Neuren Pharmaceuticals Sponsors PMSF Conference, Expands Phase 3 Koala Trial for Phelan-McDermid Syndrome

Neuren’s Pipeline Addresses Multiple Severe Neurological Disorders with Limited Therapies

Neuren Pharmaceuticals is a clinical-stage company developing novel drug therapies for serious neurological disorders caused by genetic mutations or brain injury. Its therapeutic strategy targets the critical role of Insulin-like Growth Factor 1 (IGF-1) in the brain, utilizing orally administered analogs of naturally occurring peptides. This focused approach places Neuren in a specialized and expanding therapeutic niche addressing rare neurological conditions with significant unmet needs.

The company’s clinical portfolio includes several programs. DAYBUE® (trofinetide) oral solution is approved by the US FDA, Health Canada, and Israel’s Ministry of Health, while DAYBUE STIX (trofinetide) powder is FDA-approved to treat Rett syndrome. Neuren has granted Acadia Pharmaceuticals Inc. an exclusive worldwide license for trofinetide’s development and commercialization, enabling Neuren to concentrate on its investigational programs. Its lead candidate, NNZ-2591 (ercanetide), is in clinical development for neurodevelopmental disorders including Phelan-McDermid syndrome, Pitt Hopkins syndrome, Angelman syndrome, and hypoxic ischemic encephalopathy (HIE).

Koala Phase 3 Trial Expansion Demonstrates Growing Rare Disease Clinical Network

The Koala Phase 3 clinical trial is expanding its network of sites, reflecting increased momentum in patient recruitment and clinical research. The study evaluates NNZ-2591’s safety and efficacy in children aged 3 to 12 with Phelan-McDermid syndrome through a randomized, double-blind, placebo-controlled design, followed by a 52-week open-label extension. Currently, 13 sites across the US and Canada are activated, including the first Canadian site.

Four additional sites are scheduled to open in August 2026. Chief Medical Officer Liza Squires noted the Koala study "continues to gain momentum" with 13 sites actively enrolling. Over 100 potential participants have been referred or await activation of geographically closer sites. The first participants have completed 13 weeks of randomized treatment and are progressing into the open-label extension. Additionally, the first patient from Neuren’s prior Phase 2 open-label study has re-enrolled in the Phase 3 open-label extension, indicating continuity in patient participation.

Updated Research Shows PMS Prevalence Much Higher Than Previously Estimated

Research presented at the PMSF Family Conference, supported by Neuren, significantly revises PMS prevalence estimates. Tess Levy, lead author of a study published in Autism Research, reported a prevalence of 1 in 7,300 people—much higher than earlier figures. This revision expands the recognized patient population and highlights the extensive unmet medical need in this rare genetic disorder.

Phelan-McDermid syndrome results from deletions or mutations in the 22q13 region of chromosome 22, including the SHANK3 gene. SHANK3 protein is essential for synaptic structure in the brain; its dysfunction causes severe neurological impairment. PMS is characterized by moderate to severe developmental and intellectual disabilities, delayed or absent speech, autism-like symptoms, low muscle tone, motor delays, epilepsy, and behavioral challenges impacting socialization and self-care. No approved treatments currently exist, creating a critical unmet need and significant impacts on patients and families.

Regulatory Recognitions Accelerate NNZ-2591 Development

Neuren’s investigational drug NNZ-2591 (ercanetide) has earned key regulatory designations in the US and Europe, expediting its development. Orphan drug status has been granted for Neuren’s programs targeting Phelan-McDermid syndrome, Pitt Hopkins syndrome, and Angelman syndrome in both regions, providing incentives such as extended market exclusivity.

The Phelan-McDermid syndrome program also received FDA Fast Track designation, facilitating early and frequent regulatory interactions to speed development and review. Additionally, it holds the FDA’s Rare Pediatric Disease designation, recognizing the severity and lack of approved therapies. Neuren is further developing NNZ-2591 for hypoxic ischemic encephalopathy (HIE), broadening its therapeutic ambitions across multiple neurological indications using the same compound.

