Merck & Co. said Monday that it is halting development of its two experimental Covid-19 vaccines, after early clinical-trial data showed the shots generated disappointing immune responses against the virus.
Early-stage studies of the vaccines indicated they produced inferior immune responses in subjects given the shots compared with people who survived Covid-19 or took authorized Covid-19 vaccines, the company said.
The exit removes a major vaccine player from the constellation of firms seeking shots to curb the spread of the virus, as the few companies that have been able to bring shots to market struggle to meet heavy demand.
Kenilworth, N.J.-based Merck, one of the world’s leading vaccine makers, said it would now focus on advancing two experimental Covid-19 drugs.
Merck said it expects test results for the pair of drugs in the coming weeks, and the company could ask regulators to authorize use if the results are positive.