# Novel application for the JAK inhibitor baricitinib in the treatment of Vogt–Koyanagi–Harada disease: a prospective cohort study

## TL;DR

This study shows that baricitinib, a JAK inhibitor, effectively treats both early and late stages of Vogt–Koyanagi–Harada disease with minimal side effects.

## Contribution

The novel use of baricitinib as a treatment for VKH disease is demonstrated, including its efficacy in monotherapy and combination therapy.

## Key findings

- Baricitinib monotherapy significantly improved visual acuity, reduced inflammation, and resolved subretinal fluid in VKH patients.
- No severe adverse drug reactions or disease recurrences were observed during the follow-up period.
- Baricitinib allows for a reduction in corticosteroid use while maintaining effective disease control.

## Abstract

The purpose of this study was to prospectively evaluate the clinical efficacy and safety of baricitinib, a selective Janus kinase (JAK)1/JAK2 inhibitor, in the treatment of patients with Vogt–Koyanagi–Harada (VKH) disease.

The study was designed as a prospective, open-label, longitudinal, single-center cohort study.

We enrolled 38 patients (76 eyes) with VKH disease (including both initial-onset and recurrent/chronic cases) at Tongji Hospital, Wuhan, China, between 2022 and 2024. Patients were assigned to one of two treatment protocols based on disease severity and prior treatment history: group A received oral baricitinib (4 mg/day) combined with systemic methylprednisolone, and group B received oral baricitinib monotherapy. Clinical assessments were performed at baseline and at 1, 3, 6, 12, and 18 months. Primary outcome measures included best-corrected visual acuity (BCVA), anterior chamber (AC) cell and flare grades, subfoveal choroidal thickness (SFCT), subretinal fluid (SRF) height, and angiographic inflammatory scores (fluorescein angiography [FA]/indocyanine green angiography [ICGA]). Secondary outcomes included quality-of-life scores (25-item version of the Visual Function Questionnaire [VFQ-25], SF-36), adverse drug reactions (ADRs), and recurrence rates.

The cohort included 44 eyes with early-stage (initial-onset) and 32 eyes with late-stage (recurrent) VKH disease (mean age: 43.1 years ± 12.3 years; follow-up: 6–18 months). Inflammation control was achieved in all patients in both groups. In group A, the combination therapy led to rapid resolution of inflammation. In group B (monotherapy), significant improvements were observed from baseline to the final visit, including improved BCVA (0.12 to 0.68, p < 0.001), reduced AC cell grade (1.54 to 0.05, p = 0.007), decreased SFCT (537.6 to 252.4 µm, p = 0.007), and complete resolution of SRF (p < 0.001). FA and ICGA scores significantly decreased (p < 0.05), and VFQ-25 scores improved (82.6 to 92.9, p < 0.001). No severe ADRs or disease recurrences were observed during the follow-up period.

This study demonstrates that baricitinib is a promising therapeutic option for both early- and late-stage VKH disease. It effectively controls choroidal inflammation, improves visual function, and allows for a substantial reduction in corticosteroid burden with a favorable safety profile.

http://www.chictr.org.cn, identifier ChiCTR2100048030.