Other Information
−Removed: During the three months ended September 30, 2025, none of our officers or directors adopted , modified , or terminated a "Rule 10b5-1 trading arrangement" or "non-Rule 10b5-1 trading arrangement" as defined in Item 408(c) of Regulation S-K.
+Added: None of our officers or directors adopted , modified or terminated a “Rule 10b5-1 trading arrangement” or “ non-Rule 10b5-1 trading arrangement” as defined in Item 408(c) of Regulation S-K during the three months ended March 31, 2026.
Exhibit Index
+Added: Underwriting Agreement, dated April 22, 2026, by and between by and between the Company, Leerink Partners LLC and Barclays Capital Inc., as representatives of the several underwriters named therein (incorporated by reference to Exhibit 1.1 to the Registrant’s Form 8-K filed on April 24, 2026)
Amended and Restated Certificate of Incorporation, dated October 17, 2017 (incorporated by reference to Exhibit 3.1 to the Registrant’s Form 8-K filed on October 18, 2017)
1 unchanged sentence
Certificate of Amendment to Amended and Restated Certificate of Incorporation regarding an increase in authorized shares (incorporated by reference to Exhibit 3.2 to the Registrant’s Form 8-K filed on September 13, 2018)
+Added: Certificate of Amendment to Amended and Restated Certificate of Incorporation regarding an increase in authorized shares (incorporated by reference to Exhibit 3.1 to the Registrant’s Form 8-K filed on April 16, 2026)
Amended and Restated Bylaws of Altimmune, Inc.
(incorporated by reference to Exhibit 3.2 to the Registrant’s Form 8-K filed on October 18, 2017)
−Removed: Amendment to Loan and Security Agreement, dated November 5, 2025, by and between Altimmune, Inc.
−Removed: and Hercules Capital, Inc.
−Removed: ( incorporated by reference to Exhibit 10.1 to the Registrant’s Form 8-K filed on November 6, 2025)
−Removed: Transitional Services and Release Agreement, dated September 30, 2025, by and between Altimmune, Inc.
+Added: Form of Pre-Funded Warrant (incorporated by reference to Exhibit 4.1 to the Registrant’s Form 8-K filed on January 28, 2026)
+Added: Form of Common Stock Warrant (incorporated by reference to Exhibit 4.1 to the Registrant’s Form 8-K filed on April 24, 2026)
+Added: Form of Pre-Funded Warrant (incorporated by reference to Exhibit 4.2 to the Registrant’s Form 8-K filed on April 24, 2026)
+Added: Form of Securities Purchase Agreement, dated January 27, 2026 (incorporated by (reference to Exhibit 10.1 to the Registrant’s Form 8-K filed on January 28, 2026)
+Added: Placement Agency Agreement, dated January 27, 2026 (incorporated by (reference to Exhibit 10.2 to the Registrant’s Form 8-K filed on January 28, 2026)
Certification of Principal Executive Officer Pursuant to SEC Rule 13a-14(a)/15d-14(a)
9 unchanged sentences
Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)
+Added: Filed herewith.
This certification will not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liability of that section.
Such certification will not be deemed to be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except to the extent specifically incorporated by reference into such filing.
−Removed: Filed herewith
Certain portions of this exhibit have been omitted in accordance with Item 601(b)(10)(iv) of Regulation S-K.
1 unchanged sentence
ALTIMMUNE, INC.
−Removed: November 6, 2025
+Added: /s/ Jerome Durso
President and Chief Executive Officer (Principal Executive Officer)
−Removed: November 6, 2025
/s/ Gregory Weaver
2 unchanged sentences
Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.