The US has allowed the emergency use of the experimental antiviral drug remdesivir to treat Covid-19 based on early clinical data that shows it helps coronavirus disease (Covid-19) patients recover faster.

Remdesivir, manufactured by Gilead Sciences, is the world’s first drug approved based on clinical data to treat Covid-19, which has killed close to 240,000 people worldwide and infected over three million.

Emergency-use authorization allows products to be used for treatment without full data on their safety and efficacy, which has to be still submitted as trial continue.

“This was lighting speed in terms of getting something approved. From clinical trial to getting it authorized, it was 90 days,” said US Food and drug Administration (FDA) Commissioner Stephen Hahn, speaking at the White House with President Donald Trump at his side.

Remdesivir, when administered by an intravenous infusion, helped patients recover on an average in 11 days, compared to 15 days taken by those on placebo.

The emergency use of remdesivir is limited to hospitalised Covid-19 patients with low blood-oxygen levels or who need breathing support, the FDA said in its letter of authorisation.

“Based on the totality of scientific evidence available to FDA, it is reasonable to believe that remdesivir may be effective in treating COVID-19, and that, when used under the conditions described in this authorization, the known and potential benefits of remdesivir when used to treat Covid-19 outweigh the known and potential risks of such products; and there is no adequate, approved, and available alternative,” said the FDA in the letter.

A treatment will help tide the pandemic till an effective vaccine, now expected to be ready as early as six months, is available to protect against the disease and help reopen the economies and lower social-distancing restrictions, which have led to job losses, closed schools and wrecked global economy.

“Remdesivir covered by this authorization will be used only to treat adults and children with suspected or laboratory confirmed COVID-19 and severe disease defined as SpO2 ≤ 94% on room air, requiring supplemental oxygen, mechanical ventilation, or extracorporeal membrane oxygenation (ECMO),” said FDA.

Hospitalised patients in need of oxygen support account for about 14% of Covid-19 patients, according to early studies of the outbreak. Patients on a mechanical ventilator or ECMO should be given the drug for 10 days, while those who are less sick should get it for five days, the company said.

“Gilead Sciences now plans to expand trials to many countries, excluding India. Available data shows it is one of foremost potential drugs against disease, and since the supply is limited, according to Gilead, India must consider ways to make this drug available to its population. In the past, India saved millions by providing affordable and effective anti-retroviral drugs to treat HIV and AIDS, not just to its own population, but also to other countries who needed them, including to many countries in Africa,” said Dr Nirmal K Ganguly, emeritus scientist and former director general of Indian Council of Medical Research.

Two anti-malaria drugs, hydroxychloroquine and chloroquine, have been approved for use against Covid-19 in India and the US, but these have not undergone rigorous clinical trials.

Gilead is donating its entire supply of 1.5 million doses of remdesivir to the US government, which will help treat 140,000 patients based on a 10-day treatment cycle.

“Given the severity of illness of patients appropriate for remdesivir treatment and the limited availability of drug supply, hospitals with intensive care units and other hospitals that the government deems most in need will receive priority in the distribution of remdesivir,” Gilead said in a statement.

Gilead has scaled up manufacturing of remdesivir from zero production in January to make 500,000 treatment courses by October. It plans to double that number by December through production tie-ups with a consortium of pharmaceutical companies around the world.

“One trial compared five days regimen with 10 days regimen and noted equal clinical recovery time. There was no control group and effect on deaths was not studied. Another trial was randomised, had a control group of standard care, and observed a benefit in reduction of recovery time from severe illness. The impact on death was, however, not statistically significant and hence unproven. The need for larger controlled clinical trials, which can demonstrate clear impact on hard clinical endpoints including mortality reduction, remains as search for an effective life-saving cure remains. Other trials are underway, including the World Health Organisation’s multi-country SOLIDARITY trial,” said Dr K Srinath Reddy, president, Public Health Foundation of India.

What is Remdesivir?

•Remdesivir is a nucleoside ribonucleic acid (RNA) polymerase inhibitor.

•Remdesivir for injection, 100 mg, is a sterile, preservative-free lyophilized solid that is reconstituted with 19mL of sterile water for injection and diluted into 0.9% saline prior to intravenous (IV) administration.

•Following reconstitution, each single-dose, clear glass vial contains a 5 mg/mL remdesivir concentrated solution with sufficient volume to allow withdrawal of 20 ml.

•Remdesivir Injection, 5 mg/mL, is a sterile, preservative- free, clear, solution that is to diluted into 0.9% saline prior to intravenous (IV) administration.

•Remdesivir for injection, 100 mg, vials should be stored below 30 °C until time of use. Remdesivir injection, 5 mg/mL vials should be stored at refrigerated temperatures (2 °C to 8 °C) until time of use.

•Following dilution with 0.9% saline, the solution can be stored for up to 4 hours at room temperature (20 °C to 25 °C) or 24 hours at refrigerated temperatures (2 °C to 8 °C).

Source: US FDA