Coronavirus | Why Gilead's Remdesivir trial data is significant in fight against COVID-19

US drug major Gilead Sciences on April 29 announced encouraging preliminary clinical trial data of its experimental antiviral drug Remdesivir that's been considered as a potential medication against novel coronavirus, or COVID-19, pandemic.

The study showed that 64.5 percent of the patients who received the shorter five days treatment have recovered, compared with 53.8 percent of the group who were treated for 10 days.

Also check out:  All you need to know about Gilead's experimental antiviral drug Remdesivir

The Remdesivir study is closely watched by medical experts and governments across the world as the pandemic had claimed the lives of around 2.2 lakh people. As of now, there are no approved medicines for COVID-19.

The latest announcement by Gilead comes just days after WHO accidentally posted results of a clinical trial conducted on COVID-19 patients in China that failed to show benefit when compared to the patients who got placebo or dummy pill.  Gilead called the leaked Covid-19 trial data of remdesivir as 'inconclusive'.

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What does the data tell us?
In the open-label, Phase III clinical trial, hospitalised patients with severe COVID-19 disease achieved similar improvement in clinical outcome, whether they are receiving Remdesivir for five or 10 days. The researchers said more than half of the patients in both treatment groups were discharged from the hospital within 14 days.

About 64.5 percent of the patients who received the shorter five day treatment have recovered, compared with 53.8 percent of the group who were treated for 10 days.

Outside of Italy, the overall mortality rate on Day 14 was 7 percent across both treatment groups, with 64 percent patients experiencing clinical improvement and 61 percent patients discharged from the hospital.

The initial phase of the study involved 397 patients randomised in a 1:1 ratio to receive Remdesivir 200 mg on the first day, followed by Remdesivir 100 mg each day until day five or 10, administered intravenously, in addition to standard of care. Gilead said no new safety signals were identified with Remdesivir across either treatment group.

Gilead said it plans to submit the full data for publication in a peer-reviewed journal in coming weeks.

What are the shortcomings of the trail?
Gilead trial is not a double-blind placebo controlled study, which is a gold standard for clinical trial. In controlled study -- one group of participants is given the experiment drug while those in the 'control' group get a placebo or dummy pill. The trial is useful for comparison purpose to get better understanding on the drug's effectiveness without unconscious biases affecting the conclusion. Neither the patient nor the physician knows who received the drug.

But the trial needs to be taken in the context of extraordinary circumstances.

“Unlike traditional drug development, we are attempting to evaluate an investigational agent alongside an evolving global pandemic. Multiple concurrent studies are helping inform whether Remdesivir is a safe and effective treatment for COVID-19 and how to best utilise the drug,” said Merdad Parsey, Chief Medical Officer, Gilead Sciences.

The most awaited study led by US government's National Institute of Allergy and Infectious Diseases (NIAID) that compared Remdesivir to a placebo in 800 patients will be announced later on April 29.

Will there be larger trial from Gilead?
Gilead said it also conducting an expansion phase of the study and will enrol an additional 5,600 patients, including patients on mechanical ventilation. The study is being conducted at 180 trial sites around the world, including sites in the United States, China, France, Germany, Hong Kong, Italy, Japan, Korea, the Netherlands, Singapore, Spain, Sweden, Switzerland, Taiwan and the United Kingdom.

Remdesivir journeyRemdesivir is a broad spectrum antiviral that's found to kill Ebola, Marburg, MERS and SARS viruses both in vitro and in animal models. It works by disabling virus RNA (ribonucleic acid) replication. RNA is the genetic material used by novel coronavirus to replicate itself.

The drug was tested against on Ebola but failed in late stage human trials in 2018-19. The COVID-19 pandemic has given a new lease of life for the drug that's facing oblivion. Multiple trials are ongoing currently to test the drug for COVID-19. Remdesivir is not yet licensed or approved anywhere globally.