Sanofi and Regeneron Halt Further Clinical Studies for Kevzara in COVID-19 After Disappointing Phase 3 Trial Results

Sanofi S.A. (Paris, France) and Regeneron Pharmaceuticals, Inc. (Tarrytown, NY, USA) have decided to discontinue further clinical studies for Kevzara (sarilumab) in COVID-19 after suffering a setback in the drug’s Phase 3 trial.

Kevzara is currently approved in multiple countries to treat adults with moderately to severely active rheumatoid arthritis who have not responded to or tolerated previous therapy. Kevzara was being investigated for its ability to reduce the overactive inflammatory immune response associated with COVID-19 based on evidence of markedly elevated levels of IL-6, an immune system protein, in severely ill patients infected with coronaviruses. Kevzara binds specifically to the IL-6 receptor and has been shown to inhibit IL-6 mediated signaling.


A 420-patient randomized trial was conducted outside the US in Argentina, Brazil, Canada, Chile, France, Germany, Israel, Italy, Japan, Russia and Spain (86 in placebo, 161 in 200 mg, and 173 in 400 mg arms). However, the global Phase 3 trial investigating intravenously administered Kevzara at a dose of 200 mg or 400 mga in severely or critically ill patients hospitalized with COVID-19 did not meet its primary endpoint and key secondary endpoint when Kevzara was compared to placebo added to usual hospital care.

Although not statistically significant, numerical trends were observed toward a decrease in duration of hospital stay as well as acceleration in time to improve clinical outcomes, as measured by a two-point improvement from baseline on the seven-point scale. Further, a trend was observed towards reduced mortality in the critical patient group which was not seen in the severe patient group. Finally, the time to discharge was shortened by two-three days (statistically non-significant) in the patients treated with Kevzara within the first two weeks of treatment. Serious adverse events were experienced by 26-29% of Kevzara patients and 24% of placebo patients. The incidence of adverse events leading to death was approximately 10% in all three treatment arms. Serious infections (including COVID-19 pneumonia) were observed in 11-13% of Kevzara patients and 12% of placebo patients. Sanofi and Regeneron have said that they do not anticipate conducting further clinical studies for Kevzara in COVID-19.

“Although this trial did not yield the results we hoped for, we are proud of the work that was achieved by the team to further our understanding of the potential use of Kevzara for the treatment of COVID-19,” said John Reed, M.D., Ph.D., Global Head of Research and Development, Sanofi. “In times like these, commitment to properly designed, controlled clinical trials, provides the information and understanding the scientific community needs for fact-based decision making. At Sanofi, we are committed to help combat the global COVID-19 pandemic, including developing vaccine candidates that can be manufactured at large-scale.”

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