How effective have anti-virals for coronavirus been 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 has since dropped it from the treatment options, but doctors say it has its benefit when given correctly. India also saw 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 the UK. In India, only Molnupiravir has been approved.

Why is Molnupiravir in the news today?

Globally, a section of researchers has 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 authorised for use in patients younger than 18 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, Aurobindo, and Torrent. And, in a first, advanced clinical trials were done locally as a consortium under Dr Reddy’s.

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

Some doctors in India are raising safety concerns and seeking more data from the clinical trials done locally. Merck had revised an earlier statement and said that 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 approval to make and market it in India. The drug is being rolled out in India, at different prices.

With a dosage of eight pills 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 wrong use of anti-virals?

Going by the experience of the second wave, there was “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.

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

MSD said in its statement last week that it was confident of the clinical profile of Molnupiravir, which had demonstrated a significant reduction in the risk of hospitalisation or death in the 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 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 have high risk of progression of the disease including hospitalisation or death,” subject to certain conditions.