Merck & Co. said on Monday that it is halting the development of its two Covid-19 experimental vaccines, after the first clinical trial data showed that the vaccines generated disappointing immune responses against the virus.
Early-stage studies of the vaccines indicated that they produced lower immune responses in individuals who received the injections compared to people who survived Covid-19 or received authorized Covid-19 vaccines, the company said.
The move removes a major vaccine player from the constellation of companies seeking injections to stem the spread of the virus, as the few that managed to launch vaccines on the market struggle to meet high demand.
Merck, based in Kenilworth, NJ, one of the largest vaccine manufacturers in the world, said it will now focus on the development of two Covid-19 experimental drugs.
Merck said it expects test results for the drug pair in the coming weeks, and the company may ask regulators to authorize use if the results are positive.