Sanofi/Regeneron's Kevzara fails again in serious COVID-19 cases

French pharma company Sanofi

Sanofi has drawn another blank in its attempt to repurpose its IL-6 drug Kevzara to tackle the extreme immune reaction seen in serious cases of COVID-19.

The French pharma and development partner Regeneron have been testing Kevzara (sarilumab) in patients severely or critically ill and hospitalised with COVID-19.

In severe cases of COVID-19, patients suffer a "cytokine storm" where the immune system becomes overstimulated and attacks the body.

Scientists hoped that by inhibiting interleukin (IL)-6, an important immune signalling cytokine, the potentially fatal symptoms in severe cases could be alleviated.

But in a phase 3 trial outside the US the drug failed to meet its primary endpoint of improvement in clinical symptoms, measured by a seven-point scale where one is death and seven is not hospitalised.

The results were taken from 420 patients in hospitals outside the US in countries including Argentina, Brazil, Russia and Spain.

Results mirrored those seen in a phase 3 cohort of patients in the US from Regeneron, which were announced in July.

Like the US trial there were numerical trends towards a decrease in duration of hospital stay, as well as an acceleration in time to improve clinical outcomes, as measured by a two-point improvement from baseline on the seven-point scale.

There was also a trend towards reduced mortality in critically ill patients that was not seen in severely ill patients.

The time to discharge was shortened by 2-3 days, which was not statistically significant in 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 says it plans no further clinical studies for Kevzara in COVID-19, after Roche’s rival IL-6 drug Actemra has also failed to produce convincing results in similar trials.

Detailed results will be published in a peer-reviewed journal later this year, but these latest trial results suggesting that IL-6 drugs can alleviate symptoms is flawed.