Siga Tech's tecovirimat drug could help counter monkeypox, says study

At least one antiviral medicine shows promise against monkeypox and should be investigated further, scientists said as the outbreak widens. 

The finding is based on a single case that occurred in the UK before the current flare-up. The study, which calls for more research on a drug called tecovirimat, was published in The Lancet Infectious Diseases journal. 

The study focused on seven cases of transmission outside of Africa, where the virus is considered endemic in a dozen countries. It suggests SIGA Technologies Inc.’s tecovirimat may be able to shorten symptoms and the amount of time people are contagious. 

The scientists said more work is needed to reach any conclusions but their study found little evidence that another drug, brincidofovir, was beneficial. 

“Our paper gives a signal that if you had the choice between the two drugs, tecovirimat has shown more promise so far,” Hugh Adler, a researcher at the Liverpool University Hospitals NHS Foundation Trust and lead author, told reporters in a briefing, while urging caution. 

“This is the sum total of human experience with these drugs in monkeypox so far,” he said. “We hope that by sharing this data other clinicians who are dealing with cases, particularly if they’re severe cases of monkeypox, might be able to access this drug as well, and that people will have the incentive to do a bigger study.”

The cousin of the smallpox virus has spread across Europe and the U.S. in recent days, leading to 131 confirmed cases and another 106 suspected ones across 19 nations, according to the World Health Organization.

Three of the cases of monkeypox studied were reported in 2021 in a family traveling from Nigeria. One patient was treated with tecovirimat and experienced a shorter duration of symptoms and upper respiratory tract viral shedding than the others, according to the report. The study is too small to determine its effectiveness against monkeypox, the authors said.

Throat Swabs

Tecovirimat, sold under the brand name Tpoxx, isn’t yet widely available. An oral formulation is cleared in the US, Canada and Europe to treat smallpox, while the European approval also includes monkeypox, the company said. 

Brincidofovir didn’t appear to have convincing clinical benefit in three other patients treated with the drug seven days after the initial onset of a rash, researchers said. It’s uncertain whether giving brincidofovir to people earlier in the course the disease, or at a different interval, would have led to different outcomes. The three patients, plus a health worker exposed to the virus in a hospital, fully recovered in those cases from 2018 and 2019. 

Emergent BioSolutions Inc. earlier this month reached an agreement with Chimerix Inc. to acquire rights to brincidofovir, or Tembexa, approved by the FDA to treat smallpox.