Merck says its Covid antibody treatment less effective than first thought

Merck’s Covid-19 oral antiviral treatment is not as effective as first thought, the pharma group said on Friday, after a full analysis of trial results provided new data on its ability to reduce hospitalisations and deaths.

The company said its oral drug, molnupiravir, showed a relative risk reduction of 30 per cent when compared with placebo in all 1,400 enrolled patients on the trial. It had said last month that reduction was of “approximately” 50 per cent as it published preliminary data on a smaller sample of patients.

In the full analysis, one death was reported in the molnupiravir group, and nine in the placebo group.

Merck’s New York-listed shares lost 2.6 per in cent in pre-market trading on Friday, amid a broader fall in markets.

The company said the new data continued to support “the efficacy and overall favorable benefit-risk assessment of molnupiravir for the treatment of mild to moderate Covid-19 in adults at high risk for disease progression”.

It said it had shared the additional data with the US Food and Drug Administration, which is reviewing the drug.

Merck noted that the statistical criterion for success had already been met, and that an external data board had advised stopping enrolment in the study.

Molnupiravir, co-developed with Ridgeback Biotherapeutics and also known as Lagevrio, has been approved for use in the UK. European regulators are also reviewing it. Merck has signed a deal with the Medicines Patent Pool to make the drug available to poorer nations.