Pharmaceutical giant Merck said on Monday it was halting the development of its two candidate vaccines Covid-19 after early clinical trial data showed a “lower” immune response.
Merck said in a statement posted on its website that the decision to discard the two candidate vaccines followed its review of the results of the Phase 1 clinical studies. Studies showed that both candidates were generally well tolerated, but immune responses were less than observed after natural infection with Covid-19 and those reported for other Covid-19 vaccines.
Merck was late to enter the race to develop a vaccine to protect against the virus, which has so far killed more than 2 million people worldwide and infected almost 100 million.
US regulators authorized Covid-19 vaccines from Moderna and partners Pfizer and BioNTech in December, and tens of millions of doses of both have been administered globally so far, while governments around the world are rushing to vaccinate as many people as possible to eliminate harmful blockages.
Competitors Johnson & Johnson, AstraZeneca Plc and others are also working to develop safe and effective vaccines to protect against the virus.
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Merck still plans to send the results of Phase 1 studies to the two vaccine candidates discarded for publication in a peer-reviewed newspaper, the statement said.
The company will now focus on two Covid-19 experimental drugs and other Covid-19 research, the statement added.
Reuters contributed to this report.
