An 11-mg, once-daily, modified-release formulation of the Janus kinase inhibitor Xeljanz (tofacitinib) did not meet a noninferiority of efficacy primary endpoint when compared against a 5-mg, immediate-release formulation of the drug taken twice daily in a phase 3, randomized trial of 209 Japanese patients with rheumatoid arthritis.
Although the modified-release formulation did not achieve noninferiority with the immediate-release dosing after 12 weeks, the number of patients who achieved a clinically meaningful outcome was similar in both groups, Yoshiya Tanaka, MD, PhD, and his colleagues reported online Aug. 17 in Rheumatology.
Noninferiority between the two formulations “was to be declared if the upper bound of the two-sided 95% [confidence interval] for the difference in [Disease Activity Score in 28 Joints–C-reactive protein] between treatment groups was less than 0.6,” they said. The difference in DAS28-CRP scores of 0.43 had a 95% CI upper bound of 0.69, demonstrating a lack of noninferiority.
The percentages of patients achieving 1.2 or more points improvement in DAS28-CRP were similar at 89% of patients on the modified-release tofacitinib and 85% of those on immediate-release tofacitinib. At baseline, patients in the study were on a stable dose of methotrexate at 6-16 mg/week (mean of about 9.5 mg/week) for 6 or more weeks.
About half of patients in both groups reported adverse events, and serious adverse events occurred in 4%-5%.
Pfizer funded the study.
SOURCE: Tanaka Y et al. Rheumatology (Oxford). 2018 Aug 17. doi: 10.1093/rheumatology/key250.