Lymphoma in the Tofacitinib Rheumatoid Arthritis Clinical Development Program.

OBJECTIVE: Tofacitinib is an oral JAK inhibitor indicated for the treatment of rheumatoid arthritis (RA). We characterized lymphoma events in the tofacitinib RA clinical development program.

METHODS: Lymphoma events (up to March 2015) were identified from 19 tofacitinib studies (2 phase I, 9 phase II, 6 phase III, and 2 long-term extension) of patients with moderate to severe RA. Patients in these studies received tofacitinib dosed at 1-30 mg twice daily or 20 mg once daily, as monotherapy or with conventional synthetic disease-modifying antirheumatic drugs. Lymphoma incidence rates (IRs; number of patients with events/100 patient-years) and standardized incidence ratios (SIRs) were calculated. A descriptive case-matched control analysis (1:4) was performed to identify potential risk factors for lymphoma.

RESULTS: A total of 6,194 patients received tofacitinib (19,406 patient-years of exposure, 3.4 years median treatment duration). Nineteen lymphomas occurred (IR 0.10 [95% confidence interval (95% CI) 0.06-0.15]), with no increase observed with time of exposure. The age- and sex-adjusted SIR of lymphoma was 2.62 (95% CI 1.58-4.09) (Surveillance, Epidemiology, and End Results [SEER] program database). The clinical characteristics of the 19 lymphomas were typical for the RA population. Three lymphomas were positive for Epstein-Barr virus, 8 were negative, 2 were equivocal, and 6 were untested. Numerically, more lymphoma cases had a history of Sjögren's syndrome and were positive for anti-cyclic citrullinated protein and rheumatoid factor at baseline versus matched controls. The mean corticosteroid dose was higher for lymphoma cases versus controls.

CONCLUSION: In the tofacitinib RA clinical development program, lymphoma rates were stable over time and there were minimal differences in the baseline characteristics of patients with and without lymphoma.