Neuren Pharmaceuticals (ASX: NEU) has taken a major step forward, confirming the primary endpoints for its pivotal Phase 3 trial of NNZ-2591 in children with Phelan-McDermid syndrome (PMS) following a positive Type C meeting with the US FDA.
This Phase 3 trial will be the first of its kind for PMS, a rare neurodevelopmental disorder with no approved treatments. It’s a significant moment—not just for Neuren, but for the families impacted by this condition.
The trial will assess changes over 13 weeks in two key areas: receptive communication (via the VABS-3 Receptive-Raw Score) and the overall clinical impression of improvement (via the PMSA-C score). Both of these were standouts in Neuren’s earlier Phase 2 open-label study, where 16 out of 18 children showed meaningful improvements across both measures. In particular, receptive communication is considered a core challenge in PMS, and any progress there could be life-changing.
Neuren CEO Jon Pilcher said the company was “very pleased” with the FDA discussions and confirmed the trial remains on track to begin around mid-2025, pending final protocol review. Importantly, the company noted that no additional funding is needed to carry out the trial, underlining its strong financial position.
This FDA green light builds on earlier alignment achieved during the End-of-Phase-2 meeting, which had already cleared the path for most of the Phase 3 study design. Now, with the primary endpoints confirmed, Neuren is gearing up to potentially deliver the first approved treatment for PMS—an area of high unmet need.
Neuren is also continuing to develop NNZ-2591 across a suite of other neurodevelopmental disorders, including Pitt Hopkins and Angelman syndromes, with all programs benefiting from orphan drug designation in the US. Its first approved product, DAYBUE™ (trofinetide), is already on the market for Rett syndrome, licensed to Acadia Pharmaceuticals.
