SIGA Announces Retirement of Chief Scientific Officer Dennis Hruby, Ph.D.

Concludes 30-Year Tenure Leading Development of TPOXX®, the First FDA-Approved Antiviral for the Treatment of Smallpox

NEW YORK, Nov. 09, 2026 (GLOBE NEWSWIRE) -- SIGA Technologies (NASDAQ: SIGA), a commercial stage pharmaceutical company, announced today that Dennis Hruby, Ph.D., Executive Vice President and Chief Scientific Officer, will retire effective today, concluding more than 30 years with the Company.

Dr. Hruby joined SIGA in 1996 as a senior scientific advisor, became Vice President of Research in 1997, and has served as Chief Scientific Officer since 2000. Over that period, he led the development of tecovirimat, now marketed as TPOXX^®, from early-stage research through U.S. FDA approval of the oral formulation in 2018 and the intravenous formulation in 2022, as well as regulatory approvals in Canada, the European Union, the United Kingdom and Japan. TPOXX was the first antiviral therapeutic approved for the treatment of smallpox and has been sold to more than 30 countries.

“Dennis Hruby's 30 years of service reflect a distinguished career defined by scientific rigor, vision, and an unwavering commitment to public health. As a foremost expert in infectious disease, he played an instrumental role in the development of TPOXX, a medical countermeasure that has fundamentally strengthened our nation's preparedness against smallpox,” said Diem Nguyen, Chief Executive Officer. “On behalf of everyone at SIGA whose work he shaped, I want to thank Dennis for his extraordinary contributions and wish him well in the exciting chapter ahead.”

“I’m so proud of what we built at SIGA. When I joined, there was no antiviral treatment for smallpox. There is one now, and it is approved, stockpiled, and ready if ever needed to help save lives,” said Dr. Hruby. “I'm leaving the rest to a strong, successful team, and I look forward to seeing what comes next.”

Following his retirement, Dr. Hruby will continue to support the Company in an advisory capacity.

ABOUT SIGA
SIGA is a commercial-stage pharmaceutical company and leader in global health focused on the development of innovative medicines to treat and prevent infectious diseases. With a primary focus on smallpox, we are dedicated to protecting humanity against the world’s most severe infectious diseases, including those that occur naturally, accidentally, or intentionally. Through partnerships with governments and public health agencies, we work to build a healthier and safer world by providing essential countermeasures against these global health threats. For more information about SIGA, visit www.siga.com.

Investor and Media Contact
Suzanne Harnett
sharnett@siga.com