TOPLINE

Delaying JAK inhibitor therapy until after completing the recombinant zoster vaccine (RZV) doses resulted in enhanced early antibody responses in patients with rheumatoid arthritis (RA), whereas immediate treatment led to an earlier reduction in symptoms of arthritis. By 12 weeks, antibody responses were similar between the timing strategies.

METHODOLOGY

• Researchers investigated how the timing of JAK inhibitor initiation and RZV administration influenced vaccine effectiveness and safety in patients with RA in the STOP-HZ study, a multicenter, open-label, exploratory randomized clinical study conducted at 12 sites in Japan.
• Patients aged 50 years or older with RA who initiated tofacitinib therapy were enrolled; all participants received RZV on day 1 and at week 8 and were randomly assigned to initiate tofacitinib either on day 1 or at week 8. After exclusions, 29 and 30 patients, respectively, were analyzed.
• The primary endpoint was the geometric mean fold rise in varicella zoster virus (VZV)-specific immunoglobulin G antibody titers at week 12 compared with baseline within each group.
• Secondary outcomes were antibody responses over time, changes in disease activity index scores, and safety.

TAKEAWAY

• At week 12, VZV-specific antibody titers increased in both the day-1 and week-8 tofacitinib initiation groups, with a geometric mean fold rise of 2.66 (90% CI, 1.96-3.60) and 2.91 (90% CI, 2.17-3.91), respectively. The between-group ratio was 1.10 (90% CI, 0.73-1.64), suggesting comparable responses regardless of the timing of initiating the JAK inhibitor.
• At week 4, geometric mean titers were lower in the day-1 tofacitinib initiation group than in the week-8 tofacitinib initiation group; similarly, the proportion of patients who achieved a ≥ 1.5-fold increase in antibody titers was lower in the day-1 tofacitinib initiation group at week 4 (44.8% vs 80.0%). Both geometric mean estimates and the proportions of patients were similar between groups at week 12.
• Symptoms of arthritis reduced earlier in those who initiated tofacitinib on day 1, with Clinical Disease Activity Index scores at weeks 4 and 8 lower for these patients than for those who initiated tofacitinib at week 8, although estimates were similar by week 12.
• Adverse events occurred more frequently among those who initiated tofacitinib on day 1 (58.6%) vs at week 8 (23.3%), with exacerbation of arthritis occurring in 6.9% and 13.3% of patients in the respective groups.

IN PRACTICE

“[The] timing of JAK inhibitor initiation relative to RZV administration affects early immune responses and disease control, supporting an individualized approach,” the authors of the study concluded.

SOURCE

The study was led by Satoshi Takanashi, MD, PhD, Keio University School of Medicine, Tokyo, Japan. It was published online as a brief research report on July 21, 2026, in Annals of Internal Medicine.

LIMITATIONS

The sample size was small, the follow-up duration was short, and data on clinical herpes zoster incidence were lacking. Residual imbalances may have existed in baseline characteristics despite randomization, and unmeasured confounding could not be ruled out. The study lacked adequate statistical power for between-group comparisons.

DISCLOSURES

The study received financial support from Pfizer. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.