Updated Trial Data Shows Lower Efficacy for Merck’s Oral COVID-19 Pill

November 26th, 2021 – Last month, Merck unveiled game-changing Phase 3 results for molnupiravir, an investigational oral antiviral for COVID-19 it is developing with Ridgeback Biotherapeutics. Interim results assessed from the 775 participants suggested that a five-day course of the drug significantly benefitted COVID-19 patients by cutting the risk of hospitalization or death by 50%!

The results were so overwhelming that Merck decided to stop further trial recruitment, following the recommendation of an independent Data Monitoring Committee and in consultation with the FDA. Several experts acknowledged that the result could prove to be a major breakthrough as oral antivirals could significantly cut transmission rates by minimizing healthcare center visits.

However, updated data from the study has now shown that the pill’s efficacy is much lower. Earlier today, Merck provided an update on the MOVe-OUT study where it was found that the efficacy of molnupiravir in reducing the risk of hospitalization and deaths was just 30%. As a result, Merck’s shares dipped 3% in premarket trading.

Updated Phase 3 Data

The Phase 3 MOVe-OUT trial is a randomized, placebo-controlled, double-blind, multi-site study of non-hospitalized adult patients with mild to moderate COVID-19. The updated data from 1433 participants showed that molnupiravir reduced the risk of hospitalization or death from 9.7% in the placebo group (68/699) to 6.8% (48/709) in the molnupiravir group, for an absolute risk reduction of 3.0% and a relative risk reduction of 30%.

Nine deaths were reported in the placebo group and one in the molnupiravir group. The adverse event profile for molnupiravir remained consistent with the profile reported at the planned interim analysis, the company said.

Merck still claims that both the interim analysis and the additional analyses support the efficacy and overall favorable benefit-risk assessment of molnupiravir for treating mild to moderate COVID-19 in adults at high risk for disease progression.

Molnupiravir has already bagged the emergency use approval in the UK, and Merck expects it to obtain the FDA nod as well, after having submitted a EUA application for the drug on October 11th. In a press release, the company said that it has shared these additional analyses with the FDA, and they will be presented to the FDA’s Antimicrobial Drugs Advisory Committee on November 30^th.

Competition from Other Oral Pills

The big competition for molnupiravir would be from Pfizer’s specifically designed SARS-CoV-2-3CL protease inhibitor. Three weeks ago, Pfizer announced that its investigational oral antiviral candidate, PAXLOVID, was found to significantly reduce hospitalization and death by 89%, according to interim Phase 2/3 data. Pfizer, too has submitted an application to the FDA last week for authorization.

Meanwhile, on November 17th, Japan’s Shionogi joined forces with long-time collaborator Ildong Pharmaceutical to co-develop an investigational oral COVID-19 pill called S-217622. Under the agreement, Ildong will conduct clinical trials of the oral candidate in South Korea, while Shionogi will test the pill in Japan and Singapore.

Author

Rajaneesh K. Gopinath