PHARMATHENE, INC. (NYSEMKT:PIP) Files An 8-K Results of Operations and Financial Condition

Item 2.02.

On March 14, 2017, PharmAthene,Inc. (the Company) issued a press
release (the Press Release) announcing its financial and
operational results for the fiscal year ended December 31, 2016.
A copy of the Press Release is furnished as Exhibit99.1 to this
Current Report on Form8-K.

In accordance with General Instruction B.2. of Form8-K, the
information in this Item 2.02 of this Current Report on Form8-K,
including Exhibit99.1, shall not be deemed to be filed for
purposes of Section18 of the Securities Exchange Act of 1934, as
amended (the Exchange Act), or otherwise subject to the
liabilities of that section, and shall not be deemed incorporated
by reference into any filing under the Securities Act of 1933, as
amended, or the Exchange Act, except as expressly set forth by
specific reference in such filing.

The portions of the Press Release that relate solely to the
proposed merger transaction involving the Company and Altimmune,
Inc. are being filed herewith as Exhibit 99.1 to this Current
Report on Form 8-K in compliance with Rule 425 of the Securities
Act of 1933, as amended.

The Company’s Board of Directors confirmed that the stockholder
rights plan previously adopted by the Company on November 25,
2015 (the Rights Plan) is now terminated and that all purchases
of the Company’s common stock on or after January 1, 2017 are to
be treated as Exempted Transactions under the Rights Plan.
Stockholders are not required to take any action as a result of
this termination. In connection with the termination of the
Rights Plan, the Company will be taking routine actions to
deregister the related preferred share purchase rights under the
Exchange Act. These actions are administrative in nature and will
have no effect on the Company’s common stock, which continues to
be listed on NYSE MKT.

(d)Exhibits

Important Additional Information about the Proposed
Merger Transaction

In connection with a proposed merger transaction involving
Altimmune, Inc. and PharmAthene, Inc., PharmAthene has filed a
registration statement on Form S-4 (File No. 333-215891) (the
Registration Statement) with the U.S. Securities and Exchange
Commission (the SEC), which contains a preliminary proxy
statement/prospectus/consent solicitation and other relevant
materials, and plans to file with the SEC other documents
regarding the proposed transaction. The information in the
preliminary proxy statement/prospectus/consent solicitation is
not complete and may be changed. The final proxy
statement/prospectus/consent solicitation will be sent to the
stockholders of PharmAthene and Altimmune in connection with the
special meeting of stockholders to be held to vote on matters
relating to the proposed transaction. The final proxy
statement/prospectus/consent solicitation will contain
information about PharmAthene, Altimmune, the proposed merger
transaction, and related matters. STOCKHOLDERS ARE URGED TO READ
THE FINAL PROXY STATEMENT/PROSPECTUS/CONSENT SOLICITATION
(INCLUDING ANY AMENDMENTS OR SUPPLEMENTS THERETO) AND OTHER
DOCUMENTS FILED WITH THE SEC CAREFULLY IN THEIR ENTIRETY, AS THEY
CONTAIN IMPORTANT INFORMATION THAT STOCKHOLDERS SHOULD CONSIDER
BEFORE MAKING A DECISION ABOUT THE MERGER TRANSACTION AND RELATED
MATTERS. In addition to receiving the proxy
statement/prospectus/consent solicitation and proxy card by mail,
stockholders will also be able to obtain the proxy
statement/prospectus/consent solicitation, as well as other
filings containing information about PharmAthene, without charge,
from the SECs website (http://www.sec.gov) or, without charge, by
directing a written request to: PharmAthene, Inc., One Park
Place, Suite 450, Annapolis, Maryland 21401, Attention: Investor
Relations.

No Offer or Solicitation

This communication is not intended to and does not constitute an
offer to sell or the solicitation of an offer to subscribe for or
buy or an invitation to purchase or subscribe for any securities
or the solicitation of any vote or approval in any jurisdiction
in connection with the merger transaction or otherwise, nor shall
there be any sale, issuance or transfer of securities in any
jurisdiction in contravention of applicable law. No offer of
securities shall be made except by means of a prospectus meeting
the requirements of Section 10 of the Securities Act of 1933, as
amended.

Participants in Solicitation

PharmAthene and its executive officers and directors may be
deemed to be participants in the solicitation of proxies from
PharmAthenes stockholders with respect to the matters relating to
the proposed merger transaction. Altimmune and its officers and
directors may also be deemed participants in such solicitation.
Information regarding PharmAthenes executive officers and
directors will be available in PharmAthenes Annual Report on Form
10-K, which is expected be filed with the SEC on March 14, 2017.
Information regarding any interest that PharmAthene, Altimmune or
any of the executive officers or directors of PharmAthene or
Altimmune may have in the transaction with Altimmune is set forth
in the proxy statement/prospectus/consent solicitation.

Forward-Looking Statements

Except for the historical information presented herein, matters
discussed may constitute forward-looking statements within the
meaning of the Private Securities Litigation Reform Act of 1995
that are subject to certain risks and uncertainties that could
cause actual results to differ materially from any future
results, performance or achievements expressed or implied by such
statements. Statements that are not historical facts, including
statements preceded by, followed by, or that include the words
will; potential; believe; anticipate; intend; plan; expect;
estimate; could; may; should; or similar statements are
forward-looking statements. Risks and uncertainties include risks
associated with our ability to consummate the mergers with
Altimmune, our ability to advance our next generation anthrax
vaccine programs; and other risks detailed from time to time in
PharmAthenes Forms 10-K and 10-Q under the caption Risk Factors,
its Registration Statement on Form S-4 filed with the SEC on
February 3, 2017 and in its other reports and registration
statements filed with the U.S. Securities and Exchange
Commission. PharmAthene disclaims any intent or obligation to
update these forward-looking statements other than as required by
law. Copies of PharmAthenes public disclosure filings are
available from its investor relations department and its website
under the investor relations tab at http://www.pharmathene.com.

About PHARMATHENE, INC. (NYSEMKT:PIP)

Pharmathene, Inc. (Pharmathene) is a biodefense company. The Company is focused on the development of medical counter measures against biological and chemical threats. The Company is involved in the development of two next generation anthrax vaccines. The Company’s anthrax vaccines use recombinant protective antigen (rPA) manufacturing processes. The Company’s product portfolio includes recombinant butyrylcholinesterase (rBChE) bioscavenger, which is used in prevention and treatment of nerve agent poisoning. The Company has developed a recombinant form of human butyrylcholinesterase for pre- and post-exposure therapy to patients with nerve agent attacks. Its rBChE bioscavenger acts with mechanism, which includes reversal of the acute toxicity associated with organophosphate poisoning agents used in chemical warfare (cholinergic crisis). Its development program also includes Valortim for monoclonal human antibody treatment.

PHARMATHENE, INC. (NYSEMKT:PIP) Recent Trading Information

PHARMATHENE, INC. (NYSEMKT:PIP) closed its last trading session down -0.071 at 0.784 with 2,255,742 shares trading hands.