Merck, Partner Halt Covid-19 Treatment Trial for Hospitalized Patients

By Jared S. Hopkins and Betsy McKay 

Merck & Co. and its partner Ridgeback Biotherapeutics LP said they are stopping a trial of their experimental Covid-19 drug after it failed to help hospitalized patients, delivering another setback to doctors seeking treatments to use for the disease.

The companies said they would move forward with a separate study that is testing the oral antiviral drug in treating patients early in the course of the disease and who are at high risk of Covid-19 complications.

Early study results on hospitalized patients found that the treatment is unlikely to reduce hospitalization stays and deaths, the companies said Thursday.

Merck said testing found that the drug, called molnupiravir, inhibits replication of the virus. But the trial of people who weren't hospitalized was too small to show that the drug reduced clinical symptoms during their early treatment, Merck said.

If the drug is proven effective in outpatients after the next, larger round of testing, Merck could file for an emergency-use authorization in the second half of this year, the company said.

"Early treatment is really important," said Roy Baynes, Merck's chief medical officer and head of global clinical development. "This could have a big impact if indeed it could reduce the burden of serious illness."

Researchers didn't observe any serious side effects related to the drug, Merck said.

Merck and Ridgeback announced the findings after reviewing early data from a pair of studies testing the drug in hospitalized and nonhospitalized patients. Results haven't yet been published in a peer-reviewed scientific journal.

Merck is still looking to play a direct role in responding to the pandemic after several setbacks. Its two experimental vaccines failed in testing, and it is helping to manufacture Johnson & Johnson's vaccine.

If approved by regulators, molnupiravir, which comes in a pill form, would immediately boost the limited toolbox of treatments for the disease. Molnupiravir would fill a key role by conveniently helping people who are sick but not yet hospitalized, potentially becoming a kind of Tamiflu for the disease.

More than a year into the pandemic, there are still no easy-to-dispense treatments that can be given to newly diagnosed patients to prevent them from becoming gravely ill. While vaccines are rolling out around the world, they remain inaccessible to many people or are refused by others who could become sick.

Remdesivir, from Gilead Sciences Inc., is the only antiviral authorized by the Food and Drug Administration and has shown to provide only a modest benefit for hospitalized patients.

The FDA has also cleared for use three monoclonal-antibody drugs made by Eli Lilly & Co. and Regeneron Pharmaceuticals Inc. for people with mild to moderate Covid-19. Yet their use has been limited, partly because they are given by intravenous infusion, which can be laborious for hospitals to administer.

In the halted Merck study of about 300 hospitalized subjects, researchers gave patients one of three doses of molnupiravir, or a placebo, twice a day for five days and monitored them for about a month. Molnupiravir reduced replication of the virus in the patients, but the results still suggested the drug is unlikely to help them, Merck said.

"The hospitalized patient population typically has been symptomatic for a lot longer so they're further along in their illness so it appears that may mitigate against favorable outcomes," Dr. Baynes said.

Researchers evaluated the same doses in a study of similar-size groups of people who were sick but not yet hospitalized. They found the percentage who were hospitalized or died was lower in the more than 200 subjects who received molnupiravir compared with the 74 people given a placebo, according to Merck.

Merck will test the dose found to have the most potential in a larger study of 1,850 subjects.

Kenilworth, N.J.-based Merck and Miami-based Ridgeback said they would also begin another new trial this year studying whether molnupiravir could prevent infection after people are exposed to the virus.

The new Merck results build upon earlier findings released in March that found that the drug significantly reduced infectious virus in subjects after five days of treatment.

Merck also said Thursday that it would halt development of an experimental Covid-19 drug it acquired through a $425 million acquisition of the firm OncoImmune. The drug showed promise in an early look from a late-stage study, but regulators requested more clinical data.

Even if proven successful and cleared by regulators, the drug wouldn't be available until next year because of additional testing and manufacturing by Merck, Dr. Baynes said.

Write to Jared S. Hopkins at [e-mail] and Betsy McKay at [e-mail]

(END) Dow Jones Newswires

April 15, 2021 07:00 ET (11:00 GMT)

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