San Francisco, April 17 : After shares of pharmaceutical major Gilead Sciences surged following a media report that the company's antiviral drug remdesivir showed promise in treating COVID-19 patients in a "closely watched clinical trial", analysts at Robert W. Baird & Co. said that the results need to be critically looked into. According to a report in the health-oriented news website STAT, most of the patients recruited for the studies reported fast recoveries in fever and respiratory symptoms. Following the treatment almost all of them were discharged in less than a week, while only two died, according to the report. But in an investment research report, the Baird analysts pointed out that the results reported by STAT were based on "uncontrolled, anecdotal data, which often winds up not being confirmed in controlled studies". STAT did say that all the patients in the trials were given remdesivir, suggesting that there were no control populations. Moreover, the results of the studies were leaked. An infectious disease specialist at University of Chicago discussed the trial results with other University of Chicago faculty members. STAT obtained a copy of the recorded conversation. The Baird analysts said that these results need to be cautiously interpreted and added that the more definitive answer will come from the double-blind placebo controlled study by National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health, expected in late May. Remdesivir is an investigational broad-spectrum antiviral treatment. It was previously tested in humans with Ebola virus disease and has shown promise in animal models for treating Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS), which are caused by other coronaviruses. The safety and efficacy of remdesivir to treat COVID-19 are being evaluated in multiple ongoing Phase 2 and 3 clinical trials. Gilead earlier said that a study in China in patients with severe disease was terminated early due to low enrollment. But the study in China in patients with mild-to-moderate disease is ongoing, it added. Additional studies of remdesivir and other investigational treatments for Covid-19, based on a master protocol by the World Health Organization, have also begun to enroll patients in countries around the world. /IANS