ATLANTA – Treatment of polyarticular-course juvenile idiopathic arthritis with tofacitinib led to significantly fewer disease flares and greater improvement in disease activity than with placebo in a phase 3, multinational, randomized, double-blind, controlled withdrawal presented at the annual meeting of the American College of Rheumatology.
, director of the division of rheumatology at Cincinnati Children’s Hospital Medical Center, and colleagues conducted the study in 225 patients between 2 and less than 18 years old with polyarticular-course juvenile idiopathic arthritis (pJIA; n = 184), psoriatic arthritis (PsA; n = 20), or enthesitis-related arthritis (ERA; n = 21). Patients were included if they had an inadequate response or intolerance to a disease-modifying antirheumatic drug and active disease with five or more active joints in the case of pJIA and three or more active joints in PsA or ERA.
Dr. Brunner presented results only for pJIA patients; the results for PsA and ERA patients will be assessed and presented separately.
The researchers divided their study into two sections. In the open-label portion of the study, patients received twice-daily tofacitinib (Xeljanz) at a dose of 5 mg or a weight-based lower dose in patients under 40 kg for 18 weeks. A total of 173 patients met JIA ACR30 response criteria, defined as 30% or greater improvement in three of six JIA core set variables and worsening in no more than one of the core set variables, and then were randomized in part 2 of the study to continue the same dose of tofacitinib or receive placebo until 44 weeks. Dr. Brunner noted that most patients who discontinued treatment in parts 1 and 2 did so because of insufficient clinical response rather than from adverse events.
Disease flare occurrence between 18 and 44 weeks was measured as a primary endpoint, and key secondary endpoints included JIA ACR30/50/70 response and change in Childhood Health Assessment Questionnaire Disability Index (CHAQ-DI) scores from part 2 baseline. The researchers used a “gatekeeping approach” that sequenced outcome measures in their statistical analysis to control for false positives in primary and secondary outcomes, where statistical significance could be achieved only if the previous outcome in the sequence was statistically significant.
Patients had a median age of 13 years, and most were female, white (about 87%), and between one-third and one-half of patients were based in North America. JIA disease duration was a median of about 2.5 years, C-reactive protein was about 0.3 mg/dL, and median CHAQ-DI scores were about 0.9 across tofacitinib and placebo groups. Other baseline characteristics were balanced between the two groups, Dr. Brunner said.
“Patients with polyarticular-course JIA in the open-label study experienced a rapid improvement of their disease activity from very high to moderate within 18 weeks,” Dr. Brunner said in her presentation. “[T]ofacitinib demonstrated significantly greater efficacy versus placebo in patients with polyarticular-course JIA based on occurrence of fewer flares in part 2.”
Specifically, disease flare occurred in 29.2% of patients by 44 weeks in the tofacitinib group, compared with 52.9% of patients in the placebo group (P = .0031), for an overall 54% lower risk of flare among patients receiving tofacitinib (hazard ratio, 0.459; 95% confidence interval, 0.268-0.785; P = .0037). The response rate was higher for patients receiving tofacitinib at 44 weeks when measured by JIA ACR30 (70.8% vs. 47.1% with placebo; P = .0031) or by JIA ACR50 (66.7% vs. 47.1%; P = .0166) and JIA ACR70 criteria (54.2% vs. 37.1%; P = .0387). The change in CHAQ-DI score also improved at 44 weeks to a significantly greater extent in the tofacitinib group than with placebo (–0.09 vs. 0.03; P = .0292).
“The safety profile of tofacitinib in children with JIA was comparable to what you have seen or known in the [rheumatoid arthritis] population, and no new safety risks were identified in this pediatric population,” Dr. Brunner said.
The researchers reported ties with Pfizer, which funded the study, and more than two dozen other pharmaceutical companies.
SOURCE: Brunner HI et al. Arthritis Rheumatol. 2019;71(suppl 10), Abstract .