US giant Merck stops development of two COVID-19 vaccine candidates

Both V590 and V591 were generally well tolerated, but the immune responses were inferior to those seen following natural infection and those reported for other COVID-19 vaccines, said Merck

Viswanath Pilla
January 25, 2021 / 06:57 PM IST

Merck will focus its research strategy and production capabilities on advancing therapeutic drug candidates, MK-4482 and MK-7110. (Representative image)

US pharmaceutical gaint Merck, which is known in India as MSD, on January 25 said it is discontinuing development of its COVID-19 vaccine candidates, V590 and V591, and plans to focus its research strategy and production capabilities on advancing therapeutic drug candidates, MK-4482 and MK-7110.

This decision follows Merck’s review of findings from Phase 1 clinical studies for the vaccines.

"In these studies, both V590 and V591 were generally well tolerated, but the immune responses were inferior to those seen following natural infection and those reported for other COVID-19 vaccines," Merck said.

Merck's V590 uses rVSV viral vector and V591 vaccine candidate uses a measles virus vector to deliver the antigens to the body to spur immune response.

Merck said it would continue to advance clinical programmes and to scale-up manufacturing for two investigational medicines, MK-7110 (antibody drug) and MK-4482 (molnupiravir); molnupiravir is being developed in collaboration with Ridgeback Bio.

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COVID-19 Vaccine

Frequently Asked Questions

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How does a vaccine work?

A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.

How many types of vaccines are there?

There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.

What does it take to develop a vaccine of this kind?

Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.

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“We are grateful to our collaborators who worked with us on these vaccine candidates and to the volunteers in the trials,” said Dr. Dean Y. Li, President, Merck Research Laboratories.

“We are resolute in our commitment to contribute to the global effort to relieve the burden of this pandemic on patients, healthcare systems and communities.”

Due to the discontinuation, the company will record a charge in the fourth quarter of 2020, Merck said.

Merck and its collaborators plan to submit the results of the Phase 1 studies for V590 and V591 for publication in a peer-reviewed journal. In addition to advancing the development and production of MK-7110 and MK-4482, Merck will continue to conduct COVID-19 research.

Merck said it would also continue to evaluate the potential of the measles-virus vector and vesicular stomatitis virus vector-based platforms and pursue broader pandemic-response capabilities.

Merck would be second the drug maker to abandon COVID-19 vaccine development. Earlier, a COVID-19 vaccine developed by the University of Australia was abandoned after trial participants returned false positive test results of HIV.

In December last year, French drug maker Sanofi and British drug maker GSK, which are developing COVID-19 vaccine together, said that their recombinant protein vaccine showed poor response in older adults likely due to an insufficient concentration of antigen.
Viswanath Pilla is a business journalist with 14 years of reporting experience. Based in Mumbai, Pilla covers pharma, healthcare and infrastructure sectors for Moneycontrol.
TAGS: #Business #Companies #coronavirus #COVID-19 vaccine tracker #Health #Merck #world
first published: Jan 25, 2021 06:57 pm