Abbott Laboratories (ABBOTT PARK, Illinois) reported that more psoriasis patients achieve efficacy when they receive continuous treatment with Humira^® (adalimumab) compared with patients who interrupt their therapy. The findings were from the company's pivotal, 52-week study, REVEAL (The Randomized Controlled EValuation of Adalimumab Every Other Week in Moderate to Severe Psoriasis Trial), and the period of open-label treatment that followed. REVEAL was a double-blind, randomized, placebo-controlled phase III trial to evaluate the efficacy and safety of the drug in 1212 adults with moderate-to-severe chronic psoriasis in the US and Canada.

The subgroup analysis was designed to determine whether interrupting Humira treatment would affect efficacy in psoriasis patients who had already achieved good response to the drug. After 33 weeks, patients who had achieved PASI 75 were randomized into two groups: one continued to receive Humira and the other was given placebo. Beginning at week 52, all patients received drug therapy during the open-label extension period.

Patients who had maintained adequate response after Humira was discontinued were more likely to achieve a PASI 75 response when they were restarted on treatment. Among those who discontinued and then re-started the drug, 84% of the 161 patients who had maintained adequate response achieved PASI 75 after 24 weeks of re-treatment compared with 55% of the 66 patients who had lost adequate response after stopping treatment. A loss of adequate response was defined as less than PASI 50 response relative to baseline and at least a 6-point increase in PASI score relative to week 33.

A separate subgroup analysis of REVEAL evaluated whether specific patient characteristics would affect the efficacy of Humira therapy. The analysis found that the drug effectively treats psoriasis regardless of a patient's age; disease duration; whether the patient has a diagnosis of psoriatic arthritis; or a recent history of systemic therapy, including biologic treatments. At 16 weeks, 71% of patients treated with Humira achieved a PASI 75 response compared with 6.5% of patients treated with placebo, with similar results seen among the patient subgroups.

Humira, which blocks TNFα, is the only fully-human monoclonal antibody approved in the US and Europe for the treatment of rheumatoid arthritis, psoriatic arthritis, psoriasis, ankylosing spondylitis, Crohn's disease, and juvenile idiopathic arthritis. To date, the drug has been approved in 76 countries and >270,000 people worldwide are on the therapy. Clinical trials are underway evaluating the potential of Humira in ulcerative colitis.