ABSTRACTBackgroundOpaganib, an oral sphingosine kinase-2 inhibitor with antiviral and anti-inflammatory properties, was shown to inhibit SARS-CoV-2 replication in vitro. We thus considered that opaganib could be beneficial for moderate to severe COVID-19 pneumonia. The objective of the study was to evaluate the effect of opaganib on supplemental oxygen requirements, time to hospital discharge and its safety in COVID-19 pneumonia hospitalized patients requiring supplemental oxygen.MethodsThis Phase 2a, randomized, double-blind, placebo-controlled study was conducted between July and December 2020 in eight sites in the USA. Forty-two enrolled patients received opaganib (n=23) or placebo (n=19) added to standard of care for up to 14 days and were followed up for 28 days after their last dose of opaganib/placebo.ResultsThe relative decrease in total supplemental oxygen requirement from baseline to Day 14 was 61.6% in the opaganib versus 46.7% in the placebo arms. By Day 14, 50.0% of patients in the opaganib and 22.2% in the placebo group no longer required supplemental oxygen for at least 24 hours, while 86.4% and 55.6%, respectively, were discharged from hospital. The incidence of ≥ Grade 3 treatment-emergent adverse events was 17.4% and 33.3% in the opaganib and placebo groups, respectively. Three deaths occurred in each group.ConclusionsIn this proof-of-concept study, hypoxic, hospitalized patients receiving oral opaganib required less supplementary oxygen and had earlier hospital discharge, with no safety concerns arising. These findings support further evaluation of opaganib in this population.SummaryUpon receiving opaganib, patients with COVID-19 pneumonia who were hospitalized and required supplemental oxygen showed symptomatic clinical improvement compared to placebo, with less supplemental oxygen requirement, resulting in earlier hospital discharge, and no safety concerns arising.