A biologic designed to treat inflammatory diseases, Siliq (brodalumab), has been approved by the U.S. Food and Drug Administration (FDA) for use by adults with moderate-to-severe plaque psoriasis.
But the approval comes with a strict warning, and tightly regulated access, because Siliq’s use was seen in clinical studies to possibly increase the risk of suicide, or suicidal thoughts, among people with histories of depression, mood swings, or other mental health problems. The drug will only be available through a restricted program, called Siliq Risk Evaluation and Mitigation Strategy (REMS).
Under this program, doctors who prescribe the drug and pharmacies that dispense it will have to be certified with the program. Doctors must also counsel patients about suicide risk and refer anyone with new or worsening symptoms of depression or suicidal behaviors and inclinations to a mental health professional.
Patients wanting to use the drug will need to sign a Patient-Prescriber Agreement Form, and be advised to seek medical attention should they experiece mood changes, anxiety, depression, and suicidal thought. Pharmacies will only be allowed to dispense Siliq to patients authorized to receive it. A box label on the packaging will warn about the increased risk of suicide.
Siliq injection is intended for plaque psoriasis patients who are candidates for systemic therapy or phototherapy (UV light treatment), and who are no longer responding to, or never responded to, other systemic therapies. (A systemic therapy is an oral or injected treatment, meaning it travels in the blood stream and can affect organs throughout the body.)
The drug works by inhibiting the inflammatory response, binding to and inactivating a protein called IL-7, which has been shown to be involved in psoriasis.
Its safety and efficacy were tested in three Phase 3 clinical trials under the AMAGINE clinical program. A total of 4,373 adults with moderate-to-severe plaque psoriasis who were candidates for systemic therapy or phototherapy participated in these placebo-controlled and randomized trials.
A total of six suicides were recorded during the trials, a higher suicide rate higher than typically observed in clinical trials for psychiatric drugs. However, according to the FDA, no causal relationship between Siliq use and suicidal thoughts or behaviors was established, and these tendencies were observed in people with a history of suicidality or depression.
Trial results showed that Siliq was highly effective in reducing plaque psoriasis, to a great extent than that seen with other drugs available to treat the condition. Treatment led to more patients having skin clear or almost clear of plaque psoriasis compared to those given placebo. Results reported in a study published in The New England Journal of Medicine in October 2015 found that “Brodalumab treatment resulted in a rapid reduction in the signs and symptoms of psoriasis.”
“Moderate-to-severe plaque psoriasis can cause significant skin irritation and discomfort for patients, and today’s approval provides patients with another treatment option for their psoriasis,” Dr. Julie Beitz, director of the Office of Drug Evaluation III in the FDA’s Center for Drug Evaluation and Research, said in an agency press release. ”Patients and their health care providers should discuss the benefits and risks of Siliq before considering treatment.”
Because it directly affects the immune system, Siliq is associated with an increased risk of infection and allergy. Adverse side effects include low white blood cell count, influenza, and fungal infections. Other adverse effects are joint, throat and muscle pain, headache, fatigue, diarrhea, nausea, reaction at the site of injection. The drug, which will be marketed by Valeant Pharmaceuticals, is not to be used by people with Crohn’s disease and active tuberculosis infection. Patients using Siliq should not be vaccinated with live vaccines.