UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):

July 10, 2025

MILESTONE PHARMACEUTICALS INC.

(Exact name of registrant as specified in its charter)

Québec		001-38899		Not applicable
(state or other jurisdiction of incorporation)		(Commission File Number)		(I.R.S. Employer Identification No.)

1111 Dr. Frederik-Philips Boulevard,
Suite 420
Montréal, Québec CA		H4M 2X6
(Address of principal executive offices)		(Zip Code)

Registrant's telephone number, including area code: (514) 336-0444

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Shares		MIST		The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b–2 of the Securities Exchange Act of 1934 (§ 240.12b–2 of this chapter).

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. ¨

Item 1.01 Entry into a Material Definitive Agreement.

On July 10, 2025, Milestone Pharmaceuticals Inc. (the “Company”) entered into an amendment (the “Amendment”) to its existing Purchase and Sale Agreement (the “Royalty Purchase Agreement”) with RTW Royalty I DAC, an affiliate of RTW Investments, LP. Pursuant to the Amendment, the Marketing Approval Deadline (as defined in the Royalty Purchase Agreement) has been extended from September 30, 2025 to December 31, 2025.

References to the terms of the Amendment are qualified in their entirety by reference to the full text of the Amendment, which will be filed as an exhibit to the Company’s next applicable periodic report.

Item 8.01 Other Events.

On July 11, 2025, the Company issued a press release announcing that the U.S. Food and Drug Administration has accepted for review the Company’s response to issues raised in the Complete Response Letter regarding its New Drug Application for CARDAMYST (etripamil) nasal spray for the management of paroxysmal supraventricular tachycardia and assigned a new Prescription Drug User Fee Act (PDUFA) target action date of December 13, 2025.

A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.		Description
99.1		Press Release, dated July 11, 2025
104		Cover Page Interactive Data File (the cover page XBRL tags are embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	MILESTONE PHARMACEUTICALS INC.

Dated: July 11, 2025	By:	/s/Amit Hasija
		Amit Hasija
		Chief Financial Officer

Milestone Pharmaceuticals Inc. 8-K