Gilead shares slip as a 2nd remdesivir COVID-19 trial halted in China

After having to halt enrollment in its severe COVID-19 trial due to a lack of patients, a second test of Gilead’s old Ebola drug remdesivir has befallen the same fate, this time in patients with a milder form of the disease.

In an update via posted today, the Gilead trial, being undertaken in China, is now registered as “Suspended (The epidemic of COVID-19 has been controlled well at present, no eligible patients can be recruited.”

Shares in the Big Biotech were down around 3% Wednesday morning on the news.

Even though Gilead has repeatedly stated this drug will not be the cornerstone of its pipeline future, many are betting it will be a consequential therapy for the company, especially if it managed to help patients suffering from the disease, given how widespread and desperate the need for any viable drug currently is.

Analyst Brian Abrahams from RBC said in a note to clients that it was still "50/50" if the drug could work.

This comes less than a week after a test for the drug in more severe cases of COVID-19 was also stopped due to poor enrollment.

This latest test was focused on mild to moderate forms of the disease, but still in those ill enough to be in hospital. The primary outcome measure was time to clinical recovery, which was for up to 28 days, with the leading secondary being all cause mortality. This population was seen as being more likely to benefit from the drug ahead of the severe cases, which are typically harder to treat.

Remdesivir, a nucleotide analogue prodrug originally tested in Ebola patients, has emerged as one of the top near-term hopes of improving outcomes in COVID-19 patients. Responding to the dire need, Gilead has made remdesivir available to more than 1,700 people on a compassionate use basis while also providing it to subjects in its own clinical trials and those run by other sponsors.

Gilead earlier this month provided a snapshot of the experiences of patients treated on a compassionate use basis in a paper published in The New England Journal of Medicine. The study covered 61 patients, eight of whom were excluded due to a lack of post-treatment data or a dosing error.

That left Gilead with an analyzable cohort of 53 patients, 30 of whom were on mechanical ventilation at the start of the study. The patients received 10 days of treatment with remdesivir and were then tracked for a median of 18 days.

As of the end of the follow-up period, 68% had an improvement in oxygen-class support. More than half of the mechanically ventilated patients were extubated. Almost half of the patients in the study were discharged in the analyzed period. Seven patients died. All bar one of the people who died were receiving invasive ventilation at baseline.

The lack of a control arm makes it hard to interpret the data. It is possible to compare the death rate to that seen in a clinical trial of Abbott’s Kaletra, 22%, to make the case that remdesivir is doing some good. But such cross-trial comparisons are rendered unreliable by confounding variables, such as the characteristics of the patients enrolled.

Given the remdesivir study lacked a control arm, few hard conclusions can be drawn from the data. One clear positive is the lack of safety red flags, although that was arguably to be expected based on how remdesivir performed in a larger study of Ebola patients. 

Other trials in Europe and the U.S. are still ongoing.