Key drug doesn't work against deadly new Mpox virus, study says – POLITICO

“These results are disappointing, but they provide us with important information and underscore the need to identify other therapeutic candidates for Mpox as we continue research into the use of tecovirimat in other populations with Mpox,” said Jeanne Marrazzo, director of the U.S. National Institute of Allergy and Infectious Diseases (NIAID).

The NIAID-supported study showed that deaths could be avoided when patients receiving MPOX were treated in the hospital. Researchers enrolled 597 MPOX patients in the study, all of whom were hospitalized for at least 14 days. The mortality rate – including those who received a placebo – was 1.7 percent, compared with at least 3.6 percent of all cases in the Democratic Republic of Congo, they said.

“This shows that people with MPOX may have better outcomes when they are hospitalized and receive high-quality supportive care,” the National Institutes of Health said in a statement.

Manufacturer SIGA also found that there was a “significant improvement” in those who were treated early and had the most severe disease. Although the data is not statistically significant, SIGA believes further studies in these groups are warranted. SIGA's share price fell more than 40 percent after the results were announced, but had recovered by about half by Friday afternoon.

Tecovirimat is approved in the EU for the treatment of smallpox and monkeypox, but is based only on animal studies. The approval was granted under “exceptional circumstances” without the clinical efficacy data normally required.

The European Commission bought stocks of the drug during the 2022-23 outbreak, while authorities in the UK recommended it as an option for hospitalized patients. The US also made the drug available to some MPOX patients in 2022 as part of studies on its effectiveness.