By Joseph Walker 

Regeneron Pharmaceuticals Inc. and Sanofi SA said Monday they will shut down part of a study exploring whether their arthritis therapy could treat certain hospitalized Covid-19 patients because the drug looked unlikely to help them.

An early look at ongoing trial results indicated the therapy, named Kevzara, wasn't helping patients who were hospitalized with a severe form of Covid-19 but don't require a ventilator's assistance with breathing, the companies said.

The study will continue, however, for an even sicker set of hospitalized Covid-19 patients who require the help of ventilators or other high-flow oxygen support, the companies said.

In the second, sicker group of patients, the drug showed a relatively small potential benefit over placebo -- substances with no actual pharmaceutical effect -- though that will need to be confirmed in the ongoing study, the companies said. Results are expected in June.

"There's still hope it might help, but more modest than people hoped," Regeneron Chief Medical Officer George D. Yancopoulos said in an interview. "It doesn't look like the magic panacea that everyone would've wanted for the pandemic."

Dr. Yancopoulos said the results underscored the need to perform placebo-controlled studies of potential treatments for Covid-19 and not rely on anecdotal reports that have circulated in the medical community as doctors have scrambled to find treatments.

"We don't want mirages, we don't want fake cures, we want real therapeutics that make a difference," he said.

Kevzara was approved in 2017 to treat rheumatoid arthritis, a disease caused by an immune system that attacks healthy tissue. Researchers theorized the drug might help Covid-19 patients whose immune systems go haywire in response to the new coronavirus.

Regeneron and Sanofi launched a U.S. clinical trial last month to study the drug's ability to stop the hyperactive immune response of some coronavirus patients that is thought to contribute to a higher risk of death. The companies began studying the drug based on a small, non-placebo-controlled study in China that showed a similar drug helped nearly all study subjects recover from Covid-19.

The trial was divided into two parts: a smaller, phase 2 study and a larger, phase 3 study. Normally the third phase follows completion of the second, but the companies began conducting the two simultaneously to more quickly determine whether the drug worked in treating Covid-19. It usually takes years to advance drug studies into phase 3, which is usually the final stage before a drug is considered for regulatory approval.

Both phases compared Kevzara to placebo in two groups of hospitalized patients. Patients were assigned to a "severe" group if they were receiving oxygen support short of being on ventilators or receiving high-flow oxygen through nasal tubes; a second group was termed "critical" if they were on ventilators, receiving high-flow oxygen support or in an intensive-care unit.

An independent committee monitoring the study found that the severe patients receiving Kevzara in the phase 2 segment appeared to do worse than the placebo group, the companies said. In the larger phase 3 segment, severe patients did about the same in both the Kevzara and placebo groups.

The committee recommended that the companies stop treating severe patients because the drug was unlikely to help them, the companies said.

The severe group taking placebos did better than the companies had expected, which Dr. Yancopoulos said indicated the course of the disease in hospitalized patients still isn't well understood.

If the study didn't have a placebo group, it may have looked as though the drug was helping patients recover, though they would have even without treatment, Dr. Yancopoulos said.

Data from the phase 2 study suggests the drug may help some critical patients, but the results will have to be confirmed in the phase 3 study, the companies said.

Among critical patients receiving placebo, 55% died or were on ventilators after the study, compared with 46% of patients treated with 200 milligram doses of Kevzara, and 32% of patients receiving 400 milligram doses of Kevzara, the companies said.

At the advice of the independent committee, the companies said they would continue treating critical patients in the phase 3 study using only the 400 milligram dose or placebo.

Write to Joseph Walker at


(END) Dow Jones Newswires

April 27, 2020 07:14 ET (11:14 GMT)

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