As mpox continues As the epidemic spreads in Central Africa, a promising antiviral drug to treat the infection has failed to improve patients’ symptoms in clinical trials in the Democratic Republic of Congo, the epicenter of the outbreak.
In the trial, the drug tecovirimat, also known as TPOXX, did not reduce the characteristic blister-like rash seen in patients with MPOX, formerly known as monkeypox.Unusually, the National Institute of Allergy and Infectious Diseases (NIAID), which sponsored the study, released initial results earlier this month before the full findings had been peer-reviewed and published in a scientific journal.
Lori Dodd, branch chief of NIAID’s clinical trials research and statistics division, told WIRED that the agency shared the initial results “because of the urgent need for scientific evidence on the use of tecovirimat in MPOX treatment,” which she said was heightened by the World Health Organization’s designation of the MPOX epidemic in Central Africa as a global health emergency on August 14, the second time it has done so in two years.
The results are particularly disappointing as Central African countries continue to struggle to contain MPOX infections. According to an August 25 report from the Africa Centers for Disease Control and Prevention, 13 African countries have recorded a total of 20,720 confirmed or suspected cases of MPOX and 582 deaths since the beginning of the year.
On Monday, the World Health Organization released a six-month strategic plan aimed at containing the outbreak. The plan, estimated to cost $135 million, includes strengthening surveillance and improving access to testing and vaccines. “The MPOX epidemic in the Democratic Republic of the Congo and neighboring countries is controllable and can be stopped,” WHO Director-General Tedros Adhanom Ghebreyesus said in a statement.
There is an approved vaccine to prevent variola, but no medications are indicated to treat the disease. Tecovirimat was approved by the U.S. Food and Drug Administration in 2018 to treat the smallpox virus, and clinical trials for the drug began in 2022 to treat variola amid a global pandemic. The drug is also available in the U.S. for the treatment of variola through an expanded access program, allowing doctors to treat patients with investigational drugs outside of clinical trials. In the UK and Europe, TPOXX was approved for the treatment of variola under exceptional circumstances, without comprehensive data on its effectiveness.
As part of a clinical trial in the Democratic Republic of Congo, nearly 600 participants were randomly assigned to receive either tecovirimat or a placebo and were closely monitored in hospital for at least 14 days. All participants received supportive care, including nutrition, hydration, and treatment of secondary infections. The drug was found to be safe but was no better than a placebo at clearing lesions in patients.
Of note, mortality was low, and patients’ lesions healed more quickly than expected, whether they received Tecovirimat or a placebo. Mortality across the study’s participants was 1.7 percent, regardless of whether they received the drug, far lower than the MPOX mortality rate of more than 3.6 percent in all cases reported in the Democratic Republic of Congo.
