PIP Pharmathene, (delisted)

On August 21, 2017, Altimmune, Inc. (the “Company”) closed its previously announced offering of 15,655.714 shares of the Company’s Series B Convertible Preferred Stock, par value $0.0001 per share (the “Preferred Stock”) which are initially convertible into an aggregate of 5,863,564 shares of Common Stock (without regard to any limitation on conversion set forth in the Certificate of Designations (as defined below)) at an initial conversion price of $2.67 per share of Common Stock, and Warrants initially exercisable to purchase an aggregate of 2,345,427 shares of Common Stock (without regard to any limitation on exercise set forth in the Warrants) at an initial exercise price of $2.67 per share of Common Stock, all upon the terms and conditions set forth in the securities purchase agreement, dated August 16, 2017, by and between the Company and the investors party thereto (the “Securities Purchase Agreement”), for an aggregate offering price of $14.7 million (the “Offering”). Each Warrant is immediately exercisable and will expire on August 15, 2022. On August 21, 2017, the Company filed the Certificate of Designations, Preferences and Rights of Series B Convertible Preferred Stock of the Company (the “Certificate of Designations”) with respect to the Preferred Stock with the Secretary of the State of Delaware to establish the preferences, limitations and relative rights of the Preferred Stock.

Piper Jaffray & Co. acted as placement agent in connection with the Offering pursuant to the previously announced Placement Agency Agreement, dated August 16, 2017 (the “Placement Agency Agreement”). We received approximately $13.0 in net proceeds from the Offering, after deducting the placement agent fee, an additional fee related to our completed merger paid to the placement agent, and our estimated offering expenses. If a Warrant holder elects to exercise the Warrants issued in the Offering by paying the exercise price in cash, we would also receive proceeds from the exercise of the Warrants. The Offering was conducted pursuant to the Company’s existing shelf registration statement on Form S-3 (File No. 333-217034), which was filed with the U.S. Securities and Exchange Commission (the “Commission”) on March 30, 2017 and declared effective by the Commission on April 6, 2017.

The terms of the Placement Agency Agreement, the Securities Purchase Agreement, the Certificate of Designations, and the Form of Warrant are discussed in more detail in Item 1.01 of the Company’s Current Report on Form 8-K filed on August 17, 2017, and such description is incorporated by reference herein, and the description of the Placement Agency Agreement, the Securities Purchase Agreement, the Certificate of Designations, and the Form of Warrant included in this Current Report on Form 8-K and incorporated by reference herein does not purport to be complete. The foregoing description is qualified in its entirety by reference to the Placement Agency Agreement, the Securities Purchase Agreement, the Certificate of Designations, and the Form of Warrant, which are filed as Exhibits 1.1, 2.1, 3.1, and 4.1, respectively, to this Current Report on Form 8-K and incorporated herein by reference.