Merck’s COVID-19 Drug Fails to Show ‘Statistically Significant Reduction’ in Infection Risk

Molnupiravir, a COVID-19 treatment pill, is seen in this handout photo released by Merck & Co. Inc., on May 17, 2021. (Merck & Co. Inc./Handout via Reuters)

The phase 3 clinical trial of Merck’s COVID-19 antiviral molnupiravir, branded as Lagevrio, has ended up in failure, as participants who took the medication did not exhibit any significant reduction in the risk of contracting the illness.

The trial was conducted among 1,500 participants who randomly received Lagevrio or a placebo orally every 12 hours for five days. It evaluated people who did not have symptoms of COVID-19, but lived in a household where another individual was recently confirmed with the infection.

“In the primary endpoint of participants who did not have evidence of SARS-CoV-2 infection at baseline (confirmed by a negative SARS-CoV-2 test), the Lagevrio-treated group was observed to be 23.6 percent less likely than those who received placebo to develop COVID-19 through Day 14 (a positive post-baseline SARS-CoV-2 test with evidence of signs and symptoms),” the company said, according to a press release on Feb. 21.

With molnupiravir users only 23.6 percent less likely to get infected with COVID-19 than the placebo group, the test failed to “demonstrate a statistically significant reduction in the risk of COVID-19 following household exposure to another individual with COVID-19.”

Lagevrio is currently approved or authorized for use in the United States, Japan, United Kingdom, China, and Australia for treating certain adults who have contracted COVID-19.

Using Lagevrio for Other Illness

Though Merck’s Lagevrio failed to prove the drug as an effective preventive option for COVID-19, the company still sees the medication as a viable treatment for other infections.

“We remain focused on our ongoing efforts to bring Lagevrio as treatment to appropriate high-risk patients with COVID-19 where its use is authorized or approved, as well as to further study the ways it may benefit patients with other infectious diseases, such as RSV,” said Dr. Dean Y. Li, president, Merck Research Laboratories, according to the release.

RSV refers to respiratory syncytial virus that usually triggers mild, cold-like symptoms in people. Though most individuals recover in a week or two, RSV can be serious for infants and older adults.

Among U.S. children below the age of one year, RSV is the most common cause of pneumonia and bronchitis. In November, Merck began a small study to evaluate the use of Lagevrio as a treatment option for RSV.

Merck has not released data from the phase 3 COVID-19 clinical trial. However, the company intends to release full results at a later time in a publication or a scientific meeting.

In April last year, Pfizer’s COVID-19 antiviral Paxlovid also failed to show any “statistically significant” result in preventing household spread of the infection.

Hospitalizations and Deaths

A study published in The Lancet in December had found that molnupiravir had little impact in preventing hospitalizations or deaths from COVID-19.

The study found that out of the 12,529 participants who were given molnupiravir, 105 were recorded to have died or been hospitalized due to the infection. In contrast, among the 12,525 participants who were given usual care, hospitalizations and deaths came in at 98.

However, the researchers did find that participants who received molnupiravir recovered faster than those who received usual care, saw reduced viral load, had a higher rate of early sustained recovery, and sought fewer general practitioner consultations.

The median recovery time among participants who took molnupiravir was found to be nine days. Among those who received usual care, recovery took 15 days.

Last year, Lagevrio generated around $5.7 billion in sales for Merck. However, the company expects revenues from the pill to fall to $1 billion in 2023.