(Bloomberg) -- Roche Holding AG’s arthritis drug Actemra doesn’t help all Covid-19 patients, and in fact might harm some, Brazilian researchers said in the latest seemingly contradictory study results to emerge on the medicine.

Adding Actemra to standard treatment not only didn’t improve outcomes in a trial in Brazil last summer, it may have led to more deaths, according to results published late Wednesday in the British Medical Journal. The study was stopped early after a monitoring committee raised concerns about the deaths.

Though the trial, with 129 participants, is too small to be definitive, it highlights the unanswered questions surrounding the use of the Roche arthritis medicine for Covid patients after a handful of trials returned different results. Positive findings from another recent study led the U.K. earlier this month to say it would start using Actemra widely.

“We don’t have enough big trial evidence to know, first of all, convincingly whether the treatment works or not,” said Martin Landray, a professor of medicine and epidemiology at the University of Oxford, who wasn’t involved with the Brazil trial.

Bigger Study

Landray helps lead a much larger study, called Recovery, that is also investigating Actemra. It may have data within weeks, he said. The totality of the evidence so far looks hopeful for a benefit in at least a subset of patients, he said.

“In a sense, although we are only waiting for one more trial to come in, we’re only a third of the way through this particular story,” Landray said. “It’s worth waiting a few weeks before making definitive decisions about exactly what the role of this drug is.”

Doctors in the Brazil study gave Actemra plus standard treatment to 65 patients in nine hospitals last May, June and July, comparing their results with those of 64 people who got only standard care. The team focused on very sick patients who showed strong signs of inflammation, hoping that the arthritis medicine would allay the inflammatory response, said Joao Prats, a researcher and consultant in infectious diseases at BP, a large hospital in Sao Paulo, and one of the study’s co-authors.

“The bottom line ends up being that we haven’t found yet the population that is likely to benefit from the drug,” Prats said. It might be necessary to combine the drug with something else or focus on more narrowly defined patient groups, he said.

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