop, in-license or acquire additional product candidates or technologies, our strategy may not deliver anticipated results or we may refine or otherwise alter our growth strategy;

●

we may seek to acquire businesses or undertake business combinations, collaborations or other strategic transactions that may not be successful or on favorable terms, if at all, and we may not realize the intended benefits of such transactions;

●

we have entered into and may seek to enter into collaboration, licensing or other strategic transactions or arrangements to further develop, commercialize or otherwise attempt to realize value from one or more of our products and product candidates; such arrangements or transactions may not be successful or on favorable terms, which could adversely affect our ability to develop, commercialize or attempt to realize value from our products and product candidates;

●

we may be adversely affected by continuing geopolitical tensions, including the introduction of tariffs or reciprocal tariffs that may be imposed by the United States and its global trading partners that could collectively cause economic uncertainty and increased costs to product development and manufacturing;

●

the concentration of ownership of the voting power of our ordinary shares, including our Class B ordinary shares, and conversion rights of the holders of our Class A1 and Class B1 ordinary shares, which are held primarily by entities affiliated with certain of our directors, may prevent new investors from influencing significant corporate decisions and may have an adverse effect on the price of our Class A ordinary shares; and

●

the rights afforded to our shareholders are governed by English law; not all rights available to shareholders under United States law will be available to holders of our ordinary shares.

Industry and other data

Unless otherwise indicated, certain industry data and market data included in this Quarterly Report were obtained from independent third party surveys, market research, publicly available information, reports of governmental agencies and industry publications and surveys. All of the market data used in this Quarterly Report involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. We believe that the information from these industry publications and surveys included in this Quarterly Report is reliable.

ARCALYST is a registered trademark of Regeneron. Solely for convenience, trademarks, service marks, and trade names referred to in this Quarterly Report may be listed without identifying symbols.

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Part I — Financial Information

Item 1. Financial Statements (unaudited)

KINIKSA PHARMACEUTICALS INTERNATIONAL, PLC

CONSOLIDATED BALANCE SHEETS

(In thousands, except share and per share amounts)

(Unaudited)


	September 30,		December 31,
	2025		2024
Assets
Current assets:
Cash and cash equivalents	$	174,858	$	183,581
Short-term investments		177,244		60,046
Accounts receivable, net		51,742		41,724
Inventory		41,396		26,364
Prepaid expenses and other current assets		30,290		20,084
Total current assets		475,530		331,799
Property and equipment, net		1,655		662
Operating lease right-of-use assets		10,073		10,376
Other long-term assets		8,288		10,315
Intangible asset, net		15,500		16,250
Deferred tax assets		201,287		211,151
Total assets	$	712,333	$	580,553

Liabilities and Shareholders’ Equity
Current liabilities:
Accounts payable	$	6,150	$	2,039
Accrued collaboration expenses		63,282		48,157
Accrued expenses		30,941		32,355
Operating lease liabilities		2,696		1,993
Other current liabilities		20,523		16,077
Total current liabilities		123,592		100,621
Non-current liabilities:
Non-current deferred revenue		31,811		31,811
Non-current operating lease liabilities		7,022		7,862
Other long-term liabilities		14,525		1,823
Total liabilities		176,950		142,117
Commitments and contingencies (Note 13)
Shareholders’ equity:
Class A ordinary shares, nominal value of $0.000273235 per share; 44,789,913 shares and 41,881,319 shares issued and outstanding as of September 30, 2025 and December 31, 2024, respectively		12		11
Class B ordinary shares, nominal value of $0.000273235 per share; 1,795,158 shares issued and outstanding as of September 30, 2025 and December 31, 2024		1		1
Class A1 ordinary shares, nominal value of $0.000273235 per share; 12,781,964 shares issued and outstanding as of September 30, 2025 and December 31, 2024		4		4
Class B1 ordinary shares, $0.000273235 nominal value; 16,057,618 shares issued and outstanding as of September 30, 2025 and December 31, 2024		4		4
Additional paid-in capital		1,011,854		959,722
Accumulated other comprehensive loss		(155)		(163)
Accumulated deficit		(476,337)		(521,143)
Total shareholders’ equity		535,383		438,436
Total liabilities and shareholders’ equity	$	712,333	$	580,553

The accompanying notes are an integral part of these consolidated financial statements.

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KINIKSA PHARMACEUTICALS INTERNATIONAL, PLC

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS)

(In thousands, except share and per share amounts)

(Unaudited)


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2025		2024		2025		2024
Revenue:
Product revenue, net	$	180,855	$	112,214	$	475,437	$	294,493
License and collaboration revenue		—		—		—		6,210
Total revenue		180,855		112,214		475,437		300,703
Costs and operating expenses:
Cost of goods sold		20,257		20,109		56,728		43,014
Collaboration expenses		63,307		29,307		159,515		80,122
Research and development		24,166		26,057		62,244		76,408
Selling, general and administrative		49,104		46,399		139,497		127,476
Total operating expenses		156,834		121,872		417,984		327,020
Income (loss) from operations		24,021		(9,658)		57,453		(26,317)
Other income		3,136		2,457		8,146		7,144
Income (loss) before income taxes		27,157		(7,201)		65,599		(19,173)
Provision for income taxes		(8,722)		(5,492)		(20,793)		(15,132)
Net income (loss)	$	18,435	$	(12,693)	$	44,806	$	(34,305)
Net income (loss) per share attributable to ordinary shareholders—basic	$	0.25	$	(0.18)	$	0.61	$	(0.48)
Net income (loss) per share attributable to ordinary shareholders—diluted	$	0.23	$	(0.18)	$	0.57	$	(0.48)
Weighted average ordinary shares outstanding—basic		74,714,846		71,726,685		73,605,690		71,123,658
Weighted average ordinary shares outstanding—diluted		80,035,400		71,726,685		78,027,370		71,123,658
Comprehensive income (loss)
Net income (loss)	$	18,435	$	(12,693)	$	44,806	$	(34,305)
Other comprehensive income (loss)
Unrealized gain (loss) on short-term investments and currency translation adjustments, net of tax		(102)		89		8		(47)
Total other comprehensive income (loss)		(102)		89		8		(47)
Total comprehensive income (loss)	$	18,333	$	(12,604)	$	44,814	$	(34,352)

The accompanying notes are an integral part of these consolidated financial statements.

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KINIKSA PHARMACEUTICALS INTERNATIONAL, PLC

CONSOLIDATED STATEMENTS OF SHAREHOLDERS’ EQUITY

(In thousands, except share amounts)

(Unaudited)


	Ordinary Shares			Additional		Accumulated				Total
	(Class A, B, A1 and B1)			Paid-In		Other Comprehensive		Accumulated		Shareholders'
	Shares	Amount		Capital		Loss		Deficit		Equity
Balances at December 31, 2024	72,516,059	$	20	$	959,722	$	(163)	$	(521,143)	$	438,436
Issuance of Class A ordinary shares under incentive award plans	281,273		—		2,768		—		—		2,768
Share-based compensation expense	—		—		7,748		—		—		7,748
Unrealized loss on short-term investments and currency translation adjustments, net of tax	—		—		—		(2)		—		(2)
Net income	—		—		—		—		8,539		8,539
Balances at March 31, 2025	72,797,332	$	20	$	970,238	$	(165)	$	(512,604)	$	457,489
Issuance of Class A ordinary shares under incentive award plans	1,235,031		1		10,697		—		—		10,698
Share-based compensation expense	—		—		8,876		—		—		8,876
Unrealized gain on short-term investments and currency translation adjustments, net of tax	—		—		—		112		—		112
Net income	—		—		—		—		17,832		17,832
Balances at June 30, 2025	74,032,363	$	21	$	989,811	$	(53)	$	(494,772)	$	495,007
Issuance of Class A ordinary shares under incentive award plans	1,392,290		—		11,899		—		—		11,899
Share-based compensation expense	—		—		10,144		—		—		10,144
Unrealized loss on short-term investments and currency translation adjustments, net of tax	—		—		—		(102)		—		(102)
Net income	—		—		—		—		18,435		18,435
Balances at September 30, 2025	75,424,653	$	21	$	1,011,854	$	(155)	$	(476,337)	$	535,383

	Ordinary Shares			Additional		Accumulated				Total
	(Class A, B, A1 and B1)			Paid-In		Other Comprehensive		Accumulated		Shareholders'
	Shares	Amount		Capital		Income (Loss)		Deficit		Equity
Balances at December 31, 2023	70,460,617	$	20	$	916,763	$	6	$	(477,950)	$	438,839
Issuance of Class A ordinary shares under incentive award plans	358,479		—		3,613		—		—		3,613
Share-based compensation expense	—		—		7,206		—		—		7,206
Unrealized loss on short-term investments and currency translation adjustments, net of tax	—		—		—		(59)		—		(59)
Net loss	—		—		—		—		(17,704)		(17,704)
Balances at March 31, 2024	70,819,096	$	20	$	927,582	$	(53)	$	(495,654)	$	431,895
Issuance of Class A ordinary shares under incentive award plans	263,182		—		(178)		—		—		(178)
Share-based compensation expense	—		—		7,363		—		—		7,363
Unrealized loss on short-term investments and currency translation adjustments, net of tax	—		—		—		(77)		—		(77)
Net loss	—		—		—		—		(3,908)		(3,908)
Balances at June 30, 2024	71,082,278	$	20	$	934,767	$	(130)	$	(499,562)	$	435,095
Issuance of Class A ordinary shares under incentive award plans	1,075,911		—		6,689		—		—		6,689
Share-based compensation expense	—		—		7,826		—		—		7,826
Unrealized gain on short-term investments and currency translation adjustments, net of tax	—		—		—		89		—		89
Net loss	—		—		—		—		(12,693)		(12,693)
Balances at September 30, 2024	72,158,189	$	20	$	949,282	$	(41)	$	(512,255)	$	437,006

The accompanying notes are an integral part of these consolidated financial statements.

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KINIKSA PHARMACEUTICALS INTERNATIONAL, PLC

CONSOLIDATED STATEMENTS OF CASH FLOWS

(In thousands)

(Unaudited)


	Nine Months Ended
	September 30,
	2025		2024
Cash flows from operating activities:
Net income (loss)	$	44,806	$	(34,305)
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Depreciation and amortization expense		1,087		1,295
Share-based compensation expense		26,768		22,395
Non-cash lease expense		2,703		2,369
Net amortization of premiums and accretion of discounts on short-term investments		14		(378)
Net gain on disposal of property and equipment		(67)		(24)
Deferred income taxes		9,864		11,295
Changes in operating assets and liabilities:
Prepaid expenses and other current assets		(10,165)		(16,509)
Accounts receivable, net		(10,018)		(3,622)
Inventory		(15,032)		2,442
Other long-term assets		1,832		(7,211)
Accounts payable		4,264		(22)
Accrued expenses, accrued collaboration expenses and other current liabilities		17,870		32,736
Operating lease liabilities		(2,537)		(3,196)
Deferred revenue		—		(450)
Other long-term liabilities		12,702		104
Net cash provided by operating activities		84,091		6,919
Cash flows from investing activities:
Proceeds from sale of property and equipment		—		25
Purchases of property and equipment		(935)		(84)
Purchases of short-term investments		(275,953)		(180,020)
Proceeds from the maturities of short-term investments		158,709		152,458
Net cash used in investing activities		(118,179)		(27,621)
Cash flows from financing activities:
Proceeds from issuance of Class A ordinary shares under incentive award plans and employee share purchase plan		32,177		14,530
Payments in connection with ordinary shares tendered for employee tax obligations		(6,812)		(4,406)
Net cash provided by financing activities		25,365		10,124
Net decrease in cash and cash equivalents		(8,723)		(10,578)
Cash and cash equivalents at beginning of period		183,581		107,954
Cash and cash equivalents at end of period	$	174,858	$	97,376

Supplemental information:
Cash paid for income taxes	$	3,009	$	741

Supplemental disclosure of non-cash investing and financing activities:
Change in right-of-use asset as a result of new, modified, and terminated leases	$	2,400	$	1,533
Additions to property and equipment included in accounts payable and accrued expenses and other liabilities		287		201

The accompanying notes are an integral part of these consolidated financial statements.

