The Progressive Supranuclear Palsy Clinical Trial Platform - Regimen B: LM11A-31

The Progressive Supranuclear Palsy Clinical Trial Platform (PTP) is a multi-center, multi-regimen clinical trial evaluating the safety and efficacy of investigational products for the treatment of PSP. Regimen B will evaluate the safety and efficacy of a single study drug, LM11A-31, in participants with PSP.

Study Overview

• Status: Not yet recruiting
• Conditions: PSP - Progressive Supranuclear Palsy
• Intervention / Treatment: Drug: LM11A-31; Drug: Matching Placebo

Detailed Description

The Progressive Supranuclear Palsy Clinical Trial Platform (PTP) is designed as a perpetual platform trial. This means that there is a single Master Protocol dictating the conduct of the trial. The PTP Master Protocol is registered as NCT07173803. Once a participant enrolls into the Master Protocol and meets all eligibility criteria, the participant will be eligible to be randomized into any currently enrolling regimen. All participants will have an equal chance to be randomized to all regimens that are active at the time of screening. If a participant is randomized to Regimen B: LM11A-31, participants will complete a baseline assessment and be randomized in a 3:1 ratio to either active LM11A-31 or matching placebo. Participants must first enroll into the Master Protocol and be eligible to participate in the Master Protocol before being able to be randomly assigned to Regimen B. For a list of enrolling sites, please see the PTP Master Protocol under NCT07173803.

• Study Type: Interventional
• Enrollment (Estimated): 147
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: PTP Recruitment and Retention (RER) Team; Phone Number: 213-821-0569; Email: psp-participate@usc.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Clinical diagnosis of possible or probable PSP Richardson's Syndrome as defined by the 2017 Movement Disorder Society (MDS) criteria.
2. Presence of PSP symptoms for ≤5 years at screening (based on the best judgment of the site PI).
3. Mini-Mental State Examination (MMSE) score at screening of ≥25.
4. Able to walk at least 10 steps with minimal assistance (e.g., one arm for safety, but not postural support).
5. Stable doses of permitted medications as described per protocol for 30 days prior to screening.
6. Resides at home or in the community (assisted living is acceptable).
7. As assessed by the site PI, participant is likely to be able to comply with the protocol for the duration of the study, and has adequate vision, hearing (hearing aid permitted), and literacy (English or Spanish) sufficient for compliance with the required testing procedures.

Exclusion Criteria:

1. Females who are breastfeeding or pregnant (as documented by a urine pregnancy test) during screening, or plan to become pregnant during the study.
2. Females of childbearing potential who did not use a highly effective method of contraception within 28 days of screening and/or are not willing to use a highly effective method of contraception for the duration of their participation in the study.
3. Lacks good venous access such that multiple blood draws would be precluded.
4. Weighs less than 40kg, or more than 136kg at screening.
5. Blood transfusion within 4 weeks of screening.
6. Contraindications to MRI studies, including metal (ferromagnetic) implants, a cardiac pacemaker that is not compatible with MRI, and/or severe claustrophobia.
7. Screening MRI scan showing structural evidence of alternative pathology not consistent with PSP that could explain a substantial portion of the participant's symptoms as indicated by the central MRI read.
8. Any unstable and/or clinically significant medical condition likely to hamper the evaluation of safety and/or efficacy of study drug (e.g., clinically significant reduction in serum B12 or folate levels, clinically significant abnormalities of thyroid function, stroke, or other cerebrovascular or cardiovascular conditions), as per the site PI's judgment.
9. History of severe allergic reaction (e.g., anaphylaxis) including but not limited to: severe allergic reaction to previous vaccines, foods, and/or medications.
10. Hospitalization within 30 days prior to screening or baseline.
11. Infections or major surgical procedures within 3 months prior to screening, judged to be clinically significant by the site PI.
12. Myocardial infarction within 1 year prior to baseline, unstable angina pectoris, symptomatic congestive heart failure.
13. History of cancer within the past 5 years other than treated skin squamous cell carcinoma, basal cell carcinoma, and melanoma in-situ, localized prostate cancer not requiring treatment, or prostate or breast cancer, which have been fully removed and are considered cured.
14. History or presence of immunological or inflammatory conditions, including neurological disorders, meningitis or meningoencephalitis.
15. History or presence of epilepsy requiring ongoing use of antiepileptic medications. Antiepileptic medications are permitted for pain or psychiatric use per the protocol.
16. DSM-5 criteria for drug or alcohol abuse or dependence currently met within the past 5 years.
17. Clinically significant abnormal vital signs including sustained sitting blood pressure >160/100 mm Hg.
18. Diabetes mellitus with hemoglobin A1c (HbA1c) levels of ≥8.0%.
19. Known history of human immunodeficiency virus (HIV-1 or 2).
20. Known history of acute/chronic hepatitis B or C unless treated curatively.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Matching Placebo	Drug: Matching Placebo; Matching placebo is administered orally twice daily.
Experimental: Regimen B: LM11A-31	Drug: LM11A-31; LM11A-31 is administered orally twice daily.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Disease progression	Change in disease severity as measured by the 15-item modified Progressive Supranuclear Palsy Rating Scale (mPSPRS-15) in which the minimum score is 0 and the maximum score is 52, with higher scores indicating a worse outcome.	52 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Disease progression	Change in disease severity as measured by the 10-item modified Progressive Supranuclear Palsy Rating Scale (mPSPRS-10) in which the minimum score is 0 and the maximum score is 30, with higher scores indicating a worse outcome.	52 weeks
Disease progression	Change in disease severity as measured by the 28-item Progressive Supranuclear Palsy Rating Scale (28-item PSPRS) in which the minimum score is 0 and the maximum score is 100, with higher scores indicating a worse outcome.	52 weeks
Experiences of daily living	Change in experiences of daily living over time as measured by the Cortical Basal ganglia Functional Scale (CBFS) in which the minimum score is 0 and the maximum score is 124, with higher scores indicating a worse outcome.	52 weeks
Activities of daily living	Change in activities of daily living over time as measured by the Schwab and England Activities of Daily Living Scale (SE-ADL) in which the minimum score is 0% and the maximum score is 100%, with lower scores indicating a worse outcome.	52 weeks
Disease severity	Change in disease severity over time as measured by the Clinical Global Impression of disease severity (CGIds) using a 7-point scale, ranging from 1 (normal, not ill) to 7 (extremely ill), with a higher score indicating a worse outcome.	52 weeks
Disease progression	Change in disease severity over time as measured by the Clinical Global Impression of Change (CGIC) using a 7-point scale, ranging from 1 (very much improved) to 7 (very much worse), with a score of 4 indicating no change.	52 weeks
Health-related quality of life	Change in quality of life over time as measured by the EuroQoL 5 Dimension - 5 Level (EQ-5D-5L) questionnaire in which the minimum score is 0 and the maximum score is 1, with lower scores indicating a worse outcome.	52 weeks
Brain volume	Change in volume in midbrain, pontine and other regions over time as measured by volumetric MRI.	52 weeks
Neurodegeneration	Change in plasma neurofilament light chain (NfL) concentration.	52 weeks

Collaborators and Investigators

• Sponsor: Adam Boxer
• Collaborators: Massachusetts General Hospital; University of California, San Diego; National Institute on Aging (NIA); University of Southern California; Alzheimer's Therapeutic Research Institute; Alzheimer's Clinical Trials Consortium; PharmatrophiX Inc.
• Investigators: Principal Investigator: Adam Boxer, MD, PhD, University of California, San Francisco; Principal Investigator: Anne-Marie Wills, MD, Massachusetts General Hospital; Principal Investigator: Irene Litvan, MD, University of California, San Diego; Principal Investigator: Julio Rojas-Martinez, MD, PhD, University of California, San Francisco

Study record dates

Study Major Dates

• Study Start (Estimated): June 30, 2026
• Primary Completion (Estimated): September 28, 2030
• Study Completion (Estimated): September 28, 2030

Study Registration Dates

• First Submitted: November 24, 2025
• First Submitted That Met QC Criteria: November 24, 2025
• First Posted (Actual): December 4, 2025

Study Record Updates

• Last Update Posted (Actual): April 27, 2026
• Last Update Submitted That Met QC Criteria: April 24, 2026
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Double-Blind; PSP; Placebo-Controlled; Disease modifying; Oral treatment; Tau Protein; Regimen Specific Appendix; LM11A-31; P75 neurotrophin receptor; Synaptic resilience
• Additional Relevant MeSH Terms: Neurologic Manifestations; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Mental Disorders; Metabolic Diseases; Neurocognitive Disorders; Eye Diseases; Dementia; Tauopathies; Neurodegenerative Diseases; Movement Disorders; Basal Ganglia Diseases; Cranial Nerve Diseases; TDP-43 Proteinopathies; Proteostasis Deficiencies; Ophthalmoplegia; Ocular Motility Disorders; Paralysis; Frontotemporal Lobar Degeneration; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Frontotemporal Dementia; Supranuclear Palsy, Progressive; LM11A-31
• Other Study ID Numbers: ATRI-015-B; R01AG085029 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No