Merck, one of the world’s leading vaccine makers, is ending its Covid-19 vaccine development after its two candidates failed to elicit immune responses as strong as those seen from shots that are already available.
The US pharmaceutical company also said on Monday that its phase 1 trials showed participants’ response was not as robust as the immune response seen in recovered Covid-19 patients. There were no significant safety issues.
Shares in Merck fell 1.8 per cent to $79.51 in pre-market trading in New York as the company said it would record an unspecified charge in the fourth quarter.
Dean Li, president of Merck research laboratories, said the company remained “resolute in our commitment to contribute to the global effort to relieve the burden of this pandemic on patients, healthcare systems and communities”.
Merck was slow to announce its entry into the race for a Covid-19 vaccine, despite prior successes in vaccines. Instead, the first available shots have been developed by companies that previously had no vaccine products on the market: BioNTech and Moderna.
Before Covid-19, Merck had developed a mumps shot in what was then a record-breaking four years, created the first Ebola vaccine approved by a US regulator and launched the first vaccine designed to prevent cervical cancer.
Merck will now focus on its potential drugs for treating Covid-19. The company has a deal with the US government worth up to $356m to sell a drug to treat the inflammatory response for severe Covid-19 patients if it receives emergency use authorisation.
The second drug is an antiviral in phase 2/3 clinical trials, being developed with Ridgeback Bio. It could be the first oral therapeutic, which patients would be able to take outside the hospital.