UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, DC 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): November 6, 2025

ALTIMMUNE, INC.

(Exact name of registrant as specified in its charter)


Delaware	001-32587	20-2726770
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

910 Clopper Road, Suite 201S Gaithersburg, Maryland		20878
(Address of principal executive offices)		(Zip Code)

Registrant’s telephone number including area code: (240) 654-1450

(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:


☐	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 stock, par value $0.0001 per share	ALT	The NASDAQ Global Market

Indicate by check mark whether the registrant is an emerging growth company 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 November 6, 2025, Altimmune, Inc. (the “Company”) entered into an Equity Distribution Agreement (the “November 2025 Agreement”) with Leerink Partners LLC, serving as sales agent (the “Sales Agent”) with respect to an at-the-market offering program under which the Company may offer and sell, from time to time at its sole discretion, shares of its common stock, par value $0.0001 per share (the “Common Stock”), having an aggregate offering price of up to $200.0 million (the “Shares”) through the Sales Agent (the “November 2025 Offering”). All Shares offered and sold in the November 2025 Offering will be issued pursuant to the Company’s Registration Statement on Form S-3 filed with the Securities and Exchange Commission (the “SEC”) on February 27, 2025, which was declared effective on March 13, 2025, and the prospectus supplement related to the November 2025 Offering that forms a part of the Registration Statement.

The Sales Agent may sell the Shares by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415(a)(4) of the Securities Act of 1933, as amended, including, without limitation, sales made through The Nasdaq Global Market (“Nasdaq”) or on any other existing trading market for the Common Stock. The Sales Agent will use commercially reasonable efforts to sell the Shares from time to time consistent with their normal sales practices and applicable federal rules, regulations and Nasdaq rules, based upon instructions from the Company (including any price, time or size limits or other customary parameters or conditions the Company may impose). The Company will pay the Sales Agent a commission of up to three percent (3.0%) of the gross sales proceeds of any Shares sold through the Sales Agent under the November 2025 Agreement, and also has provided the Sales Agent with customary indemnification and contribution rights.

The Sales Agent is not required to sell any specific number or dollar amount of securities, but will use commercially reasonable efforts to sell, on behalf of the Company, all of the shares of Common Stock requested to be sold by the Company, consistent with its normal trading and sales practices, on mutually agreed terms between the Sales Agent and the Company. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The November 2025 Agreement contains customary representations and warranties and conditions to the placement of the Shares pursuant thereto.

The foregoing description of the November 2025 Agreement is not complete and is qualified in its entirety by reference to the full text of the November 2025 Agreement, a copy of which is filed herewith as Exhibit 1.1 to this Current Report on Form 8-K and is incorporated herein by reference. A copy of the opinion of Goodwin Procter LLP relating to the legality of the issuance and sale of the shares in the Offering is attached as Exhibit 5.1 hereto.

This Current Report on Form 8-K shall not constitute an offer to sell or the solicitation of an offer to buy the securities discussed herein, nor shall there be any offer, solicitation, or sale of the securities in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state.

Item 1.02. Termination of a Material Definitive Agreement.

As previously disclosed, on February 27, 2025, the Company entered into that certain Equity Distribution Agreement (the “February 2025 Agreement”) with Leerink Partners LLC, Piper Sandler & Co. and Stifel, Nicolaus & Company, Incorporated, serving as sales agents (the “February 2025 Sales Agents”) with respect to an at-the-market offerings program under which the Company may offer and sell, from time to time at its sole discretion, shares of its common stock, having an aggregate offering price of up to $150.0 million (the “February 2025 Shares”) through the February 2025 Sales Agents (the “February 2025 Offering”).

Prior to entering the November 2025 Agreement, the Company provided notice to the February 2025 Sales Agents to terminate the February 2025 Agreement effective November 6, 2025. The Company is not subject to any termination penalties related to the termination of the 2025 Agreement.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits


Exhibit No.		Description

1.1		Equity Distribution Agreement, dated as of November 6, 2025 between the Company and Leerink Partners LLC

5.1		Opinion of Goodwin Procter LLP

23.1		Consent of Goodwin Procter LLP (included in Exhibit 5.1)

104		Cover Page Interactive Data File (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.


	ALTIMMUNE, INC.

	By:		/s/ Gregory Weaver
			Name: Gregory Weaver
			Title: Chief Financial Officer

Dated: November 6, 2025

Altimmune, Inc. 8-K