Priovant Therapeutics' brepocitinib, a dual TYK2/JAK1 inhibitor, is showing promise in treating non-infectious uveitis (NIU). Data from the Phase 2 NEPTUNE trial, presented at the American Academy of Ophthalmology (AAO) 2024 meeting, revealed significant reductions in treatment failure among patients with non-infectious intermediate, posterior, and panuveitis.
NEPTUNE Trial Results
The NEPTUNE trial (NCT05523765) randomized patients to either brepocitinib 45mg once daily (n=17) or 15mg once daily (n=9) over 52 weeks, with a primary endpoint of treatment failure assessed between Weeks 6 and 24. Treatment failure was defined by worsening best corrected visual acuity (BCVA), inflammation, or new inflammatory lesions. All patients received an initial prednisone dose of 60mg, tapered over six weeks.
At six weeks, the brepocitinib 15mg group showed a 44% treatment failure rate (p < 0.05), while the 45mg group had a 29% rate (p < 0.0001), compared to a prespecified historical placebo control rate of 80%. A dose-dependent reduction was observed in components of treatment failure, including worsening of BCVA and vitreous hemorrhage (VH). By Week 24, the 45mg group showed a 4.4-point reduction in posterior segment inflammation based on fluorescein angiography (FA) score, while the 15mg group showed a 0.5-point reduction, also dose-dependent. The 45mg group also achieved a 15.4% mean change from baseline in central subfield thickness (CST), indicating sustained improvement, especially in patients with baseline macular edema.
CLARITY Phase 3 Trial
Building on these results, Priovant has initiated the CLARITY Phase 3 trial (NCT06431373) to further evaluate brepocitinib in non-anterior NIU. This global, multi-center program will compare brepocitinib 45 mg to placebo in two sub-studies, each with 150 subjects randomized 1:1. The primary endpoint is time to treatment failure, closely modeled after the NEPTUNE study.
FDA Fast Track Designation
The FDA has granted Fast Track Designation to brepocitinib for NIU, designed to expedite the development and review of drugs addressing serious conditions with unmet medical needs. Brepocitinib is a potential first-in-class dual selective inhibitor of TYK2 and JAK1, administered orally once daily.
Expert Commentary
Dr. Quan Dong Nguyen, CLARITY investigator and Professor of Ophthalmology at the Byers Eye Institute, Stanford University School of Medicine, noted that current treatment options for NIU are inadequate and that brepocitinib's Phase 2 results suggest it could be a transformative therapy for controlling inflammation and improving visual acuity.
Dr. Dilraj Grewal, Associate Professor of Ophthalmology at Duke University, highlighted that the NEPTUNE trial's wide-field FA results showed a clinically meaningful, dose-dependent improvement in posterior segment inflammation with brepocitinib.
Safety Profile
In the NEPTUNE trial, brepocitinib was generally well-tolerated. No thrombolytic events, major adverse cardiovascular events (MACE), malignancies, or deaths were reported. One severe adverse event (SAE) of moderate hypersensitivity was reported in the 15mg arm, treated with oral diphenhydramine, and another SAE was reported for costochondritis. Common treatment-emergent adverse events (TEAEs) included rash and arthralgia, with other TEAEs being mild or moderate and unrelated to uveitis.
Future Outlook
Top-line 52-week Phase 2 data from NEPTUNE is expected by the end of the year. Priovant is also evaluating brepocitinib in a Phase 3 study for dermatomyositis (VALOR), with top-line data expected in the second half of 2025.
