Lupus corralled some major gains this week.
The Food and Drug Administration approved the first new drug to treat the incurable disease in 56 years. On the same day, two new studies revealed the origins of lupus, paving the way for new diagnostics and molecular treatments.
Lupus, a chronic autoimmune disease (where the body attacks itself), affects the joints and most major organs in the body, including the heart, kidneys, skin, lungs, and brain. This debilitating immune system disorder is little understood and afflicts as many as 1.5 million people in the US.
Known as Benlysta (belimumab), the monthly injectable drug relieves flare-ups and pain by reducing the number of abnormal immune cells that destroy healthy tissue. Benlysta will cost about $35,000 per year for each patient and should be available within about two weeks
Biotech drugmaker Human Genome Sciences Inc. spent 15 years developing the drug, and the approval marks a huge turnaround for the company, which has no other products on the market. It will co-market the drug with GlaxoSmithKline.
According to WSJ, Benlysta is widely expected to have annual sales eventually topping $1 billion; some forecasts suggest $2 billion by 2015 [Reuters], and others estimate annual sales exceeding $3 billion within 5 years [AP].
Before Benlysta, FDA last approved drugs to treat lupus – Plaquenil (hydroxychloroquine) and corticosteroids – in 1955. Aspirin was approved to treat lupus in 1948.
Two clinical studies involving 1,684 lupus patients demonstrated the safety and effectiveness of the drug, which is specifically approved for systemic lupus erythematosus, the most common form. About 200,000 patients in the US could benefit from the drug. AP reports:
But experts stress that Benlysta is not a miracle drug: It only worked in 35% of North American patients tested and was not effective for patients with the deadliest form of the disease. Additionally, it did not show positive results in African Americans, who are disproportionately affected by lupus.
The disease occurs when the body's antibodies stop differentiating between foreign invaders and healthy cells, and start forming antibody complexes against its own DNA. The cause of this malfunction isn’t well understood, but two new studies in Science Translational Medicine this week shed light on its origins.
In particular, they show that neutrophils – the most common type of immune cell – aid the development of lupus. They create things known as neutrophil extracellular traps (or NETs, pictured), which enter the liquid space between cells and help kill bacteria in healthy people.
“They’re called NETs because they really look like a net, like a spider web,” says Michel Gilliet of University Hospital Lausanne, who coauthored one study. The cells, he says, “shoot them out.”
But in lupus patients, antibodies trigger the neutrophils to release more NETs, which go on to attack the body’s own tissues.
“It is one of the most complex clinical diagnoses,” says Virginia Pascual at Baylor Institute of Immunology Research, who authored the other study. “It might lead to better diagnostic tests.”
This post was originally published on Smartplanet.com