Safety of JAK inhibitor use in patients with rheumatoid arthritis who developed herpes zoster after receiving JAK inhibitors

Abstract

Introduction: To determine the safety of Janus kinase inhibitor (JAKi) use following herpes zoster (HZ) reactivation in patients with rheumatoid arthritis (RA).

Methods: Medical records of all patients who received JAKi at a tertiary referral center between August 2015 and June 2021 were retrospectively reviewed. Data from patients who developed HZ reactivation were collected, and the HZ-related safety of those who continued JAKis after reactivation was evaluated.

Results: Of the 416 patients who received JAKis, 33 (7.9%) developed HZ reactivation during treatment (tofacitinib, n = 22; baricitinib, n = 11). The mean age of the patients was 60.2 ± 11.8 years. Fourteen patients (42.4%) received glucocorticoids with a median dose of 3.75 mg of prednisone (IQR, 2.5-5.0). The median duration of JAKi administration before HZ reactivation was 11 months (IQR, 4-29). JAKi was continued in 24 (72.7%) patients during the HZ episode, while it was temporarily discontinued and then resumed after the HZ episode in 5 (15.2%) patients. Three (9.1%) patients had acute complications, such as encephalitis with HZ ophthalmicus. Four (12.1%) patients, including the 3 with complications, permanently discontinued JAKis. Of the 29 patients who were observed for a median of 12 months (IQR, 6-21) after the initial HZ reactivation episode, reactivation recurred in one (3.4%); this patient maintained JAKi treatment for a further 18 months without additional HZ recurrence.

Conclusion: JAKis were commonly continued or re-administered in patients with HZ reactivation, and the majority of these patients did not experience significant complications or recurrence of HZ reactivation. Thus, the use of JAKi after HZ reactivation episode seems to be tolerated.