Background  Certolizumab pegol (CZP) is a PEGylated antitumour necrosis factor agent.

Objectives  To evaluate the efficacy and safety of CZP in patients with plaque psoriasis.

Methods  In a randomized, placebo-controlled, double-blind study, 176 patients with moderate to severe psoriasis received placebo or CZP 400 mg at week 0 followed by placebo or CZP (200 or 400 mg) every other week until week 10. Co-primary endpoints were ≥ 75% improvement from baseline in Psoriasis Area and Severity Index (PASI 75) and a Physician’s Global Assessment (PGA) of clear-almost clear at week 12. A re-treatment extension study was conducted in 71 CZP PASI 75 responders who relapsed during a 12- to 24-week observation period without treatment.

Results  PASI 75 was achieved by 44/59 (75%), 48/58 (83%) and 4/59 (7%) patients in the CZP 200 mg, CZP 400 mg and placebo groups, respectively (< 0·001 for both treatment arms vs. placebo). A PGA score of clear-almost clear was achieved by 53%, 72% and 2%, respectively (< 0·001 for both treatment arms vs. placebo). In the re-treatment study median PASI scores were similar at week 12 in the first treatment and re-treatment periods for both CZP groups. Serious adverse events occurred in 3%, 5% and 2% of CZP 200 mg, CZP 400 mg and placebo patients, respectively.

Conclusions  Treatment with CZP significantly improved psoriasis at week 12. Similar efficacy was observed at week 12 in patients receiving re-treatment for loss of response after drug withdrawal.