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Merck Terminates Development of COVID-19 Vaccine Candidates
Although the COVID-19 vaccine candidates were generally well-tolerated in Phase 1 clinical studies, immune responses were lesser than those reported for other candidates.
Merck recently announced that it is discontinuing development of its COVID-19 vaccine candidates, V590 and V591, and will focus its research strategy on advancing its two other candidates, MK-4482 and MK-7110.
The decision to discontinue the development of the vaccine candidates is based on findings from Phase 1 clinical studies which showed that V590 and V591 were generally well-tolerated, but the immune responses were lesser than those reported for other COVID-19 vaccines.
“We are grateful to our collaborators who worked with us on these vaccine candidates and to the volunteers in the trials,” Dean Y. Li, MD, president of Merck research laboratories, said in the announcement.
“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,” Li continued.
Merck stated that it will record a charge in the fourth quarter of 2020, but this will not impact non-GAAP results. And the results for the Phase 1 studies of V590 and V591 will be submitted in a peer-reviewed journal.
The company plans to advance clinical programs and scale-up manufacturing for MK-4482 and MK-7110. Additionally, Merck will continue to conduct SARS-CoV-2/ COVID-19 research.
MK-4482 is an oral novel investigational antiviral agent being developed in collaboration with Ridgeback Bio. The antiviral is currently being evaluated in Phase 2/3 clinical trials in both hospitals and outpatient settings.
MK-7110 is a first-in-class investigational recombinant fusion protein that regulates the inflammatory response to COVID-19 by targeting a novel immune pathway checkpoint, Merck explained.
Interim results from a Phase 3 study of MK-7110 showed a greater than 50 percent reduction in the risk of death or respiratory failure in patients hospitalized with moderate to severe COVID-19.
The expected completion date for the Phase 2/3 studies is May 2021, with initial efficacy data in the first quarter of 2021. While complete results from the MK-7110 study are expected in the first quarter of 2021.
At the end of May 2020, Merck and IAVI announced a partnership to explore the development of an investigational COVID-19 vaccine candidate that will use vesicular stomatitis virus (rVSV) technology, which is the basis for Merck’s Ebola Zaire virus vaccine, ERVEBO.
Then at the beginning of November, the companies began enrollment for the Phase 1 trial of V590. The trial would include nearly 252 participants ages 18 and up, including seniors.
The study planned to assess the safety, tolerability, and immunogenicity of V590 compared to placebo. At enrollment, most participants had no evidence of prior COVID-19 infection or detectable coronavirus antibodies.
This comes as the US gravely needs more vaccines, Mark Feinberg, MD, PhD, president and CEO of IAVI, said in a press release following the discontinuation of the candidates.
“These results are not the ones we hoped for, but we conduct studies in order to learn the answer to a question. In this case, the answer is clear: more work is needed,” Feinberg stated. “We fully intend to make a contribution to ensure that all people, no matter where they live, are able to access COVID-19 vaccines so that individuals, families, and communities everywhere are protected.”
Additionally, an IAVI spokesperson noted that an award from the Defense Threat Reduction Agency (DTRA) of the Department of Defense (DoD) will continue to help support nonclinical research into rVSV-vectored COVID-19 vaccine candidates at IAVI’s vaccine design and development lab in New York.
Commitment from the Government of Japan in partnership with the World Bank will also contribute to IAVI's COVID-19 vaccine development program.
