Investors are struggling to decipher the significance of clashing scientific studies about the prospects of Gilead Sciences’ potential coronavirus drug, which has been touted as one of the most promising Covid-19 treatments.
The company said on Wednesday that a US study run by leading coronavirus task force doctor Anthony Fauci’s team at the National Institutes of Health showed positive results for the drug remdesivir, buoying Gilead’s stock and the entire S&P 500.
But hours later, a paper in a prestigious medical journal confirmed that the drug had failed to help patients in its first randomised clinical trial. Results from a trial in Wuhan, China — first reported by the Financial Times last week, now peer-reviewed and published in The Lancet — showed treatment with remdesivir did not speed recovery or reduce deaths from Covid-19.
“Unfortunately, our trial found that while safe and adequately tolerated, remdesivir did not provide significant benefits over placebo,” said Bin Cao, a professor from the China-Japan Friendship Hospital and Capital Medical University in China, who led the research.
Hopes that remdesivir could be a prospective treatment for the virus continued to move markets, despite contradictory and inconclusive evidence about whether it works. Shares in Gilead were up 4.4 per cent to $82.15.
The stock initially jumped as much as 8 per cent when Gilead said it was aware of “positive data” from the study run by the US National Institute of Allergy and Infectious Diseases. The NIAID did not respond to a request for comment.
“We understand that the trial has met its primary endpoint and that NIAID will provide detailed information at an upcoming briefing,” Gilead said.
Analysts at RBC Capital Markets said the details on the NIAID study were “scant”. However, if this is an interim analysis, performed during a trial, the fact they are releasing them may mean the benefits are “somewhat definitive”, RBC added.
Gilead also released results from its own study on Wednesday, which appeared to show patients did just as well after a five-day course of the drug as after 10 days. However, the study had some key flaws: it did not have a control arm comparing patients on remdesivir to patients who were not taking it and it was not peer-reviewed. Gilead said it intended to submit it for peer review by other scientists.
Merdad Parsey, chief medical officer at Gilead, said the study “complements” the placebo-controlled study by NIAID. If patients do not require a ten-day course of the drug, “it could significantly expand the number of patients who could be treated with our current supply of remdesivir”, he said.
Andrew Hill, senior visiting research fellow at the University of Liverpool’s Institute of Translational Medicine, said the newly announced Gilead study was “very hard to interpret”. He added: “It either shows that both doses work, or neither.”
Gilead originally developed remdesivir as a drug for Ebola, but it was never approved. Many hoped the antiviral could work in a similar way against Covid-19 — and so there are trials all over the world to test it against the virus.
However, last week, the World Health Organization accidentally published results from the first randomised control trial on the drug. The Chinese trial showed remdesivir did not improve patients’ condition or reduce the presence of the pathogen in the bloodstream. The full results from this trial are expected soon.
The Chinese trial of 237 patients did not finish enrolling, as the number of Covid-19 patients in China fell. Gilead said last week that the summary of the trial that was published in error included “inappropriate characterisations” and noted that some data suggested there might be a “potential benefit for remdesivir, particularly among patients treated early in the disease”.
On Wednesday, the company said in its own study patients who received the drug within 10 days of first developing symptoms did better than those that received it later. By day 14, about 62 per cent of patients treated early were discharged from hospital, compared with 49 per cent of those treated late.
Aruna Subramanian, one of the lead investigators and a professor at Stanford University, said: “While additional data are still needed, these results help to bring a clearer understanding of how treatment with remdesivir may be optimised, if proven safe and effective.”