9 things you need to know about Merck's new Covid-19 treatment pill

The pills are meant for people who are sick with Covid-19 but are not in the hospital. PHOTO: NYTIMES

NEW YORK (NYTIMES) - American pharmaceutical firm Merck has announced that its new pill to treat Covid-19 reduced the risk of hospitalisation and death by about 50 per cent.

Merck plans to seek emergency authorisation for the antiviral pills to be used in the United States. Here's what you need to know.

1. Who will get the pills?

The pills are meant for people who are sick with Covid-19 but are not in the hospital. Merck's phase three clinical trial enrolled only unvaccinated people who were considered high risk, such as older people or those with medical conditions such as diabetes or heart disease. Initially, the drug might be available only for those people, but experts expect it to eventually become more widely available.

The pills are designed to be taken as soon as possible once a person shows symptoms of having Covid-19 - a time when the virus is replicating rapidly and the immune system has not yet mounted a defence.

In Merck's trial, volunteers had to have shown symptoms within the past five days, and some researchers think the pills must be taken even earlier to be most effective.

2. How effective are they?

Merck said the drug cut the risk of hospitalisation or death in half. In the phase three trial, 7 per cent of volunteers in the group who received the drug were hospitalised, and none died. In the group that got a placebo, 14 per cent were hospitalised or died.

The 50 per cent efficacy is lower than monoclonal antibodies, the intravenous cocktail used to treat high-risk people with mild or moderate Covid-19. Studies have shown that those antibodies reduce hospitalisations and deaths by up to 85 per cent among those patients.

But experts said the new antiviral pills will most likely have a bigger overall impact on Covid-19 than the cumbersome antibodies, because the pills can reach more people.

3. When will the pills become available?

Merck said last Friday (Oct 1) that it plans to seek emergency authorisation from the US Food and Drug Administration (FDA) as soon as possible. Regulators could then authorise the drug before the end of this year, if all goes well.

Dr Anthony Fauci, US President Joe Biden's top medical adviser for the coronavirus, said at a White House briefing last Friday that he could not give a specific timeline for approval.

"The FDA will look at the data, and in their usual very efficient and effective way, will examine the data as quickly as they possibly can, and then it will be taken from there," he said.

4. How does the pill work?

Antiviral pills are designed to block the virus from replicating. Molnupiravir tricks the coronavirus into using the drug to try to replicate the virus' genetic material. Once that process is under way, the drug inserts errors into the genetic code.

"If you create enough errors or you create errors in parts of the virus that are absolutely critical, the virus can't replicate," said Dr Daria Hazuda, vice-president of infectious disease and vaccine research at Merck.

5. What does taking the pill involve?

The regimen is familiar to anyone who has taken Tamiflu for the seasonal flu or an antibiotic for a urinary tract infection. People will need to get a prescription, which they will fill at a pharmacy. Patients will take four capsules twice a day for five days - in other words, 40 pills over the course of the treatment.

6. Are there concerns about side effects?

Merck did not report any serious side effects among volunteers in its clinical trial. Any side effects, which typically involve mild complaints such as headaches, can be hard to distinguish from feeling ill from Covid-19, researchers said.

7. Will there be enough pills?

Merck expects to be able to make enough pills for 10 million people by the end of this year. The US government has already ordered 1.7 million courses of treatment.

That is nowhere near enough for everyone in the US who gets sick with Covid-19 to receive the pills.

Remote video URL

8. How much will the treatment cost?

The federal government is paying about US$700 (S$951) per course of treatment. That is about one-third of the cost of a monoclonal antibody treatment. The plan is to make the pills free for Americans, like the Covid-19 vaccines. Whether there are any out-of-pocket costs is likely to be determined after the pills are authorised for use by regulators.

9. Are there other antiviral pills on the way?

Pfizer is developing a similar pill, as are Atea Pharmaceuticals and Roche. Results from their clinical trials are expected within the next few months. They are unlikely to be available for use until next year.

Join ST's Telegram channel and get the latest breaking news delivered to you.