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1. Nature of the Business and Basis of Presentation

Kiniksa Pharmaceuticals International, plc (the “Company” or “Kiniksa International”) is a biopharmaceutical company developing and commercializing novel therapies for diseases with unmet medical need, with a focus on cardiovascular indications. The Company’s portfolio of immune-modulating assets is based on strong biologic rationale or validated mechanisms, targets a spectrum of underserved cardiovascular and autoimmune conditions and offers the potential for differentiation.

The Company is the successor issuer to Kiniksa Pharmaceuticals, Ltd. (“Kiniksa Bermuda”). On June 27, 2024, the Company and Kiniksa Bermuda completed a transaction pursuant to a Bermuda court-approved scheme of arrangement (the “Scheme”), which had been previously approved by Kiniksa Bermuda’s shareholders. Pursuant to the Scheme, the shareholders of Kiniksa Bermuda became the shareholders of the Company and the Company became the ultimate parent and holding company of the Kiniksa organization, thereby effecting a change of incorporation from Bermuda to the United Kingdom (the “UK”) (the “Redomiciliation”). As used herein, and unless the context otherwise requires, references to the “Company” prior to the Redomiciliation shall refer to Kiniksa Bermuda and from and after the Redomiciliation, to Kiniksa International. In addition, references to “ordinary shares” prior to the Redomiciliation are to Kiniksa Bermuda’s common shares and from and after the Redomiciliation are to Kiniksa International’s ordinary shares.

The Company is subject to risks common to companies in the biopharmaceuticals industry including, but not limited to, commercialization of existing and new products, conducting clinical research and development, its current and future products and product candidates, risks from existing or new competition, protection of proprietary intellectual and other technology and compliance with United States and foreign regulations and approval requirements.

Principles of Consolidation

The Redomiciliation was accounted for as a change in the reporting entity between entities under common control and the historical basis of accounting was retained as if the entities had always been combined for financial reporting purposes. The consolidated financial statements for periods prior to the Redomiciliation are the consolidated statements of Kiniksa Bermuda as the predecessor to the Company for accounting and reporting purposes and, upon completion of the Redomiciliation, such historical consolidated financial statements became Kiniksa International’s historical consolidated financial statements.

The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiaries, Kiniksa Pharmaceuticals Corp. (“Kiniksa US”), Kiniksa Bermuda and Kiniksa Pharmaceuticals (UK), Ltd. (“Kiniksa UK”) as well as the subsidiary of Kiniksa US, Primatope Therapeutics, Inc. (“Primatope”) and subsidiaries of Kiniksa UK, Kiniksa Pharmaceuticals (Germany) GmbH (“Kiniksa Germany”), Kiniksa Pharmaceuticals (France) SARL (“Kiniksa France”), and Kiniksa Pharmaceuticals, GmbH (“Kiniksa Switzerland”), after elimination of all significant intercompany accounts and transactions. Where the Kiniksa Pharmaceuticals International, plc entity is referred to in its single, unconsolidated form, it is referred to as “Kiniksa International”.

Use of Estimates

The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the recognition of revenue, the accrual for research and development expenses, uncertain tax positions, and the valuation of the Company’s deferred tax assets. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates.

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Unaudited Interim Consolidated Financial Information

The accompanying unaudited consolidated financial statements have been prepared in accordance with GAAP for interim financial information. The accompanying unaudited consolidated financial statements do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the Company’s audited consolidated financial statements and the accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024 (the “2024 Form 10-K”). The Company’s accounting policies are described in the Notes to Consolidated Financial Statements included in the Company’s 2024 Form 10-K and updated, as necessary, in this report. The accompanying year-end consolidated balance sheet was derived from audited financial statements but does not include all disclosures required by GAAP. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of September 30, 2025 and the results of its operations for the three and nine months ended September 30, 2025 and 2024, the changes in its shareholders’ equity for the three and nine months ended September 30, 2025 and 2024 and its cash flows for the nine months ended September 30, 2025 and 2024. The results for the three and nine months ended September 30, 2025 are not necessarily indicative of results to be expected for the year ending December 31, 2025, any other interim periods or any future year or period.

Liquidity

The Company has evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the consolidated financial statements are issued. As of September 30, 2025, the Company had an accumulated deficit of $476,337. During the nine months ended September 30, 2025, the Company reported a net income of $44,806 and had cash provided from operating activities of $84,091. As of September 30, 2025, the Company had cash, cash equivalents and short-term investments of $352,102. Based on its current operating plan, the Company expects that its cash, cash equivalents and short-term investments will be sufficient to fund its operations and capital expenditure requirements for at least twelve months from the issuance date of these consolidated financial statements.

Recently Issued Accounting Pronouncements

In December 2023, the Financing Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments require (i) enhanced disclosures in connection with an entity's effective tax rate reconciliation and (ii) income taxes paid disaggregated by jurisdiction. The amendments are effective for annual periods beginning after December 15, 2024. The Company does not expect the adoption of the amendments to have a material impact on its financial statements.

In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, requiring public entities to disclose additional information about specific expense categories in the notes to the financial statements on an interim and annual basis. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and for interim periods beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the impact of adopting ASU 2024-03.

2. Fair Value of Financial Assets and Liabilities

Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

●

Level 1—Quoted prices in active markets for identical assets or liabilities.

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●

Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

●

Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

The following tables present information about the Company’s financial instruments measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values:


	Fair Value Measurements
	as of September 30, 2025 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents — money market funds	$	52,231	$	—	$	—	$	52,231
Cash equivalents — U.S. Treasury notes		—		77,320		—		77,320
Short-term investments — U.S. Treasury notes		—		177,244		—		177,244
	$	52,231	$	254,564	$	—	$	306,795


	Fair Value Measurements
	as of December 31, 2024 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents — money market funds	$	135,275	$	—	$	—	$	135,275
Short-term investments — U.S. Treasury notes		—		60,046		—		60,046
	$	135,275	$	60,046	$	—	$	195,321

During the nine months ended September 30, 2025 and the year ended December 31, 2024, there were no transfers between Level 1, Level 2 and Level 3. The money market funds were valued using quoted prices in active markets, which represent a Level 1 measurement in the fair value hierarchy. The Company’s cash equivalents and short-term investments as of September 30, 2025 and December 31, 2024 included U.S. Treasury notes, which are not traded on a daily basis and, therefore, represent a Level 2 measurement in the fair value hierarchy at each period end.


			Gross		Gross
	Amortized		Unrealized		Unrealized		Credit		Fair
	Cost		Gains		Losses		Losses		Value
September 30, 2025
Cash Equivalents - U.S. Treasury notes	$	77,323	$	—	$	(3)	$	—	$	77,320
Short-term investments — U.S. Treasury notes		177,251		1		(8)		—		177,244
	$	254,574	$	1	$	(11)	$	—	$	254,564


			Gross		Gross
	Amortized		Unrealized		Unrealized		Credit		Fair
	Cost		Gains		Losses		Losses		Value
December 31, 2024
Short-term investments — U.S. Treasury notes	$	60,022	$	24	$	—	$	—	$	60,046
	$	60,022	$	24	$	—	$	—	$	60,046

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As of September 30, 2025, the Company considers the unrealized losses in its investment portfolio to be temporary in nature and not due to credit losses. The Company has the ability to hold such investments until recovery of the fair value. The Company utilizes the specific identification method in computing realized gains and losses. The Company had no realized gains and losses on its available-for-sale securities for the three and nine months ended September 30, 2025 or 2024.

3. Product Revenue, Net

The Company derives substantially all of its product revenue, net from sales of ARCALYST in the United States, which was as follows:


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2025		2024		2025		2024
Product revenue, net	$	180,855	$	112,214	$	475,437	$	294,493

The following table summarizes balances and activity in each of the product revenue allowance and reserve categories for the nine months ended September 30, 2025:


	Contractual		Government
	Adjustments		Rebates		Returns		Total
Balance at December 31, 2024	$	3,495	$	8,640	$	2,294	$	14,429
Current provisions relating to sales in the current year		25,660		19,804		1,465		46,929
Adjustments relating to prior years		—		(721)		—		(721)
Payments/returns relating to sales in the current year		(23,895)		(10,293)		—		(34,188)
Payments/returns relating to sales in the prior years		(3,495)		(5,227)		(155)		(8,877)
Balance at September 30, 2025	$	1,765	$	12,203	$	3,604	$	17,572

Total revenue-related reserves as of September 30, 2025 and December 31, 2024, included in the Company’s consolidated balance sheets, are summarized as follows:


	September 30,		December 31,
	2025		2024
Components of accounts receivable	$	(648)	$	(444)
Components of other current liabilities		18,220		14,873
Total revenue-related reserves	$	17,572	$	14,429

Primarily all of the Company’s trade accounts receivable arise from product revenue in the United States due from the Company’s third party logistics provider.

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4. Inventory

Inventory consisted of the following:


	September 30,		December 31,
	2025		2024
Raw materials	$	9,832	$	9,972
Semi-finished goods		24,765		—
Finished goods		11,826		21,246
Total inventory	$	46,423	$	31,218
Balance Sheet Classification:
Inventory	$	41,396	$	26,364
Other long-term assets		5,027		4,854
Total inventory	$	46,423	$	31,218

As of September 30, 2025, $17,538 of semi-finished goods were associated with the Company’s technology transfer of ARCALYST drug substance manufacturing to a new facility, which is pending regulatory approval. The Company believes it is probable that regulatory approval will be obtained, and all such inventory will be available for commercial distribution in the future.

5. Property and Equipment, Net

Property and equipment, net consisted of the following:


	September 30,		December 31,
	2025		2024
Furniture, fixtures and vehicles	$	177	$	183
Computer hardware and software		379		379
Leasehold improvements		3,920		3,931
Lab equipment		4,034		4,207
Construction in progress		963		155
Total property and equipment		9,473		8,855
Less: Accumulated depreciation		(7,818)		(8,193)
Total property and equipment, net	$	1,655	$	662

Depreciation expense was $27 and $87 during the three months ended September 30, 2025 and 2024, respectively, and $75 and $360 during the nine months ended September 30, 2025 and 2024, respectively.

6. Intangible Assets

Intangible assets, net of accumulated amortization as of September 30, 2025 and December 31, 2024 are summarized in the following table.


		As of September 30, 2025						As of December 31, 2024
	Estimated			Accumulated						Accumulated
	life	Cost		Amortization		Net		Cost		Amortization		Net
Regulatory milestone	20 years	$	20,000	$	4,500	$	15,500	$	20,000	$	3,750	$	16,250

Amortization expense was $250 during the three months ended September 30, 2025 and 2024 and $750 during the nine months ended September 30, 2025 and 2024.

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7. Accrued Expenses

Accrued expenses consisted of the following:


	September 30,		December 31,
	2025		2024
Accrued research and development expenses	$	8,969	$	11,004
Accrued employee compensation and benefits		17,037		17,046
Accrued legal, commercial and professional fees		4,307		3,617
Other		628		688
	$	30,941	$	32,355

8. Share-Based Compensation

As part of the Redomiciliation, Kiniksa International assumed the sponsorship of, and all rights and obligations of Kiniksa Bermuda under Kiniksa Bermuda’s equity compensation plans, which include the 2018 Incentive Award Plan (the “2018 Plan”) and the 2018 Employee Share Purchase Plan (the “2018 ESPP”). Upon the effectiveness of the 2018 Plan, the Company ceased granting awards under its 2015 Equity Incentive Plan (as amended, the “2015 Plan” and together with the 2018 Plan, the “Plans”).

2015 Plan

As of September 30, 2025, there were 941,874 Class A ordinary shares reserved for issuance pursuant to outstanding awards under the 2015 Plan that were granted prior to the effectiveness of the 2018 Plan.

2018 Plan

The 2018 Plan provides for the grant of incentive share options, nonqualified share options, share appreciation rights, restricted shares, dividend equivalents, restricted share units (“RSUs”), PSUs (as defined below) and other share- or cash- based awards. Pursuant to the 2018 Plan’s evergreen provision, the number of shares available for future issuance under the 2018 Plan, as of January 1, 2025, increased by 2,900,642 Class A ordinary shares. As of September 30, 2025, 5,532,977 shares remained available for future grant under the 2018 Plan.

