A Randomized, Double-Blind, Placebo controlled, Parallel-group, Multicenter Study to Assess the Efficacy and Safety of JNJ-63733657, an anti-tau Monoclonal Antibody, in Participants with Early Alzheimer's Disease

Alzheimer's disease (AD) is a fatal neurodegenerative disease that is manifested by progressive cognitive deficits including memory loss followed by loss of independent function as well as neuropsychiatric symptoms such as apathy, depression, anxiety, agitation and psychosis. JNJ-63733657 is a humanized monoclonal anti-tau antibody which binds to phosphorylated tau (P-tau). The study will evaluate whether JNJ-63733657 can slow clinical (cognitive and functional) decline in participants with Early AD with evidence of elevated brain tau (T+) and assess its safety and tolerability. The study consists of: screening period (13 weeks), double-blind treatment period (up to 232 weeks), and a follow-up period (13 weeks). Safety and tolerability assessments will include adverse events (AEs), vital signs, electrocardiogram (ECG), early discontinuations, physical and neurological examinations, safety laboratory evaluations, suicidality risks (Columbia Suicide Severity Rating Scale [CSSRS]) and brain MRI will be performed during the study. The maximum treatment duration is up to 232 weeks (4.5 years).

Inclusion Criteria:

• Early Alzheimer's disease (AD): Gradual and progressive subjective decline in the participant's cognition over at least the past 6 months, as reported by the participant and informant (study partner) and Clinical Dementia Rating-Global Score (CDR-GS) of 0.5 and memory box score greater than or equal to (>=) 0.5 at screening
• Participants must have positive tau PET results
• Able to read and write and with a minimum 5 years of formal education as reported by participant and study partner at screening
• Have a designated study partner who has adequate literacy to participate and be judged to have high likelihood of completing the study with the participant
• Male participants must agree not to donate sperm during the study and up to 16 weeks after the last dose of study intervention

Exclusion Criteria:

• Participants with CDR GS >=2 at predose baseline CDR administration
• Participants who fulfill diagnostic criteria for Mild Cognitive Impairment (MCI) or dementia/mild or major neurocognitive disorder suspected to be due to any etiology other than AD (eg, MCI/dementia due to frontotemporal lobar degeneration, diffuse lewy body disease, parkinson's disease, cerebrovascular disease, normal pressure hydrocephalus, head injury, drug or alcohol abuse/dependence, anoxic brain injury, (Et cetera[etc])
• Geriatric Depression Scale (GDS) 30 score >12
• Hachinski Ischemic Scale (HIS) >4
• Has received medications that affect the central nervous system (CNS), except treatments for AD, for less than 2 months; that is, doses of chronic medications that effect the CNS should be stable for at least 2 months before the start of screening. Chronic use of benzodiazepines is not permitted