Armata Pharmaceuticals Announces Closing of Second and Final Tranche of $20 Million Private Placement with Innoviva

Armata Pharmaceuticals Announces Closing

of Second and Final Tranche of $20 Million Private Placement with Innoviva

MARINA DEL REY, California, March 17, 2021

- Armata Pharmaceuticals, Inc. (NYSE American: ARMP) ("Armata" or the "Company"), a biotechnology

company focused on pathogen-specific bacteriophage therapeutics for antibiotic-resistant and difficult-to-treat bacterial infections,

today announced that, following a vote in favor of the transaction by the Armata shareholders, the Company has completed the closing

of the second and final tranche of the Company's $20 million private placement of its common stock with Innoviva Strategic

Opportunities LLC, a wholly-owned subsidiary of Innoviva, Inc. (NASDAQ: INVA) (together, "Innoviva"). In connection

with the second closing, Armata issued 4,285,935 common shares and 4,285,935 warrants with an exercise price of $3.25 per share,

at a per unit price of $3.25 per unit, in exchange for gross proceeds of approximately $13.9 million. Approximately 99% of the

Armata shares represented and voting at the special meeting of shareholders voted in favor of the transaction.

The Company and Innoviva closed an initial

tranche of the investment on January 26, 2021, which raised gross proceeds of approximately $6.1 million through the issuance of

1,867,912 common shares and warrants to purchase an additional 1,867,912 common shares at a strike price of $3.25 per share.

As of March 17, 2021, and following the

second closing, Armata has 24,940,442 shares outstanding and warrants exercisable for 16,649,465 shares of common stock.

Armata was represented in the transaction

by Thompson Hine LLP, and Ladenburg Thalmann & Co. Inc. acted as Armata's financial advisor.

Willkie Farr & Gallagher LLP represented

Innoviva in the transaction.

This release does not constitute an offer

to sell or the solicitation of an offer to buy any security. The shares offered have not been registered under the Securities Act

of 1933, as amended, or applicable state securities laws and may not be offered or sold in the United States or any state thereof

absent registration under the securities act and applicable state securities laws or an applicable exemption from registration

About Armata Pharmaceuticals, Inc.

Armata is a clinical-stage biotechnology

company focused on the development of precisely targeted bacteriophage therapeutics for the treatment of antibiotic-resistant and

difficult-to-treat bacterial infections using its proprietary bacteriophage-based technology. Armata is developing and advancing

a broad pipeline of natural and synthetic phage candidates, including clinical candidates for Pseudomonas aeruginosa, Staphylococcus

aureus, and other pathogens. In addition, in collaboration with Merck, known as MSD outside of the United States and Canada, Armata

is developing proprietary synthetic phage candidates to target an undisclosed infectious disease agent. Armata is committed to

advancing phage with drug development expertise that spans bench to clinic including in-house phage specific GMP manufacturing.

Forward Looking Statements

This communication contains "forward-looking"

statements, including, without limitation, statements related to the use of proceeds from the securities offering, Armata's bacteriophage

development programs, Armata's ability to meet expected milestones, and Armata's ability to be a leader in the development of phage-based

therapeutics. Any statements contained in this communication that are not statements of historical fact may be deemed to be forward-looking

statements. These forward-looking statements are based upon Armata's current expectations. Forward-looking statements involve risks

and uncertainties. Armata's actual results and the timing of events could differ materially from those anticipated in such forward-looking

statements as a result of these risks and uncertainties, which include, without limitation, risks related to the ability of Armata's

lead clinical candidates, AP-PA02 and AP-SA02, to be more effective than previous candidates; Armata's ability to expedite development

of AP-PA02; Armata's ability to advance its preclinical and clinical programs and the uncertain and time-consuming regulatory approval

process; Armata's ability to develop products based on bacteriophages and synthetic phages to kill bacterial pathogens; the Company's

expected market opportunity for its products; Armata's ability to sufficiently fund its operations as expected, including obtaining

additional funding as needed; and any delays or adverse events within, or outside of, Armata's control, caused by the recent outbreak

of COVID-19. Additional risks and uncertainties relating to Armata and its business can be found under the caption "Risk Factors"

and elsewhere in Armata's filings and reports with the SEC, including in Armata's Annual Report on Form 10-K, filed with the SEC

on March 19, 2020, and in its subsequent filings with the SEC.

Armata expressly disclaims any obligation or undertaking to

release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in Armata's

expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.

Armata Pharmaceuticals, Inc.

Armata Investor Relations:

LifeSci Advisors, LLC