2018 ESPP

In December 2024, the Company’s board of directors approved an increase, as of January 1, 2025, of 90,000 Class A ordinary shares under the 2018 ESPP. As of September 30, 2025, 690,063 Class A ordinary shares were available for future issuance under the 2018 ESPP.

Restricted Share Units

The Company grants RSUs with service conditions to eligible employees as part of its equity incentive compensation. Such RSUs typically vest 25% on each of the first, second, third and fourth anniversaries of the date of grant, subject to continued employment through such dates.

Market and Performance-Based Share Units

In the second quarter of 2024, the Company began periodically granting performance-based restricted share units to certain employees under the 2018 Plan that are earned based upon (i) the achievement of certain specified ARCALYST revenue targets (“Revenue PSUs”) and (ii) the Company’s total shareholder return (“TSR”) relative to the TSR of each member of a specified peer group (“TSR PSUs”). The TSR PSUs and Revenue PSUs are subject to a three-year service period.

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In addition, the Company from time-to-time grants performance-based restricted share units to certain eligible employees pursuant to the 2018 Plan that are earned based upon certain development and regulatory milestones (“Development PSUs” and, together with the Revenue PSUs and TSR PSUs, “PSUs”). The Company’s currently outstanding Development PSUs are subject to earnout percentages based upon the date of applicable milestone achievement.

Performance Share Options

Beginning in the second quarter of 2025, the Company began granting performance share options (“PSOs”) to certain eligible employees pursuant to the 2018 Plan representing the right to purchase shares of the Company’s Class A ordinary shares. Such PSOs vest, if at all, upon the achievement of certain specified development and regulatory milestones and are subject to earnout percentages based upon the date of applicable milestone achievement.

The following table summarizes RSU and PSU activity for the nine months ended September 30, 2025:


	RSUs			PSUs
		Weighted			Weighted
		Average			Average
	Number of	Grant Date		Number of	Grant Date
	Shares	Fair Value		Shares	Fair Value
Unvested as of December 31, 2024	2,250,602	$	17.36	59,137	$	22.06
Granted	1,083,649	$	27.46	424,303	$	27.73
Vested	(698,136)	$	16.25	—	$	-
Forfeited	(434,034)	$	19.70	(64,710)	$	27.11
Unvested as of September 30, 2025	2,202,081	$	22.22	418,730	$	26.96

The following table summarizes share option and PSO activity for the nine months ended September 30, 2025:


	Options			PSOs
		Weighted			Weighted
	Number of	Average		Number of	Average
	Shares	Exercise Price		Shares	Exercise Price
Outstanding as of December 31, 2024	11,286,994	$	15.25	—	$	—
Granted	1,892,890	$	27.67	372,756	$	27.90
Exercised	(2,383,522)	$	13.02	—	$	—
Forfeited	(555,026)	$	21.36	(67,701)	$	28.15
Outstanding as of September 30, 2025	10,241,336	$	17.74	305,055	$	27.85
Share options exercisable as of September 30, 2025	6,648,521	$	15.12	—	$	—
Share options vested and expected to vest as of September 30, 2025	10,241,336	$	17.74	305,055	$	27.85

As of September 30, 2025, total unrecognized compensation cost related to RSUs, Revenue PSUs, TSR PSUs, and share options was $99,143 which is expected to be recognized over a weighted average remaining period of 2.64 years. As of September 30, 2025, total unrecognized compensation cost related to outstanding Development PSUs and PSOs was $9,474 which will be recognized when the applicable milestones are deemed probable of achievement through the date the awards vests with a cumulative catch-up.

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Share-Based Compensation

Share-based compensation expense was classified in the consolidated statements of operations and comprehensive loss as follows:


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2025		2024		2025		2024
Cost of goods sold	$	551	$	447	$	1,546	$	1,159
Research and development expenses		1,691		1,608		4,910		4,562
Selling, general and administrative expenses		7,902		5,771		20,312		16,674
	$	10,144	$	7,826	$	26,768	$	22,395

9. Out-Licensing Agreements

Genentech License Agreement

In August 2022, the Company entered into a license agreement (the “Genentech License Agreement”) with Genentech, Inc. and F. Hoffmann-La Roche Ltd (collectively, “Genentech”), pursuant to which the Company granted Genentech exclusive worldwide rights to develop, manufacture and commercialize vixarelimab and related antibodies (each, a “Genentech Licensed Product”). The Genentech License Agreement became effective in September 2022 (the “Genentech Effective Date”).

Under the Genentech License Agreement, the Company received an upfront payment of $80,000 for the license. During the year ended December 31, 2023, the Company received cash payments of $20,000 following delivery of certain drug supplies to Genentech and $15,000 following Genentech’s achievement of a development milestone related to a new indication under the Genentech License Agreement. In the fourth quarter of 2023, following the achievement of a development milestone related to a second indication under the Genentech License Agreement, Genentech became obligated to make an additional cash payment of $10,000 which the Company received in the first quarter of 2024. In the second quarter of 2024, the Company received a cash payment of $5,000 following the achievement of a development milestone related to the third indication under the Genentech License Agreement. Under the terms of the Genentech License Agreement, the Company is eligible to receive a total of approximately $600,000 in contingent payments, including specified development, regulatory and sales-based milestones, before fulfilling the Company’s upstream financial obligations, of which approximately $570,000 remained as of September 30, 2025. The Company will also be eligible to receive tiered percentage royalties on a Genentech Licensed Product-by-Genentech Licensed Product basis ranging from low-double digits to mid-teens on annual net sales of each Genentech Licensed Product, subject to certain customary reductions, with an aggregate minimum floor, before fulfilling the Company’s upstream financial obligations. Royalties will be payable on a Genentech Licensed Product-by-Genentech Licensed Product and country-by-country basis until the latest to occur of the expiration of certain patents that cover a Genentech Licensed Product, the expiration of regulatory exclusivity for such Genentech Licensed Product, or the tenth anniversary of first commercial sale of such Genentech Licensed Product in such country.

Pursuant and subject to the terms of the Genentech License Agreement, Genentech has the exclusive worldwide right to conduct development and commercialization activities for Genentech Licensed Products at its sole cost. In 2024, the Company fulfilled its responsibility under the Genentech License Agreement with respect to completing its Phase 2b clinical trial assessing the efficacy, safety and tolerability of vixarelimab in reducing pruritus in prurigo nodularis.

Accounting for the Genentech License Agreement

As of the Genentech Effective Date, the Company identified the following performance obligations in the Genentech License Agreement: (i) the delivery of the exclusive license for vixarelimab; (ii) an initial drug supply delivery; (iii) a drug product resupply delivery; and (iv) completion of the Phase 2b clinical trial for vixarelimab.

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The Company determined the transaction price of the Genentech License Agreement consisted of the $80,000 upfront payment and the $20,000 variable consideration related to the delivery of the initial drug supply and drug product resupply which was added to the transaction price in 2022. In 2023 and 2024, the Company added $25,000 and $5,000, respectively, to the transaction price following Genentech’s achievement of development milestones under the Genentech License Agreement.

As noted above, the Company identified four performance obligations in the Genentech License Agreement: (i) the delivery of the exclusive license for vixarelimab; (ii) an initial drug supply delivery; (iii) a drug product resupply delivery; and (iv) completion of the Phase 2b clinical trial for vixarelimab. The selling price of each performance obligation in the Genentech License Agreement was determined based on the Company’s standalone selling price with the objective of determining the price at which it would sell such an item if it were to be sold regularly on a standalone basis. The Company allocated the transaction price to each of the four performance obligations noted above.


Performance Obligation		Method of Recognition
Exclusive license for vixarelimab		Point in time; that is upon transfer of the license to Genentech, as control of the license was transferred on the Genentech Effective Date and Genentech could begin to use and benefit from the license on that date.
Initial drug supply delivery		Point in time upon delivery.
Drug product resupply delivery		Point in time upon delivery.
Completion of the phase 2b clinical trial for vixarelimab		Over time, using the cost-to-cost input method, which is believed to best depict the transfer of control to the customer. Under the cost-to-cost input method, the percent of completion is based on the ratio of actual costs incurred as of the period end to the total estimated costs. Revenue is recorded as a percentage of the allocated transaction price times the percent of completion.

The Company did not recognize any collaboration revenue under the Genentech License Agreement during the three and nine months ended September 30, 2025. The Company did not recognize any collaboration revenue under the Genentech License Agreement during the three months ended September 30, 2024. The Company recognized $5,261 of collaboration revenue under the Genentech License Agreement during the nine months ended September 30, 2024. As a result of the $5,000 development milestone the Company recognized revenue of $4,989 during the nine months ended September 30, 2024, related to performance obligations satisfied in prior periods. As of September 30, 2025, the Company had recognized the entire transaction price under the Genentech License Agreement as revenue.

Huadong Collaboration Agreements

In February 2022 (the “Effective Date”), the Company entered into two collaboration and license agreements (each, a “Huadong Collaboration Agreement” and together, the “Huadong Collaboration Agreements”) with Hangzhou Zhongmei Huadong Pharmaceutical Co., Ltd. (“Huadong”), pursuant to which the Company granted Huadong exclusive rights to develop and commercialize ARCALYST and develop, manufacture and commercialize mavrilimumab in the following countries: People’s Republic of China, Hong Kong SAR, Macao SAR, Taiwan Region, South Korea, Indonesia, Singapore, The Philippines, Thailand, Australia, Bangladesh, Bhutan, Brunei, Burma, Cambodia, India, Laos, Malaysia, Maldives, Mongolia, Nepal, New Zealand, Sri Lanka, and Vietnam (collectively, the “Huadong Territory”). The Company otherwise retained its current rights to ARCALYST and mavrilimumab outside the Huadong Territory.

In April 2025, the Company and Huadong entered into a mutual termination agreement pursuant to which the parties agreed to terminate the mavrilimumab Huadong Collaboration Agreement and release all claims related thereto. The ARCALYST Huadong Collaboration Agreement remains in effect.

Under the Huadong Collaboration Agreements, the Company received a total upfront cash payment of $22,000, which included $12,000 for the Huadong Territory license of ARCALYST and $10,000 for the Huadong Territory license of mavrilimumab. In 2024, following the achievement of a regulatory milestone under the ARCALYST Huadong Collaboration Agreement, Huadong became obligated to make an additional cash payment of $20,000 to the Company which the Company received in the first quarter of 2025. The Company will be eligible to receive up to approximately $50,000 in contingent sales-based milestone payments for ARCALYST, all of which remain outstanding as of

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September 30, 2025. Due to its termination, the Company does not expect to receive any future payments under the mavrilimumab Huadong Collaboration Agreement. Huadong will also be obligated to pay the Company tiered percentage royalties ranging from the low-to-mid teens on annual net sales of ARCALYST in the Huadong Territory, subject to certain reductions tied to ARCALYST manufacturing costs and certain other customary reductions, with an aggregate minimum floor. Royalties will be payable on a country-by-country or region-by-region basis until the later of (i) 12 years after the first commercial sale of ARCALYST in such country or region in the Huadong Territory, (ii) the date of expiration of the last valid patent claim of the Company’s patent rights or any joint collaboration patent rights that covers ARCALYST in such country or region in the Huadong Territory, and (iii) the expiration of the last regulatory exclusivity for ARCALYST in such country or region in the Huadong Territory.

The Company concluded that the Huadong Collaboration Agreements should not be combined and treated as a single arrangement for accounting purposes as the Huadong Collaboration Agreements were negotiated separately with separate and distinct commercial objectives, the amount of consideration in one Huadong Collaboration Agreement is not dependent on the price or performance of the other Huadong Collaboration Agreement, and the goods and services promised in the Huadong Collaboration Agreements are not a single performance obligation.

Accounting for the Mavrilimumab Huadong Collaboration Agreement

As of the Effective Date, the Company identified the following performance obligations in the mavrilimumab Huadong Collaboration Agreement: delivery of (i) exclusive license for mavrilimumab in the Huadong Territory and (ii) clinical manufacturing supply of certain materials for mavrilimumab products in the Huadong Territory.

The Company determined the transaction price at the inception of the mavrilimumab Huadong Collaboration Agreement which includes $10,000, consisting of the upfront payment. The Company also included an estimate of variable consideration associated with the clinical manufacturing supply of certain materials when those materials were shipped.

