Two phase III studies in China testing Gilead Sciences Inc.’s antiviral drug, remdesivir, in patients with COVID-19 infection have been halted after Chinese authorities reported a lack of eligible patients. Other studies, including trials sponsored by the Foster City, Calif.-based company, remain ongoing.
Remdesivir, which targets RNA-dependent RNA polymerase, was identified early on as a possible treatment against SARS-CoV-2, the coronavirus that causes COVID-19. A paper published Jan. 31 in The New England Journal of Medicine (NEJM) suggested the drug, previously developed for use against Ebola virus, might prove effective in patients diagnosed with COVID-19.
According to clinicaltrials.gov, a phase III study in Beijing enrolling 237 adults with severe COVID-19 infection was terminated because, at the current time, the outbreak in China is being well-controlled and no eligible patients are available for enrollment. That study had been measuring time to clinical improvement as the primary endpoint, defined as the time from randomization – patients receiving either remdesivir or placebo – until a decline of two categories on a six-category scale that ranges from discharge from hospital care to death or live discharge from hospital.
A second phase III study, taking place in Hubei province, the epicenter of the coronavirus outbreak, has been suspended, also due to the lack of new patients. That study, which began in early February, was designed to enroll hospitalized patients with mild to moderate COVID-19 infection. The primary endpoint was defined as time to clinical recovery, based on initiation of study treatment until normalization of fever, respiratory rate and oxygen saturation and alleviation of cough, sustained for at least 72 hours, or live discharge from hospital, whichever comes first.
Meanwhile, Gilead is continuing with a phase III parallel-assignment study, anticipated to enroll 2,400 patients, 12 and older, with severe COVID-19 at 152 sites worldwide. The study will test two regimens of remdesivir, measuring the odds of ratio for improvement on a seven-point ordinal scale at day 14 as the primary endpoint. Another phase III study is enrolling 1,600 patients, 12 and older, testing remdesivir vs. standard of care, using the same endpoint.
The drug also is being administered to patients under compassionate use protocols and is included in the World Health Organization’s Solidarity study aimed at testing a variety of potential treatments in patients with COVID-19 infection.
Earlier this week, promising – though limited – compassionate use data published in NEJM from a cohort analysis of 53 severe patients hospitalized with severe complications from COVID-19 showed a cumulative incidence of clinical improvement of 84% after 28 days of follow-up, according to Kaplan-Meier analysis.
Shares of Gilead (NASDAQ:GILD) fell 4% to close April 15 at $74.63.