The drug was granted so-called fast-track status by the Food and Drug Administration in January, Dr. Steiner said. The designation is intended to prompt faster development and review of new treatments that address unmet medical needs and target serious or life-threatening conditions.

Dr. Steiner said the company plans to meet with the agency later this month and will be applying for emergency-use authorization for sabizabulin. An F.D.A. spokeswoman declined to comment, saying the agency did not confirm, deny or comment on pending applications.

No safety concerns related to the drug were identified in the course of the clinical trial, company officials said.

“Despite it being two and a half years into the battle, we are still working hard to get highly effective drugs into the mix to treat this specific population of patients, and this is a fairly dramatic improvement in 60-day mortality,” said Dr. Michael Gordon, one of the trial investigators and chief medical officer at HonorHealth Research and Innovation Institute in Scottsdale, Ariz.

But Dr. Gordon leavened his optimism with caution, saying he was eager to see more detailed analyses. Additional data were still being analyzed on Monday, including the proportion of treated patients without respiratory failure, the number of days they spent in intensive care, the length of their hospital stay and how long they were on mechanical ventilation.

“No drug works for everybody,” Dr. Gordon said. “The benefit that was seen is mortality — who is living and who is dying — not who is getting off oxygen, though I anticipate we will see improvement in other parameters, too.”

Patients on both arms of the multicenter trial received all standard care and treatment. The participants were in the United States, Brazil, Argentina, Mexico, Colombia and Bulgaria, and they had been infected with both the Delta and Omicron variants. The drug is effective regardless of the variant type, Dr. Gordon and company officials said.