New York, April 12 : Treatment with Gilead Sciences's experimental drug remdesivir led to clinical improvement in 68 per cent of 53 patients hospitalised with severe complications of COVID-19, says a study. The drug was provided on an individual compassionate use basis. Nearly two thirds of patients in this cohort were on mechanical ventilation at baseline, including four patients also on extracorporeal membrane oxygenation (ECMO). Treatment with remdesivir resulted in an improvement in oxygen support class for 36 of patients over a median follow-up of 18 days from the first dose of remdesivir, according to the findings published in The New England Journal of Medicine. More than half of patients on mechanical ventilation were extubated and nearly half of all patients were discharged from the hospital following treatment with remdesivir. After 28 days of follow-up, the cumulative incidence of clinical improvement, defined as discharge from the hospital and/or at least a two-point improvement from baseline on a predefined six-point scale, was 84 per cent. "Currently there is no proven treatment for COVID-19. We cannot draw definitive conclusions from these data, but the observations from this group of hospitalized patients who received remdesivir are hopeful," said Jonathan D. Grein, Director of Hospital Epidemiology, Cedars-Sinai Medical Center, Los Angeles, and lead author of the journal article. "We look forward to the results of controlled clinical trials to potentially validate these findings," Grein said. According to the report, 7 patents died. Factors associated with an increased risk of mortality included age greater than 70 years and higher baseline serum creatinine levels, indicating reduced kidney function. Mild to moderate liver enzyme elevations were observed in this cohort. No new safety signals were detected during short-term remdesivir therapy, said the study. Gilead is conducting two Phase 3 clinical trials of remdesivir, the SIMPLE studies, in countries with high prevalence of COVID-19. Data from the SIMPLE study in patients with severe disease are expected this month, followed by data from the SIMPLE study in patients with moderate disease in May. In addition, the California-based biotechnology company is supporting multiple clinical trials led by other organisations, including two studies conducted in Hubei Province, China. Since January 25, 2020, the company has been providing emergency access to remdesivir for qualifying patients with severe complications of COVID-19 who are unable to enroll in ongoing clinical trials. More than 1,800 patients have been treated with remdesivir through individual compassionate use protocols. Remdesivir is not yet licensed or approved anywhere globally and has not been demonstrated to be safe or effective for the treatment of COVID-19. /IANS