SIGA Technologies’ antiviral treatment TEPOXX (tecovirimat 200 mg capsules), marketed as TPOXX in the United States, has received regulatory approval in Japan for the treatment of smallpox, mpox, cowpox, as well as complications following smallpox vaccination in adults and pediatric patients weighing at least 13 kg. TEPOXX is the first antiviral therapy approved by the Pharmaceuticals and Medical Devices Agency (PMDA), in collaboration with the Japan Ministry of Health, Labour and Welfare, for the treatment of orthopoxviruses.
In partnership with Japan Biotechno Pharma, SIGA’s exclusive distributor in Japan, SIGA has delivered an order of TEPOXX to help build Japan’s strategic national stockpile.
“The approval of TEPOXX in Japan marks another significant milestone in our mission to expand access to this critical antiviral treatment worldwide to support an effective response to an orthopoxvirus outbreak. As a capsule with a long shelf life, TEPOXX can easily be deployed in time sensitive emergencies,” said Diem Nguyen, Chief Executive Officer.
“We are grateful for the close collaboration with the Japanese regulatory authorities and strong partnership with Japan Biotechno Pharma that made this accomplishment possible. This approval highlights the importance of stockpiling effective antiviral therapies as a cornerstone of innovative solutions to safeguard public health against serious and potentially devastating infectious diseases, such as smallpox.”
The Japanese approval is based on data from 15 clinical trials of oral TEPOXX in over 800 healthy volunteers, including a pivotal repeat-dose phase 1 pharmacokinetics (PK) trial involving 20 healthy volunteers conducted in Japan. These studies showed no drug-related serious adverse events and quantifiable PK within efficacious dose ranges.
Four pivotal studies in non-human primates (NHPs) and two pivotal studies in rabbits demonstrated that TEPOXX significantly reduced both mortality and viral load. The results of the animal efficacy studies were published in the July 5, 2018 issue of the New England Journal of Medicine. TEPOXX has also been studied in NHPs infected with variola virus, the virus which causes smallpox, where TEPOXX demonstrated improved survival and reduction in lesions.
“This milestone reflects years of dedication and scientific innovation,” said Dennis Hruby, Ph.D., Chief Scientific Officer. “TEPOXX was designed with a deep understanding of orthopoxviruses and has the potential to deliver an effective treatment option for managing these potentially devastating diseases. We are proud to see our work contribute to enhanced preparedness and public health resilience in Japan.”
TEPOXX is a highly targeted small-molecule antiviral that inhibits the VP37 protein found on the surface of all orthopoxviruses. By preventing the virus from exiting infected cells, TEPOXX slows the spread of the infection, enabling the immune system to clear the virus.
TPOXX is approved in the U.S. and Canada for the treatment of smallpox. In the European Union and United Kingdom, marketed as Tecovirimat-SIGA, it is approved for the treatment of smallpox, mpox, cowpox, and to treat complications following smallpox vaccination.
