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Could Ebola trial drug be answer to Covid-19?
India is participating in the trial. Gilead has also started two Phase 3 clinical trials on the safety and efficacy of the drug .
A new study has shown that the antiviral remdesivir, an experimental Ebola drug, may stop Sars-CoV-2, which causes Covid-19, from replicating, thereby rendering the virus harmless.
It is developed by US-based biotechnology company Gilead Sciences Inc., which has a patent on the drug in India. Remdesivir is among four treatments being assessed under the World Health Organization’s (WHO’s) solidarity trial to find an effective treatment for Covid 19. India is participating in the trial. Gilead has also started two Phase 3 clinical trials on the safety and efficacy of the drug . Phase 3 trials are required by the US Food and Drug Administration and other regulators to approve the drug.
According to a research paper in the Journal of Biological Chemistry on Monday, remdesivir can inhibit coronavirus polymrerases -- enzymes that bring about the formation of polymers, particularly DNA and RNA -- in cell culture.
The polymerase of Sars-CoV-2 is like the engine of the virus, said Matthias Götte, chair of medical microbiology and immunology at the faculty of medicine and dentistry at the University of Alberta, Canada, who conducted the study. Remdesivir tricks the virus by mimicking its building blocks. “These coronavirus polymerases are sloppy and they get fooled, so the inhibitor gets incorporated many times and the virus can no longer replicate,” Götte explained in a statement.
A 35-year-old man who returned to the US after a family visit to the Chinese city of Wuhan, the original epicentre of the virus, with a four-day cough and subjective fever, was found to have improved after receiving remdesivir, the New England Journal of Medicine wrote in an article on the first case of Covid 19 in the US.
The man developed pneumonia and recorded an oxygen saturation of 90%. Treatment with intravenous remdesivir started on the evening of day 7. On day 8, his condition is said to have improved and his oxygen saturation values improved to 94-96%.
In another paper published on April 10, the journal chronicled the case of 53 patients with severe symptoms of Covid-19 who were treated with remdesivir; clinical improvement was seen in 36 of them. However, only placebo-controlled trials can provide an accurate picture.
Remdesivir has been previously tested for treatment of Ebola. It has generated promising results in animal studies for Middle East Respiratory Syndrome (Mers-CoV) and severe acute respiratory syndrome (Sars), which are also caused by coronaviruses, suggesting it may have some effect in patients with COVID-19, according to WHO.
“Two Phase 3 studies are being run by Gilead in areas with a high prevalence of Covid-19 in the United States, Asia and Europe. One of these is for patients with severe disease and the other studies remdesivir in patients with more moderate symptoms. One of the many questions that these studies aim to answer is whether treatment duration can be shortened from 10 days to 5 days,” Gilead’s chairman and CEO Daniel O’Day said in a statement on the company’s website.
But Gilead’s patent on the drug could mean it may take long to reach patients on a large scale. “Remdesivir was used in Ebola. And in a Covid-19 observational study it was found to benefit 2 in 3 patients in terms of critical patients going off ventilator and not needing oxygen support. It’s Gilead’s product. It’s not available in India yet but since we are a participant in WHO’s solidarity trial, which is a five-arm global trial, and remdesivir is one of the arms, it is being tried on our patents as well as part of the study,” said Dr Raman R Gangakhedkar, chief of the epidemiology and communicable disease division at the Indian Council of Medical Research (ICMR).
“The Indian government has policy options. The government should ask US government or Gilead for some dosages of remdesivir and it should be immediately administered to say 500 patients to see if it’s truly effective. At the same time the government should put in place financial and technological measures to manufacture the drug generically. Thirdly the government can issue an order under section 100 of the Patents Act to use the drug for emergency requirement by the government,” said KM Gopakumar, an intellectual property rights expert. In this case, the section would allow the federal government to authorise generics makers here to use the patent “for the purpose of government”.
