Leflunomide for the Treatment of Severe COVID-19 in Patients With a Concurrent Malignancy

This phase I/II trial investigates the best dose and side effects of leflunomide and how well it works in treating patients with COVID-19 and a past or present cancer. Leflunomide has been used since the 1990s as a treatment for rheumatoid arthritis. Experiments done with human cells that were given severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing COVID-19, showed that leflunomide was able to reduce the ability of the virus to make copies of itself. The coronavirus uses ribonucleic acid (RNA), a very long molecule that contains genetic information that is like a blueprint for making more copies of itself. Leflunomide inhibits the formation of RNA. The information gained from this study may help researchers to learn whether leflunomide is safe for use in treating patients with COVID-19, and whether it is potentially effective against the disease.