Efficacy of ustekinumab in biologic-naïve patients with psoriatic arthritis by prior treatment exposure and disease duration: data from PSUMMIT 1 and PSUMMIT 2.

Objective: To evaluate the efficacy of ustekinumab by prior treatment exposure and disease duration in tumour necrosis factor inhibitor (TNF)-naïve patients with psoriatic arthritis (PsA) in the PSUMMIT 1 and PSUMMIT 2 studies. Methods: In the phase 3, randomised, placebo-controlled PSUMMIT 1 and PSUMMIT 2 studies, adults with active PsA for ≥6 months despite conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and/or non-steroidal anti-inflammatory drugs (NSAIDs) (PSUMMIT 1) or csDMARDs, NSAIDs and/or anti-TNF agents (PSUMMIT 2) were enrolled. Patients were randomised to subcutaneous injections of placebo, ustekinumab 45 mg or ustekinumab 90 mg at weeks 0 and 4 and every 12 weeks. Efficacy was assessed at week 24 using the American College of Rheumatology criteria and 28-joint count disease activity score using C reactive protein (DAS28-CRP); radiographical progression, enthesitis, and dactylitis were also assessed in this post hoc analysis. Results: A total of 747 patients were included; all 747 were TNF-naïve, of which, 179 were methotrexate-naïve and TNF-naïve, and 146 were all csDMARD-naïve and TNF-naïve. At week 24, greater proportions of ustekinumab-treated patients had ≥20%/50%/70% improvement in American College of Rheumatology criteria (ACR20/ACR50/ACR70) responses, DAS28-CRP response and DAS28-CRP remission versus placebo in all three prior-treatment populations, with similar differences between treatment groups. Greater proportions of ustekinumab-treated patients also had complete resolution of enthesitis and dactylitis at week 24 across the three prior-treatment populations. Mean changes from baseline in total van der Heijde-Sharp Score at week 24 were generally smaller for ustekinumab-treated patients versus placebo but were statistically significant only in the full TNF-naïve population. Response rates for ACR20/ACR50/ACR70 were similar for TNF-naïve patients with PsA durations of <1 year, ≥1 to <3 years, and ≥3 years. Conclusion: Ustekinumab-treated patients demonstrated greater clinical response at week 24 compared with placebo regardless of prior treatment exposure and PsA disease duration.