Doctors around the world, trying to save seriously ill coronavirus patients, have been dosing them with rheumatoid arthritis drugs that can squelch immune responses. The theory was that many were dying because their immune systems went into overdrive, creating a fatal storm that attacked their lungs.
But now, preliminary results on treatments with one of these drugs, sarilumab, marketed as Kevzara and made by Regeneron and Sanofi, indicate that it does not help patients who are hospitalized but not using ventilators.
The rush to treat patients with rheumatoid arthritis drugs began with a tiny study in China in February. It involved just 21 patients, all of whom were hospitalized with Covid-19. All of the patients received a drug made by Roche, tocilizumab, that is very similar to sarilumab. The doctors reported that the patients’ fevers disappeared within days and, the doctors wrote, that “all other symptoms improved remarkably.” They ended on an optimistic note, writing, “Tocilizumab is an effective treatment in severe patients with Covid-19.”
Dr. George D. Yancopoulos, chief scientific officer of Regeneron, said the company had rushed to start a clinical trial of its drug in coronavirus patients. But he was not optimistic. Drugs like sarilumab and tocilizumab were specifically designed for arthritis, not Covid, he noted.
“Repurposing existing drugs has not had a history of success in the pharmaceutical industry,” he said.
But, with doctors around the world dosing ill patients with the arthritis drugs, Regeneron and Sanofi decided it was urgent to get reliable data.
Their clinical trial randomly assigned 457 hospitalized Covid-19 patients to receive either 400 milligrams or 200 milligrams of sarilumab, or a placebo. The patients fell into two groups — “severe,” meaning they required oxygen but did not need a ventilator or so-called high flow oxygen, and “critical,” those who needed a ventilator, high flow oxygen or were in intensive care.
Although the drug reduced c-reactive protein, which rises in severe inflammation, it did not help the severely ill patients, the companies reported on Monday. Many of those patients recovered on their own. Eighty percent were discharged from the hospital, whether or not they were given the drug. Ten percent remained hospitalized, and ten percent died.
The results for the critically ill patients are not conclusive but there is a hint that such patients may be helped, so the study will continue with only critically ill patients. More than 600 have been enrolled. Results are expected in early June.
To date, even small controlled studies of 25, 30 or 50 patients are misleading, Dr. Yancopoulos said. What is needed are rigorous studies with sufficient numbers of patients to get reliable results.
The companies are also conducting a second controlled trial of the arthritis drug in 400 critically ill patients outside the United States. Preliminary results will be available in the third quarter, the companies say.
Regeneron has also designed a monoclonal antibody drug that is targeted specifically to the coronavirus, in the same way it designed the only drug that has worked against Ebola. Clinical trials of the drug will start in June.