Regeneron Pharmaceuticals Inc. /zigman2/quotes/203149337/composite REGN -0.53% and Sanofi SA /zigman2/quotes/201967021/composite SNY -2.67% said Monday that the first patient in a global clinical trial testing Kevzara as a therapy for patients hospitalized with severe cases of COVID-19 has been treated. The patient is not located in the U.S., though the Phase 2/3 trial is being conducted in seven countries, including the U.S. A second trial is based in the U.S. The companies developed and marketed Kevzara as a treatment for rheumatoid arthritis. "These trials will provide important data to determine whether Kevzara ameliorates the life-threatening complications of COVID-19 infections by counteracting the overactive inflammatory immune responses in the lungs when damaged by the virus," Dr. John Reed, Sanofi's global head of research and development, said in a statement. Regeneron's stock is up 1% in premarket trading on Monday, while it has gained 19% year-to-date. Shares of Sanofi are up 0.2% in premarket trading on Monday. Year-to-date, the company's stock is down 15%. The S&P 500 /zigman2/quotes/210599714/realtime SPX +0.16% is down 21% since the start of the year.