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Naarden, Netherlands & Waltham, Mass. & Barcelona, ​​Spain, October 07, — Prilenia Therapeutics B.V. and Ferrer today announced the presentation of their planned pivotal Phase 3 study of pridopidine in Amyotrophic Lateral Sclerosis (ALS) at the upcoming Northeast Amyotrophic Lateral Sclerosis Consortium (NEALS) 2025 Annual Meeting, Florida, October 7-10, 2025.

“The opportunity to potentially bring a much-needed new therapy for a disease as intractable as ALS is exciting and daunting in equal measure. The ALS community deserves to see progress in the management of the disease – we hope to make some of that progress. Early next year we expect to initiate the study at some of the leading ALS centers in the world, allowing us to begin enrolling participants with early and rapidly progressive ALS,” said Dr. Michael R. Hayden, CEO of Prilenia.

“In the phase 2 HEALEY ALS platform trial we have seen important improvements in global function (ALSFRS-R scores), speech, respiratory function and survival with pridopidine in people with early and rapidly progressive disease. Personally, the benefits in terms of speech were of special significance – helping patients to maintain the ability to communicate with their families at such fragile times brings a value that cannot be expressed clinically,” said Oscar Pérez, Chief Scientific Officer at Ferrer. “These signals provide hope that a sigma-1 receptor agonist like pridopidine can have a major positive impact for people living with ALS, and being on the cusp of being able to further explore that potential is a privilege.”

Details of the pivotal Phase 3 study and the in vivo neuronal survival data will be presented in two posters at NEALS:

Poster 1: A Planned Phase 3, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Efficacy and Safety of Pridopidine in Participants with ALS (poster #191 to be presented by Sabrina Paganoni, Healey Center for ALS at MGH, Boston, Thursday October 9th 2025).

The study will have an initial 48-week double-blind treatment period followed by a 48-week open-label extension phase, with a primary endpoint of change from baseline in ALSFRS-R adjusted for mortality at 48 weeks. Secondary endpoints will include the effect of pridopidine on survival, measures of speech, respiratory (SVC) and bulbar function, and quality of life (ALSAQ-40). The study will also evaluate patient-reported outcomes of communication, as well as plasma biomarkers. Enrollment of participants with early and rapidly progressive ALSii is expected to start in January 2026, subject to regulatory acceptance, at leading ALS treatment centers in the US, Canada and European countries (site opening will be on a rolling basis and subject to local regulatory requirements). The study population is defined to enable determination of a therapeutic effect within the limited timeframe of the trial.

Poster 2: Pridopidine exerts neuroprotective effects through the activation of the Sigma-1 receptor (S1R) by modulating ER stress in iPSC-derived neural progenitor cells (poster #192 to be presented by May Meltzer, Prilenia, Thursday October 9th, 2025).

Prolonged endoplasmic reticulum (ER) stress is an early hallmark of ALS and many other neurodegenerative diseases, implicated in increased mitochondrial dysfunction and reduced neuronal survival. S1R plays a role in pathways that help mitigate ER stress and mitochondrial dysfunction, translating into enhanced neuronal survival. Pridopidine significantly reduced expression of two key markers of ER stress, BiP and CHOPiii, by 72% and 52% respectively (p<0.0001), correlating with improved cell viability and growth (50% increase, p<0.0001). A selective S1R antagonist was then used to block pridopidine’s effect and demonstrate that restoration of mitochondrial function and cell survival was indeed S1R-dependent.