BACKGROUND: We assessed the efficacy and safety of brodalumab, a human 
monoclonal antibody against interleukin-17 receptor A (IL17RA), in a phase 2, 
randomized, double-blind, placebo-controlled study involving patients with 
psoriatic arthritis.
METHODS: We randomly assigned patients with active psoriatic arthritis to 
receive brodalumab (140 or 280 mg subcutaneously) or placebo on day 1 and at 
weeks 1, 2, 4, 6, 8, and 10. At week 12, patients who had not discontinued their 
participation in the study were offered open-label brodalumab (280 mg) every 2 
weeks. The primary end point was 20% improvement in American College of 
Rheumatology response criteria (ACR 20) at week 12.
RESULTS: Of the 168 patients who underwent randomization (57 in the brodalumab 
140-mg group, 56 in the brodalumab 280-mg group, and 55 in the placebo group), 
159 completed the double-blind phase and 134 completed 40 weeks of the 
open-label extension. At week 12, the brodalumab 140-mg and 280-mg groups had 
higher rates of ACR 20 than the placebo group (37% [P=0.03] and 39% [P=0.02], 
respectively, vs. 18%); they also had higher rates of 50% improvement (ACR 50) 
(14% [P=0.05] and 14% [P=0.05] vs. 4%). Rates of 70% improvement were not 
significantly higher in the brodalumab groups. Similar degrees of improvement 
were noted among patients who had received previous biologic therapy and those 
who had not received such therapy. At week 24, ACR 20 response rates in the 
brodalumab 140-mg and 280-mg groups were 51% and 64%, respectively, as compared 
with 44% among patients who switched from placebo to open-label brodalumab; 
responses were sustained through week 52. At week 12, serious adverse events had 
occurred in 3% of patients in the brodalumab groups and in 2% of those in the 
placebo group.
CONCLUSIONS: Brodalumab significantly improved response rates among patients 
with psoriatic arthritis. Larger studies of longer duration are necessary to 
assess adverse events. (Funded by Amgen; ClinicalTrials.gov number, NCT01516957 
.).