The Company recognized revenue for the license performance obligations at a point in time, that is upon transfer of the license to Huadong. As control of the license was transferred on the Effective Date and Huadong could begin to use and benefit from the license, the Company recognized $10,000 of collaboration revenue during the year ended December 31, 2022 under the mavrilimumab Huadong Collaboration Agreement. Due to the termination of the mavrilimumab Huadong Collaboration Agreement in April 2025, the Company will not recognize any additional revenue from this agreement.

Accounting for the ARCALYST Huadong Collaboration Agreement

As of the Effective Date, the Company identified one performance obligation in the ARCALYST Huadong Collaboration Agreement: the exclusive license for ARCALYST and clinical and commercial manufacturing obligations for ARCALYST products in the Huadong Territory. Huadong cannot exploit the value of the exclusive license for ARCALYST products in the Huadong Territory without receipt of supply as the exclusive license for ARCALYST products in the Huadong Territory does not convey to Huadong the right to manufacture and therefore the Company has combined the exclusive license for ARCALYST products in the Huadong Territory and the manufacturing obligations into one performance obligation.

The Company determined the transaction price at the inception of the ARCALYST Huadong Collaboration Agreement, which includes $12,000, consisting of the upfront payment. In 2024, the Company added $20,000 to the transaction price following the achievement of a regulatory milestone. The Company also includes an estimate of variable consideration associated with the clinical and commercial manufacturing supply of certain materials when those materials are shipped. The Company determined that any variable consideration related to development and regulatory milestones, sales milestones and royalties are deemed fully constrained and therefore excluded from the transaction price due to the high degree of uncertainty and risk associated with these potential payments, as the Company determined that it could not assert that it was probable that a significant reversal in the amount of cumulative revenue recognized will not occur. Royalties and sales milestones will be recognized as the Company delivers the commercial manufactured product

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to Huadong. Any changes in estimates may result in a cumulative catch-up based on the number of units of manufactured product delivered.

The Company recognizes revenue for the single performance obligation in the ARCALYST Huadong Collaboration Agreement consisting of the exclusive license for ARCALYST and clinical and commercial manufacturing obligations for ARCALYST products in the Huadong Territory at a point in time, upon which control of materials are transferred to Huadong for each delivery of the associated materials. The Company currently expects to recognize the revenue over the life of the agreement. This estimate considers the timing of development and commercial activities under the ARCALYST Huadong Collaboration Agreement and may be reduced or increased based on changes in the various activities.

The Company did not recognize any revenue under the ARCALYST Huadong Collaboration Agreement during the three and nine months ended September 30, 2025. The Company recognized $189 of the upfront payment in collaboration revenue during the nine months ended September 30, 2024, under the ARCALYST Huadong Collaboration Agreement related to materials delivered. The Company did not recognize any revenue under the ARCALYST Huadong Collaboration Agreement during the three months ended September 30, 2024. As of September 30, 2025, $31,811 of the transaction price is recorded in non-current deferred revenue, based upon timing of anticipated future shipments.

The following table summarizes the Company’s contract liabilities in connection with license and collaboration agreements for the nine months ended September 30, 2025:


	Balance at				Revenue				Balance at End
	Beginning of Period		Additions		Recognized		Reclassification		of Period
Nine Months Ended September 30, 2025
Contract Liabilities:
Huadong ARCALYST	$	31,811	$	—	$	—	$	—	$	31,811

10. License and Acquisition Agreements

Biogen Asset Purchase Agreement

In September 2016, the Company entered into an asset purchase agreement (the “Biogen Agreement”) with Biogen MA Inc. (“Biogen”) to acquire all of Biogen’s right, title and interest in and to certain assets used in or relating to vixarelimab and other antibodies covered by certain patent rights, including patents and other intellectual property rights, clinical data, know-how, and clinical drug supply. In addition, Biogen granted the Company a non-exclusive, sublicensable, worldwide license to certain background patent rights related to the vixarelimab program. The Company is obligated to use commercially reasonable efforts to develop and commercialize such acquired products.

Under the Biogen Agreement, the Company is obligated to make payments to Biogen of up to $179,000 upon the achievement of specified clinical and regulatory milestones in multiple indications in various territories, of which $165,000 remains as of September 30, 2025. Additionally, the Company could be obligated to make up to an aggregate of $150,000 of payments upon the achievement of specified annual net sales milestones and to pay tiered royalties on escalating tiers of annual net sales of licensed products starting in the high single-digit percentages and ending below the teens.

The Company also agreed to pay certain obligations under third party contracts retained by Biogen that relate to the vixarelimab program. Under these retained contracts, the Company paid a one-time upfront sublicense fee and is obligated to pay insignificant annual maintenance fees as well as clinical and regulatory milestone payments of up to an aggregate of $1,575.

The Biogen Agreement will terminate upon the expiration of all payment obligations with respect to the last product in all countries in the territory. The Company has the right to terminate the agreement with 90 days’ prior

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written notice. Both parties may terminate by mutual written consent or in the event of material breach of the agreement by the other party that remains uncured for 90 days (or 30 days for payment-related breaches).

The Company and Biogen have amended the Biogen Agreement twice following its initial effective date. The first amendment, in July 2017, clarified the scope of the antibodies subject to the Biogen Agreement. The second amendment, effective in August 2022, was entered into in connection with the Genentech License Agreement, and amended certain defined terms, including “Net Sales,” “Indication,” “Product,” “Combination Product” and “Valid Claim.” In addition, the tiered royalty rates to be paid by the Company to Biogen increased by an amount equal to less than one percent. Upon the termination or expiration of the Genentech License Agreement all terms of the Biogen Agreement will revert to the version of such terms in effect as of immediately prior to the effective date of the Genentech License Agreement.

During the three months ended September 30, 2025, the Company did not record any expenses in connection with the Biogen Agreement. During the nine months ended September 30, 2025, the Company recorded expenses of $44 related to milestone payments and the annual maintenance fee in connection with the Biogen Agreement. During the three and nine months ended September 30, 2024, the Company recorded expenses of $72 and $144, respectively, related to a milestone and the annual maintenance fee in connection with the Biogen Agreement.

Beth Israel Deaconess Medical Center License Agreement

In 2019, the Company acquired all of the outstanding securities of Primatope Therapeutics, Inc. (“Primatope”), the company that owned or controlled the intellectual property related to abiprubart. In connection with the Company’s acquisition of Primatope, the Company acquired the rights to an exclusive license to certain intellectual property rights controlled by Beth Israel Deaconess Medical Center, Inc. (“BIDMC”) to make, use, develop and commercialize abiprubart (the “BIDMC Agreement”). Under the BIDMC Agreement, the Company is solely responsible for all development, regulatory and commercial activities and costs. The Company is also responsible for costs related to filing, prosecuting and maintaining the licensed patent rights. Under the BIDMC Agreement, the Company is obligated to pay an insignificant annual maintenance fee as well as clinical and regulatory milestone payments of up to an aggregate of $1,200 to BIDMC. The Company is also obligated to pay a low single-digit royalty on annual net sales of products licensed under the agreement.

During the three and nine months ended September 30, 2025, the Company did not record any expenses in connection with the BIDMC Agreement. During the three and nine months ended September 30, 2024, the Company recorded expenses of $6 and $41, respectively, in connection with the BIDMC Agreement.

Regeneron License Agreement

In September 2017, the Company entered into a license agreement (the “Regeneron Agreement”) with Regeneron Pharmaceuticals, Inc. (“Regeneron”), pursuant to which the Company has been granted an exclusive license under certain intellectual property rights controlled by Regeneron to develop and commercialize ARCALYST worldwide, excluding the Middle East and North Africa, for all indications other than those in oncology and local administration to the eye or ear. Upon receiving positive data in RHAPSODY, the Company’s pivotal Phase 3 clinical trial of ARCALYST, Regeneron transferred the biologics license application (“BLA”) for ARCALYST to the Company. In March 2021, when the FDA granted approval of ARCALYST for the treatment of recurrent pericarditis and reduction in risk of recurrence in adults and children 12 years and older, the Company assumed the sales and distribution of ARCALYST for Cryopyrin-Associated Periodic Syndromes and Deficiency of Interleukin-1 Receptor Antagonist in the United States.

The Company evenly splits profits on sales of ARCALYST with Regeneron, where profits are determined after deducting from net sales of ARCALYST certain costs related to the manufacturing and commercialization of ARCALYST. Such costs include but are not limited to (i) the Company’s cost of goods sold for product used, sold or otherwise distributed for patient use by the Company; (ii) customary commercialization expenses, including the cost of the Company’s field force, and (iii) the Company’s cost to market, advertise and otherwise promote ARCALYST, with such costs identified in subsection (iii) subject to specified limits.  To the extent permitted in accordance with the

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Regeneron Agreement, the fully-burdened costs incurred by each of the Company and Regeneron in performing (or having performed) the technology transfer of the manufacturing process for ARCALYST drug substance will also be deducted from net sales of ARCALYST to determine profit. The Company also evenly splits with Regeneron any proceeds received by the Company from any licensees, sublicensees and distributors in consideration for the sale, license or other disposition of rights with respect to ARCALYST, including upfront payments, milestone payments and royalties. For the three and nine months ended September 30, 2025, the Company recognized $63,282 and $159,446 respectively, of expenses related to the profit sharing agreement presented within collaboration expenses. For the three and nine months ended September 30, 2024, the Company recognized $29,152 and $79,218 respectively, of expenses related to the profit sharing agreement presented within collaboration expenses.

The Company has a supply agreement with Regeneron pursuant to which the Company may order both clinical and commercial product. The supply agreement terminates upon the termination of the Regeneron Agreement or the date of completion of the transfer of technology related to the manufacture of ARCALYST. During the three and nine months ended September 30, 2025 and 2024, the Company did not incur any research and development expense related to the purchase of drug materials under the supply agreement. As of September 30, 2025 and December 31, 2024, the Company recorded inventory of $19,053 and $21,246 respectively, related to the purchase of commercial product under the supply agreement. As of September 30, 2025, the Company had non-cancelable purchase commitments under the supply agreement (see Note 13).

The Regeneron Agreement will expire when the Company is no longer developing or commercializing any licensed product under the Regeneron Agreement. Either party may terminate the agreement upon the other party’s insolvency or bankruptcy or for material breach of the agreement by the other party that remains uncured for 90 days (or 30 days for payment related breaches). Regeneron has the right to terminate the agreement if the Company suspends its development or commercialization activities for a consecutive 12 month period or does not grant a sublicense to a third party to perform such activities, or if the Company challenges any of the licensed patent rights. The Company may terminate the agreement at any time with one year’s written notice. The Company may also terminate the agreement with three months’ written notice if the licensed product is determined to have certain safety concerns.

MedImmune License Agreement

In December 2017, the Company entered into a license agreement (as amended from time to time, the “MedImmune Agreement”) with MedImmune, Limited (subsequently acquired by AstraZeneca PLC) (“MedImmune”), pursuant to which MedImmune granted the Company an exclusive, sublicensable, worldwide license to certain intellectual property rights to make, use, develop and commercialize mavrilimumab. Under the MedImmune Agreement, the Company also acquired reference rights to relevant manufacturing and regulatory documents and MedImmune’s existing supply of mavrilimumab drug substance and product. The Company was obligated to use commercially reasonable efforts to develop and commercialize the licensed products.

In February 2025, the Company delivered a notice of termination to MedImmune, notifying them of its intent to terminate the MedImmune Agreement, for convenience, effective May 22, 2025. Following such date, the exclusive worldwide sublicense rights to certain intellectual property rights to make, use, develop and commercialize mavrilimumab were returned to MedImmune. The Company did not record any significant charges related to the termination of the MedImmune Agreement.

During the three and nine months ended September 30, 2025 and 2024, the Company did not record any expenses in connection with milestone payments due under the MedImmune Agreement.

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11. Net Income (Loss) per Share

The rights, including the liquidation and dividend rights, of the holders of Class A, Class B, Class A1 and Class B1 ordinary shares are identical, except with respect to voting, transferability and conversion (see Exhibit 4.2 to the Company’s Current Report on Form 8-K12B, filed on June 28, 2024). As the liquidation and dividend rights are identical, losses are allocated on a proportionate basis and the resulting net income (loss) per share attributed to ordinary shareholders will, therefore, be the same for both Class A and Class B ordinary shares on an individual or combined basis.

