“Organizations are encouraged to consider prescribing either tocilizumab or sarilumab in the treatment of patients admitted to intensive care with Covid-19 pneumonia,” the new guidance from British health authorities said. Dr. Gordon noted that this is the strongest official advice issued to date on the pair of immune drugs.
Some experts outside of Britain are treading more cautiously. Both Dr. Schwartz and Dr. Kaplan-Lewis noted that although the data might be enough to persuade the F.D.A. to authorize tocilizumab and sarilumab for emergency use in the United States, the jury is still out on these drugs. And Dr. Boghuma Kabisen Titanji, an infectious disease physician at Emory University, pointed out that only about 4 percent of the study volunteers identified as Black, which may make the results less applicable to the general population given the heightened vulnerability of communities of color to Covid-19.
More studies will be needed to clarify when, and in which patients, tocilizumab and sarilumab work best, and to untangle why their benefits cropped up clearly in some studies, but not others, Dr. Kaplan-Lewis said. It’s also challenging to compare studies coming out now to earlier trials that were conducted when the virus was much less understood, treatments were doled out with less know-how and mortality rates were even higher.
“If patients get better supportive care, maybe their outcomes would be much improved,” said Dr. Krutika Kuppalli, an infectious disease physician at the Medical University of South Carolina who was not involved in the study. “Yes, therapeutics are helpful. But it’s also about improving the standard of care for people.”
The new study and others have hinted that the drugs’ window of opportunity is narrow — within the first day or so of admission to an I.C.U., Dr. Kaplan-Lewis said. Given too early, the drugs might not make a measurable dent in the immune response; delivered too late, and the damage may have already been done. “Maybe it’s when a person has just tipped over into being critical,” she said.
That inflection point isn’t always easy to define. Patients enter intensive care in different states, and the threshold for critical illness may not be uniform across hospitals. And, like all other immunosuppressive drugs, tocilizumab and sarilumab can raise the risk of infection by other viruses or bacteria.
The data is “encouraging,” Dr. Kuppalli said. “But I think we need to understand why this data looks different from other studies, before we start implementing this as widespread policy.”