Sanofi and Regeneron provide update on Kevzara Phase 3 Covid-19 trials

Failed to meet primary and critical secondary endpoints

Photo by National Cancer Institute on Unsplash

Sanofi and Regeneron Pharmaceuticals announced that the US Phase 3 trial of Kevzara (sarilumab) 400 mg in Covid-19 patients requiring mechanical ventilation did not meet its primary and key secondary endpoints when Kevzara was added to best supportive care compared to best supportive care alone (placebo).

According to the press release, minor positive trends were observed in the primary pre-specified analysis group (critical patients on Kevzara 400 mg who were mechanically ventilated at baseline) that did not reach statistical significance, and these were countered by negative trends in a subgroup of critical patients. The latter were not mechanically ventilated at baseline. In the primary analysis group, adverse events were experienced by 80% of Kevzara patients and 77% of placebo patients. Serious adverse events in at least 3% of patients and more frequently among Kevzara patients were multi-organ dysfunction syndrome (6% Kevzara, 5% placebo) and hypotension (4% Kevzara, 3% placebo).

Based on the results, the US-based trial has been stopped, including in a second cohort of patients who received a higher dose of Kevzara (800 mg). Detailed results will be submitted to a peer-reviewed publication later this year.

The primary analysis group included 194 patients who were critically ill with Covid-19 and receiving mechanical ventilation at the time of enrolment. The primary endpoint assessed the percentage of patients who achieved at least a 1-point change from baseline on a 7-point scale, which consisted of death; hospitalized, requiring invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO); hospitalized, requiring non-invasive ventilation or high flow oxygen devices; hospitalized, requiring supplemental oxygen; hospitalized, not requiring supplemental oxygen – requiring ongoing medical care (COVID-19 related or otherwise); hospitalized, not requiring supplemental oxygen – no longer requires ongoing medical care; discharged from hospital. A second cohort, which was partially recruited (n=27), compared Kevzara 800 mg versus placebo.

The Kevzara trial was designed after a small (n=21), single-arm study in China (Xu et al) among mostly severe, febrile hospitalized COVID-19 patients found elevated IL-6 levels. They suggested that inhibiting this pathway with the IL-6 blocker tocilizumab rapidly reduced fever and improved oxygenation in severe patients, allowing for successful hospital discharge. The Phase 3 Kevzara trial was designed to evaluate this hypothesis in a large, placebo-controlled trial. The trial has been funded in part with federal funds from the Department of Health and Human Services, office of the assistant secretary for Preparedness and Response; Biomedical Advanced Research and Development Authority (BARDA), under OT number: HHSO100201700020C.

A separate Sanofi-led trial outside of the US in hospitalized patients with severe and critical Covid-19 using a different dosing regimen is ongoing. The same Independent Data Monitoring Committee (IDMC) oversees both the Regeneron-led US trial and the Sanofi-led trial outside of US, which has recommended that the trial outside of the US continue. The companies expect to report results in Q3 2020.

Endpoints that showed positive trends in patients on mechanical ventilation at baseline, and were countered by negative trends in patients who were not mechanically ventilated at baseline included: the proportion of patients with a 1-point improvement on day 22 (primary endpoint for mechanical ventilation group); the proportion of patients who died by day 29; and proportion of patients who recovered by day 22.

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.


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