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We completed the recruitment of 220 patients for PROSPER, the Phase II clinical trial in progressive supranuclear palsy

Ferrer's corporate green ribbon on a wooden table, with the slogan "for good" in the foreground and the background blurred.

Barcelona, October 21, 2025 – Ferrer announces the completion of recruitment for the PROSPER study, a Phase II clinical trial, designed to evaluate the efficacy, safety and pharmacokinetics of FNP-223, a potent and selective OGA enzyme inhibitor, available orally, licensed from Asceneuron, intended to slow the progression of progressive supranuclear palsy (PSP)1.

 

It is a rare, rapidly progressive, and ultimately fatal neurodegenerative disease2. So far, no disease-modifying treatment has been approved for PSP. 

 

The PROSPER study is a randomized, double-blind, placebo-controlledtrial3, which has successfully enrolledthe expected number[CT1] of 220 people with PSP in just 14 months, reaching this milestone on October 6, two months ahead of schedule. In total, 44 centres from different countries of the European Union, the United Kingdom and the United States are participating. The design envisages a screening period of six weeks, followed by 52 weeks of treatment with PNF-223 or placebo, and a subsequent follow-up of four weeks after completion of treatment3.

 

The study investigates a population with progressive supranuclear palsy-Richardson syndrome (PSP-RS) in early stages, a critical time when early intervention may have the greatest impact on slowing disease progression. Detecting the disease in these people is a great challenge due to the speed of its progression and complexity of diagnosis, which makes it even more important to have reached this milestone earlier than expected.

 

Günter Höglinger, Professor of Medicine at the University of Munich (Ludwig-Maximilians-Universität) and principal investigator and coordinator of the PROSPER study, said: "I am deeply grateful to the patients, their caregivers and the dedicated teams at our academic centres for their extraordinary commitment, which has enabled us to reach this important milestone so quickly. Together we are making significant progress toward answering a crucial scientific question: the role of OGA inhibition in PSP. Our shared efforts bring us closer to developing solutions that can truly improve the lives of patients."

 

According to Kristophe Diaz, Chief Executive Officer of Cure PSP, "Completing recruitment in a clinical trial on PSP is no easy task, and Ferrer's success with the PROSPER study represents a true milestone, both scientifically and humanly. Behind this breakthrough are patients and families who choose to transform hope into action, and their participation accelerates the entire ecosystem toward meaningful therapies for this disease. For our community, steps like this bring us a little closer to lasting change."

 

For his part, Oscar Pérez, Chief Scientific Officer of Ferrer, pointed out that "the early termination of recruitment is a key step in Ferrer's commitment to accelerate clinical research programs in highly complex and low-prevalence pathologies, such as PSP. In line with our purpose of using the business to fight for social justice, we hope to be able to bring a potential solution that transforms both the lives of people who have this disease, and those around them. We want to deeply thank patients, families, caregivers, researchers and patient associations for their trust and support, without which this milestone would not be possible."

 

Likewise, Ferrer has incorporated the voice of patients, caregivers and medical professionals into the design of the PROSPER study, with the aim of adapting clinical research to the real needs of the participants, thus improving their experience and ensuring clinical research with greater impact.

 

Ferrer acquired the exclusive worldwide rights to develop and commercialize FNP-223 from Asceneuron, a Swiss biotechnology company specializing in the clinical phase.

 


Ferrer's research commitment

Ferrer is an international company headquartered in Barcelona and firmly committed to the research and development of innovative therapies in areas of high unmet medical need, such as rare neurological diseases and vascular and interstitial lung diseases. The company is committed to complex and global clinical developments, advancing projects in different stages of development.

 

With studies such as PROSPER, Ferrer reinforces its mission to generate a positive social impact by working to provide transformative solutions for serious and low-prevalence diseases that do not have authorized or available treatments.

