US giant Merck ends COVID-19 vaccine after poor response


Merck received interim results from its trials this month.

Merck & Co. is discontinuing development of its two experimental Covid-19 vaccines after early experimental data showed they could not generate immune responses comparable to a natural infection or existing vaccines.

The American drug giant, long-established successful vaccine maker, had adopted a different strategy than rivals Pfizer Inc., Moderna Inc., and Johnson & Johnson, taking a more traditional approach, focusing on gunshots that target weakened viruses based. One, called V590, borrowed technology from Merck’s Ebola vaccine, while the other, V591, is based on a measles vaccine used in Europe.

Both V590 and V591 had lagged behind in the race for vaccine development. Merck ended recruiting the first participants for early-stage safety studies in late 2020 as front-runners Pfizer and Moderna prepared to report late-stage data on the effectiveness of their shots. Merck received interim results from its trials this month.

The results were “disappointing and a little surprising,” said Nick Kartsonis, senior vice president of clinical research for infectious diseases and vaccines at Merck Research Laboratories. Both shots produced fewer neutralizing antibodies to stop the infection than other Covid-19 vaccines and produced poorer immune responses compared to people who were naturally infected with the coronavirus.

“We didn’t have what we needed to move forward,” said Kartsonis in an interview on Sunday. After evaluating the data, Merck management decided to discontinue the programs and dedicate resources to the company’s efforts to develop Covid-19 treatments.

Fear of vaccination

While Merck’s vaccines were not expected to be part of the initial US vaccination push, the development is due to mounting concerns about vaccine supplies and the slow pace of injections. The emergence of new variants of the coronavirus has also raised questions about whether the approved shots lose their effectiveness if the pathogen mutates.

Merck’s candidate failure will also keep it away from a market that could eventually be dominated by two of its historic rivals in the US. Pfizer was the first drug company to receive approval for a Covid vaccine in the US, followed closely by Moderna. In the coming weeks, Johnson & Johnson is expected to release data on the effectiveness of its vaccine and apply for emergency approval.

None of Merck’s candidates ultimately made it into the six primary vaccines in the US government’s Operation Warp Speed ​​portfolio, despite leadership watching them closely. The drug maker and its partner, the International AIDS Vaccine Initiative (IAVI), have received research funding from the government. Both candidates would have been single dose exposures.

Merck of Kenilworth, New Jersey, will collect a pre-tax fee for the fourth quarter of 2020 for costs related to the termination of the programs. The amount of the fee was not disclosed on Monday. The early-stage study results will be submitted to a peer-reviewed medical journal.

Two coronavirus vaccines have been approved for use in the United States, but a continued surge in infections has highlighted the need for further treatment options. According to Kartsonis, Merck will focus resources on two drugs that are in late development to combat the disease.


“In the world of pharmaceutical development, a quick kill isn’t a bad thing because it allows you to reposition and reuse your assets,” he said.

Several of Merck’s vaccine manufacturing operations are being converted to manufacture one of its Covid-19 drug candidates, MK-7110, which is complex and difficult to manufacture on a large scale. In an interim study, intravenous therapy significantly improved the likelihood and speed of recovery in severe and critical Covid-19 patients in need of oxygen, and reduced the risk of respiratory failure and death by more than 50%. The full study results are expected in the first quarter.

Merck executives believe US regulators will issue emergency approval for the drug following these results, and Kartsonis said it could reach sick patients by the middle of the year. The US has already agreed to pay $ 365 million for 60,000 to 100,000 cans.

Antiviral pill

Merck is also working on a pill for Covid-19 patients in earlier stages of the disease. The antiviral therapy known as molnupiravir was discovered by scientists at Emory University and is being studied in late-stage studies in both hospital and outpatient settings. Merck and partner Ridgeback Biotherapeutics LP expect to have initial data on the drug’s effectiveness in the first quarter and to complete the studies in May, the company said in a statement.

Michael Nally, chief marketing officer, said in December that if it proves successful, Merck will expect regulatory approval shortly after the company reports data.

The antiviral should be taken twice a day for a total of ten capsules for five days. Merck expects it will be able to manufacture more than 20 million treatment cycles, or 200 million capsules, by 2021, Nally said.

The vaccine’s slow roll-out shows that the need for therapeutics will persist, Kartsonis said, and the drugs could work against future viruses.

(Except for the headline, this story was not edited by GossipMantri staff and published from a syndicated feed.)


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