Regeneron's Covid-19 antibody gets an in-patient boost
Regeneron’s latest trial of its antibody cocktail Regen-Cov was intended to broaden the use of the treatment to patients hospitalised with Covid-19. And it looks to have succeeded, at least in some patients. In a phase 2/3 trial the combination of casirivimab and imdevimab met the primary endpoint of significantly reducing viral load within seven days of treatment. More importantly, it reduced the risk of death by 36% compared with placebo at day 29 for hospitalised Covid-19 patients not requiring high-flow oxygen or mechanical ventilation. However, this was not significant, as the trial was stopped early because of slow enrolment. And in an echo of the much larger Recovery trial, the greatest benefit was in seronegative patients – those who fail to mount an adequate response to infection – with the risk reduction here rising to 56%. Regen-Cov is not yet authorised for hospitalised patients, but the latest data could help support a nod here, at least in a seronegative population. This should give a much-needed option for in patients, but serostatus testing will have to become routine.