Gene therapy for frontotemporal dementia in patients with specific genetic mutations

A Phase 1b Open-Label, Multicenter, Dose-Escalation Study to Assess the Safety, Tolerability, and Pharmacodynamic Effects of a Single Dose of PBFT02 Delivered Into the ICM of Adults With FTD and Mutations in the GRN or C9ORF72 Genes

This study is testing a one-time gene therapy injection for people with frontotemporal dementia caused by specific genetic mutations to see if it can help improve their condition.

Quick facts

• Phase: Phase1; Phase2
• Study type: Interventional
• Enrollment: 30 (estimated)
• Ages: 35 Years to 75 Years
• Sex: All
• Sponsor: Passage Bio, Inc. (Industry-sponsored)
• Locations: 10 sites (Ann Arbor, Michigan and 9 other locations)
• Trial ID: NCT04747431 on ClinicalTrials.gov

What this trial studies

This study evaluates PBFT02, a gene therapy designed to deliver a functional copy of the GRN gene to the brain, in patients diagnosed with frontotemporal dementia (FTD) who have mutations in the GRN or C9ORF72 genes. The therapy is administered as a one-time injection into the cisterna magna and aims to assess its safety, tolerability, and efficacy. Participants aged 35 to 75 years with early symptomatic FTD-GRN or symptomatic FTD-C9orf72 will be enrolled in this multicenter, open-label study over a five-year period, including a two-year main study followed by a three-year safety extension.

Who should consider this trial

Good fit: Ideal candidates are individuals aged 35 to 75 with a clinical diagnosis of frontotemporal dementia and documented pathogenic mutations in the GRN or C9ORF72 genes.

Not a fit: Patients with non-pathogenic mutations or those who have previously received gene therapy may not benefit from this study.

Why it matters

Potential benefit: If successful, this therapy could provide a novel treatment option that addresses the underlying genetic causes of frontotemporal dementia.

How similar studies have performed: While gene therapy for neurodegenerative diseases is an emerging field, this specific approach targeting frontotemporal dementia is novel and has not been extensively tested in prior studies.

Eligibility criteria

Inclusion Criteria:

1. Documented to be a pathogenic carrier of GRN or C9orf72 mutation
2. Clinical diagnosis of frontotemporal dementia
3. Have a reliable informant / caregiver (and back-up informant / caregiver) who personally speaks with or sees the subject at least weekly
4. Living in the community (i.e., not in a nursing home); assisted living may be permitted at the discretion of the investigator

Exclusion Criteria:

1. Classification of the GRN mutation as "not pathogenic," "likely benign variant," "benign variant," or "pathogenic nature unclear" (FTD- GRN Cohorts 1-3) or C9orf72 HRE length ≤ 30 (FTD-C9orf72 Cohorts 4-5).
2. Previous treatment with any gene therapy. Any other therapies with the potential to alter PGRN levels must be washed out for at least 5 half-lives prior to entry into this study
3. Homozygous GRN mutation carrier (FTD-GRN Cohorts 1-3) or homozygous C9orf72 mutation carrier (FTD-C9orf72 Cohorts 4-5).
4. Rosen-modified Hachinski Ischemic Scale score \> 7
5. Known presence of a structural brain lesion (eg, tumor, cortical infarct) that could reasonably explain symptoms in a symptomatic subject
6. Known presence of an AD-causing mutation in PSEN1, PSEN2 or APP based on genetic testing history (if performed)
7. Previous history of Korsakoff encephalopathy, severe alcohol or substance dependence (within 5 years of onset of dementia), except where onset of increased alcohol consumption occurs at the time of FTD disease onset
8. History of untreated vitamin B12 deficiency
9. Presence of untreated hypothyroidism (thyroid stimulating hormone \[TSH\] \> ULN and free T4 \< LLN)
10. eGFR ≤ 30 ml/min (as calculated using the CKD-EPI equation)
11. Alanine aminotransferase \[ALT\] or aspartate aminotransferase \[AST\] \> 2 × ULN, or total bilirubin \> ULN)
12. Respiratory failure that requires supplemental oxygen, tracheostomy, or reliance on non-invasive ventilation for \>2 hours during waking hours
13. Inability to provide full consent or the lack of a legally authorized caregiver with adequate contact who can provide consent
14. Any contraindication to MRI or lumbar puncture (LP) (eg, local infection, history of thrombocytopenia, coagulopathy)
15. Any contraindication to the ICM administration procedure
16. Medical conditions or laboratory or vital sign abnormalities that would increase risk of complications from ICM injection, anesthesia, LP, and/or MRI (e.g., fever, hypoxia, tachycardia, or evidence of active infection)
17. Immunocompromised status
18. Peripheral axonal sensory neuropathy
19. Receipt of a vaccine within 14 days of dosing
20. A positive test result for human immunodeficiency virus (HIV), human T cell leukemia virus (HTLV) type 1 or type 2, or Hepatitis B or C; a Mycobacterium tuberculosis positive test within 1 year of or determined at screening
21. Malignant neoplasia (except localized skin cancer) or a documented history of hereditary cancer syndrome
22. Any concurrent disease that, in the opinion of the investigator, may cause cognitive impairment unrelated to GRN or C9orf72 mutations, including other causes of dementia, neurosyphilis, hydrocephalus, stroke, small vessel ischemic disease, uncontrolled hypothyroidism, or vitamin deficiency
23. Current or recent history of clinically significant suicidal ideation within the past 6 months
24. For women of childbearing potential, a positive serum pregnancy test at the screening visit, a positive serum result on Day 1 prior to administration of the investigational product, or unwillingness to have additional pregnancy tests during the study. Women of childbearing potential must use a highly effective method of birth control or engage in abstinence until 90 days postdose
25. Women who are breastfeeding
26. For sexually active men, unwillingness to use a medically accepted method of double-barrier contraception (such as a condom/diaphragm used with spermicide) or engage in abstinence from the date of screening until 90 days postdose
27. Any condition (eg, history of any disease, evidence of any current disease, any finding upon physical examination, or any laboratory abnormality) that, in the opinion of the investigator, would put the subject at undue risk or would interfere with evaluation of the investigational product or interpretation of subject safety or study results
28. Any acute illness requiring hospitalization within 30 days of enrollment
29. Failure to meet the protocol-specified coagulation test criteria:

    * Platelet count \> 100,000 per uL
    * INR \< 1.5
    * aPTT \< 40 seconds
30. Use of anticoagulants in the 2 weeks prior to screening
31. Hypersensitivity or contraindications to corticosteroid use
32. Known or suspected intolerance or hypersensitivity to PBFT02 or any of its ingredients or to closely related compounds
33. Any condition expected to increase risk of thrombosis
34. Hypersensitivity or contraindications to apixaban

    Additional Criteria for FTD-C9orf72 (Cohorts 4-5) ONLY: Presence of concurrent ALS is permitted provided the following criteria are NOT met:
35. ALSFRS-R \< 35 at screening.
36. SVC \< 75% of predicted normal adjusted for sex, age, and height (from the sitting position).
37. Bulbar-onset ALS.
38. Current or anticipated need, in the opinion of the Investigator for a diaphragm pacing system (DPS) during the study period.
39. If taking riluzole or edaravone, participant's dose has not been stable for ≥ 30 days prior to Day 1 and/or dose adjustments are anticipated before the Day 60 study visit.

Where this trial is running

Ann Arbor, Michigan and 9 other locations

• Michigan Alzheimer's Disease Center — Ann Arbor, Michigan, United States (Recruiting)
• University of Pennsylvania — Philadelphia, Pennsylvania, United States (Recruiting)
• Vanderbilt University Medical Center — Nashville, Tennessee, United States (Recruiting)
• University of Texas at Houston — Houston, Texas, United States (Recruiting)
• Eastern Health-Box Hill Hospital — Melbourne, Victoria, Australia (Recruiting)
• Hospital das Clinicas da Universidade Federal de Minas Gerais (UFMG) — Minas Gerais, Brazil (Recruiting)
• Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo (HCFMUSP) — São Paulo, Brazil (Recruiting)
• University of Toronto, Toronto Western Hospital — Toronto, Ontario, Canada (Recruiting)
• Montreal Neurological Institute-Hospital — Montreal, Quebec, Canada (Recruiting)
• Centro Hospitalar e Universitário de Coimbra — Coimbra, Portugal (Recruiting)

Study contacts

• Study coordinator: Patient/Family Inquiries

Conditions Frontotemporal Dementia; FTD; FTD-GRN; Dementia Frontotemporal; C9orf72; frontotemporal dementia; Progranulin Mutations; Gene Therapy