Mpox Antiviral Lacks Efficacy Data

According to an analysis from the U.S. Centers for Disease Control and Prevention (CDC) and published by NEJM Evidence on September 13, 2024, SIGA Technologies, Inc. mpox treatment tecovirimat (TPOXX®) safety and effectiveness against the monkeypox virus clade 2 virus can't be determined from data.

CDC researchers evaluated data from over 7,100 patients prescribed tecovirimat, a virostatic antiviral drug, from May 29, 2022, through July 10, 2023.

They wrote, 'Although relatively few serious adverse events (SAEs) were reported, because of the passive nature of reporting, we cannot definitively conclude that tecovirimat treatment was always safe. Similar to data from case reports and other published observational studies, our data, in the absence of comparison data from untreated patients, cannot be used to infer clinical effectiveness, or lack thereof, of tecovirimat treatment.'

Overall, 223 SAEs and 40 deaths were reported. Most events were among patients who were severely immunocompromised.

Despite the inclusion of many patients with severe disease for whom the CDC was consulted, outcomes were favorable for most of the treated patients in this cohort.

This analysis did not review the current mpox clade 1 outbreak impacting countries in Africa.