And because the drug weakens the body's immune defenses, it comes with serious side effects. These include infections, cancers, depression, and suicide.
But the announcement comes as welcome news to patients and doctors frustrated by the limited treatment options available to lupus patients. And it comes even as scientists gain a new understanding of what lupus is, what goes wrong, and where researchers should look for new treatments.
What should lupus patients and their families know about Benlysta? WebMD consulted Eric L. Greidinger, MD, chief of rheumatism and immunology at the University of Miami Miller School of Medicine, FDA briefing documents, and the FDA approval announcement.
Officially known as systemic lupus erythematosus (SLE), lupus is an autoimmune disease. It's relatively common, affecting about one in 1,000 people. But some people with lupus have such mild disease they may never know they have it.
Others have relatively mild disease that can be controlled with current treatments. These include over-the-counter NSAIDs such as ibuprofen, corticosteroids such as prednisone, antimalaria drugs such as hydroxychloroquine, powerful immunosuppressants, and cancer chemotherapies. (Lupus is not caused by malaria and is not a cancer, but malarial drugs and chemotherapies suppress various manifestations of lupus).
Still other patients experience frequent lupus flare-ups and suffer devastating side effects from current treatments. And finally, there are patients with life-threatening lupus, at risk of major organ failure.
"In all those cases, the current drugs -- while not perfect -- provide a good series of choices," Greidinger says.
Patients with mild disease may not need treatment, or may be able to keep their symptoms under control with relatively safe antimalaria drugs.
Patients with the most severe disease -- including lupus affecting the kidneys or brain -- can benefit from more aggressive treatments.
But patients in the middle category are more difficult to treat, Greidinger says. They may not get relief from the safest lupus treatments. But stronger treatments, continued over time, may cause side effects that are worse than a patient's symptoms.
Which lupus patients might benefit most from Benlysta?
Many patients with mild-to-moderate lupus can't keep their flare-ups under control with antimalaria drugs.
"Their only real option at present is the use of corticosteroids like prednisone," Greidinger says. "But many of these patients have persistently active disease and thus may be exposed to substantial doses of steroids for months and years with a very high risk of serious side effects."