• Primary endpoints for Phase 3 trial of NNZ-2591 in Phelan-McDermid syndrome (PMS) confirmed with FDA
• Co-primary endpoints are change in Receptive Communication and overall Phelan-McDermid Syndrome Assessment of Change
• Endpoints align with key symptoms and caregiver/clinician assessments from positive Phase 2 data

Neuren Pharmaceuticals (ASX: NEU) has announced that the primary endpoints for its planned single Phase 3 pivotal clinical trial of NNZ-2591 in Phelan-McDermid syndrome (PMS) have been confirmed at a productive Type C Meeting with the US Food and Drug Administration (FDA). The co-primary endpoints in the double-blind placebo-controlled study of treatment for 13 weeks will be the change from baseline in the Receptive Communication sub-domain of the Vineland Adaptive Behavior Scales, Third Edition (VABS-3 Receptive-Raw Score) and the overall score in the Phelan-McDermid Syndrome Assessment of Change (PMSA-C, previously referred to as CGI-I in Neuren's Phase 2 trial). Both measures were robustly positive with clinically meaningful improvement in Neuren's Phase 2 open-label clinical trial. Communication is one of the most impactful health concerns in PMS reported by caregivers, and receptive communication is a foundational skill for the development of learning, social interaction, and speech. Alignment with FDA was previously reached on the other key features of the Phase 3 program at an End of Phase 2 Meeting. Neuren remains on-track to commence the Phase 3 trial mid-year 2025, subject to FDA review of the final version of the trial protocol.

Neuren is excited to move forward as planned with the first ever Phase 3 trial in children with Phelan-McDermid syndrome, building on the positive results from its Phase 2 open-label clinical trial.