Basic and diluted net income (loss) attributable to ordinary shareholders was calculated as follows:


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2025		2024		2025		2024
Numerator:
Net income (loss) attributable to ordinary shareholders	$	18,435	$	(12,693)	$	44,806	$	(34,305)
Denominator:
Weighted-average shares outstanding		74,714,846		71,726,685		73,605,690		71,123,658
Effect of dilutive securities
Options to purchase ordinary shares		4,135,876		—		3,489,094		—
Performance options to purchase ordinary shares		—		—		—		—
Unvested RSUs		1,080,414		—		857,156		—
Unvested PSUs		104,264		—		75,430		—
Weighted-average shares outstanding		80,035,400		71,726,685		78,027,370		71,123,658

Basic net income (loss) per share	$	0.25	$	(0.18)	$	0.61	$	(0.48)
Diluted net income (loss) per share	$	0.23	$	(0.18)	$	0.57	$	(0.48)

The Company’s unvested RSUs and PSUs have been excluded from the computation of basic net loss per share attributable to ordinary shareholders.

For the three and nine months ended September 30, 2025 diluted earnings per share includes the assumed exercise of dilutive options and the assumed issuance of ordinary shares for unvested RSUs and PSUs for which the market or performance condition has been met as of the date of determination, using the treasury stock method unless the effect is anti-dilutive. The treasury stock method assumes that proceeds, including cash received from the exercise of employee share options and the average unrecognized compensation expense for unvested share-based compensation awards, would be used to purchase the Company’s ordinary shares at the average market price during the period.

For the three and nine months ended September 30, 2024 the Company’s potentially dilutive securities, which include options, unvested RSUs and unvested PSUs, have been excluded from the computation of diluted net loss per share attributable to ordinary shareholders as the effect would be to reduce the earnings per share (“EPS”) attributable to ordinary shareholders. Therefore, the weighted average number of ordinary shares outstanding used to calculate both basic and diluted EPS attributable to ordinary shareholders is the same. The Company excluded the following potential ordinary shares, presented based on amounts outstanding at each period end, from the computation of diluted EPS attributable to ordinary shareholders for the periods indicated because including them would have had an anti-dilutive effect:

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	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2025		2024		2025		2024
Share options to purchase ordinary shares		2,333,366		11,628,675		3,327,181		11,628,675
Performance share options to purchase ordinary shares		—		—		—		—
Unvested RSUs		462,422		2,385,277		935,314		2,385,277
Unvested PSUs		—		42,030		—		42,030
Total anti-dilutive shares		2,795,788		14,055,982		4,262,495		14,055,982

PSUs and PSOs that are outstanding and contain performance-based or market-based vesting criteria for which the performance or market conditions have not been met are excluded from the presentation of common stock equivalents outstanding in the table above.

12. Income Taxes

Prior to the Redomiciliation, the Company was incorporated and principally subject to taxation in Bermuda. Following the Redomiciliation, the Company is incorporated and principally subject to taxation in the UK. Under the laws of Bermuda, tax on a company’s income is assessed at a zero percent tax rate. As a result, the Company has not recorded any income tax benefits from its losses incurred in Bermuda during the reporting periods in which the Company was incorporated there, and no net operating loss carryforwards will be available to the Company for those losses. Following the Redomiciliation, the Company’s income is subject to the enacted UK statutory corporate tax rate and net operating losses incurred have an indefinite carryforward. The Company’s wholly owned United States subsidiaries, Kiniksa US and Primatope, are subject to federal and state income taxes in the United States. The Company’s wholly owned subsidiary Kiniksa Bermuda remains subject to taxation, if any, in Bermuda. The Company’s wholly owned subsidiary Kiniksa UK, and Kiniksa UK’s wholly owned subsidiaries, Kiniksa Germany, Kiniksa France, and Kiniksa Switzerland and Kiniksa UK’s Swiss branch office, are subject to taxation in their respective countries. Certain of the Company’s subsidiaries operate under cost plus arrangements.

The Company’s income tax rate for the three and nine months ended September 30, 2025 is attributable to Kiniksa Switzerland’s, Kiniksa UK’s Swiss branch office’s, Kiniksa UK’s and Kiniksa US’s income or loss subject to taxation in each of their respective countries. Income tax provision for the three and nine months ended September 30, 2025 was $8,722 and $20,793, respectively. The provision for income taxes is driven primarily by income earned in Switzerland, UK, United States and uncertain tax positions offset in part by tax benefits related to share-based compensation, United States federal and state research and development credits (“R&D Credits”), and the Foreign Derived Intangible Income (“FDII”) deduction. The Company’s uncertain tax position increased during the three and nine months ended September 30, 2025, driven by increased profitability within the Company’s tax jurisdictions.

Although Kiniksa Bermuda had no corporate income tax, the Company’s income tax rate for the three and nine months ended September 30, 2024 was due to Kiniksa Switzerland’s, Kiniksa UK’s Swiss branch office’s, Kiniksa UK’s and Kiniksa US’s income or loss subject to taxation in each of their respective countries. Income tax provision for the three and nine months ended September 30, 2024 was $5,492 and $15,132, respectively. The provision for income taxes is driven primarily by income earned in the UK, Switzerland and United States offset in part by tax benefits from FDII deduction and R&D Credits.

Management regularly assesses the need for a valuation allowance on the Company’s deferred income tax assets. Valuation allowances require an assessment of both positive and negative evidence when determining whether it is more likely than not that the Company will be able to recover its deferred tax assets. Such assessment is required on a jurisdiction-by-jurisdiction basis. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible.

Since 2021, the Company has engaged in a series of intra-entity asset transfers and allocations to contribute assets to its wholly owned Switzerland subsidiary, UK subsidiary and its UK Swiss branch office.

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In January 2021, in connection with its launch readiness activities, Kiniksa Bermuda contributed all of its rights, title and interest in, among other things, certain contracts (including the Regeneron Agreement), intellectual property rights, product filings and approvals and other information, plans and materials owned or controlled by Kiniksa Bermuda insofar as they related exclusively or primarily to ARCALYST to Kiniksa UK.

In February 2022, Kiniksa Bermuda contributed its exclusive rights to develop and commercialize mavrilimumab in the Huadong Territory to Kiniksa UK. Subsequent to the contribution there was a triggering event in 2024 resulting in decreases to the tax asset balance related to mavrilimumab intangible assets.

In July 2022, Kiniksa Bermuda contributed all of its rights, title and interest in, among other things, certain contracts (including the Biogen Agreement), intellectual property rights, product filings and approvals and other information, plans and materials owned or controlled by Kiniksa Bermuda insofar as they related exclusively or primarily to vixarelimab to Kiniksa UK.

The consolidated Company did not incur tax liabilities on any of these intra-entity transfers since the transferor, Kiniksa Bermuda, is exempt from income tax in Bermuda, its jurisdiction of incorporation. Kiniksa UK accounted for the 2021 and 2022 intra-entity transfers as transfers of assets between related parties and received stepped up tax bases in the contributed intellectual property assets, equal to the fair value of the assets at the time of transfer. The Company recorded UK deferred tax assets as a result of these contributions, which represent the difference between the stepped-up tax bases and the book bases for financial statement purposes. At the time of the 2021 and 2022 transfers of the relevant assets, the Company recorded a valuation allowance on the full amount of the recognized deferred tax assets.

The fair value of the January 2021 transfer of ARCALYST intellectual property assets was determined utilizing forecasted cash flows attributable to commercial operations and estimated probabilities of success of such cash flows, discounted to present value utilizing the discounted cash flow method. The fair values of the transferred mavrilimumab and vixarelimab intellectual property assets were determined utilizing future cash flows related to agreements with third parties for the use of the applicable intellectual property and estimated probabilities of success of such cash flows, discounted to present value utilizing the discounted cash flow method.

In December 2023, Kiniksa UK allocated all of its rights, title and interest in, among other things, certain contracts (including the Regeneron Agreement), intellectual property rights, product filings and approvals and other information, plans and inventory owned or controlled by the Company insofar as they related exclusively or primarily to ARCALYST to Kiniksa UK’s Swiss branch office.

The December 2023 allocation of the assets to the Swiss branch did not result in a taxable disposal for Kiniksa UK as the allocation was to a branch within the entity. The future results of Kiniksa UK’s Swiss branch office are subject to income taxes in Switzerland. Kiniksa UK’s Swiss branch office received a step up in basis resulting in a Swiss deferred tax asset. The fair value of the allocated ARCALYST intellectual property assets was determined utilizing forecasted cash flows attributable to commercial operations and estimated probabilities of success of such cash flows, discounted to present value utilizing the discounted cash flow method. The fair value of the ARCALYST inventory was determined utilizing the average net selling price less estimated costs to sell.

In January 2024, Kiniksa Bermuda transferred to Kiniksa Switzerland all rights, title and interest in, among other things, certain contracts, intellectual property rights, product filings and approvals and other information, plans and materials owned insofar as they related exclusively or primarily to abiprubart, mavrilimumab, KPL-387, KPL-1161 and certain preclinical assets. In June 2024, Kiniksa UK terminated its exclusive rights to develop and commercialize mavrilimumab in the Huadong Territory, with such rights reverting to Kiniksa Switzerland. Thereafter Kiniksa Switzerland held worldwide rights to develop and commercialize mavrilimumab until the MedImmune Agreement was terminated in May 2025. In October 2024, Kiniksa UK contributed all of its rights, title and interest in, among other things, certain contracts (including the Biogen Agreement), intellectual property rights, product filings and approvals and other information, plans and materials owned or controlled by Kiniksa UK insofar as they related exclusively or primarily to vixarelimab to Kiniksa Switzerland.

The consolidated Company did not incur tax liabilities on any of the January 2024 intra-entity transfers since the transferor, Kiniksa Bermuda, is exempt from income tax in Bermuda. Kiniksa Switzerland accounted for the intra-entity transfers as transfers of assets between related parties and received stepped up tax bases in the contributed

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intellectual property assets, equal to the fair value of the assets at the time of transfer. In relation to the June 2024 transaction, Kiniksa UK received consideration in exchange for the termination of exclusive rights. Neither Kiniksa UK nor Kiniksa Switzerland incurred any tax liabilities as a result of the transaction. The consolidated Company did not incur tax liabilities on any of the October 2024 intra-entity transfers since the transferor, Kiniksa UK, is the sole direct shareholder of Kiniksa Switzerland. Kiniksa Switzerland accounted for the intra-entity transfers as transfers of assets between related parties and received stepped up tax bases in the contributed intellectual property assets, equal to the fair value of the assets at the time of transfer.

The fair values of the transferred assets were determined utilizing future cash flows of projected operations and estimated probabilities of success of such cash flows, discounted to present value utilizing the discounted cash flow method. The Company recorded deferred tax assets as a result of these contributions, which represent the difference between the stepped-up tax bases and the book bases for financial statement purposes. The Company maintains a valuation allowance on the full amount of the Kiniksa Switzerland deferred tax assets. There are no material deferred tax assets in the jurisdictions outside the United States, UK and Switzerland.

13. Commitments and Contingencies

License Agreements

The Company has entered into license agreements with various parties under which it is obligated to make contingent and non-contingent payments (see Note 10).

Manufacturing Commitments

The Company has a supply agreement with Regeneron pursuant to which the Company may order both clinical and commercial product (see Note 10). In June 2024, the Company entered into a Master Services Agreement and a Product Specific Agreement with Samsung as part of its technology transfer of the manufacturing process for ARCALYST drug substance. The Company has additionally entered into agreements with several contract development and manufacturing organizations to provide the Company with preclinical and clinical trial materials for its non-ARCALYST assets. As of September 30, 2025, the Company had committed to minimum purchase commitments under all of these agreements totaling $204,982, of which $86,572 is due within one year.

The Company issued termination notices to CDMOs in February 2025 to terminate the clinical supply agreements for the production of abiprubart. During the nine months ended September 30, 2025, the Company recorded and paid $2,500 in research and development expenses because of these terminations. During the three months ended September 30, 2025, the Company did not record any expenses in connection with these terminations. The Company does not expect to incur any additional expenses because of these terminations.

