The US Food and Drug Administration (FDA) has approved tecovirimat (TPOXX) as the first drug indicated for smallpox, an infectious disease caused by the variola virus.
The drug has been approved under the FDA’s Animal Rule, which allows for efficacy results from qualified animal studies to support a drug approval when human trials would be considered unethical.
Although the disease was declared to be eradicated in 1980, there have been concerns regarding the potential use of the disease as a bioweapon.
“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 a statement
. “Today’s approval provides an important milestone in these efforts.”
With this approval, tecovirimat has become the first product to be awarded a Material Threat Medical Countermeasure priority review voucher, according to Dr Gottlieb. Its application was previously granted Fast Track and Priority Review designations, along with an orphan drug designation.
Approval of the drug, developed in conjunction with the US Department of Health and Human Services, was supported by trials reporting its efficacy in animal models infected with viruses closely related to the smallpox virus, and a trial reporting its safety in 359 healthy human volunteers without the virus.
In the animal trials, researchers measured subject survival at the end of the studies. They reported that more animals that were administered tecovirimat had survived versus those treated with placebo. In the human safety trials, the most frequently reported side effects were headache, nausea ,and abdominal pain.
The telltale symptoms associated with smallpox include fever, exhaustion, headache, and backache within 10 to 14 days of infection, as well as a rash of small, pink bumps that could potentially develop into sores.
Furthermore, complications commonly associated with smallpox included encephalitis, corneal ulcerations, and blindness.
“Today’s action reflects the FDA’s commitment to ensuring that the US is prepared for any public health emergency with timely, safe and effective medical products,” Dr Gottlieb concluded.