A Study of JNJ-63733657 in Participants With Early Alzheimer's Disease

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 for the purpose of reproduction during the study and up to 16 weeks after receiving the last dose of study intervention

Exclusion Criteria:

* Participants with CDR GS \>=2 at predose baseline Clinical Dementia Rating (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 (example, 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 greater than (\>) 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. If a participant has recently stopped a chronic medication that effects the CNS, he or she must have discontinued treatment at least 2 months before the start of screening. Chronic use of benzodiazepines is not permitted