The trial did not meet the clinical co-primary endpoint of slowing FTD-GRN progression, as measured by the Clinical Dementia Rating® plus National Alzheimer's Coordinating Center Frontotemporal Lobar Degeneration Sum of Boxes (CDR® plus NACC FTLD-SB)

A phase 3 double blind, placebo controlled study evaluating the efficacy and safety of AL001 in participants at risk for or with frontotemporal dementia due to heterozygous mutations in the progranulin gene.

This is a phase 3 double blind, placebo controlled study evaluating the efficacy and safety of AL001 administered intravenously in participants at risk for or with frontotemporal dementia due to heterozygous mutations in the progranulin gene. Study completion marks the end of the open label extension period following the 96-week blinded portion of the study.

Inclusion Criteria:

• Persons with a progranulin gene mutation and at risk of developing FTD symptoms as evidenced by a biomarker, or persons with a progranulin gene mutation and diagnosed with FTD.
• If symptomatic, one or more of the criteria for the diagnosis of possible behavioral variant FTD, or a diagnosis of Primary Progressive Aphasia.
• Study partner who consents to study participation and who cares for/visits the participant daily for at least 5 hours per week.
• Written informed consent must be obtained and documented (from the participant or, where jurisdictions allow it, from their legal decision maker).

Exclusion Criteria:

• Dementia due to a condition other than FTD including, but not limited to, Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies, Huntington disease, or vascular dementia.
• Known history of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric, human, or humanized antibodies or fusion proteins.
• Current uncontrolled hypertension, diabetes mellitus or thyroid disease. Clinically significant heart disease, liver disease or kidney disease. History or evidence of clinically significant brain disease other than FTD.
• Females who are pregnant or breastfeeding, or planning to conceive within the study period.
• Any experimental vaccine or gene therapy.
• History of cancer within the last 5 years.
• Current use of anticoagulant medications (e.g., coumadin, heparinoids, apixaban).
• Residence in a skilled nursing facility, convalescent home, or long term care facility at screening; or requires continuous nursing care.