The Efficacy and Safety of Clazakizumab, an Anti-Interleukin-6 Monoclonal Antibody, in a Phase 2b Study of Adults with Active Psoriatic Arthritis
Mease et al. - Arthritis Rheumatol. 2016 Mar 24. DOI 10.1002/art.39700 [Epub ahead of print]
Encouraging results have been seen with clazakizumab in RA, but the results of anti-IL6 therapy in patients with psoriatic arthritis (PsA) have so far been unclear. This Phase 2b dose-ranging study examined the efficacy and safety of clazakizumab given subcutaneously q4w, with or without MTX, in 165 patients with PsA who had inadequate response to NSAIDs.
ACR20 response at Week 16, the primary endpoint, was significantly higher in patients receiving clazakizumab 100 mg compared with placebo (52.4% versus 29.3%); only numerical increases were seen for clazakizumab 25 mg and 200 mg, and no dose response was observed. Improvements to joints were seen as early as Week 1, and were sustained to Week 24, the end of the double-blind treatment period. However, only small improvements in skin were reported. Overall, the 200 mg dose did not perform as well as the other doses; its lower tolerability and patient reported outcomes possibly contributing to reduced efficacy outcomes.
Study limitations included an unexplained higher placebo response than earlier studies, and possible unrealistic statistical assumptions with respect to missing data. However, this first controlled study of clazakizumab in PsA does show it could be useful in improving physical function in patients with PsA who have well-controlled skin disease, including patients with enthesitis and dactylitis. Further studies are needed to confirm which dose to use, and whether there are any benefits in using MTX in conjunction with clazakizumab.