Sanofi and Regeneron Pharmaceuticals are set to continue the Phase II/III clinical trial of Kevzara (sarilumab) in hospitalised patients having critical respiratory illness caused by Covid-19.

The move is based on a recommendation by the Independent Data Monitoring Committee (IDMC), which reviewed available Phase II and Phase III findings.

Sanofi and Regeneron will immediately amend the trial protocol to enrol only critical patients in 400mg Kevzara or placebo arms, and a 200mg dose of the drug will be discontinued.

The Phase II part of the trial compared intravenous 200mg or 400mg Kevzara and placebo in a total of 457 hospitalised patients.

At baseline, participants were classified as suffering from ‘severe’ illness, ‘critical’ illness or ‘multi-system organ dysfunction’.

Patients were categorised as ‘severe’ if they needed oxygen supplementation without mechanical or high-flow oxygenation and “critical” if they needed mechanical ventilation or high-flow oxygenation or treatment in an intensive care unit.

Preliminary findings from the Phase II showed that the drug reached the primary endpoint of the study by rapidly decreasing the C-reactive protein, an important marker of inflammation.

Data revealed increased baseline levels of IL-6 in all treatment arms and higher levels observed in critical patients compared to severe patients.

Investigators did not report any new safety findings with the drug.

Preliminary analysis demonstrated no notable benefit with the drug on clinical outcomes when comparing the severe plus critical groups to placebo.

Negative trends were observed for several outcomes in the severe group, while the trends were positive for all outcomes in the critical group.

Regeneron Pharmaceuticals co-founder, president and chief scientific officer George Yancopoulos said: “Emerging evidence with Kevzara and other repurposed drugs in the Covid-19 crisis highlight the challenges of making decisions about existing medicines for new viral threats using small, uncontrolled studies.

“We await results of the ongoing Phase III trial to learn more about Covid-19, and better understand whether some patients may benefit from Kevzara treatment.”

The Phase III part of the trial is ongoing and has so far enrolled more than 600 patients in the ‘critical’ group. Enrolment is still underway and results are expected to be available in June.

Sanofi is also conducting a Phase II/III trial of Kevzara (sarilumab) in patients hospitalised with severe Covid-19 infection outside of the US.