Direct Patient and Clinical Engagement at PMSF Conference Strengthens Community Ties

As Presenting Sponsor of the Phelan-McDermid Syndrome Foundation Family Conference, Neuren engaged directly with patients, families, researchers, and clinicians. The event, held in Colorado from 15–19 July 2026 and themed "The climb we make together," attracted more than 800 participants. CEO Jon Pilcher spoke at both the opening and closing sessions, while Chief Medical Officer Liza Squires presented the NNZ-2591 development program and Koala trial updates.

A 12-member Neuren team hosted both a corporate booth and a dedicated Koala study booth, facilitating direct communication with families and stakeholders. CEO Jon Pilcher described the conference as "inspiring and energising," emphasizing the importance of conversations with families caring for loved ones with PMS. He highlighted that the "courage, determination, and support of PMS families," alongside ongoing collaboration with clinicians, researchers, PMSF, and CureSHANK, will be vital as Neuren pursues the potential first approved treatment for PMS.

Collaboration with Advocacy Groups Reinforces Neuren’s Commitment

Neuren’s Presenting Sponsor role at the PMSF Family Conference reflects its strategic partnership with patient advocacy organizations and community-driven research. PMSF CEO Robbie Baker acknowledged Neuren’s "generous support" in sponsoring the 2026 conference, which facilitated connections among families, researchers, and clinicians to advance PMS research and care. Baker noted that the community is "in an unprecedented era of research and therapeutic development," with Neuren’s Phase 3 Koala study marking "a landmark as the first-ever Phase 3 clinical trial specifically for PMS."

For a rare disorder with no approved treatments, Baker emphasized that the Koala trial milestone represents both scientific progress and hope. This collaborative approach—combining patient engagement, clinical partnerships, and advocacy support—positions Neuren as a key contributor to improving diagnosis, accelerating genetic testing, and advancing therapies for PMS. Neuren’s support of research revising PMS prevalence further demonstrates its commitment beyond clinical trials.

Robust Clinical Trial Design Underpins Neuren’s Scientific Approach

The Koala Phase 3 trial employs a rigorous randomized, double-blind, placebo-controlled design in children aged 3 to 12 with PMS, complemented by a 52-week open-label extension. This structure ensures robust data for regulatory review while enabling long-term safety and efficacy evaluation.

With 13 sites activated and four more planned, the trial’s expansion aligns with a well-managed Phase 3 program. Over 100 potential participants have been referred or await site activation, indicating promising enrollment momentum, especially given the revised higher PMS prevalence. Allowing Phase 2 participants to transition into the Phase 3 open-label extension supports continuity of care and participant retention.

Market Potential and Unmet Needs Support Commercial Viability

The updated prevalence estimate of 1 in 7,300 substantially enlarges the addressable PMS patient population. Combined with the absence of approved treatments, this creates a significant commercial opportunity for a first-in-class therapy. The Koala trial’s status as the first Phase 3 study designed specifically for PMS positions Neuren to potentially be the first to market a disease-modifying treatment.

PMS’s severe developmental, intellectual, motor, and behavioral impairments profoundly affect patients and families. A safe, effective therapy would address a critical unmet need and likely generate strong clinical demand. Neuren’s broader NNZ-2591 program targeting Pitt Hopkins syndrome, Angelman syndrome, and HIE also offers potential commercial expansion across multiple indications using the same compound, pending successful clinical outcomes.

Risks and Challenges in Rare Disease Development

Despite encouraging progress, Neuren faces challenges typical of rare disease drug development. Recruiting sufficient participants across activated and upcoming sites depends on ongoing patient identification, caregiver consent, and site capacity. Any enrollment delays could impact trial timelines and regulatory submissions. The randomized placebo-controlled design in a pediatric population with severe symptoms may pose ethical or practical recruitment challenges if early efficacy signals emerge.

Regulatory approval is not guaranteed despite orphan drug and Fast Track designations. The trial must demonstrate safety and efficacy in a controlled setting; adverse events could delay or halt development. Additionally, Neuren’s commercial success depends on partnerships, such as the licensing agreement with Acadia Pharmaceuticals for trofinetide, which may affect the company’s ability to capture value from NNZ-2591. The company cautions that forward-looking statements are subject to risks and uncertainties that could materially affect actual results.