Treatment with Xeljanz (tofacitinib) reduces disease flares, improves physical functioning, and significantly eases symptoms of polyarticular juvenile idiopathic arthritis (pJIA), results from a Phase 3 clinical trial show.
The research, “Tofacitinib for the Treatment of Polyarticular Course Juvenile Idiopathic Arthritis: Results of a Phase 3 Randomized, Double-blind, Placebo-controlled Withdrawal Study,” will be presented today at the 2019 American College of Rheumatology and the Association of Rheumatology Professionals (ACR/ARP) Annual Meeting, in Atlanta, Georgia.
Pfizer‘s Xeljanz is a small molecule designed to specifically inhibit the activity of a cellular enzyme called janus-activated kinase (JAK), which plays a key role in the activation of pro-inflammatory signals. It is approved as an oral treatment for adults with rheumatoid arthritis, psoriatic arthritis and ulcerative colitis in both the U.S. and the European Union, but its effectiveness in pediatric patients is still being investigated.
The safety and therapeutic activity of Xeljanz was explored in a Phase 3 clinical trial (NCT02592434) sponsored by Pfizer, which included 225 pediatric patients (median age 13 years, range 2-17) with JIA. Among the participants, 184 had pJIA, 20 had psoriatic arthritis, and 21 had enthesitis-related arthritis. They had had the disease for a median of 2.5 years.
All received Xeljanz for 18 weeks. Those fulfilling the ACR30 criterion were then assigned randomly to continue taking the therapy, or start receiving a placebo for 26 additional weeks. Of note, ACR30 means 30% less tender and swollen joints, and a 30% improvement/reduction in three of five criteria: patient global assessment, physician global assessment, functional ability, a pain scale, and markers of inflammation.
Xeljanz was administered according to each patient’s body weight, with twice-daily 2−4 mg oral solution for patients weighing less than 40 kilograms (about 88 pounds) and 5 mg tablets or oral solution twice-daily for heavier patients.
Results at the end of second part of the trial (week 44) showed that children with pJIA treated with Xeljanz had significantly fewer disease flares compared to those receiving a placebo (29.2% versus 52.9%). Staying on Xeljanz also led to longer time without disease flares than switching to a placebo.
Continued treatment with Xeljanz also increased the number of participants achieving ACR30 or better (50 and 70, meaning 50% and 70% improvement in the same parameters), as well as the children’s physical functioning, assessed by greater changes in Childhood Health Assessment Questionnaire Disability Index (CHAQ-DI) at week 44, compared to baseline.
The therapy also reduced signs and symptoms of pJIA, and led to stable disease activity, in contrast to the deterioration seen with placebo.
Safety results were similar with Xeljanz and placebo, and consistent with previous reports from adults with rheumatoid arthritis. Adverse events (side effects) were seen in 77.3% participants on Xejlanz and 74.1% on placebo.
The most common side effects in both groups were upper respiratory tract infection, headache, inflammation of the nose and throat, and nausea. Only 1.1% of patients on Xeljanz experienced serious side effects, with no opportunistic infections.
“[T]reatment with tofacitinib [Xeljanz] vs [placebo] resulted in significantly fewer disease flares, improved time to flare, improvements in disease signs and symptoms and physical functioning, and a sustained clinically meaningful improvement in disease activity,” in patients with pJIA, the researchers wrote.