Permission to end late-stage trials of their generic versions of Merck & Co’s promising experimental oral antiviral drug molnupiravir to treat moderate Covid-19 has been sought by two Indian pharmaceutical companies. It was just a week ago that Merck had announced success of its own trial for mild-to-moderate patients being treated with the medicine.

Development of molnupiravir as a treatment for hospitalised Covid-19 patients has been suspended earlier this year by Merck as the company cited the fact that many of the patients had progressed to a situation of the disease where there would be very little or no effect of an antiviral drug.

According to study documents, the Indian companies Aurobindo Pharma Ltd and MSN Laboratories had included hospitalised patients in their trial and while designing their moderate Covid-19 trials, though it is unclear whether the trials ultimately included people in hospitals.

Merck and the Indian companies had different definitions of “moderate” disease, said Merck spokeswoman Melissa Moody.

The FDA definition for moderate Covid-19, which the level of oxygen in a patient should not be lower than 93 per cent, was the basis of Merck’s trials. According to the FDA, severe Covid-19 occurs when a patient’s level of oxygen in the blood is at 93 per cent or lower.

According to the trial documents for the two companies, moderate Covid-19 is said to happen when patients have blood oxygen levels of between 90 per cent and 93 per cent.

According to trial documents and the website of the Indian drug regulator’s internal expert committee, Aurobindo and MSN are continuing to conduct molnupiravir studies in patients with mild Covid-19 who have not been hospitalised.

Last week, Merck and its partner Ridgeback Biotherapeutics announced that molnupiravir had nearly halved the risk of hospitalisation or death in at-risk non-hospitalized Covid-19 patients, and their findings were hailed by experts as potentially a major breakthrough in the fight against the illness.

On its website, the Indian drug regulator’s committee also stated that Aurobindo and MSN had presented their interim clinical trial data for moderate Covid-19 patients and requested that the trials be ended.

The Merck drug has not exhibited any “significant efficacy” against moderate Covid-19, according to a source with the Drug Controller General of India, though it is effective against mild cases.

In August, Aurobindo began a planned 100-patient trial of its generic version of the Merck pill against moderate Covid-19, as well as a trial with a goal of 1,200 patients testing the pill against mild disease, the company said.

There were no comments from MSN.

Merck has struck into voluntary licencing agreements for molnupiravir with at least eight Indian drugmakers, with the goal of turning India into a manufacturing hub for the drug to supply low- and middle-income countries. 

A joint trial for the antiviral drug only in mild Covid-19 patients in an outpatient setting is being carried out by five of the eight Indian companies – Dr Reddy’s Laboratories, Cipla, Sun Pharma, Torrent Pharmaceuticals and Emcure Pharmaceuticals.

Interim data from its own late-stage trial of generic molnupiravir in mild Covid-19 patients was announced in early July by the other licensed company, Hetero. The Indian company has also filed a request with the Indian regulator for emergency usage of the drug.

(Adapted from USNews.com)