Performance Cash Awards

Beginning in the second quarter of 2025, the Company began granting cash awards (“Performance Cash Awards”) to certain eligible employees pursuant to the 2018 Plan, which were eligible to be received upon the achievement of certain specified development and regulatory milestones and that are subject to earnout percentages based upon the date of applicable milestone achievement. As of September 30, 2025, the Company estimates the future cash payments under such Performance Cash Awards to be $22,660 if the milestones are achieved. The Performance Cash Awards will be recognized when the applicable milestones are deemed probable of achievement with a cumulative catch-up and recognized over the remaining term. The Company has not deemed any of the Performance Cash Award development or regulatory milestones as probable as of September 30, 2025, and no expense has been recognized related to such awards.

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Indemnification Agreements

The Company is not aware of any claims under indemnification arrangements that are expected to have a material effect on its financial position, results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its consolidated financial statements as of September 30, 2025 or December 31, 2024.

Legal Proceedings

The Company is not a party to any material litigation and does not have contingency reserves established for any litigation liabilities.

14. Segment Information and Geographic Data

The Company manages its operations as a single operating segment for the purposes of assessing performance and making operating decisions. The Company’s singular focus is on developing and commercializing novel therapies that target cardiovascular diseases with significant unmet medical need. The Company’s Chief Operating Decision Maker (“CODM”) is the Chief Executive Officer. The Company’s CODM reviews consolidated operating results and decides how to allocate resources based on net income that also is reported on the income statement as consolidated net income. The measure of segment assets is reported on the balance sheet as total consolidated assets. The CODM utilizes net income to make key decisions about how to allocate resources across the Company’s commercial product and development programs.

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The following table presents selected financial information with respect to the Company’s single operating segment for the three and nine months ended September 30, 2025 and 2024:


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2025		2024		2025		2024
Revenue:
Product revenue, net	$	180,855	$	112,214	$	475,437	$	294,493
License and collaboration revenue		-		-		-		6,210
Total revenue		180,855		112,214		475,437		300,703
Operating expenses:
Cost of goods sold		20,257		20,109		56,728		43,014
Collaboration expenses		63,307		29,307		159,515		80,122
Direct research and development expenses by program:
ARCALYST		269		245		795		955
KPL-387		11,380		6,827		25,043		9,545
KPL-1161		1,792		260		2,262		360
Abiprubart		708		8,485		5,710		35,942
Vixarelimab		-		161		-		1,194
Mavrilimumab		-		4		120		382
Unallocated research and development expenses		10,017		10,075		28,314		28,030
Selling, general and administrative		49,104		46,399		139,497		127,476
Total operating expenses		156,834		121,872		417,984		327,020
Other income (1)		3,136		2,457		8,146		7,144
Income (loss) before income taxes		27,157		(7,201)		65,599		(19,173)
Provision for income taxes		(8,722)		(5,492)		(20,793)		(15,132)
Net income (loss)	$	18,435	$	(12,693)	$	44,806	$	(34,305)

Other significant noncash items:
Share-based compensation expense	$	10,144	$	7,826	$	26,768	$	22,395
Non-cash lease expense		944		754		2,703		2,369
Deferred income taxes		4,227		(3,639)		9,864		11,295

(1)	Includes interest income of $3,149 and $8,170 for the three and nine months ended September 30, 2025, respectively. Includes interest income of $2,287 and $6,781 for the three and nine months ended September 30, 2024, respectively.

The following table presents total revenue by geographic region of the customer for the three and nine months ended September 30, 2025 and 2024:


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2025		2024		2025		2024
Revenue:
United States	$	180,709	$	111,937	$	474,811	$	299,255
United Kingdom		146		277		626		573
Rest of world		-		-		-		875
Total revenue	$	180,855	$	112,214	$	475,437	$	300,703

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The following table presents property and equipment, net by geographic region (in thousands):


	September 30,		December 31,
	2025		2024
Property and Equipment, net
United States	$	1,387	$	313
United Kingdom		81		99
Rest of world		187		250
Total property and equipment, net	$	1,655	$	662

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Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our unaudited consolidated financial statements and related notes included elsewhere in this Quarterly Report, and our audited consolidated financial statements and related notes for the year ended December 31, 2024 included in our Annual Report on Form 10-K (our “Annual Report”). Some of the information contained in this discussion and analysis or set forth elsewhere in this Quarterly Report, including information with respect to our plans and strategy for our business, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth in the risks identified in Part II-Item 1A “Risk Factors” section of this Quarterly Report and our other filings with the Securities and Exchange Commission (the “SEC”) our actual results could differ materially from the results, performance or achievements expressed in or implied by these forward-looking statements.

Overview

We are a biopharmaceutical company developing and commercializing novel therapies for diseases with unmet need, with a focus on cardiovascular indications. Our portfolio of assets is based on strong biologic rationale or validated mechanisms and offers the potential for differentiation.

ARCALYST is an interleukin-1α (“IL-1α”) and interleukin-1β (“IL-1β”) cytokine trap. In 2017, we licensed ARCALYST from Regeneron, which discovered and initially developed the drug. Our exclusive license to ARCALYST from Regeneron includes worldwide rights, excluding the Middle East and North Africa, for all applications other than those in oncology and local administration to the eye or ear. We received FDA approval of ARCALYST for the treatment of recurrent pericarditis and reduction in risk of recurrence in adults and children 12 years and older in March 2021. Recurrent pericarditis is a painful inflammatory cardiovascular disease with an estimated United States prevalent population of approximately 40,000 patients seeking and receiving medical treatment. ARCALYST is also approved in the United States for the treatment of Cryopyrin-Associated Periodic Syndromes (“CAPS”), including Familial Cold Autoinflammatory Syndrome and Muckle-Wells Syndrome in adults and children 12 years and older, and the maintenance of remission in Deficiency of Interleukin-1 Receptor Antagonist (“DIRA”) in adults and children weighing 10 kg or more. ARCALYST is commercially available across the United States through a select network of specialty pharmacies. We are responsible for sales and distribution of ARCALYST in all approved indications in the United States, and evenly split profits on sales, as well as third party proceeds, with Regeneron. In 2022, we granted Hangzhou Zhongmei Huadong Pharmaceutical Co., Ltd. (“Huadong”) exclusive rights to develop and commercialize ARCALYST in the Huadong Territory (as defined below). In 2023, Regeneron initiated a technology transfer of the manufacturing process for ARCALYST drug substance, and we are working to qualify Samsung as our replacement CDMO. In December 2024, we initiated a collaborative study agreement with The Mayo Clinic (together with Johns Hopkins University) to investigate the effects of ARCALYST in the treatment of cardiac sarcoidosis.

KPL-387 is an investigational, fully human immunoglobulin G2 monoclonal antibody that binds human interleukin-1 receptor 1 (“IL-1R1”), inhibiting IL-1α- and IL-1β-mediated signaling. KPL-387 is an independently developed asset that we believe has the potential to help grow the market and to further advance recurrent pericarditis treatment options for patients by potentially enabling dosing with a single monthly subcutaneous self-injection in a liquid formulation. In June 2024, we initiated a Phase 1 clinical trial of KPL-387 in normal healthy volunteers. In July 2025, we announced that the Phase 2 dose-focusing portion of the Phase 2/3 clinical trial of KPL-387 in recurrent pericarditis had begun recruiting. We expect data from the Phase 2 portion of the trial in the second half of 2026. In September 2025, we announced plans to conduct a supplemental Phase 2 transition to KPL-387 monotherapy dosing and administration study to evaluate the efficacy and safety of the dosing regimens used to transition patients from standard therapies to KPL-387 monotherapy. In October 2025, the FDA granted Orphan Drug Designation to KPL-387 for the treatment of pericarditis.

KPL-1161 is an independently developed, pre-clinical, Fc-modified immunoglobulin G2 monoclonal antibody that binds IL-1R1, inhibiting IL-1α- and IL-1β-mediated signaling. KPL-1161 is a modified version of KPL-387 designed to have an increased drug half-life that we believe could support quarterly subcutaneous dosing. We are currently conducting IND-enabling activities with respect to this asset.

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Abiprubart is an investigational monoclonal antibody inhibitor of CD40-CD154 costimulatory interaction, which we believe to be an attractive approach to address multiple autoimmune disease pathologies. We hold an exclusive worldwide license to abiprubart from Beth Israel Deaconess Medical Center, Inc. (“BIDMC”). We previously announced a Phase 2b clinical trial of abiprubart in Sjögren’s Disease. In February 2025, we announced our plans to discontinue development of abiprubart in the indication and to explore strategic alternatives for the asset.

Mavrilimumab is an investigational monoclonal antibody inhibitor targeting granulocyte-macrophage colony stimulating factor receptor alpha (“GM-CSFRα”). In 2017, we licensed exclusive worldwide rights in all indications to mavrilimumab from MedImmune, Limited, which has since been acquired by AstraZeneca PLC (“MedImmune”). In February 2025, we announced our termination of our license agreement from MedImmune for convenience, effective in May 2025. In April 2025, we entered into a mutual termination agreement with Huadong with respect to the mavrilimumab Huadong Collaboration Agreement (as defined below), pursuant to which we agreed to terminate the agreement and to release all claims related thereto.

We were initially incorporated under the laws of Bermuda in July 2015 and, in April 2024, subsequently announced the completion of the change of place of incorporation of our principal holding company from Bermuda to the United Kingdom (the “UK”), pursuant to a scheme of arrangement approved by both the Bermuda Supreme Court and our shareholders (the “Redomiciliation”), which caused the shareholders of our former parent company, Kiniksa Pharmaceuticals, Ltd. (“Kiniksa Bermuda”), to become the shareholders of our current parent company, Kiniksa Pharmaceuticals International, plc (the “Company” or “Kiniksa International”). As used herein, and unless the context otherwise requires, references to “we,” “us,” “our” and similar words or phrases prior to the Redomiciliation shall refer to Kiniksa Bermuda and from and after the Redomiciliation, to Kiniksa International. In addition, references to “ordinary shares” prior to the Redomiciliation are to Kiniksa Bermuda’s common shares and from and after the Redomiciliation are to Kiniksa International’s ordinary shares.

Our ability to generate product revenue sufficient to sustain our organization will depend heavily on a number of factors, including the continued commercialization of ARCALYST, the development and eventual commercialization of one or more of our current or future product candidates, if approved, and the management of our costs consistent with our current operating plan. For the nine months ended September 30, 2025, our net income was $44.8 million. As of September 30, 2025, we had an accumulated deficit of $476.3 million.

As of September 30, 2025, we had cash, cash equivalents and short-term investments of $352.1 million. We believe that our existing cash, cash equivalents and short-term investments will enable us to fund our operating expenses and capital expenditure requirements for at least the next 12 months from the date of issuance of the unaudited consolidated financial statements included in this Quarterly Report. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. See “— Liquidity and Capital Resources.”

Components of Our Results of Operations

Product revenue, net

We have been generating product revenue from sales of ARCALYST since April 2021. ARCALYST is sold through a third party logistics provider that distributes primarily through a select network of specialty pharmacies (collectively, “customers”), which deliver the medication to patients by mail. ARCALYST is currently approved for sale only in the United States, and, therefore, we expect to derive substantially all of our product revenue from the United States for the foreseeable future.

Net revenue from product sales is recognized at the transaction price when the customer obtains control of our product, which occurs at a point in time, typically upon shipment of the product from the third party logistics provider.

Our net revenues represent total revenues adjusted for discounts and allowances, including estimated cash discounts, chargebacks, rebates, returns, copay assistance, and specialty pharmacy and distributor fees. These adjustments represent variable consideration under ASC 606 and are estimated using the expected value method and are recorded when revenue is recognized on the sale of the product. These adjustments are established by management as its

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best estimate based on available information and will be adjusted to reflect known changes in the factors that impact such allowances. Adjustments for variable consideration are determined based on the contractual terms with customers, historical trends, communications with customers and the levels of inventory remaining in the distribution channel, as well as expectations about the market for the product and anticipated introduction of competitive products.

License and collaboration revenue

License and collaboration revenue includes amounts recognized related to upfront payments, royalty revenue, milestone payments and products sold under collaboration agreements.

