Japan Approves SIGA Technologies Antiviral As First For Smallpox, Mpox

On Thursday, the Japan Ministry of Health, Labour and Welfare approved SIGA Technologies SIGA antiviral treatment TEPOXX (tecovirimat 200 mg capsules) for 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 for orthopoxviruses approved by Japan's drug regulator in collaboration with the Ministry of Health, Labour, and Welfare.  

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.

Also Read: In NIH-Cosponsored Mpox Virus Study In Congo, SIGA Technologies' Antiviral Tecovirimat Did Not Improve Lesion Resolution, Stock Tanks

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 mortality and viral load.

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 for smallpox in the U.S. and Canada. In the European Union and the UK, marketed as Tecovirimat-SIGA, it is approved for smallpox, mpox, and cowpox and to treat complications following smallpox vaccination.

Earlier this year, the National Institutes of Health's National Institute of Allergy and Infectious Diseases announced topline results from a preliminary analysis of the PALM 007 trial of tecovirimat for mpox.

The study did not meet its primary endpoint of a statistically significant improvement in time to lesion resolution within 28 days post-randomization for patients in the Democratic Republic of the Congo with mpox who were administered SIGA's tecovirimat versus placebo, weighing on the share price.

Price Action: At last check Thursday, SIGA stock was up 3.01% at $6.19.

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