Roivant and Priovant Therapeutics have announced positive outcomes from the Phase II NEPTUNE clinical trial of brepocitinib in non-anterior non-infectious uveitis (NIU).

The double-blind trial involved 26 participants with active NIU, who were randomised into a 2:1 ratio to receive either brepocitinib 45mg or brepocitinib 15mg once a day.

A 60mg per day prednisone burst was administered for two weeks at the start, followed by a six-week tapering off period.

The primary efficacy endpoint was the treatment failure rate at week 24, with results showing lower rates, indicating a greater treatment benefit.

In the 45mg brepocitinib arm, 29% of subjects experienced treatment failure, compared to 44% in the 15mg arm at week 24.

The treatment failure rate from disease activity alone was 18% in the higher dose group.

This result is approximately double the benefit observed in the registrational study for the only approved non-steroidal therapy in NIU.

Secondary efficacy endpoints at week 24, including haze grades, visual acuity, and macular thickness, also showed positive and dose-responsive outcomes.

In the trial, 43% of subjects with uveitic macular oedema at baseline in the 45mg arm achieved resolution by week 24, and none developed macular oedema.

The safety and tolerability profile of brepocitinib was in line with prior data, without any new concerns being detected.

Based on these data, Priovant is planning to launch a Phase III programme in NIU in the second half of this year.

In addition, the ongoing Phase III study of brepocitinib in dermatomyositis is on track for full enrolment by the third quarter of 2024, with results anticipated in 2025.

Priovant CEO Ben Zimmer said: “The NEPTUNE study was designed to minimise the likelihood of false signals of benefit by tapering patients with active disease from 60mg/day of prednisone to 0mg/day in just six weeks, more than twice as fast as steroid tapers in precedent studies.

“Against that backdrop, we are thrilled to see a failure rate of only 29% in the brepocitinib 45mg arm, better than any precedent study was able to achieve, even with more lenient tapers.

“The magnitude and consistency of the dose-dependent benefit across multiple independent measurements of inflammation, visual acuity, and macular oedema give us high confidence heading into Phase III.”