CHICAGO – Rheumatoid arthritis patients treated with tofacitinib did not have a significantly increased incidence of hospitalization for venous thromboembolism, compared with patients treated with a tumor necrosis factor (TNF) inhibitor, in a study of more than 50,000 U.S. patients culled from a pair of health insurance databases.
The Janus kinase inhibitor class of agents, including tofacitinib (), has acquired a reputation for causing an excess of venous thromboembolic events (VTE) ( ). To assess this in a real-world setting , and her associates took data from Medicare patients during 2012-2015 and from Truven MarketScan for commercially insured patients during 2012-2016 and derived a database of 16,091 RA patients on newly begun treatment with a TNF inhibitor and 995 newly begun on tofacitinib in the Medicare data, and 32,164 RA patients newly started on a TNF inhibitor and 1,910 on tofacitinib in the Truven database. The analysis excluded patients with a history of VTE.
Using propensity score–adjusted matching of patients in the two treatment arms in both of these databases, and using a VTE event – either a pulmonary embolism or deep-vein thrombosis that resulted in hospitalization – as the primary endpoint, the results showed statistically nonsignificant excesses of VTE in the patients treated with tofacitinib, compared with a TNF inhibitor, Dr. Kim reported in a poster she presented at the annual meeting of the American College of Rheumatology.
In the adjusted comparison, the Medicare data showed a nonsignificant 12% higher VTE rate in the tofacitinib-treated patients, while the Truven data showed a nonsignificant 55% higher rate of VTE during tofacitinib treatment. When the data were pooled, the result was a 33% higher rate of VTE while on tofacitinib treatment, which was not statistically significant.
Dr. Kim cautioned that the low rate of VTE events, especially among the patients on tofacitinib, limited the precision of the results. The combined data included 2,905 patients on tofacitinib treatment who had 15 VTE events, a rate of 0.77 events/100 person-years of follow-up. This compared with a rate of 0.52/100 person-years among patients on a TNF inhibitor. Thus, in both treatment groups the absolute VTE rate was low.
The most reliable finding from the analysis is that it “rules out a large increase in the risk for VTE events with tofacitinib,” said Dr. Kim, a rheumatologist at Brigham and Women’s Hospital in Boston.
The researchers also ran an analysis that included not only VTE events that resulted in hospitalization but also VTE events managed on an outpatient basis. Dr. Kim did not report the specific numbers involved in this calculation, but she reported that, when her group included both types of VTE events, the patients treated with tofacitinib had a nonsignificant 12% lower rate of events, compared with patients treated with a TNF inhibitor.
Dr. Kim has received research support from Bristol-Myers Squibb, Pfizer, and Roche.
SOURCE: Desai RJ et al. Arthritis Rheumatol. 2018;70(suppl 10), .