From glut to shortage: Story of remdesivir, the drug of hope in Covid-19 surge

Remdesivir is in short supply as India battles a second wave of Covid-19, and the government has banned its export.

A crowd at Chemists Association of Pune District for the remdesivir injection. (Express Photo: Pavan Khengre)

5 min readMumbaiApr 15, 2021 09:15 AM IST First published on: Apr 13, 2021 at 06:46 PM IST

The antiviral remdesivir, which was widely discussed during the first wave of the novel coronavirus pandemic in India in the summer and monsoon of last year, is being talked about again. The drug is in short supply as the country battles a second wave of infections, and the government has banned its export.

There is a controversy in Gujarat over the BJP distributing remdesivir for free at its party office, and the Gujarat High Court has asked some tough questions of the state about the shortage of the drug.

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What is remdesivir?

It was manufactured in 2014 by the US-based biotechnology firm Gilead Sciences for the treatment of Ebola, a viral haemorrhagic fever caused in humans and primates by ebolaviruses. The drug was subsequently used to treat patients of Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS), both of which are caused by coronaviruses.

While the drug did not get much success against either of these two diseases, it was reported to have worked to some extent against the SARS-CoV-2, the coronavirus that causes Covid-19. A range of studies have not been able to establish this, however, and the World Health Organisation’s multi-country Solidarity Therapeutic Trials concluded that remdesivir (as also three other therapeutic regimens) “appeared to have little or no effect on hospitalized COVID-19, as indicated by overall mortality, initiation of ventilation and duration of hospital stay”.

How is remdesivir supposed to work?

Remdesivir is designed to obstruct the stage of replication, when the coronavirus creates copies of itself, followed endlessly by the copies creating copies of themselves.

Once the virus enters the human cell, it releases its genetic material, which is then copied using the body’s existing mechanism. At every stage of infection, various human proteins, virus proteins, and their interactions come into play. At the replication stage, the key viral protein at play is an enzyme called RdRp. This enzyme is the “engine” of the virus.

Remdesivir acts by attacking RdRp — this engine. In order to replicate, the engine processes raw material from the virus RNA, broken down by another enzyme with that specific function. When a patient is given remdesivir — the inhibitor — it mimics some of this material, and gets incorporated in the replication site. With remdesivir replacing the material it needs, the virus fails to replicate further.

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How has the drug been used in India?

The Drug Controller General of India approved emergency use of remdesivir on June 1, 2020, and the government subsequently released guidelines for doctors to use the antiviral for treatment of Covid-19 patients. It has thereafter been used widely in the country — there has, in fact, been concern that it has been prescribed even to those who were unlikely to benefit from it.

An ampule of antiviral remdesivir. (AP Photo)

Cipla, Mylan, Dr Reddy’s Laboratories, Hetero Healthcare, Jubilant Generics and Zydus Cadila were among the companies that received permission to produce and supply the drug in India. These companies tied up with Gilead Life Sciences to be able to make generic versions of remdesivir for the Indian and other markets under a voluntary licence. Some of these companies further employed contract manufacturers to make the drug for them to supply to Indian patients.

Most of the companies began supplying remdesivir in the second half of 2020. As of September 8, 2020, the companies had collectively made around 2.44 million vials of the drug, according to the Ministry of Chemicals and Fertilizers. The capacity of all remdesivir producers combined has since gone up to a total of 3.16 million vials a month, Minister of State for Chemicals and Fertilizers Mansukh Mandaviya has been quoted as saying by PTI.

So what is the problem now?

The sudden decline in the Covid caseload after September 2020 started reducing the demand for remdesivir. Last December, several suppliers and manufacturers were left with huge stockpiles. They had anticipated sales and scaled up production, but the fall in Covid cases hit their plans. Some manufacturers were forced to destroy expired stocks of the drug.

As a result, most manufacturers scaled down production in January, and for the first three months this year, remdesivir production was negligible or nil. Hetero Healthcare, India’s largest manufacturer of remdesivir, scaled down production to 5%-10%. Kamla Lifesciences, which supplies remdesivir to Cipla, stopped manufacturing from January 31 to March 1.

That slowdown has affected supplies now. Cases began rising from February, but manufacturing resumed to an extent only in March. The cycle from production to transportation of remdesivir can take 20-25 days. Production scaled up last month; it will take another week for fresh stocks to hit markets.

The Department of Pharmaceuticals has asked all manufacturers to scale up to their maximum capacity of 38.80 lakh vials per month. Hetero can produce 10.50 lakh, Cipla 6.20 lakh, Zydus Cadila 5 lakh and Mylan 4 lakh vials per month.

(With Prabha Raghavan and Kabir Firaque)