A Randomized, Placebo-controlled, Double-blinded Trial of the Safety and Efficacy of Tecovirimat for the Treatment of Adult and Pediatric Patients With Monkeypox Virus Disease - Extension Amendment

This open-label extension to the PALM007 protocol began in July 2024 after enrollment into the main study ended. It will further clinically characterize the natural history of mpox, and continue to identify recrudescent cases. Participants were initially provided SOC as well as open-access tecovirimat. The results of PALM007 were unblinded in August 2024, and although no safety concerns were observed with tecovirimat use, efficacy, defined by improvement in days to complete mpox skin lesion resolution, was not observed for tecovirimat compared to placebo. Therefore, the administration of tecovirimat in the extension amendment was discontinued in early August 2024, once these results were known, and only SOC continues to be provided.

Participants are admitted to the hospital and receive SOC for mpox until they have recovered. Recovery is defined as resolution of all lesions and a negative blood test for MPXV. Participants will remain on study through day 59 but will not have a scheduled study visit unless they present with new mpox symptoms. Sick visits will be available for participants who reach full body lesion resolution but subsequently develop at least 1 new lesion consistent with mpox after discharge and on or before day 59, at which time viral PCR and clinical laboratory testing will be performed and participants will be offered standard of care.

Initially, all participants presenting with mpox were eligible to enroll in this extension, regardless of disease severity. As of 05May2025, only patients with severe disease, defined as the presence of any of the following: flat lesions, pregnancy (due to risk for serious complications), suspected sickle cell disease, or severe clinical disease will be enrolled.