Pfizer has commenced dosing in a pivotal randomised, double-blind Phase II/III clinical trial of its oral antiviral drug, PF-07321332, to treat Covid-19 in non-hospitalised patients who are at low risk of severe disease. The drug is a protease inhibitor developed to hinder the activity of the main protease enzyme that SARS-CoV-2 requires for replication. The study aims to recruit around 1,140 patients, who will receive a combination of PF-07321332 and ritonavir – another protease inhibitor, generally used as part of combination HIV therapies – or placebo.

Moderna has started its submission to the US Food and Drug Administration seeking authorisation for a booster shot of its Covid-19 vaccine, mRNA-1273, at the 50µg dose. The filing is backed by data demonstrating strong antibody responses against the SARS-CoV-2 Delta variant, the company said. These data will also be submitted to the European Medicines Agency and other global regulatory authorities soon.

Merck and Ridgeback Biotherapeutics have launched the global Phase III MOVe-AHEAD trial of molnupiravir to prevent Covid-19. The trial will involve people aged 18 years and above who live in the same household as a symptomatic Covid-19 patient. Currently, the drug is in Part 2 of the Phase III MOVe-OUT trial to treat certain adult outpatients with mild to moderate Covid-19, with results expected in the coming months.