Adalimumab treatment optimization for psoriasis: Results of a long-term phase 2/3 Japanese study

The tumor necrosis factor- inhibitor, adalimumab, is approved to treat moderate-to-severe plaque psoriasis (40mg every-other-week or 80mg every-other-week following inadequate response at 40mg in Japan). This open-label extension (OLE) trial evaluated the optimal adalimumab dose for long-term efficacy and safety in Japanese patients with moderate-to-severe plaque psoriasis following a prior 24-week, phase 2/3, randomized, double-blind study. Of the 169 patients from the phase 2/3 trial, 147 entered the OLE on 40mg (n=89) or 80mg (n=58) adalimumab every-other-week. Patients on 40mg with Psoriasis Area and Severity Index (PASI) of less than 50 could escalate to 80mg. At week 52 (28 of OLE), patients entering the OLE on 80mg were reduced to 40mg, with the option to re-escalate. For patients entering the OLE on 40mg, final PASI 50/75/90 response rates were 85.1%/73.3%/60.4%, respectively, including effects of dose escalation. Among patients whose dose was escalated, final PASI 50/75/90 response rates were 70.0%/53.3%/36.7%, respectively. For patients entering the OLE on 80mg, final PASI 50/75/90 response rates were 92.5%/84.9%/73.6%, respectively, including effects of dose re-escalation. Overall incidence rates of adverse events (AE) and injection-site reaction AE declined over time; rates for serious AE and infections were generally stable. Clinically meaningful efficacy of adalimumab was sustained to 4years. Dose escalation to 80mg every-other-week for patients with suboptimal response to 40mg every-other-week, and dose reduction to 40mg every-other-week for patients satisfactorily controlled on 80mg every-other-week, are viable strategies for adalimumab optimization.