It's the second time a trial for the drug was halted in China because testers were unable to find eligible patients for a clinical trial.
The first trial was supposed to test patients with severe cases of COVID-19, the disease caused by the novel coronavirus. The trial terminated most recently was supposed to test patients with mild symptoms.
There currently is no clinical treatment for COVID-19, which has infected more than 2 million people globally, killing nearly 130,000.
Earlier this week, Gilead shares rose after data presented by the company showed that remdesivir improved clinical outcomes for two-thirds of a small group of 53 hospitalized patients who were given the drug on a "compassionate use basis."
Analysts at J.P. Morgan said that it was a "promising first look" for the drug, but also noted that "the results need to be kept in context."
The results of that trial, which were published in the New England Journal of Medicine, showed that 36 patients (68%) showed improvement in oxygen-support class, including 17 of 30 patients (57%) receiving mechanical ventilation assistance.
The NEJM concluded that "measurement of efficacy will require ongoing randomized, placebo-controlled trials," leading to Wednesday's market reaction to the canceled tests in China.
Gilead shares were down 3.9% to $74.72 in a trading session that saw all three major indices falling by much more than 1%.
Year to date, Gilead has risen nearly 15%.