Study on ustekinumab for treatment of psoriatic arthritis published

A group of patients suffering from potentially debilitating psoriatic arthritis showed significant and prolonged improvement after treatment with ustekinumab, according to data from a randomized, double-blind, placebo-controlled study in patients with moderate to severe psoriatic arthritis (PsA).

The Phase 2 study was published in the British medical journal The Lancet.

"This is a positive development for patients living with the joint pain and swelling that characterizes the disease, even as more research is needed to further test the efficacy of this treatment in psoriatic arthritis," said Alice Gottlieb, MD, Chairperson of the Department of Dermatology at Tufts Medical Center and lead author of the study.

Tufts Medical Center was among several academic medical centers which participated in the study. Tufts Medical Center is a 451-bed hospital in Boston and the primary teaching hospital for Tufts University School of Medicine.

Ustekinumab is a human immunoglobulin monoclonal antibody that is also being studied for treatment of patients with moderate-to-severe plaque psoriasis. Researchers conducting the study published in The Lancet reported that at week 12 of the study, 42 percent of patients given 63 or 90 mg of the drug at weeks 0, 1, 2 and 3 showed significant improvement in their pain, stiffness and other symptoms defined by the American College of Rheumatology (ACR20) score compared with 14 percent of patients who received placebo at the same time points (P < 0.001). At week 36, 33 weeks after their last dose, approximately three quarters of patients who had achieved ACR 20 sustained the improvement in their psoriatic arthritis symptoms. Also at week 24, 12 weeks after their initial ustekinumab dose, 51 percent of patients who had initially received placebo at Weeks 0, 1, 2 and 3 achieved ACR 20 following two doses of ustekinumab at weeks 12 and 16.

A secondary endpoint of the study showed that of patients who had plaque psoriasis on at least 3 percent of their body, 52 percent receiving 63 or 90 mg ustekinumab at weeks 0, 1, 2 and 3 achieved at least a 75 percent improvement in psoriasis from baseline as measured by the Psoriasis Area and Severity Index (PASI 75) at week 12 compared with five percent of patients receiving placebo (P < 0.001).

Through week 12, the placebo-controlled portion of the study, the proportion of patients with at least one adverse event (AE) was similar between patients in Group 1 receiving ustekinumab (61 percent) and those in Group 2 receiving placebo (63 percent). There were no serious AEs in Group 1 versus 4 percent of patients (n=3) in Group 2. There were no deaths, no reports of malignancy, tuberculosis or serious infections in either group. Through week 36, after the placebo crossover, the pattern of AEs was similar to that observed through week 12 of the trial.