The drug blocks a specific part of the body's immune system that can go into overdrive in serious and critical Covid-19 cases.
Treating severely ill Covid-19 patients with the arthritis drug tocilizumab has no clinical benefit, according to the results of a trial stopped early due to an increase in deaths among those receiving it.
The trial, published Thursday in the BMJ medical journal, appeared to contradict earlier studies in which tocilizumab seemed to show promise in reducing the length of hospital stays for some patients.
The drug, a common treatment for arthritis, blocks a specific part of the body's immune system that can go into overdrive in serious and critical Covid-19 cases.
It had been hoped that the treatment could help to tamp down some of the more extreme inflammatory responses that can lead to death.
Researchers in Brazil conducted a randomised control trial among 129 patients with confirmed Covid-19 at nine hospitals.
They were all either receiving oxygen support or mechanical ventilation and had abnormal levels of at least two inflammation-causing chemicals in their blood.
Sixty five patients received tocilizumab plus standard care, while 64 were given standard care alone.
All patients were monitored for 15 days, by which time 18 (28%) in the tocilizumab group and 13 (20%) in the standard care group were either on ventilators or had died.
In all, 17% of the tocilizumab group had died due to acute respiratory failure or multiple organ failure within 15 days, compared to 3% in the control group.
Due to the increased number of deaths in the first group, the trial was stopped early, researchers said.
The results clash with other studies, including one this month - yet to be peer-reviewed - that appeared to show a beneficial effect on organ function and mortality within 21 days of treatment with tocilizumab.
Thursday's research, which has been reviewed by experts,concluded that in patients with severe or critical Covid-19, “tocilizumab plus standard care was not superior to standard care alone in improving clinical status at 15 days and might increase mortality.”
They said the results “raise questions about an anti-inflammatory approach in the treatment of Covid-19” beyond standard steroids.
The authors did highlight some limitations to the research, including a relatively small sample size. However, they said the results were consistent after adjusting for levels of respiratory support needed by patients at the start of the trial.
This suggests that the findings are accurate, they said.