Ferrer Completes Patient Enrollment for the PROSPER Phase II Clinical Trial in Progressive Supranuclear Palsy Ahead of Schedule
Barcelona, Spain — [October 2025] — Ferrer, the international pharmaceutical company headquartered in Spain, today announced the successful completion of patient recruitment for its PROSPER study, a Phase II clinical trial evaluating FNP-223, a novel investigational therapy aimed at slowing the progression of Progressive Supranuclear Palsy (PSP). The company achieved full enrollment of 220 participants two months ahead of schedule, marking a significant milestone in the development of potential disease-modifying treatments for this rare and devastating neurodegenerative disorder.
The PROSPER study is designed to assess the efficacy, safety, and pharmacokinetics of FNP-223, an orally available, potent, and selective inhibitor of the O-GlcNAcase (OGA) enzyme, in patients diagnosed with PSP. FNP-223 was in-licensed from Asceneuron, a clinical-stage biotechnology company focused on developing small molecule therapeutics for neurodegenerative diseases. By inhibiting OGA, FNP-223 aims to reduce the pathological accumulation of tau proteins in the brain — a hallmark of PSP and other tauopathies — potentially slowing or halting disease progression.
About Progressive Supranuclear Palsy (PSP)
Progressive Supranuclear Palsy is a rare, rapidly progressive, and ultimately fatal neurodegenerative disease characterized by severe impairments in balance, movement, vision, and cognition. The condition is caused by the abnormal accumulation of tau protein within brain cells, leading to neuronal dysfunction and death. PSP often begins with symptoms such as loss of balance, stiffness, and difficulty with eye movements and speech, progressing to severe disability within a few years of onset. To date, no disease-modifying therapies have been approved for PSP, leaving patients and families with only limited symptomatic treatment options.
The rarity and complexity of PSP, coupled with its diagnostic challenges, make clinical research in this field exceptionally demanding. The early completion of enrollment for the PROSPER study therefore represents a significant achievement for Ferrer and the broader PSP research community.
Study Design and Objectives
The PROSPER study is a randomized, double-blind, placebo-controlled Phase II clinical trial that successfully recruited 220 participants with PSP across 44 clinical centers located in the European Union, the United Kingdom, and the United States. The study reached its recruitment target on October 6, 2025, just 14 months after initiation and two months ahead of schedule, demonstrating the strong engagement of investigators, patients, and caregivers.
The study protocol includes a six-week screening period, followed by 52 weeks of treatment with either FNP-223 or placebo, and a four-week follow-up period after treatment completion. Participants were carefully selected to represent individuals in the early stages of Progressive Supranuclear Palsy–Richardson Syndrome (PSP-RS), the most common clinical phenotype of PSP. Focusing on early-stage patients is a critical strategy, as therapeutic intervention at this stage offers the greatest potential to slow or modify disease progression.
Recruiting patients at early disease stages presents significant challenges due to the rapid progression of PSP and the need for precise diagnostic criteria. Ferrer’s ability to achieve its recruitment milestone early highlights both the dedication of its clinical partners and the strong interest from the PSP community in advancing potential treatments.
Global Collaboration and Community Commitment
Prof. Dr. Med. Günter Höglinger, from the Ludwig-Maximilian University of Munich, serves as the principal investigator and coordinator of the PROSPER study. Commenting on the achievement, he stated:
I am deeply grateful to the patients, their caregivers, and the dedicated teams at our academic centers for their outstanding commitment, which has enabled us to reach this important milestone so swiftly. Together, we are making significant progress toward answering a critical scientific question: the role of OGA inhibition in PSP. Our shared efforts bring us closer to developing solutions that may truly improve the lives of patients.
Kristophe Diaz, Chief Executive Officer of CurePSP, a leading advocacy organization for PSP and related diseases, also recognized the significance of the milestone:
Achieving full enrollment in a PSP clinical trial is no small feat, and Ferrer’s success with the PROSPER study is both a scientific and human milestone. Behind this progress are patients and families who choose to turn hope into action. Their participation accelerates the entire ecosystem toward meaningful therapies for PSP. For our community, each step like this brings us closer to lasting change.
Ferrer’s Commitment to Rare Disease Research
Oscar Pérez, Chief Scientific Officer at Ferrer, highlighted the importance of the milestone in the company’s broader mission to address unmet medical needs:
The early completion of recruitment marks a key step in Ferrer’s commitment to accelerating clinical research programs for complex and rare diseases such as PSP. In line with our purpose of using business to fight for social justice, we hope to deliver a potential solution that transforms the lives of people affected by this disease and those around them. We are deeply grateful to the patients, families, caregivers, investigators, and patient associations for their trust and support, without which this milestone would not have been possible.
Ferrer has made a deliberate effort to incorporate patient and caregiver perspectives into the PROSPER study’s design. The company worked closely with patient advocacy groups and healthcare professionals to tailor study procedures to real-world needs, improve the participant experience, and ensure that clinical research remains both patient-centered and scientifically rigorous. This inclusive approach underscores Ferrer’s philosophy that meaningful innovation must begin with understanding the people it seeks to help.
Advancing a Global Vision for Science and Social Impact
Headquartered in Barcelona, Spain, Ferrer is an international pharmaceutical company dedicated to developing innovative therapies in areas of high unmet medical need, particularly within rare neurological diseases and pulmonary vascular and interstitial disorders. The company’s strategy integrates global scientific excellence with a strong ethical and social mission, ensuring that business growth contributes directly to human and societal wellbeing.
Ferrer’s research and development pipeline focuses on complex, multi-center clinical programs spanning early discovery through late-stage trials. Studies like PROSPER reflect the company’s long-term vision to generate transformative impact through science — developing disease-modifying therapies where none currently exist and advancing equitable access to healthcare worldwide.
As the PROSPER trial progresses into its treatment and analysis phases, Ferrer and its partners remain focused on uncovering the potential of OGA inhibition as a novel therapeutic pathway in PSP. The completion of patient recruitment not only represents operational excellence but also a step forward in the collective global effort to confront one of the most challenging neurodegenerative diseases known today.
Through collaboration, innovation, and patient-centered science, Ferrer continues to move closer to achieving its ultimate goal: to improve lives and bring hope to those facing rare and debilitating diseases.
