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): ~~September~~October 251, 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

Not Applicable

(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 5.0702 ~~Submission~~Departure of ~~Matters~~Directors toor aCertain ~~Vote~~Officers; Election of ~~Security~~Directors; ~~Holders~~Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

OnAs ~~September~~previously 25disclosed on February 24, 2025, Altimmune, Inc.’s (the “Company’s”) ~~held~~former ~~its~~Chief ~~2025~~Medical ~~Annual~~Officer, ~~Meeting of Stockholders (the “2025 Annual Meeting”)~~Dr. AsScott ~~of August 12~~Harris, ~~2025,~~provided the ~~record~~Company ~~date~~advance ~~for~~notice ~~the~~of ~~2025~~his ~~Annual~~intention ~~Meeting,~~to ~~there~~retire ~~were~~from ~~88,257,253~~Altimmune ~~shares~~as of ~~the~~February ~~Company’s~~28, ~~common~~2026 ~~stock outstanding and entitled to vote at~~ (the ~~2025~~“Separation ~~Annual Meeting~~Date”). AOn ~~total~~September of29, 512025,~~688,116~~ ~~shares~~the ofCompany ~~common~~announced ~~stock~~that ~~were~~Christophe ~~present~~Arbet-Engels, orMD, ~~represented~~PhD byjoined ~~proxy~~the atCompany ~~the~~as ~~2025~~Chief ~~Annual~~Medical ~~Meeting~~Officer, ~~representing~~effective ~~58.6%~~October of1, ~~the~~2025 ~~issued~~ and ~~outstanding~~that ~~shares~~Dr. ~~entitled~~Harris towill ~~vote~~remain atwith the ~~meeting,~~Company ~~representing~~as a ~~quorum.~~Senior ~~The~~Strategic ~~proposals~~Advisor ~~voted~~through ~~upon and~~ the ~~final~~Separation ~~results of the vote were as follows:~~Date.

~~Proposal~~On NoOctober 1, 2025, the Company and Dr. Harris entered into a Transitional Services and Release Agreement (the “Transition Agreement”). Pursuant to the Transition Agreement, Dr. Harris will step down from his role as the Company’s Chief Medical Officer, effective October 1:, ~~Election~~2025 (the “Transition Date”, and the period of ~~Directors.~~time ~~The~~between ~~results~~the ~~were~~Transition Date and the Separation Date, the “Transition Period”), and will continue as ~~follows:~~an employee of the Company in a transitional role as a Senior Strategic Advisor through the Separation Date.


			Broker
Director	For	Withhold	Non-Votes
Jerome Durso, Chairman	20,607,586	1,229,401	29,851,129
Vipin K. Garg, Ph.D.	17,425,330	4,411,657	29,851,129
John M. Gill	18,050,621	3,786,366	29,851,129
Philip L. Hodges	14,680,278	7,156,709	29,851,129
Diane Jorkasky, M.D.	14,778,350	7,058,637	29,851,129
Teri Lawver	16,535,619	5,301,368	29,851,129
Wayne Pisano	18,052,060	3,784,927	29,851,129
Mitchel Sayare, Ph.D.	17,619,208	4,217,779	29,851,129
Klaus O. Schafer, M.D., MPH	14,643,908	7,193,079	29,851,129
Catherine Sohn, Pharm D	14,454,283	7,382,704	29,851,129

During the Transition Period, Dr. Harris will, among other things, assist in transitioning his duties to the new Chief Medical Officer and provide such other transitional services as the Company reasonably requests. Pursuant to the Transition Agreement, Dr. Harris will (i) continue to receive his current salary and benefits during the Transition Period, (ii) be entitled to the continued vesting of all outstanding equity awards through the Separation Date; (iii) receive an extension of the time period during which he is eligible to exercise his vested stock options until the 12 month anniversary of the Separation Date; and (iv) remain eligible to receive a full cash bonus for fiscal year 2025, subject to bonus criteria achievement as determined by the Board and his full compliance with the Transition Agreement.

The payments and benefits described above are subject to Dr. Harris’ non-revocation of a general release of claims in favor of the Company and continued compliance with the terms of the Transition Agreement, including customary restrictive covenants.

~~Proposal~~The ~~No.~~foregoing 2:description ~~Ratification~~ of the ~~appointment~~Transition ofAgreement ~~Ernst~~does &not ~~Young~~purport ~~LLP~~to asbe ~~the~~complete ~~Company’s~~and ~~independent~~is ~~registered~~qualified ~~public~~in ~~accounting~~its ~~firm~~entirety ~~for~~by reference to the ~~year~~full ~~ending~~text ~~December~~of 31the Transition Agreement, ~~2025.~~a ~~The~~copy ~~results~~of ~~were~~which aswill ~~follows:~~be filed with the Company’s next Quarterly Report on Form 10-Q.


For	Against	Abstain
48,959,891	1,355,769	1,372,456

Proposal No. 3: Advisory vote on the Compensation of the Company’s named executive officers as disclosed in the Proxy Statement pursuant to the SEC’s compensation rules (referred to as the “say-on-pay” proposal). The results were as follows:


For	Against	Abstain	Broker Non-Votes
14,885,881	6,683,682	267,424	29,851,129

~~Proposal No. 4: Vote to authorize the adjournment of the 2025 Annual Meeting to enable the Board of Directors to solicit additional proxies. The results were as follows:~~


For	Against	Abstain
33,695,815	16,363,206	1,629,095

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: October 3, 2025

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: September 25, 2025

Filing Compare · Altimmune, Inc.