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Assessing FNP-223 for slowing progression of Progressive Supranuclear Palsy

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)

Phase 2 Interventional Ferrer Internacional S.A. · NCT06355531

This study is testing if a new drug called FNP-223 can help slow down the progression of Progressive Supranuclear Palsy in people living with the condition.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment220 (estimated)
Ages50 Years to 80 Years
SexAll
SponsorFerrer Internacional S.A. Industry-sponsored
Locations42 sites (Carlsbad, California and 41 other locations)
Trial IDNCT06355531 on ClinicalTrials.gov

What this trial studies

This trial evaluates the efficacy and safety of FNP-223 in slowing the progression of Progressive Supranuclear Palsy (PSP) over a 52-week period. Participants will be assessed using the PSP Rating Scale to measure changes in their condition. The study includes both an active treatment group receiving FNP-223 and a placebo group for comparison. The aim is to determine if FNP-223 can effectively slow disease progression in individuals diagnosed with PSP.

Who should consider this trial

Good fit: Ideal candidates are males and females aged 50 to 80 with a diagnosis of possible or probable PSP-RS and specific clinical features.

Not a fit: Patients with advanced PSP symptoms or those residing in skilled nursing facilities may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly slow the progression of PSP, improving quality of life for patients.

How similar studies have performed: While there have been studies on PSP treatments, the specific approach with FNP-223 is novel and has not been extensively tested.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Male or female participants aged 50 to 80 years, inclusive, at the time of informed consent.
* Diagnosis of possible or probable PSP of the Richardson's Syndrome (PSP-RS) phenotypes according to the Movement Disorders Society's Progressive Supranuclear Palsy (MDS PSP) clinical features criteria. At least 1 (either 1 or both) of the following 2 items must be met:

  1. Vertical supranuclear gaze palsy.
  2. Slowing of vertical saccades AND postural instability with falls within the first 3 years of PSP symptoms.
* Presence of PSP symptoms within ≤3 years prior to screening.
* MoCA score ≥23
* Full 28-item PSPRS score ≤40.
* Able to ambulate independently or with minimal assistance defined as the ability to take at least 10 steps (stabilization of 1 arm \[ie, use of cane\]).
* Body weight range ≥43 kg/95 lbs to ≤120 kg/265 lbs.
* Reside outside a skilled nursing facility or dementia care facility, except for participants residing in an assisted living facility.
* Has a caregiver or study partner who will accompany them to the study visits. The caregiver or study partner must be a person who has frequent contact (at least 7 hours per week at 1 time or in different days) with the participant and is able to provide information about the participant's medication and overall condition. Prior to the conduct of any study procedures, the caregiver or study partner must be willing to sign the independent ethics committee (IEC)/institutional review board (IRB) approved informed consent.

Exclusion Criteria:

Non-PSP- RS Movement Disorders or other central nervous system (CNS) Diseases

* Score of 3 on any functional domain in the PSP-CDS.
* Participants with known PSP genetic mutation (based on familiar or clinical history).
* Evidence of other neurological disorder that could explain signs of PSP (eg, Parkinson's disease, Alzheimer disease, etc.).
* Brain magnetic resonance imaging (MRI) within 1 year of screening consistent with:
* Primary degenerative diseases other than PSP.

Procedures

* For the optional substudy only: Contraindication or refusal to undergo 2 lumbar punctures for obtaining CSF.
* Contraindication or inability to tolerate MRI for screening MRI and volumetric brain MRI assessments throughout the substudy.

Where this trial is running

Carlsbad, California and 41 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Progressive Supranuclear PalsyDisease progressionFNP-223
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.