BL Explainer. Antivirals and their risks: Know your molnupiravir

How effective have been anti-virals for coronavirus so far?

Anti-virals are medicines that are effective when used with precision, at the right point in an infection, in the dosage required and for a set number of days.

The first re-purposed antiviral widely prescribed in India and overseas in treating Covid-19 was Remdesivir, an injectable. The World Health Organization (WHO) has since dropped it from the treatment options, but doctors say it has its benefit when given correctly. India also saw a wide use of Favipiravir, but some doctors did not prescribe the drug, seeking more data.

In November 2021, there was much optimism over Ridgeback Biotherapeutics and Merck‘s antiviral Molnupiravir and Pfizer’s Paxlovid - touted to be “game changers” in Covid-19 treatment. Both have been approved in the US and UK. In India, only Molnupiravir has been approved at present.

Why is Molnupiravir in the news today?

Globally, a section of researchers have raised safety concerns on the use of the anti-viral, especially in pregnant women, those planning a pregnancy and in young people. Molnupiravir is not authorized for use in patients younger than 18 years of age because it may affect bone and cartilage growth, the US regulator has said.

Molnupiravir is a medication that works by introducing errors into the SARS-CoV-2 virus’ genetic code, which prevents the virus from further replicating, the US Food and Drug Administration explains. Researchers are concerned, if it could do the same to the host.

Were clinical trials done in India?

In India, Merck Sharpe Dohme (MSD) (or Merck in the US and Canada) has voluntary licensing agreements with multiple companies on Molnupiravir, including Dr Reddy’s Laboratories, Cipla, Sun Pharma, Hetero, Emcure, Aurobind, Torrent. And in a first of sorts, advanced clinical trials were done locally as a consortium under Dr Reddy’s.

Why are a section of doctors worried about prescribing this pill?

Some doctors in India are raising safety concerns and seeking more data from clinical trials done locally. Merck had revised an earlier statement and said, the pill was 30 per cent effective in preventing hospitalisation and death, down from 50 per cent mentioned earlier.

Doctors also worry over possible “rampant” prescription of the drug, given that over a dozen companies have received regulatory approvals to make and market the drug in India. The drug is being rolled-out in India, at different prices.

With a dosage of eight pills in a day, for five days, doctors also worry that patients may not complete their treatment course – which could lead to resistance developing against the drug.

Have there been instances of over of wrong use of anti-virals?

Going by the experience of the second wave, there was an “overuse” of medicines including anti-virals, according to doctors. And they are wary, the fear of the Omicron variant of the coronavirus could trigger similar panic buying, black-marketing and use.

It is not rare to hear doctors say, they are under pressure to prescribe a certain drug, as patients demand it. Doctors urge the Government to restrict the drug’s sale and use, through water-tight distribution and prescription-led sale.

What do makers of these medicines have to say on it?

MSD said in its statement last week, they were confident of the clinical profile of Molnupiravir, which demonstrated a significant reduction in the risk of hospitalization or death in their Phase 3 clinical trial “with no observed safety concerns when compared to the placebo group (that is not given the drug)”.

What did the regulators say while approving it in India?

The Union Health Ministry said when announcing its approval, that Molnupiravir had been recommended by the Subject Expert Committee considering the emergency and unmet medical need. The recommendation was to grant restricted use under emergency situations to treat “adult patients with Covid-19, with SpO2 >93% and who have high risk of progression of the disease including hospitalization or death,” subject to certain conditions.

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