Tecovirimat Shows Limited Efficacy in Clade I Mpox but Highlights Importance of Supportive Care
Key Insights
A recent NIAID (search) study, PALM007, found that tecovirimat did not significantly reduce the duration of mpox (search) lesions in patients with clade I mpox in the Democratic Republic of the Congo.
Despite the limited efficacy of tecovirimat, the study observed a lower mortality rate (1.7%) compared to the reported mpox (search) mortality (3.6% or higher) in the DRC, emphasizing the impact of quality supportive care.
NIAID (search) is conducting ongoing clinical trials, including the STOMP trial, to evaluate tecovirimat's effectiveness against clade II mpox (search) in the United States and other affected countries.
An initial analysis of data from the NIAID (search)-sponsored PALM007 trial indicates that tecovirimat did not significantly decrease the duration of mpox (search) lesions among adults and children infected with clade I mpox in the Democratic Republic of the Congo (DRC). The randomized, placebo-controlled trial's findings, announced in August 2024, suggest that while tecovirimat may not directly shorten the duration of lesions, comprehensive supportive care plays a crucial role in improving patient outcomes.
Impact of Supportive Care
Notably, the PALM007 study reported an overall mortality rate of 1.7% among enrollees, irrespective of whether they received tecovirimat or a placebo. This figure is significantly lower than the mpox (search) mortality rate of 3.6% or higher previously reported among all cases in the DRC. This discrepancy underscores the potential for improved outcomes through hospitalization and high-quality supportive care for individuals with mpox. Further analyses and detailed results from PALM007 are expected to be released through scientific channels.
Ongoing Research and Clinical Trials
NIAID (search) is currently conducting the STOMP trial in the United States and other countries affected by clade II mpox (search). This trial aims to enroll over 500 adults and children with mpox, with remote enrollment options available within the United States. The study includes an open-label arm for adults with severe mpox or those at high risk, such as individuals with immune deficiencies, inflammatory skin conditions, or pregnant individuals, who will all receive tecovirimat. Other adult participants will be randomly assigned to receive either tecovirimat or a placebo, with investigators assessing whether tecovirimat accelerates healing compared to the placebo.
Tecovirimat and Brincidofovir: Antiviral Options
Tecovirimat (TPOXX) received FDA approval in 2018 for the treatment of smallpox (search) in adults and children and is part of the U.S. Strategic National Stockpile. NIAID (search)-funded preclinical studies have been crucial in determining its mechanism of action, safety, and efficacy. Similarly, NIAID supported the early development of brincidofovir (Tembexa), which was FDA-approved in 2021 for the treatment of smallpox based on efficacy in animal models of Orthopoxvirus infection. Both medications represent potential options for managing mpox (search), although further research is needed to fully understand their effectiveness and optimal use in different clinical contexts.
Continued Efforts in Antiviral Discovery
In addition to the research on tecovirimat and brincidofovir, NIAID (search) continues to screen novel compounds to identify potential antiviral candidates for treating mpox (search) and related conditions caused by Orthopoxviruses. These ongoing efforts are critical for expanding the arsenal of available treatments and improving outcomes for patients affected by these viral infections.