In February 2022, we entered into two collaboration and license agreements (the “Huadong Collaboration Agreements”), with Huadong, pursuant to which we granted Huadong exclusive rights to develop and commercialize ARCALYST and mavrilimumab, in the Asia Pacific region excluding Japan (the “Huadong Territory”). In April 2025, we entered into a mutual termination agreement with Huadong pursuant to which we agreed to terminate the mavrilimumab Huadong Collaboration Agreement and release all claims related thereto. The ARCALYST Huadong Collaboration Agreement remains in effect.

Under the Huadong Collaboration Agreements, we received a total upfront cash payment of $22.0 million, which included $12.0 million for the Huadong Territory license of ARCALYST and $10.0 million for the Huadong Territory license of mavrilimumab. In the fourth quarter of 2024, following the achievement of a regulatory milestone under the ARCALYST Huadong Collaboration Agreement, Huadong became obligated to make an additional cash payment of $20.0 million, which was received in the first quarter of 2025. In addition, we will be eligible to receive additional contingent sales-based milestones payments related to ARCALYST. Huadong will also be obligated to pay us tiered percentage royalties ranging from the low-to-mid teens on annual net sales of ARCALYST in the Huadong Territory, subject to certain reductions tied to ARCALYST manufacturing costs and certain other customary reductions, with an aggregate minimum floor. Royalties will be payable on a country-by-country or region-by-region basis until the later of (i) 12 years after the first commercial sale of ARCALYST in such country or region in the Huadong Territory, (ii) the date of expiration of the last valid patent claim of our patent rights or any joint collaboration patent rights that covers ARCALYST in such country or region in the Huadong Territory, and (iii) the expiration of the last regulatory exclusivity for ARCALYST in such country or region in the Huadong Territory. We recognized the $10.0 million related to the mavrilimumab license during the year ended December 31, 2022 and do not expect to recognize any additional license and collaboration revenue following the termination of the mavrilimumab Huadong Collaboration Agreement. We have recognized $0.2 million of revenue of the $32.0 million transaction price under the ARCALYST license agreement as of September 30, 2025, and will recognize the remaining revenue as materials are shipped.

We are party to a license agreement (the “Genentech License Agreement”) with Genentech, effective September 2022, pursuant to which we granted Genentech exclusive worldwide rights to develop and commercialize vixarelimab and related antibodies (each, a “Genentech Licensed Product”).

Under the Genentech License Agreement, we received an upfront payment of $80.0 million for the license. Additionally, in 2023, we received a total of $35.0 million in additional payments from Genentech related to delivery of certain drug material to Genentech and Genentech’s achievement of a development milestone. In the fourth quarter of 2023, following the achievement of a development milestone related to a second indication under the Genentech License Agreement, Genentech became obligated to make an additional cash payment of $10.0 million, which was received in the first quarter of 2024. In the second quarter of 2024, we received $5.0 million following the achievement of a development milestone related to a third indication under the Genentech License Agreement. We will be eligible to receive up to a total of approximately $600.0 million in contingent payments, including specified development, regulatory and sales-based milestones, of which approximately $570.0 million remains as of September 30, 2025. We will also be eligible to receive tiered percentage royalties on a Genentech Licensed Product-by-Genentech Licensed Product basis ranging from low-double digits to mid-teens on annual net sales of each Genentech Licensed Product, subject to certain customary reductions, with an aggregate minimum floor, before fulfilling our upstream financial obligations. Royalties will be payable on a Genentech Licensed Product-by-Genentech Licensed Product and country-by-country basis until the latest to occur of the expiration of certain patents that cover a Genentech Licensed Product, the expiration of regulatory exclusivity for such Genentech Licensed Product, or the tenth anniversary of first commercial

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sale of such Genentech Licensed Product in such country. In 2024, we completed our remaining obligations under the Genentech License Agreement and we have recognized as revenue all of the consideration received.

Operating Expenses

Cost of Goods Sold

Cost of goods sold includes production and distribution costs of ARCALYST, amortization of the $20.0 million payment we made to Regeneron in the first quarter of 2021 upon achievement of a regulatory milestone and other miscellaneous product costs associated with ARCALYST. Cost of goods sold also includes labor and overhead costs associated with the production of ARCALYST associated with supply chain, quality, and regulatory activities, and the technology transfer of the manufacturing process for the ARCALYST drug substance.

Collaboration expenses

Collaboration expenses consist of Regeneron’s share of the profit related to ARCALYST sales under the Regeneron Agreement and the cost of products sold under collaboration agreements. We evenly split profits on sales of ARCALYST with Regeneron, where profits are determined after deducting from net sales of ARCALYST certain costs related to the manufacturing and commercialization of ARCALYST. Such costs include but are not limited to (i) our cost of goods sold for product used, sold or otherwise distributed for patient use by us; (ii) customary commercialization expenses, including the cost of our field force, and (iii) our cost to market, advertise and otherwise promote ARCALYST, with such costs identified in subsection (iii) subject to specified limits. With respect to the technology transfer of ARCALYST drug substance manufacturing from Regeneron to Samsung, to the extent permitted by the Regeneron Agreement, the fully-burdened costs of each of us and Regeneron incurred in performing such technology transfer shall also be deducted from net sales of ARCALYST to determine profit. We also evenly split with Regeneron any proceeds received by us from any licensees, sublicensees and distributors in consideration for the sale, license or other disposition of rights with respect to ARCALYST, including upfront payments, milestone payments and royalties.

Research and Development Expenses

Research and development expenses consist primarily of costs incurred in connection with the research and development of our product candidates. We expense research and development costs as incurred. These expenses may include:

●expenses incurred to conduct the necessary preclinical studies and clinical trials required to obtain regulatory approval;

●expenses incurred under agreements with CROs that are primarily engaged in the oversight and conduct of our clinical trials and CDMOs that are primarily engaged to provide preclinical and clinical drug substance and product for our research and development programs for our product candidates;

●other costs related to acquiring and manufacturing preclinical and clinical trial materials, including manufacturing validation batches, as well as investigative sites and consultants that conduct our clinical trials, preclinical studies and other scientific development services;

●payments made in cash or equity securities under third party licensing, acquisition and other similar agreements;

●employee-related expenses, including salaries and benefits, travel and share-based compensation expense for employees engaged in research and development functions;

●costs related to compliance with regulatory requirements; and

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●allocated facilities-related costs, which include rent and utilities, depreciation and other expenses.

We recognize external development costs based on an evaluation of the progress to completion of specific tasks using information provided to us by our service providers. This process involves reviewing open contracts and purchase orders, communicating with our personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of actual costs. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. Such amounts are recognized as an expense as the goods are delivered or the related services are performed, or until it is no longer expected that the goods will be delivered or the services rendered.

Our direct research and development expenses are tracked on a program-by-program basis for our product candidates and consist primarily of external costs, such as fees paid to outside consultants, CROs, CDMOs and research laboratories in connection with our preclinical development, process development, manufacturing and clinical development activities. Our direct research and development expenses by program also include fees incurred under license, acquisition and other similar agreements. We do not allocate employee costs or facility expenses, including depreciation or other indirect costs, to specific programs because these costs are deployed across multiple programs and, as such, are not separately classified. We use internal resources primarily to conduct our research and discovery activities as well as for managing our preclinical and clinical development, process development and manufacturing clinical and preclinical materials.

Research and development activities are central to our business. Product candidates in later stages of clinical development generally have higher costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. As a result, we expect that our research and development expenses will be substantial over the next several years as we conduct our ongoing and/or planned clinical trials for our product candidates, as well as conduct other preclinical and clinical development, and make regulatory filings for our product candidates.

At this time, we cannot reasonably estimate or know the nature, timing and costs of the efforts that will be necessary to complete the clinical development of our current or future product candidates or when, if ever, we will realize revenue from the sale of our current or future product candidates. This uncertainty is due to the numerous risks and uncertainties, including those described in Part II, Item 1A. “Risk Factors” in this Quarterly Report.

Selling, General and Administrative Expenses

Selling, general and administrative expenses consist primarily of salaries and benefits, including share based compensation expense for personnel in selling, marketing, medical, executive, business development, finance, human resources, legal and support personnel functions. Selling, general and administrative expenses also include external commercialization, marketing, and professional fees for legal, patent, and accounting services.

We expect that our selling, general and administrative expenses will continue to increase in the future as we continue to expand our infrastructure related to the commercialization of ARCALYST and our other product candidates, if approved.

Other Income

Other income consists of interest income recognized from investments in money market funds, United States Treasury notes and other miscellaneous income offset by expenses related to investments.

Income Taxes

Prior to the Redomiciliation, our principal holding company was incorporated and principally subject to taxation in Bermuda. Following the Redomiciliation, our principal holding company is incorporated and principally subject to taxation in the UK. Under the laws of Bermuda, there is no corporate income tax levied on an exempted

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company’s income, resulting in an effective zero percent tax rate. As a result, we have not recorded any income tax benefits from our losses incurred in Bermuda during the reporting periods in which we were incorporated there, and no net operating loss carryforwards are currently available to us for those losses. Following the Redomiciliation, our income is subject to the enacted UK statutory corporate tax rate and net operating losses incurred have an indefinite carryforward. Our wholly owned United States subsidiaries, Kiniksa Pharmaceuticals, Inc. (“Kiniksa US”), and Primatope Therapeutics, Inc. are subject to federal and state income taxes in the United States. Our wholly owned subsidiary Kiniksa Pharmaceuticals (UK), Ltd. (“Kiniksa UK”), its Swiss branch office, and Kiniksa UK’s wholly owned subsidiaries, Kiniksa Pharmaceuticals (Germany) GmbH, Kiniksa Pharmaceuticals (France) SARL, and Kiniksa Pharmaceuticals, GmbH (“Kiniksa Switzerland”) are subject to taxation in their respective countries.

On July 4, 2025, new U.S tax legislation was signed into law (known as the "One Big Beautiful Bill Act" or "OBBBA") which makes permanent many of the tax provisions enacted in 2017 as part of the Tax Cuts and Jobs Act that were set to expire at the end of 2025. In addition, the OBBBA makes changes to certain U.S. corporate tax provisions, but many are generally not effective until 2026. While we continue to assess the impact of the tax provisions of the OBBBA on our consolidated financial statements, we currently believe that the tax provisions of the legislation are not expected to have a material impact on our operations.

In the first quarter of 2024, Kiniksa Bermuda transferred to Kiniksa Switzerland all rights, title and interest in, among other things, certain contracts, intellectual property rights, product filings and approvals and other information, plans and materials owned insofar as they related exclusively or primarily to abiprubart, mavrilimumab, KPL-387, KPL-1161 and other preclinical assets. In connection with the foregoing transfer, we recognized a step-up in basis and did not incur any material tax liabilities.

In the second quarter of 2024, Kiniksa UK terminated its exclusive rights to develop and commercialize mavrilimumab in the Huadong Territory, with such rights reverting to Kiniksa Switzerland. Kiniksa Switzerland held worldwide rights to develop and commercialize mavrilimumab until the cancellation of the license agreement from MedImmune, effective in May 2025. In the fourth quarter of 2024, Kiniksa UK contributed all of its rights, title and interest in, among other things, certain contracts, intellectual property rights, product filings and approvals and other information, plans and materials owned or controlled by Kiniksa UK insofar as they related exclusively or primarily to vixarelimab to Kiniksa Switzerland. In connection with the termination of Kiniksa UK rights and the contribution, we revalued the assets at fair market value and did not incur any material tax liabilities.

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Results of Operations

Comparison of the Three Months Ended September 30, 2025 and 2024

The following table summarizes our results of operations for the three months ended September 30, 2025 and 2024:


	Three Months Ended
	September 30,
	2025		2024		Change

	(in thousands)
Revenue:
Product revenue, net	$	180,855	$	112,214	$	68,641
License and collaboration revenue		—		—		—
Total revenue		180,855		112,214		68,641
Costs and Operating expenses:
Cost of goods sold		20,257		20,109		148
Collaboration expenses		63,307		29,307		34,000
Research and development		24,166		26,057		(1,891)
Selling, general and administrative		49,104		46,399		2,705
Total operating expenses		156,834		121,872		34,962
Income (loss) from operations		24,021		(9,658)		33,679
Other income		3,136		2,457		679
Income (loss) before income taxes		27,157		(7,201)		34,358
Provision for income taxes		(8,722)		(5,492)		(3,230)
Net income (loss)	$	18,435	$	(12,693)	$	31,128

Product Revenue, Net

We recognized net revenue from the sale of ARCALYST of $180.9 million for the three months ended September 30, 2025, compared to $112.2 million for the three months ended September 30, 2024, an increase of $68.6 million. The increase in product revenue was driven primarily by an increase in patient enrollment.

