The FDA has approved an oral formulation of TPOXX for the treatment of smallpox, citing concerns that the infectious disease, long considered eradicated since 1980, could potentially be used as a bioweapon, according to a press release.
“To address the risk of bioterrorism, congress has taken steps to enable the development and approval of countermeasures to thwart pathogens that could be employed as weapons,” FDA Commissioner Scott Gottlieb, MD, said in the release. “Today’s approval provides an important milestone in these efforts. This new treatment affords us an additional option should smallpox ever be used as a bioweapon.”
According to Gottlieb, TPOXX (tecovirimat, SIGA Technologies), an investigational antiviral drug, is the first product to be awarded a Material Threat Medical Countermeasure priority review voucher, which provides additional incentives for certain medical products intended to treat or prevent harm from specific chemical, biological, radiological and nuclear threats. The FDA had also approved the SIGA Technologies’ Fast Track application for the drug, as well as an Orphan Drug designation.
SIGA Technologies submitted its new drug application for tecovirimat in December 2017, based on based on efficacy data from animal trials — in which specimens were infected with viruses that are closely related to the one that causes smallpox — as well as safety and dosing data from human clinical trials. The use of animal data is permitted under the FDA’s “Animal Rule,” which allows efficacy endpoints to be assessed in animals when human efficacy trials are not ethical or feasible.
According to the FDA, more animals treated with tecovirimat lived compared with the animals treated with placebo. In addition, the human trials evaluated the drug’s safety in 359 healthy volunteers without smallpox infection. The most frequently reported side effects were headache, nausea and abdominal pain, the press release said.
TPOXX was developed by SIGA Technologies in conjunction with the U.S. Department of Health and Human Services’ Biomedical Advanced Research and Development Authority.