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): March 27, 2020

Altimmune, Inc.

(Exact name of registrant as specified in its charter)

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:

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

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.    ☐

On March 27, 2020, Altimmune, Inc. (the “Company”) entered into an Equity Distribution Agreement (the “Agreement”) with JMP Securities LLC, serving as placement agent (the “Placement 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 $50.0 million (the “Shares”) through the Placement Agent (the “Offering”). Any Shares offered and sold in the 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 April 4, 2019, which was declared effective on April 12, 2019, the prospectus supplement relating to the Offering filed with the SEC on March 27, 2020 and any applicable additional prospectus supplements related to the Offering that form a part of the Registration Statement. The aggregate market value of Shares eligible for sale in the Offering and under the Equity Distribution Agreement will be subject to the limitations of General Instruction I.B.6 of Form S-3, to the extent required under such instruction. We are only offering Shares having an aggregate offering price of $18.9 million pursuant to the prospectus supplement filed with the SEC on March 27, 2020. The Company will be required to file another prospectus supplement in the event it determines to offer more than $18.9 million of Shares in accordance with the terms of the Agreement, to the extent then permitted under General Instruction I.B.6 of Form S-3. A copy of the opinion of Goodwin Procter LLP relating to the legality of the issuance and sale of the Shares is attached as Exhibit 5.1 hereto.

The Placement Agent may sell the Shares by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415 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 Placement Agent will use commercially reasonable efforts to sell the Shares from time to time consistent with its 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 Placement Agent a commission equal to three percent (3%) of the gross sales proceeds of any Shares sold through the Placement Agent under the Agreement, and also has provided the Placement Agent with customary indemnification and contribution rights.

The Placement 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 Placement Agent and the Company. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The foregoing description of the Agreement is not complete and is qualified in its entirety by reference to the full text of the 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.

(d) Exhibits

SIGNATURES

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.