Tocilizumab, a drug used to treat some forms of arthritis, might be an effective treatment for those with severe cases of COVID-19, according to the preliminary findings of a study published Wednesday by the Proceedings of the National Academy of Sciences.
The drug is a monoclonal antibody -- a cloned immune cell -- that is intended to bind to interleukin-6, or IL-6, a type of cytokine protein research suggests is part of an overactive immune response that causes serious illness in some of those infected with the new coronavirus.
By binding to IL-6, the researchers said, tocilizumab effectively works to disrupt this immune response, allowing patients to recover.
However, the authors, from China, emphasized that the findings are preliminary and need to be confirmed in a larger study.
The drug, made from cloned antibody cells, normally is used to treat autoimmune forms of arthritis, such as rheumatoid arthritis.
The current study looked at 21 patients with serious or critical illness from COVID-19 in Anhui Province. The study participants were between 25 and 88 years old.
Before treatment, all patients had fever and evidence of lung lesions on CT scans, while 17 had abnormally low lymphocyte percentages and 20 had elevated levels of C-reactive protein, or CRP, an indicator of inflammation. All but one of the study participants received oxygen therapy before tocilizumab treatment.
After treatment with tocilizumab, all patients' body temperatures returned to normal on the first day and remained stable thereafter. Within five days of treatment, 15 patients were able to reduce oxygen intake, and lung lesions were resolved in 19 patients after treatment, the study's authors wrote.
All participants were discharged between 10 and 31 days after treatment, and no side effects were reported.
COVID-19, the disease caused by SARS-CoV-2, has sickened more than 3 million people worldwide, including more than 1 million in the United States. The virus has killed more than 60,000 Americans to date, according to Johns Hopkins University.
Antibody-based therapies have been suggested as potential treatment for the disease after another study published last month by researchers in China found that blood plasma transfused from recovered patients seemed to resolve some symptoms.
The approach is based on the theory that people who have recovered from the disease develop antibodies to the virus -- present in their blood -- that foster immunity against it.
The World Health Organization, however, last week warned that evidence exists that people with antibodies are immune from being infected more than once.