How Big a Setback Is Merck’s Vaccine Flop?

Sam Fazeli, a Bloomberg Opinion contributor who covers the pharmaceutical industry for Bloomberg Intelligence, answered questions about Merck & Co.’s decision to shut down its Covid-19 vaccine program following lackluster trial results. The conversation has been edited and condensed.

What happened with Merck’s vaccines? 

Merck made the pragmatic decision not to continue to invest in its two Covid-19 vaccine candidates after seeing low levels of immune response in early phase I trials. This is a surprise given that Merck, at the start of the pandemic, decided against going with new and untested types of vaccines such as those using messenger RNA and instead opted for a more standard approach about which it seemed very confident and had some experience. This involved using technology to alter strains of other viruses to deliver the genetic material for Sars-Cov-2, which would then trigger an immune response to the coronavirus and offer protection against Covid-19.  One of the vaccines used an altered form of the measles virus Merck obtained from its purchase last May of  biotechnology firm Themis Bioscience. The other vaccine used the same virus Merck employed in its approved Ebola vaccine. While those two efforts appear to have disappointed, we now know that at least two shots using the newer mRNA technology — from Pfizer Inc.-BioNTech SE and Moderna Inc. — have had much better success and are now at the forefront of the global vaccination effort. Other vaccines, such as the one developed by AstraZeneca Plc and the University of Oxford and the one in trials now by Johnson & Johnson, are based on a technology similar to Merck’s, but they use engineered versions of a different type of virus — the kind that causes the common cold — which seem to work better. Why exactly Merck’s went off track is unclear. We need more data to know the exact reason. 

How big a setback is it for the whole vaccine effort?

It does create a problem for the speed with which the world can get out from under the weight of the pandemic because it removes a company with the potential to manufacture high volumes of vaccine. GlaxoSmithKline Plc and Sanofi hit a similar snag late last year with the vaccine they are developing, which employs tried-and-tested technology that they have used for years. While Glaxo and Sanofi are continuing with their efforts, there is no guarantee that they will be able to fix their problem. The good news is, the Pfizer-BioNTech and Moderna shots do seem to work well, as does the vaccine developed by AstraZeneca and Oxford, though perhaps not as well as those other two.  On top of that, Johnson & Johnson and Novavax Inc. are about to report phase III data on their vaccines, which could bring them on line soon. There’s reason to believe their data will be robust, given the preclinical and early-phase data released to date, and approval of these two shots would add a combined 2 billion doses a year to the inoculation effort. So this isn’t the end of the world.

What are the implications for other vaccines?

What happened with Merck indicates that you can’t just assume that a vaccine technology that works for one infectious disease will automatically work for another. In a similar vein, you can’t assume the new mRNA vaccine technologies will work just as well for other types of disease. 

Given the possibility of vaccine shortages, is it worth pursuing even less-effective vaccines if it would add to the stockpile?
This is something to consider, especially given the variants and the risk of further mutations. For instance, the latest data from Moderna suggests that the immune response after the second dose of its vaccine is enough to inactivate the new B.1.351 virus variant found in South Africa, though the effect was diminished. This suggests that the J&J vaccine — which follows a one-shot protocol — may not work as well against this variant, dragging down its efficacy in the South African part of the trial (this is part of the data it will be releasing soon). And the Novavax trial in the U.K. will likely tell us how well it works against the B.1.1.7 variant that emerged there, which seems to have less ability to escape immunity than the South African variant. But all of this tells us that we need vaccines and dosing schedules that induce the strongest immune response possible, and we shouldn’t stop working on them and fine-tuning them. Whether Merck’s shots would have ever been helpful in the fight we don’t know, but having as many at our disposal as possible can only help. 

Merck said it is now focusing on Covid-19 treatments. Can you tell us more?
Yes, these are programs that it has been working on for quite a while. We have been waiting for progress on its anti-viral drug, which has the potential to work for other coronaviruses, too, and targets a part of the virus that may be less able to mutate. But until we see the data and the potential for development of resistant variants in the lab, it’s hard to tell just how promising it is.

What are other takeaways from Merck’s stumble and the vaccine effort to date?

Covid-19 has taught us a lesson about the power of innovation. The vaccines that are currently approved were either developed with the help of biotech companies such as BioNTech and Moderna or with academia such as the AstraZeneca-Oxford vaccine. This upends the long held notion that vaccines were a “big boys’ game” best left to stalwarts such as Merck and that new technologies such as mRNA vaccines were too risky. We should be thankful that venture capital and public market biotech investors were willing to invest in mRNA technology over the past decade, allowing us all to reap the rewards of their efforts.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Bloomberg Opinion provides commentary on business, economics, politics, technology and markets.

©2021 Bloomberg L.P.

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