A phase III randomized controlled trial of plitidepsin, a marine derived compound, in hospitalized adults with moderate COVID-19.

Background: Plitidepsin has shown potent preclinical activity against SARS-CoV-2 and was generally well tolerated in a Phase I trial of hospitalized patients with COVID-19. NEPTUNO, a Phase III, multicenter, randomized, controlled trial, was designed to evaluate the efficacy and safety of plitidepsin in the management of moderate COVID-19 in hospitalized adult patients.

Methods: Included patients had documented SARS-CoV-2 infection, required oxygen therapy, and had adequate organ function. The planned sample size was 609 patients. Patients were randomized 1:1:1 to at least 3 days of dexamethasone plus either plitidepsin (1.5 mg/day or 2.5 mg/day, for 3 days) or standard of care (control). The primary endpoint was the time to sustained withdrawal of supplemental oxygen. Secondary endpoints included time to sustained hospital discharge, clinical status, duration of oxygen support, percentage of patients requiring admission to the intensive care unit, and safety.