The drugmaker released interim data in October showing a roughly 50% reduction in hospitalisations and deaths in 775 patients.

The updated rate today is based on data from over 1,400 patients.

Merck’s shares fell 3% to US$79.41 in premarket trading, amid a fall in the broader markets.

The company said the data on the drug molnupiravir, developed with Ridgeback Biotherapeutics, had been submitted to the US Food and Drug Administration ahead of a meeting of its expert advisers on Tuesday.

A planned interim analysis of the data last month showed that 7.3% of those given molnupiravir twice a day for five days were hospitalised and none had died by 29 days after the treatment.

That compared with a hospitalisation rate of 14.1% for placebo patients.

In the updated data, 6.8% of those given molnupiravir were hospitalised and one person died, while the other placebo group had a hospitalisation rate of 9.7%.