NEW YORK, July 13, 2018 (GLOBE NEWSWIRE) — SIGA Technologies, Inc. (SIGA) (NASDAQ:SIGA), a commercial-stage pharmaceutical company focused on the health security market, today announced that the U.S. Food and Drug Administration (FDA) has approved oral TPOXX® (tecovirimat) for the treatment of smallpox to mitigate the impact of a potential outbreak. TPOXX, a small-molecule antiviral treatment for smallpox, is the first therapy specifically approved for this indication. On May 1, 2018, the FDA’s Antimicrobial Drugs Advisory Committee voted unanimously, 17 to 0, that the benefits of TPOXX outweigh its risks.
Concurrent with the approval, FDA granted SIGA’s request for a Priority Review Voucher (PRV). A PRV is a voucher that may be used to obtain an accelerated FDA review of a future SIGA product, or sold to a third party, and this is the first PRV awarded under the Material Threat Countermeasure PRV program enacted by the 2016 21st Century Cures Act. In addition, FDA approved a seven-year expiry for TPOXX. Under SIGA’s existing contract with the Biomedical Advanced Research and Development Authority (BARDA), the company will ask BARDA to exercise an option for a $50 million payment to the company based on this extended shelf-life determination. The exercise of this option is at the sole discretion of BARDA.
With the approval, SIGA is entitled to a $41 million hold back payment under the existing contract with BARDA, provided that BARDA confirms that there is no difference between the approved product and the courses of TPOXX that have already been delivered to the Strategic National Stockpile (SNS).
FDA approval is based on data from 12 clinical trials of oral TPOXX in over 700 healthy human volunteers, which showed no drug-related serious adverse events. Four pivotal trials in non-human primates (NHPs) and two pivotal trials in rabbits demonstrated that TPOXX significantly reduced both mortality and viral load in NHP infected with monkeypox virus (MPXV) and in rabbits infected with rabbitpox virus. The results of these studies were published in the July 5, 2018 issue of the New England Journal of Medicine.
”TPOXX is proof that public-private partnerships work when the partners are committed to a focused mission,” said Dr. Phil Gomez, Chief Executive Officer of SIGA Technologies, Inc. “The FDA approval of TPOXX achieves an important objective for both SIGA and our lead partner in the U.S. Government, the Biomedical Advanced Research and Development Authority (BARDA). The approval validates this novel smallpox therapy as an important medical countermeasure in response to a potential smallpox outbreak.”
“We would like to acknowledge the efforts by everyone at SIGA and our many partners who have contributed to the development and approval of TPOXX,” added Dennis Hruby, PhD, Chief Scientific Officer of SIGA Technologies, Inc. “These partners include BARDA, the National Institute of Allergy and Infectious Diseases, the Centers for Disease Control and Prevention, the Department of Defense (including the Defense Threat Reduction Agency and the U.S. Army Medical Research Institute of Infectious Diseases), our academic and clinical collaborators, and our colleagues at the FDA.”
TPOXX will be available initially only through the U.S. government’s Strategic National Stockpile (SNS). SIGA has a $472 million procurement and development contract with BARDA, as part of which 2 million courses of oral TPOXX have been delivered to the SNS. Currently, there is a Request for Proposal outstanding for the maintenance of a smallpox antiviral stockpile within the SNS. SIGA intends to explore additional markets and potential indications for TPOXX in the United States and around the world.
During the May 1, 2018 FDA Advisory committee, several members of the committee also suggested that there could be benefit in exploring additional indications post-FDA approval, including prophylactic use in individuals exposed to smallpox and other orthopoxviruses, such as monkeypox, which also infects humans. Committee members cited the likely use of TPOXX in the post-exposure prophylaxis setting in the event of a smallpox outbreak and a 15-20% mortality rate in people infected with monkeypox. SIGA will examine these potential markets and the feasibility of expanding the TPOXX label to include these indications.
Smallpox remains a significant bioterrorism threat, and the U.S. government has been focused on the development of medical countermeasures to mitigate that threat. Vaccines are an important component of a response to a smallpox outbreak, but the availability of a therapeutic such as TPOXX is critical to reduce the morbidity and mortality of such an outbreak. The risk of a smallpox outbreak is a global risk with far-reaching consequences. As such, the U.S. FDA approval is an important milestone in highlighting for international governments the safety and efficacy of TPOXX for treatment of smallpox.
TPOXX’s advanced development has been funded in partnership with BARDA.