A clutch of repurposed drugs used in treating Covid-19 appear to have fallen out of favour, after data emerging from the World Health Organization’s Solidarity Therapeutics Trial found it ineffective when it came to mortality.

Interim results from the trial “indicate that remdesivir, hydroxychloroquine, lopinavir/ritonavir and interferon regimens appeared to have little or no effect on 28-day mortality or the in-hospital course of Covid-19 among hospitalised patients,” the WHO revealed, of data that is pending peer-review and publication.

WHO Chief Scientist Soumya Swaminathan and Public Health Foundation of India-President Srinath Reddy are part of this study, along with others.

The findings from the world’s largest randomised control trial on Covid-19 therapeutics could have governments relooking at their treatment protocols, especially since antiviral drugs like remdesivir are part of it. In fact, remdesivir may still have a fighting chance and not be dropped, say experts.

Countering the WHO-coordinated trial’s findings, Gilead Sciences said, it was yet to be peer-reviewed and was “inconsistent with more robust evidence from multiple randomized, controlled studies published in peer-reviewed journals validating the clinical benefit of Veklury® (remdesivir).”

Explaining WHO’s interim findings, Srinath Reddy told BusinessLine , three of the four medicines reviewed had effectively been dropped. The trial looked at whether using these drugs saved lives and from that standpoint, “the hope laid out was not justified”, he said.

Remdesivir may still have a foot in the door. “It may be considered in a sub-trial to review its effectiveness in a sub-group”, he added. On trials being done by other institutions involving remdesivir, Reddy said, it involved a smaller patient group (1000) and they were looking at whether it reduced hospital stay.

The WHO study, which spans more than 30 countries and 11,266 adults, looked at the effects of these treatments on overall mortality, initiation of ventilation, and duration of hospital stay in hospitalized patients. Other uses of the drugs, for example in treatment of patients in the community or for prevention, would have to be examined using different trials, WHO said.

Newer antiviral drugs, immunomodulators and anti-SARS COV-2 monoclonal antibodies are now being considered for evaluation.

Story not over

Remdesivir is part of standard of care in many countries and in India, Gilead Sciences has alliances with multiple generic-drug makers to produce and sell the drug in certain markets.

Shashank Joshi with Maharashtra’s Covid taskforce said treatment protocols in the country were already restrictive on experimental drugs. The study findings will curb the indiscriminate use of remdesivir.

The WHO study looked at remdesivir through a “mortality window”, when in fact, the anti-viral is given in moderate to severe cases. It works best in the first 5-9 days when the virus is actively replicating, he said, adding that it was used to improve recovery.

“The story is not over for remdesivir and on interferon too, the last word is not out,” he said. The study has been “unfair” to HCQ, he added, given the “poisonous” dose that was considered, which is not what is given in India.

Gilead too expressed concern on limitations of the trial. “The trial design prioritised broad access, resulting in significant heterogeneity in trial adoption, implementation, controls and patient populations and consequently, it is unclear if any conclusive findings can be drawn from the study results,” the company said.

Remdesivir is not approved in the US, but has an Emergency Use Authorization for the treatment of hospitalised patients with Covid-19, including patients with moderate to severe disease, regardless of the need for supplemental oxygen.