Tofacitinib or Adalimumab versus Placebo for Psoriatic Arthritis

BACKGROUND Tofacitinib is an oral Janus kinase inhibitor that is under investigation for the treatment of psoriatic arthritis. We evaluated tofacitinib in patients with active psoriatic arthritis who previously had an inadequate response to conventional synthetic disease-modifying antirheumatic drugs (DMARDs). METHODS In this 12-month, double-blind, active-controlled and placebo-controlled, phase 3 trial, we randomly assigned patients in a 2: 2: 2: 1: 1 ratio to receive one of the following regimens: tofacitinib at a 5-mg dose taken orally twice daily (107 patients), tofacitinib at a 10-mg dose taken orally twice daily (104), adalimumab at a 40-mg dose administered subcutaneously once every 2 weeks (106), placebo with a blinded switch to the 5-mg tofacitinib dose at 3 months (52), or placebo with a blinded switch to the 10-mg tofacitinib dose at 3 months (53). Placebo groups were pooled for analyses up to month 3. Primary end points were the proportion of patients who had an American College of Rheumatology 20 (ACR20) response (>= 20% improvement from baseline in the number of tender and swollen joints and at least three of five other important domains) at month 3 and the change from baseline in the Health Assessment Questionnaire- Disability Index (HAQ-DI) score (scores range from 0 to 3, with higher scores indicating greater disability) at month 3. RESULTS ACR20 response rates at month 3 were 50% in the 5-mg tofacitinib group and 61% in the 10-mg tofacitinib group, as compared with 33% in the placebo group (P=0.01 for the comparison of the 5-mg dose with placebo; P<0.001 for the comparison of the 10-mg dose with placebo); the rate was 52% in the adalimumab group. The mean change in the HAQ-DI score was -0.35 in the 5-mg tofacitinib group and -0.40 in the 10-mg tofacitinib group, as compared with -0.18 in the placebo group (P=0.006 for the comparison of the 5-mg dose with placebo; P<0.001 for the comparison of the 10-mg dose with placebo); the score change was -0.38 in the adalimumab group. The rate of adverse events through month 12 was 66% in the 5-mg tofacitinib group, 71% in the 10-mg tofacitinib group, 72% in the adalimumab group, 69% in the placebo group that switched to the 5-mg tofacitinib dose, and 64% in the placebo group that switched to the 10-mg tofacitinib dose. There were four cases of cancer, three serious infections, and four cases of herpes zoster in patients who received tofacitinib during the trial. CONCLUSIONS The efficacy of tofacitinib was superior to that of placebo at month 3 in patients with psoriatic arthritis who had previously had an inadequate response to conventional synthetic DMARDs. Adverse events were more frequent with tofacitinib than with placebo.