NEW DELHI; With a vaccine still a long distance away, efforts to repurpose old medications used for other ailments provide hope of an early counter to COVID-19, say scientists, placing the antiviral remdesivir on top of the list of possible contenders.
As COVID-19 continues its spread — crossing 5.2 million cases and 3,38,000 fatalities on Saturday — several categories of drugs are under clinical trial. Of them, remdesivir, which initially went into trials for treating the deadly Ebola virus five years ago, has shown promise by modestly speeding recovery from COVID-19, experts said.
More than 130 drugs are under experimentation to treat COVID-19, some may have the potential to stop the virus while others may help calm overactive immune responses that damage organs, according to a tracker maintained by the Milken Institute, an independent economic think tank in the US.
“Right now, there is only one effective approach – which is to repurpose already approved drugs for other diseases if they can be used for COVID-19. One example is remdesivir,” Ram Vishwakarma, director of the Indian Institute of Integrative Medicine, CSIR, Jammu, told PTI.
Remdesivir is helping people recover faster, and is lowering the death rate among critically ill patients, Vishwakarma said, adding that it can be life-saving. “We do not have time to develop new drugs. New drug development takes five-10 years so we are using existing drugs and conducting clinical trials to find if any of them are effective,” Vishwakarma said.
He explained that some molecules available for treating diseases like HIV or other viral infections can be quickly checked against the novel coronavirus. If found effective, they can be used against COVID-19 with the appropriate approval from drug control bodies.
When drug company Gilead Sciences sought to begin clinical trials for remdesivir to treat the novel coronavirus, it immediately got approval from the US FDA. According to Vishwakarma, the other drug showing promise is favipiravir, a broad-spectrum antiviral approved in Japan, which is also under clinical trials for its effectiveness against COVID-19. India is also playing its role.
The Indian Institute of Chemical Technology (IICT), Hyderabad, has developed the technology to make favipiravir, Council of Scientific and Industrial Research (CSIR) Director General Shekar Mande announced this month.
CSIR is conducting clinical trials for favipiravir, remdesivir and an anti-inflammatory drug called colchicine, which is commonly used to treat gout, said Vishwakarma. “A number of drug trials are happening in India, which we are doing with pharmaceutical companies,” Vishwakarma said.
Of the drugs under trial, remdesivir has shown the most promising results, agreed Subhabrata Sen, professor at the Department of Chemistry in Shiv Nadar University in Uttar Pradesh. Sen, whose lab is involved in the discovery of biologically active molecules, told PTI that some of the drugs being tested are antivirals, and some are anti-malarials and antibiotics.
Of the antivirals in the tracker list, some are new molecules under trial, whereas others are old drugs being repurposed and tested for their effectiveness against COVID-19. Remdesivir, according to a study published in the New England Journal of Medicine in April, mimics the genetic material of the coronavirus. When the virus copies its RNA or genetic material, the drug replaces some of the pathogen’s building blocks.
According to the authors of this study, the drug prevents new virus copies from being produced. Preliminary results had shown that patients who received remdesivir had a 31 per cent faster time to recovery than those who received placebo.
However, another study published in the journal Lancet in April cautioned that interpretation of these findings is limited since the remdesivir study was stopped early after the scientists were unable to recruit enough patients due to the steep decline in cases in China.