Merck exits COVID-19 vaccine development, cites disappointing data

By Jane Byrne contact

- Last updated on GMT

© GettyImages/Christian Guiton
© GettyImages/Christian Guiton

Related tags: Merck, COVID-19, Vaccine

Merck is shutting down the programs linked to its two COVID-19 vaccine candidates following early trial data indicating that they failed to generate immune responses comparable to a natural infection or existing vaccines.

One of its candidates against COVID-19 was called V590; it built on Merck’s Ebola inoculation platform, while the other one, V591, was based on a measles vaccine used in Europe.

Merck, known as MSD outside of the US and Canada, will record a pretax charge in Q4, 2021 as a result of halting the programs related to V591, which it acquired with the purchase of Austrian vaccine maker, Themis Bioscience, and V590, developed with nonprofit research organization, IAVI.

The early-stage trial results will be submitted to a peer-reviewed medical journal.

Merck’s decision to discontinue the development of its COVID-19 vaccines comes at a time when many countries are struggling to have an adequate supply of vaccines to ensure robust inoculation campaigns given the recent manufacturing delays announced by both Pfizer-BioNTech and AstraZeneca; the slowdown in vaccination programs is also coupled with increased global anxiety over the emergence of new variants of the coronavirus.

The Coalition for Epidemic Preparedness Innovations (CEPI), in a statement released today, said it supports the decision by Merck to discontinue the development of the V591 vaccine candidate.

"This is a disappointing outcome, but it demonstrates the importance of robust and thorough clinical trials in delivering safe and effective vaccines."

Historically most vaccines in development do not progress through to licensure, said CEPI, with it adding that is why it has invested in a broad portfolio of 11 COVID-19 vaccine candidates to maximize its chances of success. "Through this portfolio approach we aim to develop at least three safe and effective vaccines which can be distributed and deployed to the world through COVAX."

CEPI, Gavi and the WHO have launched COVAX to ensure equitable access to COVID-19 vaccines and end the acute phase of the pandemic by the end of 2021.

Latecomer to the COVID-19 vaccine game 

Merck announced its entrance into the race to develop a vaccine against COVID-19 relatively late compared to competitors, revealing its ambitions​ in this regard in May 2020, with it publicizing its acquisition of Themis Bioscience, as well as its partnership with IAVI, in terms of vaccine development, and an alliance with Ridgeback Biotherapeutics to progress its oral antiviral candidate for the virus.

In an interview​ with Harvard Business School in July last year, Kenneth Frazier, Merck’s CEO, talked about how extraordinarily difficult vaccine development was, that it typically requires many years of investigation. 

COVID-19 treatments

In its announcement today, Merck said it will focus pandemic research on treatments; it continues to advance clinical programs and to scale-up manufacturing for two investigational medicines, MK-7110 and MK-4482.

MK-7110 (formerly CD24Fc) is a potentially first-in-class investigational recombinant fusion protein that modulates the inflammatory response to SARS-CoV-2, principally by targeting a novel immune pathway checkpoint. The company said interim results from a Phase 3 study showed a greater than 50% reduction in the risk of death or respiratory failure in patients hospitalized with moderate to severe COVID-19.  In December, Merck announced a supply agreement with the US government to advance the manufacturing and initial distribution of MK-7110.

MK-4482 or Molnupiravir is an oral novel investigational antiviral agent being developed in collaboration with Ridgeback Bio. Molnupiravir is currently being evaluated in Phase 2/3 clinical trials in both the hospital and out-patient settings. The primary completion date for the Phase 2/3 studies is May 2021. Merck said it anticipates initial efficacy data in the first quarter of 2021, which it plans to share publicly, if clinically meaningful. 

Related topics: Bio Developments

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