SIGA begins clinical program to expand use of smallpox drug for post-exposure prevention

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SIGA Technologies (NASDAQ:SIGA) said it began a clinical program to support a U.S. FDA label expansion for Post-Exposure Prophylaxis (PEP) for oral TPOXX, which was approved in July 2018 to treat smallpox.

The first study is a comparison of the enrolled participants' immune response with the Jynneos smallpox vaccines compared with the immune response with Jynneos while on TPOXX treatment.

The study is aimed at determining if TPOXX interferes with the development of an effective immune response to the vaccine.

A second clinical trial, which is also expected to begin in 2022, will look at developing an expanded safety dataset to support 28 day dosing of TPOXX for the post-exposure prevention use compared with the currently approved 14 days for treatment of smallpox indication.

SIGA has been collaborating with the U.S. Department of Defense’s Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (JPEO-CBRND) to develop the PEP indication, and this work is supported by ~$26M R&D contract.

In December 2021, oral TPOXX was approved to treat smallpox in Canada. Tecovirimat (TPOXX) was approved by the European Medicines Agency in January 2022 with a broader label that covers the treatment of smallpox, monkeypox, cowpox, and complications from vaccination for smallpox.

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