 

 

About the PSP

Progressive supranuclear palsy is a rare neurodegenerative disease that mainly affects people over 60 years of age and whose progression is rapid and highly disabling. 

 

PSP is a primary tauopathy caused by the abnormal accumulation of the Tau protein in areas of the brain that regulate movement and thinking, especially in the subcortical regions and the brainstem4,5. This accumulation damages nerve cells and alters brain function, leading to symptoms such as loss of balance, difficulty speaking or swallowing, abnormal eye movements, and cognitive or mood alterations6. 

 

Although its prevalence is low - between 5.8 and 6.5 people per 100,0007 -, its impact is profound: the loss of autonomy usually occurs within a few years7, and the average life expectancy after diagnosis is between 6 and 9 years. Cases of genetic origin are rare8, although more than ten associated genes have been identified, with mutations in the MAPT gene being the main risk factor9. The possible role of environmental factors, such as exposure to toxins or infectious agents, is also being investigated7.

 

 

References:

  1. Permanne B, Sand A, Ousson S, Nény M, Hantson J, Schubert R, Wiessner C, Quattropani A, Beher D. O-GlcNAcase Inhibitor ASN90 is a Multimodal Drug Candidate for Tau and α-Synuclein Proteinopathies. ACS Chem Neurosci. 2022 Apr 20; 13(8):1296-1314. DOI: 10.1021/acschemneuro.2C00057. Epub 2022 Mar 31. PMID: 35357812; PMCID: PMC9026285.
  2. Höglinger GU, et al. Mov Disord. 2017; 32(6):853–864; 2. Agarwal S and Gilbert R. Progressive Supranuclear Palsy. [Updated 2023 Mar 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan. Available at: www.ncbi.nlm.nih.gov/books/NBK526098/ (Accessed: August 2025); 3. Boxer LB, et al. Lancet Neurol. 2017; 16(7):552–563
  3. ClinicalTrials.gov: A Randomized, Double-blind, Placebo-controlled, Phase 2 Study to Assess the Efficacy, Safety, and Pharmacokinetics of FNP-223 (Oral Formulation) to Slow the Disease Progression of Progressive Supranuclear Palsy (PSP) (PROSPER). ClinicalTrials.gov [Internet]. Available at: https://www.clinicaltrials.gov/study/NCT06355531. Accessed on 01/10/2025
  4. Murray ME, Kouri N, Lin WL, Jack CR, Jr., Dickson DW, Vemuri P. Clinicopathologic assessment and imaging of tauopathies in neurodegenerative dementias. Alzheimers Res Ther. 2014; 6(1):1. DOI: 10.1186/ALZRT231.
  5. Planche V, Mansencal B, Manjon JV, Meissner WG, Tourdias T, Coupé P. Staging of progressive supranuclear palsy-Richardson syndrome using MRI brain charts for the human lifespan. Brain Commun. 2024; 6(2):FCAE055. DOI: 10.1093/Braincomms/FCAE055.
  6. National Institute of Neurological Disorders and Stroke (NINDS) [Internet]. Bethesda: National Institutes of Health; start date unknown [last updated date unknown; cited 23 Apr 2025].
Available at: https://www.ninds.nih.gov/health-information/disorders/progressive-supranuclear-palsy-psp.
  • Agarwal S, Gilbert R. Progressive Supranuclear Palsy. StatPearls. Treasure Island (FL): StatPearls Publishing
  • Ichikawa-Escamilla E, Velasco-Martínez RA, Adalid-Peralta L. Progressive Supranuclear Palsy syndrome: an overview. IBRO Neurosci Rep. 2024;16:598-608. doi: 10.1016/j.ibneur.2024.04.008.
  • Donker Kaat L, Boon AJ, Azmani A, Kamphorst W, Breteler MM, Anar B, et al. Familial aggregation of parkinsonism in progressive supranuclear palsy. Neurology. 2009; 73(2):98-105. doi: 10.1212/WNL.0b013e3181a92bcc.