To evaluate the efficacy and safety of leflunomide for the treatment of acute, symptomatic COVID-19.
A single-center, open-label, randomized controlled trial was performed during an outbreak of SARS-CoV-2 Omicron variant in December 2022. Symptomatic patients within 5 days of COVID-19 onset were randomly allocated to receive 5 days of either symptomatic treatment with leflunomide or symptomatic treatment alone. The primary endpoint was time to sustained clinical recovery.
Fifty-seven participants were randomized into two groups: 27 received leflunomide plus symptomatic treatment and 30 were assigned to symptomatic treatment alone. Participants treated with leflunomide had a shorter fever duration [3.0 interquartile range (IQR, 2.0–4.0) days and 4.0 (IQR, 3.0–6.0) days, respectively (
In acute adult COVID-19 patients presenting within 5 days of symptom onset, leflunomide combined with symptomatic treatment reduced fever duration and viral shedding time.