Photo/Illutration Actemra, an immunosuppressive drug for rheumatism (Provided by Chugai Pharmaceutical Co.)

An immunosuppressive drug for rheumatism shows encouraging signs of inhibiting severe pneumonia symptoms caused by COVID-19, researchers say.

Some patients severely affected by the new coronavirus underwent an improvement in their condition at a hospital in Osaka Prefecture after they were administered Actemra, also known as tocilizumab, which is used to treat rheumatoid arthritis.

Actemra is designed to inhibit the activity of a cytokine protein called interleukin-6 (IL-6) that is associated with the immune system. It was discovered by Tadamitsu Kishimoto, a specially appointed professor of immunology at Osaka University, and his team.

When IL-6 becomes overactive, it triggers a phenomenon known as a cytokine storm where fever, hypoxia and other problems emerge, occasionally resulting in fatal shock or multiple organ failure. Cytokine storms are believed to contribute to serious coronavirus cases.

China and other countries started administering Actemra for COVID-19 patients, and one report said 19 of 20 people treated with the drug regained their health.

In an article released in early April, a team of researchers primarily attached to the University of Toronto in Canada said coronavirus patients with a significantly high level of IL-6 develop severe conditions more easily and that Actemra is helpful in treating serious symptoms.

The team pointed out that the safety and effectiveness of the immunosuppressive drug need to be evaluated through large-scale clinical trials.

The article, which had yet to undergo a peer review, comprehensively analyzed eight reports, including theses that have yet to be examined by referees for assessment.

At the Osaka Habikino Medical Center in Habikino, Osaka Prefecture, a virus therapy team headed by infectious disease specialist Takayuki Nagai tested Actemra on seven patients with severe pneumonia.

An improvement of symptoms was reported in five of the test subjects as of April 13, although the health condition of the remaining two patients deteriorated.

The patients were carefully screened on the basis of inflammation test results, progress of symptoms and the degree of hypoxia because Actemra has not been approved for use in treating pneumonia.

"Our next step is to figure out when to start administering the drug so as to maximize its effect,” said Toshio Tanaka, deputy director of the medical center.

Kishimoto, who discovered IL-6, said he believes controlling cytokine storms to allow a patient’s immune system to work properly will help those infected with the virus to recover from the disease.

“Actemra does not eliminate the virus, but it may help save the lives of patients,” he said.

Pharmaceutical companies are forging ahead with plans for clinical trials to confirm the effectiveness and safety of the drug in the context of coronavirus treatment.

The Swiss-based Roche Group announced in March it will begin a clinical trial of Actemra, covering 330 patients across the world.

Chugai Pharmaceutical Co., which released Actemra as Japan’s first antibody drug, is also planning a clinical study in Japan.