People with psoriasis who haven’t seen improvement with standard treatments now have a new option. The Food and Drug Administration (FDA) has approved the injectable drug Siliq (broadalumab) for the treatment of moderate-to-severe plaque psoriasis in adults.
Because of an association with suicidal thoughts and behaviors, Siliq will be sold with a "black box" warning and should be considered only for patients whose psoriasis has not responded—or has stopped responding—to phototherapy or to other systemic medicines taken orally or via injection.
Plaque psoriasis is an autoimmune condition that causes cells to build up on the surface of the skin, forming thick red patches and flaky silver-white scales. Current treatment options for psoriasis include topical treatments (like corticosteroids) phototherapy (using an ultraviolet light box or a laser) and systemic drugs—delivered via a pill, an injection or an IV infusion—that work throughout the body.
Siliq is unique because it binds to the receptor of a protein called interleukin-17, a known contributor to inflammation. By blocking the receptor from being activated, it keeps the body from receiving signals that can fuel inflammatory responses and psoriasis progression. Two other psoriasis drugs currently on the market work similarly, but instead bind to the protein itself.
This small difference is significant, says Dr. Richard Fried, a member of the National Psoriasis Foundation medical board, since responses to drug treatments can vary dramatically from person to person. "Having another agent in our armamentarium that works by a different mechanism is a welcome addition and may prove beneficial to many psoriasis suffers," he says in an email. (Fried says he has no involvement with the drug or the drug company.)
In the three clinical trials considered for drug approval, more than 50% of patients who used Siliq achieved total skin clearance—the ultimate goal of psoriasis treatments—within a year. The most common side effects of the drug were joint and muscle pain, headache, fatigue, diarrhea, throat pain, nausea, flu, low white blood cell count, fungal infections and reactions at the injection site.
The drug also comes with a more serious warning, as well. In a total of six clinical trials totaling about 6,200 participants, six suicides were reported by people receiving Siliq. People with a history of suicide attempts or depression had an increased risk of suicidal ideation and behavior.
Because of these events, the labeling for Siliq will include a Boxed Warning, and the drug will only be available through a restricted REMS (Risk Evaluation and Mitigation Strategy) program. In order to prescribe it, doctors must be certified with the program and must counsel patients about this risk. Patients must also agree to seek medical attention should they experience new or worsening mood changes, anxiety or suicidal thoughts.
A causal association between Siliq and increased risk of suicidal ideation and behavior has not been established. Fried, a dermatologist and clinical psychologist, points out that psoriasis itself can be associated with mental health problems.
"E ffective treatment has consistently shown reduction in the incidence and severity of depression and reduced likelihood of suicide," says Fried. He adds that the data on Siliq suggests that it is not only effective in treating psoriasis, but that many patients experience improvement in anxiety and depression, as well.
Siliq, like other psoriasis medications, also affects the immune system. It can raise patients’ risk of infections and shouldn’t be used by people with certain chronic conditions, such as Crohn’s disease or active tuberculosis infections. People should also avoid immunizations with live vaccines while being treated with Siliq.
"Patients and their health care providers should discuss the benefits and risks of Siliq before considering treatment," said Dr. Julie Beitz, director of the Office of Drug Evaluation III in the FDA’s Center for Drug Evaluation and Research, in an agency press release.
The drug's recommended dosage schedule is an injection once a week for the first three weeks, followed by an injection every other week. Valeant Pharmaceuticals, Siliq's manufacturer, says that pricing information is not available at this time, and expects to begin sales and marketing in the second half of 2017.