A phase 3 trial evaluating sarilumab (Sanofi and Regeneron), an interleukin-6 antagonist, in patients with coronavirus disease 2019 (COVID-19) requiring mechanical ventilation did not meet its primary and key secondary end points.

The randomized, double-blind, placebo-controlled trial included a primary analysis group of 194 COVID-19 patients who required mechanical ventilation at the time of enrollment. Patients were randomized to receive sarilumab 400mg or placebo in addition to best supportive care. 

The primary end point was the proportion of patients with at least 1-point improvement in clinical status using a 7-point ordinal scale. Results showed that patients treated with sarilumab in the primary analysis group demonstrated minor positive trends that did not reach statistical significance, but these were offset by negative trends in a subgroup of critical patients who were not mechanically ventilated at baseline. 

Regarding safety, the frequency of adverse events were similar between sarilumab (80%) and placebo (77%). Patients in the sarilumab treatment arm experienced a higher frequency of serious adverse events compared with placebo, including multiorgan dysfunction syndrome (6% vs 5%, respectively) and hypotension (4% vs 3%, respectively).

The US-based trial, which included a second cohort of patients receiving sarilumab 800mg, has been discontinued based on recommendations from an Independent Data Monitoring Committee (IDMC). Full trial results will be submitted to a peer-reviewed publication later this year.

Sanofi will continue a separate ongoing trial outside of the US investigating sarilumab in hospitalized patients with severe and critical COVID-19 using a different dosing regimen. The Company expects trial results in the third quarter of 2020.

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Sarilumab is currently marketed under the brand name Kevzara® for the treatment of moderately to severely active rheumatoid arthritis in adults who have had an inadequate response or intolerance to 1 or more disease-modifying antirheumatic drugs.

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