SIGA Announces Collaboration with Turnstone Biologics

SIGA to supply TPOXX^® To Support Turnstone’s SKV Vaccinia Oncolytic Viral Immunotherapy Program

NEW YORK, March 02, 2020 (GLOBE NEWSWIRE) -- SIGA Technologies, Inc. (SIGA) (NASDAQ: SIGA), a commercial-stage pharmaceutical company focused on the health security market, today announced that it entered into a collaboration with Turnstone Biologics to provide TPOXX^® (tecovirimat) in connection with Turnstone’s proprietary SKV vaccinia oncolytic immunotherapy platform. The platform utilizes vaccinia viruses engineered for increased selectivity and safety, as well as high-potency immune stimulation, and allows delivery of multiple therapeutic agents directly to tumors. The collaboration will provide Turnstone with access to SIGA’s TPOXX oral antiviral capsules for use if required in future clinical programs.

“TPOXX has potential as a new tool to support the adoption of oncolytic vaccinia virus immunotherapies, including those being developed by Turnstone,” said Dr. Phil Gomez, CEO of SIGA. “The availability of a potent antiviral drug against vaccinia provides additional assurance to patients receiving these promising investigational therapies, their physicians, and regulators. We are pleased to enter into this collaboration with Turnstone Biologics, a leading innovator of next-generation oncolytic viral therapies.” 

Mike Burgess, Ph.D., President, Research and Development at Turnstone added, “For nearly a century, viruses have been used as the backbone for prophylactic vaccines that have saved more lives than any other medical innovation in human history. Turnstone is harnessing the inherent immune-stimulating properties of viruses to create novel cancer therapies. As part of our responsible stewardship of this biologic product, we are pleased to partner with SIGA to make TPOXX available if needed in clinical trials.”

In preclinical studies, TPOXX has been shown to be active against most orthopoxviruses, including vaccinia (published in NEJM, 2018¹). The unique mechanism of action of TPOXX coupled with published efficacy in animal studies, make it an important addition to development programs focused on vaccinia-based cancer therapies.

On July 13, 2018, the U.S. Food and Drug Administration (FDA) approved oral TPOXX for the treatment of smallpox to mitigate the impact of a potential outbreak or bioterror attack. TPOXX is the only FDA-approved treatment of smallpox.

ABOUT SIGA TECHNOLOGIES, INC. and TPOXX^®

SIGA Technologies, Inc. is a commercial-stage pharmaceutical company focused on the health security market. Health security comprises countermeasures for biological, chemical, radiological and nuclear attacks (biodefense market), vaccines and therapies for emerging infectious diseases, and health preparedness. Our lead product is TPOXX^®, also known as tecovirimat and ST-246®, an orally administered and IV formulation antiviral drug for the treatment of human smallpox disease caused by variola virus. TPOXX is a novel small-molecule drug of which 2 million oral courses have been delivered to the Strategic National Stockpile under Project BioShield. The oral formulation of TPOXX was approved by the FDA for the treatment of smallpox on July 13, 2018. In September 2018, SIGA signed a new contract with Biomedical Advanced Research and Development Authority (BARDA) for additional procurement and development related to both oral and intravenous formulations of TPOXX. For more information about SIGA, please visit www.siga.com

ABOUT TURNSTONE BIOLOGICS

Turnstone Biologics is developing a disruptive class of engineered viral immunotherapies, attacking cancer's complexity with medicines designed to fight malignant disease at multiple points of intervention. Turnstone’s proprietary vaccinia virus platform has been engineered to stimulate the immune system, drive antigen presentation and recognition, and re-shape the tumor microenvironment. In addition, the large transgene capacity of the virus can be utilized to deliver other agents and therapeutics directly to sites of tumors throughout the body for local expression, reducing the potential for systemic toxicity. RIVAL-01 is Turnstone’s lead candidate, consisting of the vaccinia virus backbone encoding three potent immunomodulators, Flt3 ligand, anti-CTLA-4 antibody and IL-12 cytokine, specifically designed to work together to drive immune activity and re-program the microenvironment to be best suited for tumor eradication. Learn more at www.turnstonebio.com.

FORWARD-LOOKING STATEMENTS

This press release contains certain "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. Such forward-looking statements are subject to various known and unknown risks and uncertainties, and SIGA cautions you that any forward-looking information provided by or on behalf of SIGA is not a guarantee of future performance. More detailed information about SIGA and risk factors that may affect the realization of forward-looking statements, including the forward-looking statements in this press release, is set forth in SIGA's filings with the Securities and Exchange Commission, including SIGA's Annual Report on Form 10-K for the fiscal year ended December 31, 2017, and in other documents that SIGA has filed with the SEC. SIGA urges investors and security holders to read those documents free of charge at the SEC's web site at http://www.sec.gov. Interested parties may also obtain those documents free of charge from SIGA. Forward-looking statements are current only as of the date on which such statements were made, and except for our ongoing obligations under the United States of America federal securities laws, we undertake no obligation to update publicly any forward-looking statements whether as a result of new information, future events, or otherwise.

The information contained in this press release does not necessarily reflect the position or the policy of the Government and no official endorsement should be inferred.

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¹ https://www.nejm.org/doi/full/10.1056/NEJMoa1705688

Contacts:

SIGA Investors
David Carey
212-867-1768
[email protected]

SIGA Media
Stephanie Seiler
206-713-0124
[email protected]

Turnstone Biologics
Ahmed Aneizi
613-421-8930
[email protected]

Heidi Chokeir
619-203-5391
[email protected]