Brepocitinib Phase 2 NEPTUNE Study Shows Most Potent NIU Efficacy to Date

Priovant Therapeutics has reported promising results from the Phase 2 NEPTUNE study for its drug candidate, brepocitinib, in the treatment of non-anterior non-infectious uveitis (NIU). The study involved 26 participants with active NIU, who were assigned to receive either 45 mg or 15 mg of brepocitinib daily. The participants, as well as the medical team, were unaware of the dosage received, ensuring a blinded study design.

At the 24-week mark, the study revealed that 29% of those on the 45 mg dose and 44% on the 15 mg dose experienced treatment failure, with lower rates indicating a more effective treatment. Notably, the 18% failure rate in the 45 mg group was derived from disease activity, excluding those who discontinued the study. These findings are significant, as they demonstrate a benefit roughly double that observed in a similar study for another non-steroidal NIU therapy.

The NEPTUNE study marks the seventh successful Phase 2 trial for brepocitinib, which has been administered to over 1,400 subjects and patients. The drug has shown a favorable safety profile, aligning with that of other JAK inhibitors commonly prescribed. Secondary endpoints at week 24, such as haze grades, visual acuity, and macular thickness, also indicated positive and dose-responsive results. Specifically, 43% of the 45 mg group with uveitic macular edema at the study's start saw resolution by week 24, while no new cases of macular edema emerged in those without it at baseline.

Brepocitinib's dual inhibition of TYK2 and JAK1 is believed to suppress key cytokines associated with autoimmunity, offering a targeted approach to treating NIU. Quan Dong Nguyen, a NEPTUNE investigator and ophthalmology professor, emphasized the need for new treatments given the severe impact of NIU and the inadequacy of current options.

Ben Zimmer, Priovant's CEO, highlighted the study's rigorous design, which quickly tapered patients off prednisone to minimize false positive results. He expressed optimism about the drug's potential, given its consistent dose-dependent benefits across various inflammation and vision metrics.

Priovant plans to initiate a Phase 3 NIU program in late 2024 and is also conducting a Phase 3 study for brepocitinib in dermatomyositis, with results anticipated in 2025. The company's focus is on developing innovative therapies for high-morbidity autoimmune diseases with limited treatment options.