Janus Kinase Inhibitors Associated With Thromboembolic Events

In a study, published in the European Journal of Clinical Pharmacology, researchers investigated whether Janus kinase (JAK) inhibitors were associated with increased risk of venous thromboembolic (VTE) and arterial thromboembolic (ATE) events. According to the study’s lead author, Amandine Gouverneur, the researchers’ findings suggested that baricitinib and tofacitinib were associated with an increased risk of VTE and ATE.

The self-controlled case series study utilized data from 5870 patients within the French healthcare insurance system database SNDS who were dispensed baricitinib or tofacitinib and experienced at least one VTE or ATE event between November 2017 and June 2019. Researchers used incident rate ratios (IRR) to identify potential associations between JAK inhibitor treatment and thromboembolic events within 30 or 60 days.

JAK Inhibitors Appear to Associate With VTE and ATE Events

Reportedly, among the cohort, 92 patients had incident VTE or ATE within the post-exposure periods. These patients had a median age at JAK inhibitor initiation of 65.7 years (interquartile range [IQR], 56.1-75.8), and were 65.2% female (n=60). A total of 60 patients received baricitinib, 30 received tofacitinib, and 2 received both.

VTE and ATE events occured in 38 (41.3%) and 54 (58.7%) patients, respectively, with a median time-to-event after initiating JAK inhibition of 4.6 months (IQR, 2.5-9.2) for VTE and 6.1 months (IQR, 3.0-8.5) for ATE. The IRR for VTE during JAK inhibitor treatment was 8.27 (95% CI, 3.41-20.04), and the authors noted the risk remained elevated during the 30-day post-exposure period (6.52; 95% CI, 2.02-21.11).

Likewise, ATE had an IRR of 9.27 (95% CI, 3.68-23.34) which also remained increased during the 30-day post-exposure period (10.12; 95% CI, 3.27-31.37). The authors did add that no risk increase was identified during long-term post-exposure for ATE or VTE.

Overall, the researchers concluded that their study “shows evidence of an increased risk of VTE and ATE associated with the use of baricitinib and tofacitinib.”

Browse More Related Research on the Venous Thromboembolism Knowledge Hub