China's National Health Commission published treatment guidelines Wednesday that could make a decade-old rheumatoid arthritis drug a treatment option for patients with severe SARS-CoV-2 infections.

Actemra from Roche (RHHBY -0.30%) is used to dial down out-of-control immune system responses. It's been approved in the U.S. to treat patients with severe rheumatoid arthritis -- an autoimmune disease -- since 2010. It's also been approved to treat life-threatening bouts of cytokine release syndrome (CRS) brought on by super-potent new cancer therapies.

Paging Dr. Thumbs-up

Image source: Getty Images.

While the latest weapon in the battle against the novel coronavirus won't help with containing the epidemic, it could save the lives of patients fighting off infections. That's because when the immune system overreacts to an infection, the resulting cytokine release syndrome can lead to organ failure.

Don't try this at home

Usually, dialing back the immune system by any means would be the wrong move when fighting an infection. In fact, Actemra has a black box warning on its label because it makes it easier for infections to become life-threatening. The drug is likely to do far more harm than good to anybody who isn't already experiencing a severe immune system flare-up.

In the weeks ahead, ongoing studies in the U.S. and abroad should shed some light on the value of a number of potential treatments for COVID-19 that could be used more broadly. For example, Remdesivir is an experimental antiviral from Gilead Sciences (GILD -0.30%), and there is some evidence that it's effective against other coronaviruses.