Pharmaceutical company SIGA Technologies, Inc. gained a boost to its work toward a label expansion for TPOXX, an antiviral drug for treating smallpox caused by variola virus, thanks to an increase in funding from the U.S. Department of Defense (DoD) this week.
With the addition, DoD is now pumping approximately $23 million into research and development efforts for the drug to develop a Post-Exposure Prophylaxis (PEP) indication for TPOXX. The U.S. Food and Drug Administration (FDA) would have to sign off on this.
“An expansion of the TPOXX label to include its use for PEP would provide greater flexibility to deliver TPOXX to those who might benefit from treatment during a potential outbreak,” SIGA CEO Phil Gomez said. “The recent search for prophylactic agents that could be used for PEP in patients with known exposure to the virus that causes COVID-19 underscores the importance of being able to prevent infection in at-risk individuals.”
Gomez noted that members of the FDA Advisory Committee stressed the importance of evaluating TPOXX for use on patients exposed to smallpox but not yet showing symptoms back in 2018.
While TPOXX is not a vaccine, it could shore up areas where vaccines lack. Vaccines are, as SIGA pointed out, only effective if administered before infection or up to four days after infection. As contagious as it is, smallpox is a disease that doesn’t typically produce symptoms for up to 14 days after infection. Worse, current tests cannot determine infection before those symptoms. The need for something that can treat the disease after that period is strong.
When dosed in the PEP indication, TPOXX will likely be given over 28, rather than the 14-day dosing currently recommended for active smallpox infections.