Merck Pharmaceutical COVID-19 Vaccine Candidates Discontinued

Merck & Co., a multinational pharmaceutical company, has recently announced that it will be discontinuing the development of its coronavirus disease 2019 (COVID-19) vaccine candidates V590 and V591. The decision follows a review of the 2 vaccines Phase 1 clinical trial data. Instead, the company will refocus its research strategy and production efforts to the advancement of 2 therapeutic candidates.

Although the therapies were generally well tolerated in the participants, the data reviewed by the company showed that the immune responses initiated by the 2 vaccine candidates were inferior to those observed following a natural infection with the virus.

“We are grateful to our collaborators who worked with us on these vaccine candidates and to the volunteers in the trials,” Dean Y. Li, president of Merck Research Laboratories said. “We are resolute in our commitment to contribute to the global effort to relieve the burden of this pandemic on patients, health care systems and communities.”

The 2 therapeutic candidates that will now be the company’s focal point are MK-7110 and MK-4482.

MK-7110, an investigational recombinant fusion protein, modulates the inflammatory response to the SARS-CoV-2 virus by targeting an immune pathway checkpoint. Phase 3 trial data investigating the therapy demonstrated over a 50% reduction in respiratory failure or the risk of death in patients who were hospitalized with moderate to severe forms of COVID-19. The US government and Merck recently reached a supply agreement to advance the manufacturing and distribution of MK-7710.

The second therapy, Molnupiravir (MK-4482), is a novel oral antiviral agent that is being developed in collaboration with Ridgeback Bio., a biotherapeutics and biotechnology company focused on infectious diseases. The therapy is currently undergoing Phase 2/3 clinical trials in hospital and out-patient settings, with initial efficacy data projected to be publicly available in the first quarter of 2021.