The U.S. Food and Drug Administration (FDA) has approved the biologic drug abatacept (Orencia) to treat psoriatic arthritis (PsA) in adults. It’s already approved for rheumatoid arthritis (RA) and for one subtype of juvenile idiopathic arthritis (JIA).
Abatacept is a biologic medication that works by targeting T-lymphocytes (T cells), immune cells that are overproduced in people with inflammatory arthritis. The drug, technically called a “selective costimulation modulator,” attaches to the surface of the cells, preventing them from communicating with other cells and producing chemicals that can lead to joint damage and symptoms like pain and swelling. It’s given as a monthly infusion or weekly injection.
The FDA approved abatacept based on the results of two randomized controlled trials involving nearly 600 adults with long-standing PsA. The first trial compared the infused form of abatacept with placebo in 170 patients. At the end of 24 weeks, 47 percent of those who received the drug showed at least a 20 percent improvement in symptoms. Only 19 percent of people on placebo showed at least 20 percent improvement.
The second trial compared injected abatacept with placebo. Again, a larger proportion of patients in the abatacept group showed at least a 20 percent improvement at 24 weeks compared to patients in the placebo group – 39 vs. 22 percent, respectively.
Although abatacept can be used as a first-line treatment for severe symptoms, it’s usually reserved for people who haven’t been helped by other arthritis drugs, including traditional disease-modifying antirheumatic drugs (DMARDs), such as methotrexate, as well as other types of biologics, such as tumor necrosis factor (TNF) inhibitors. Abatacept may be more effective for these patients because it fights inflammation in a different way, by attacking T-cells instead of inflammatory proteins, such as TNF-alpha.
Still, doctors are often reluctant to start patients on new drugs and are more likely to stick with ones they know, says Scott Zashin, MD, a rheumatologist and clinical professor at University of Texas Southwestern Medical School in Dallas. Although abatacept has been used for RA for more than a decade, it doesn’t have a long track record for PsA.
Like other biologics, abatacept increases the risk of serious infections and cancer. It’s also expensive. According to GoodRx, the average price for a month’s worth of abatacept syringes is around $4,000. That doesn’t include insurance or discounts, like manufacturer coupons and copay assistance programs.
AUTHOR: Linda Rath for the Arthritis Foundation