The antiviral pill co-developed by Ridgeback was approved by the US Food and Drug Administration in December 2021 for patients recently infected with Covid who are at risk for developing a severe form of the virus.

Launched shortly before Pfizer’s oral Covid treatment Paxlovid, Merck’s treatment was upstaged by its US rival, which reported an efficacy rate of 89% in preventing hospitalization and death compared with 30% for Merck’s.

Pfizer’s impressive efficacy rate was later relativized by repeated incidences of reinfection, but Paxlovid has clearly outsold Lagevrio in the products’ home market. Outside the US, however, the Merck pill has been seen to hold its own, especially in Asian markets. According to reports, it has become the primary Covid therapy in Japan.

For the 2022 second quarter, Merck reported worldwide sales of $1.2 billion for Lagevrio and has forecast revenues of $5 billion for the full year. Pfizer has forecast more than $20 billion for Paxlovid in the same timeframe.

In August, Pfizer leap-frogged over Merck again in securing access to the vast Chinese market, inking a five-year pact with Zhejiang Huahai to exclusively produce and sell the pill in the People’s Republic.

With the deal, Paxlovid is set to become the first oral antiviral Covid treatment available in China. Pfizer will provide the ingredients for the drug, while Huahai will handle manufacturing, packaging and sale.  

In late 2021, both Pfizer and Merck agreed with the Medicines Patent Pool to allow their respective technologies to be provided to poorer countries.  

Pfizer recently agreed to supply as many as six million courses of Paxlovid to the Global Fund, which seeks to help more than 100 low-to-middle income countries fight diseases such as Covid-19, HIV, tuberculosis and malaria.

Author: Dede Williams, Freelance Journalist