A Food and Drug Administration advisory committee has unanimously supported approval of the monoclonal antibody brodalumab for the treatment of moderate to severe plaque psoriasis, with the majority recommending risk management options beyond labeling to address concerns about the six completed suicides among patients treated with brodalumab in clinical trials.
Though no members of the FDA’s Dermatologic and Ophthalmic Drugs Advisory Committee disputed the drug’s efficacy for plaque psoriasis, the possibility of a signal for suicidal ideation and behavior (SIB) among the brodalumab group prompted the committee’s chair, Michael Bigby, M.D., to remark, “The big problem is that you have six completed suicides. … I would say it’s a fairly big number for a randomized controlled trial. Patients and clinicians need to be aware of this as a fact.”
Dr. Michael Bigby
Dr. Bigby, professor of dermatology at Harvard Medical School, Boston, headed the 18-member panel, which included dermatologists, psychiatrists, and cardiologists. Fourteen members voted in favor of approval with risk management measures beyond labeling; four members voted for approval with labeling alone.
Brodalumab targets interleukin-17 receptors, inhibiting IL-17 uptake and thus blocking the pathway responsible for the cutaneous and systemic signs and symptoms of psoriasis. The pivotal phase III brodalumab studies, AMAGINE-1, -2, and -3, enrolled a total of 4,373 patients with moderate to severe plaque psoriasis. AMAGINE-1 enrolled 661 patients in a 1:1:1 ratio to a randomized, double-blind placebo-controlled study that included two doses of brodalumab: 210 mg and 140 mg. The placebo-controlled phase of the study ran for 12 weeks, followed by a withdrawal and retreatment phase, and after 52 weeks, by an open label long-term extension phase.
AMAGINE-2 (1,831 patients) and AMAGINE-3 (1,881 patients) were identically designed studies that pitted both doses of brodalumab against an active comparator, ustekinumab (Stelara), as well as placebo, in a 2:2:1:1 ratio. This double-blind phase of the study also lasted 12 weeks. During weeks 12-52, patients on the brodalumab arms continued, with an exploration of wider-dose intervals for the 140-mg dose. Patients also continued with ustekinumab, with a rescue option to transition to brodalumab 210 mg. The placebo group could continue on brodalumab 210 mg as well. These two studies also had an open label long-term extension phase.
At the 12-week mark in AMAGINE-1, 41.9% of patients achieved the coprimary endpoint of 100% reduction in the Psoriasis Area and Severity Index (PASI 100) score, compared with 0.5% of those on placebo (P less than .001). AMAGINE-2 and -3 saw 44.4% and 36.7% of the brodalumab 210-mg arms achieving PASI 100 at the 12-week mark, respectively. These figures were significantly higher than the 21.7% and 18.5% reaching PASI 100 on ustekinumab (P less than .001), as well as significantly higher than the less than 1% of patients in the placebo arm who reached that endpoint.
At the end of 52 weeks, 51% of those on brodalumab 210 mg had completely clear skin, compared with 28.1% of the patients receiving ustekinumab (P less than .001).
The safety analysis for brodalumab showed that the most common adverse events were nasopharyngitis, upper respiratory tract infection, headache, and arthralgia; of these, the last two were considered adverse drug reactions. At 52 weeks, those on brodalumab had a slightly greater risk of having nonserious fungal infections than did those on ustekinumab. Overall, however, there was no difference between the brodalumab and ustekinumab arms at week 52 for treatment-emergent adverse events or for serious adverse events.
A cluster of SIB events occurred in 2013 and 2014 during the clinical trials, and the sponsor consulted the FDA. Additional monitoring for suicidal ideation and depression via the Columbia Suicide Severity Rating Scale (C-SSRS) and the Patient Health Questionnaire (PHQ) were implemented at a point where 84% of trial patients were already in the uncontrolled open label extension stage of the trial; in addition, a retrospective data review searched for suicidal ideation and attempts before the implementation of these two tools.
A total of six brodalumab patients completed suicide in all clinical trials, including those for psoriatic arthritis and RA. Suicides included two during the 12- to 52-week follow-up and four during the long-term follow-up phase. Another 29 patients attempted suicide, had intentional self-injury, or had suicidal ideation during these phases of the study, for a total of 35 SIB events. (SIB includes completed suicide, suicide attempt, suicide behavior, and suicide ideation.)*
The significance of the number of completed suicides was difficult to ascertain, given the increased baseline prevalence of depression and related illnesses among patients with psoriasis. Compared with the general population, individuals with psoriasis have hazard ratios of 1.39, 1.31, and 1.44 for depression, anxiety, and suicidality, according to a cohort study cited by Robert Levin, M.D. , director of the division of pharmacovigilance I at the FDA’s Center for Drug Evaluation and Research (CDER).