Cost of Goods Sold

We recognized cost of goods sold of $20.3 million for the three months ended September 30, 2025, compared to $20.1 million for the three months ended September 30, 2024, an increase of $0.1 million. The increase in cost of goods sold relates primarily to the increase in sales of ARCALYST offset by a decrease in technology transfer costs and favorable production variances. Cost of goods sold related to the technology transfer of the manufacturing process of ARCALYST drug substance were $4.4 million for the three months ended September 30, 2025, compared to $7.5 million for the three months ended September 30, 2024, a decrease of $3.1 million.

Collaboration Expenses

Collaboration expenses were $63.3 million for the three months ended September 30, 2025, compared to $29.3 million for the three months ended September 30, 2024, an increase of $34.0 million. Collaboration expenses increased due to increased revenue from sales of ARCALYST.

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Research and Development Expenses


	Three Months Ended
	September 30,
	2025		2024		Change

	(in thousands)
ARCALYST	$	269	$	245	$	24
KPL-387		11,380		6,827		4,553
KPL-1161		1,792		260		1,532
Abiprubart		708		8,485		(7,777)
Vixarelimab		—		161		(161)
Mavrilimumab		—		4		(4)
Unallocated research and development expenses:
Personnel related (including share-based compensation)		5,961		6,262		(301)
Other		4,056		3,813		243
Total research and development expenses	$	24,166	$	26,057	$	(1,891)

Research and development expenses were $24.2 million for the three months ended September 30, 2025, compared to $26.1 million for the three months ended September 30, 2024, a decrease of $1.9 million.

Direct costs for our KPL-387 program were $11.4 million during the three months ended September 30, 2025, compared to $6.8 million during the three months ended September 30, 2024. The increase in expenses incurred primarily related to the start-up of our Phase 2/3 clinical trial in recurrent pericarditis during the three months ended September 30, 2025, as compared to the performance of our Phase 1 clinical trial in healthy volunteers during the three months ended September 30, 2024.

Direct costs for our KPL-1161 program were $1.8 million for the three months ended September 30, 2025, compared to $0.3 million during the three months ended September 30, 2024. For the three months ended September 30, 2025 and 2024, expenses incurred primarily related to pre-clinical development.

The direct costs for our abiprubart program were $0.7 million during the three months ended September 30, 2025, compared to $8.5 million during the three months ended September 30, 2024, a decrease of $7.8 million. The decrease in expenses incurred primarily related to the close-out of our Phase 2b clinical trial in Sjögren’s Disease during the three months ended September 30, 2025, as compared to the manufacturing of clinical material, continuation of cohort four of our Phase 2 clinical trial in rheumatoid arthritis (“RA”) and start-up costs of our Phase 2b clinical trial in Sjögren’s Disease during the three months ended September 30, 2024.

Unallocated research and development expenses were $10.0 million and $10.1 million for the three months ended September 30, 2025 and September 30, 2024, respectively. Personnel-related costs for the three months ended September 30, 2025 and 2024 included share-based compensation of $1.7 million and $1.6 million, respectively.

Selling, General and Administrative Expenses

Selling, general and administrative expenses were $49.1 million for the three months ended September 30, 2025, compared to $46.4 million for the three months ended September 30, 2024. The increase of $2.7 million was primarily due to an increase of $7.9 million in personnel-related costs largely attributable to an increase in headcount offset by a decrease in sales and marketing expenses of $4.0 million largely attributable to the timing of free goods designation. Personnel-related costs for the three months ended September 30, 2025 and 2024 included share-based compensation of $7.9 million and $5.8 million, respectively.

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Provision for Income Taxes

For the three months ended September 30, 2025, we recorded an income tax provision of $8.7 million relating primarily to income earned in Switzerland, the United States, and the UK, net of benefits related to share-based compensation, United States federal and state research and development credits (“R&D Credits”), and the Foreign Derived Intangible Income (“FDII”) deduction. For the three months ended September 30, 2024, we recorded an income tax provision of $5.5 million relating primarily to income earned in the UK, Switzerland and the United States, net of the FDII deduction and R&D Credits.

Comparison of the Nine Months Ended September 30, 2025 and 2024

The following table summarizes our results of operations for the nine months ended September 30, 2025 and 2024:


	Nine Months Ended
	September 30,
	2025		2024		Change

	(in thousands)
Revenue:
Product revenue, net	$	475,437	$	294,493	$	180,944
License and collaboration revenue		—		6,210		(6,210)
Total revenue		475,437		300,703		174,734
Operating expenses:
Cost of goods sold		56,728		43,014		13,714
Collaboration expenses		159,515		80,122		79,393
Research and development		62,244		76,408		(14,164)
Selling, general and administrative		139,497		127,476		12,021
Total operating expenses		417,984		327,020		90,964
Income (loss) from operations		57,453		(26,317)		83,770
Other income		8,146		7,144		1,002
Income (loss) before income taxes		65,599		(19,173)		84,772
Provision for income taxes		(20,793)		(15,132)		(5,661)
Net income (loss)	$	44,806	$	(34,305)	$	79,111

Product Revenue, Net

We recognized net revenue from the sale of ARCALYST of $475.4 million for the nine months ended September 30, 2025, compared to $294.5 million for the nine months ended September 30, 2024, an increase of $180.9 million. The increase in product revenue was driven primarily by an increase in patient enrollment.

License and Collaboration Revenue

We reported no license and collaboration revenue for the nine months ended September 30, 2025. We reported $6.2 million of license and collaboration revenue for the nine months ended September 30, 2024, driven primarily by the achievement of a $5.0 million development milestone related to a third indication under the Genentech License Agreement and $0.7 million of products sold under the ARCALYST Huadong Collaboration Agreements

Cost of Goods Sold

We recognized cost of goods sold of $56.7 million for the nine months ended September 30, 2025, compared to $43.0 million for the nine months ended September 30, 2024, an increase of $13.7 million. The increase in cost of goods sold relates primarily to the increase in sales of ARCALYST offset by a decrease in technology transfer costs. Cost of goods sold related to the technology transfer of the manufacturing process of ARCALYST drug substance were $8.3

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million for the three months ended September 30, 2025, compared to $12.5 million for the nine months ended September 30, 2024, a decrease of $4.2 million.

Collaboration Expenses

Collaboration expenses were $159.5 million for the nine months ended September 30, 2025, compared to $80.1 million for the nine months ended September 30, 2024, an increase of $79.4 million. Collaboration expenses increased due to increased revenue from sales of ARCALYST.

Research and Development Expenses


	Nine Months Ended
	September 30,
	2025		2024			Change

	(in thousands)
ARCALYST	$	795	$	955	$	(160)
KPL-387		25,043		9,545		15,498
KPL-1161		2,262		360		1,902
Abiprubart		5,710		35,942		(30,232)
Vixarelimab		—		1,194		(1,194)
Mavrilimumab		120		382		(262)
Unallocated research and development expenses:
Personnel related (including share-based compensation)		17,607		18,151		(544)
Other		10,707		9,879		828
Total research and development expenses	$	62,244	$	76,408	$	(14,164)

Research and development expenses were $62.2 million for the nine months ended September 30, 2025, compared to $76.4 million for the nine months ended September 30, 2024, a decrease of $14.2 million.

Direct costs for our KPL-387 program were $25.0 million during the nine months ended September 30, 2025, compared to $9.5 million during the nine months ended September 30, 2024. The increase in expenses incurred primarily related to the start-up of our Phase 2/3 clinical trial in recurrent pericarditis during the nine months ended September 30, 2025, as compared to the performance of our Phase 1 clinical trial in healthy volunteers during the nine months ended September 30, 2024.

Direct costs for our KPL-1161 program were $2.3 million for the nine months ended September 30, 2025, compared to $0.4 million during the nine months ended September 30, 2024. For the nine months ended September 30, 2025 and 2024, expenses incurred primarily related to pre-clinical development.

The direct costs for our abiprubart program were $5.7 million during the nine months ended September 30, 2025, compared to $35.9 million during the nine months ended September 30, 2024, a decrease of $30.2 million. The decrease in expenses incurred primarily related to the close-out of our Phase 2b clinical trial in Sjögren’s Disease during the nine months ended September 30, 2025, as compared to the manufacturing of clinical material, continuation of cohort four of our Phase 2 clinical trial in RA and start-up costs of our Phase 2b clinical trial in Sjögren’s Disease during the nine months ended September 30, 2024.

Unallocated research and development expenses were $28.3 million for the nine months ended September 30, 2025, compared to $28.0 million for the nine months ended September 30, 2024. Personnel-related costs for the nine months ended September 30, 2025 and 2024 included share-based compensation of $4.9 million and $4.6 million, respectively.

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Selling, General and Administrative Expenses

Selling, general and administrative expenses were $139.5 million for the nine months ended September 30, 2025, compared to $127.5 million for the nine months ended September 30, 2024. The increase of $12.0 million was primarily due to an increase of $14.8 million in personnel-related costs largely attributable to an increase in headcount. Personnel-related costs for the nine months ended September 30, 2025 and 2024 included share-based compensation of $20.3 million and $16.7 million, respectively.

Provision for Income Taxes

For the nine months ended September 30, 2025, we recorded an income tax provision of $20.8 million relating primarily to income earned in Switzerland, the United States, and the UK, net of benefits related to share-based compensation, R&D Credits, and FDII deduction. For the nine months ended September 30, 2024, we recorded an income tax provision of $15.1 million relating primarily to income earned in the UK, Switzerland and the United States, net of the FDII deduction and R&D Credits.

Liquidity and Capital Resources

As of September 30, 2025, our principal source of liquidity was cash, cash equivalents and short-term investments, which totaled $352.1 million. Net income (loss) was $44.8 million and ($34.3) million for the nine months ended September 30, 2025 and 2024, respectively. We expect our cash balance and our expected cash inflows from operations to allow us to meet our current operating plan.

Under various agreements with third parties, we have agreed to make milestone payments, pay royalties, pay annual maintenance fees and to meet due diligence requirements, each based upon specified events. Pursuant to the Regeneron Agreement, we have entered into a supply agreement with Regeneron to purchase both clinical and commercial product. We have committed to minimum payments to Regeneron of $56.1 million, all of which are due within one year. We have entered into lease agreements for office and laboratory space, and vehicles, with total future lease payments of $11.7 million, of which $4.1 million are due within one year. In connection with our ongoing technology transfer of ARCALYST drug substance manufacturing, we have entered into a Master Services Agreement and a Product Specific Agreement with Samsung. Our commitments under such agreements, which include the purchase of raw materials and related service fees, will obligate us to minimum payments of $136.9 million, $18.4 million of which are due within one year. As of September 30, 2025, we have capitalized $17.5 million of production cost into inventory as semi-finished goods related to drug substance manufactured at Samsung. We have additionally entered into agreements with several CDMOs to provide us with preclinical and clinical trial materials for our non-ARCALYST assets, which obligate us to minimum payments of $12.0 million all of which are due within one year. We have long-term incentive plans for our employees that may result in cash award payments of $22.6 million, based upon the achievement of certain regulatory milestones, none of which are expected to be achieved in the next year.

Under various agreements with third parties, we are entitled to receive upfront payments, milestone payments, and royalties, each based upon specified milestones. In 2024, we received $15.0 million in development milestone payments from Genentech related to a second and third indication under the Genentech License Agreement. In 2025, we received a $20.0 million milestone payment related to Huadong’s achievement of a regulatory milestone under the ARCALYST Huadong Collaboration Agreement.

These agreements impact our short-term and long-term liquidity and capital needs.

Table of Contents

Cash Flows

The following table summarizes our cash flows for each of the periods presented:


	Nine Months Ended
	September 30,
	2025		2024

	(in thousands)
Net cash provided by operating activities	$	84,091	$	6,919
Net cash used in investing activities

Kiniksa Pharmaceuticals International, plc 10-Q