CNN  — 

Preliminary results from a clinical trial of remdesivir, an experimental antiviral drug being tested for coronavirus, could come in as little as one to two weeks, a top researcher said Sunday.

The final results aren’t expected until mid-to-late May, said Dr. Andre Kalil, a principal investigator for the trial. But he said “we can potentially have some early data in the next one or two weeks,” contingent on a preliminary analysis.

“In the next few weeks, we’re going to do the analysis, and we’re going to basically know if remdesivir is better or not than placebo,” he told CNN.

Remdesivir was originally tested by Gilead Sciences as a potential treatment for Ebola, and it showed activity against the novel coronavirus in test tubes. But whether the drug is an effective treatment for Covid-19 remains unclear, and data released thus far have been conflicting and limited.

The new study, sponsored by the National Institutes of Health, is a randomized, double-blind, placebo-controlled trial. That means it compares patients who received remdesivir with those who didn’t, and neither the patients nor the doctors treating them know who is receiving the real drug and who is receiving a placebo.

That helps protect against bias and makes the study results more believable, and the design is thought to be the gold standard for clinical research.

Enrollment for the study was completed last Sunday, Kalil said, adding that “we enrolled more people than we actually predicted.” He was unable to say how many patients total were in the trial, but said it was more than the 572 participants listed as a target.

Reuters reported on Friday that the study was running ahead of schedule, with results potentially coming soon.

Study includes patients from around the world

The trial began at the University of Nebraska Medical Center, where Kalil is a professor of medicine, but it has since expanded to nearly 70 sites around the world, from South Korea to Germany.

Kalil said he wants to see results that show “meaningful clinical benefits” for patients. “We want to see something that really matters, something that really changed the outcomes of these patients,” he said. The idea “is not just feeling a little bit better,” such as a minor shortening of fever.

While the hope is that patients’ infections will resolve more quickly on remdesivir, Kalil said he wouldn’t speculate on the outcome of the trial. “This is not a time to guess, this is a time to really get the data,” he said.

“If the drug works, great. If the drug doesn’t work, we can remove the drug from the trial and try other therapies.”

Leaked data and early results paint a confusing picture

The data on remdesivir are confusing at best. Earlier this month, the maker of the drug, Gilead, released information on 53 patients, the majority of whom showed clinical improvement after receiving infusions of remdesivir.

While Gilead called that data “encouraging,” the study had no control group, making it difficult to know whether remdesivir actually helped the patients more than supportive care, the current standard.

Information leaked to STAT News also suggested that coronavirus patients receiving remdesivir in a clinical trial were recovering quickly. But STAT’s report was based on a recorded discussion of the trial, and it offered few details.

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Last week, the World Health Organization accidentally published a summary of results from a clinical trial of the drug in patients with severe Covid-19. A screenshot of the summary published by STAT showed “remdesivir use was not associated with a difference in time to clinical improvement.”

But that trial was terminated early due to low enrollment, and Gilead said the results were posted prematurely. The study was inconclusive, the company said, and “the post included inappropriate characterizations of the study.”