Some analysts see promise, but remain cautious over early results for Gilead's remdesivir in COVID-19

Analysts are weighing in on early data from a small study showing Gilead Sciences' remdesivir improved clinical outcomes in 68% of hospitalised patients with COVID-19, saying that while the findings appear promising, they are still cautious about the experimental antiviral drug's efficacy against the novel coronavirus. J.P. Morgan analyst Cory Kasimov called the results a "promising first look," but said the data, released by Gilead late last week, "need to be kept in context. It's difficult, if not impossible, to make any firm conclusions from an uncontrolled data set with a small sample size."

In the study, remdesivir was provided on a compassionate-use basis to patients from nine countries who were hospitalised with confirmed SARS-CoV-2 infection. Participants had oxygen saturation of 94% or less while they were breathing ambient air or were receiving oxygen support. Investigators identified 61 patients who received at least one dose of remdesivir, noting that of the 53 patients whose data were analysed, 30 were on mechanical ventilation at baseline, while four were receiving extracorporeal membrane oxygenation.

Results, which were published in the NEJM, showed that during a median follow-up of 18 days, 68% of trial participants had an improvement in oxygen-support class, including 17 of 30 patients receiving mechanical ventilation who were extubated. The researchers said a total of 25 patients were discharged, while seven patients died. For related analysis, see ViewPoints: Any data is good data for remdesivir.

Evercore ISI analyst Umer Raffat said the results made him "cautiously optimistic," and even though he wished there was a comparator arm, "the discharge rate in patients not needing invasive oxygen support looks encouraging." RBC analyst Brian Abrahams was reluctant to draw any definitive conclusions from the study data, but suggested remdesivir "still has a shot at showing a benefit" in late-stage testing, "especially with the endpoints now made more sensitive, though still not an overwhelming likelihood of dramatic effects."

Cantor Fitzgerald's Alethia Young noted that "median duration of invasive mechanical ventilation was two days before starting treatment; we think that this is noteworthy since the longer patients stay on ventilator, the bigger the risk of death." However, she acknowledged that this population nevertheless "remains the most urgent since studies in China have shown that upwards of 80% of patients on ventilators unfortunately don't survive."

In regards to the mortality data, analyst Geoffrey Porges of SVB Leerink was positive after only 13% of the patients had died, as of the update given late last week, but he predicted others deaths in the group would likely follow. "By comparison, in most of the other large studies we have identified, the mortality for [intensive care unit]-admitted patients is 50% or higher, and the mortality in ventilated patients is 60% to 90%." Meanwhile, Raymond James analyst Steven Seedhouse indicated that the mortality data were not noteworthy, saying "our conclusion is, unfortunately, remdesivir may not be doing much."

According to ClinicalTrials.gov, there are at least 11 clinical trials under way, in the US and abroad, that are testing remdesivir in COVID-19 patients, including a randomised, placebo-controlled study with 440 participants that is being run by the US National Institute of Allergy and Infectious Diseases. Gilead is expected to share findings from two Phase III trials evaluating remdesivir in moderate and severe COVID-19 patients in May. Last week, the company raised the number of participants in those studies, from 600 to 1600 patients in the moderate trial, and from 400 to 2400 in the severe trial.

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