Merck (MSD) and Ridgeback Biotherapeutics have commenced a Phase III MOVe-AHEAD clinical trial of their oral drug, molnupiravir, to prevent Covid-19.

An experimental antiviral therapy, molnupiravir is an oral form of a potent ribonucleoside analogue that hinders the replication of various ribonucleic acid (RNA) viruses such as SARS-CoV-2.

The multi-centre, randomised, double-blind, placebo-controlled Phase III trial will assess the efficacy and safety of molnupiravir versus placebo in preventing Covid-19 spread within households.The trial plans to enrol nearly 1,332 adult subjects, who will be categorised to receive an oral dose of either 800mg molnupiravir or placebo every 12 hours for five days.

People living in the same household with someone who has tested positive for Covid-19, at least one related symptom and has not had signs or symptoms for more than five days will be eligible for the trial.

The percentage of subjects with Covid-19 through day 14, an adverse event and discontinuation of study intervention because of an adverse event, will be the trial’s primary goals.

Merck and Ridgeback anticipate carrying out the trial in several countries, including Argentina, Brazil, Colombia, France, Guatemala and the US among others.

Merck Research Laboratories clinical research vaccines and infectious diseases senior vice-president Dr Nick Kartsonis said: “As the pandemic continues to evolve and surges are being reported in many places around the world, it is important that we investigate new ways to protect individuals exposed to the virus from becoming infected with symptomatic disease.