Participants will be assigned to treatment with EXV-802 capsules administered twice a day over a 6-week period.

Participants will be assigned to treatment with placebo capsules administered twice a day over a 6-week period.

Participants will be assigned to treatment with EXV-801 capsules administered twice a day over a 6-week period.

Specified dose twice daily

The CMAI is used to assess the frequency of manifestations of agitated behaviors in elderly persons. It consists of 29 agitated behaviors that are further categorized into distinct agitation syndromes, also known as CMAI factors of agitation. These distinct agitation syndromes include aggressive behavior, physically nonaggressive behavior, and verbally agitated behavior. Each of the 29 items is rated on a 7-point scale of frequency (1 = never, 2 = less than once a week but still occurring, 3 = once or twice a week, 4 = several times a week, 5 = once or twice a day, 6 = several times a day, 7 = several times an hour). The ratings are based on the 2 weeks preceding assessment of the CMAI. Higher scores indicate higher frequency of agitated behaviors while lower scores indicate lower frequency of agitated behaviors The CMAI-IPA includes 19 items that were mapped to IPA agitation domains. The total score ranges from 19 to 133 with higher scores indicating more severity.

The CGI-S is an observer-rated scale that measures illness severity. The CGI-S is a 7-point (1-7) scale (1 = normal, not at all ill; 7 = extremely ill) that assessed the severity of agitation in this study. Higher scores indicate severe agitation, while the lower scores indicate little or no agitation.

The NPI-C is a retrospective interview covering 14 neuropsychiatric symptom domains. The NPI-C version of the NPI scale was designed to be administered by the clinician to the participant and the caregiver. The caregiver is first asked to provide frequency, severity, and distress ratings for each individual item across the domains. Frequency is rated on a scale from 0 to 4. Severity is rated on a scale from 0 to 3. Separately, the rater interviews the patient to assess frequency (0 to 4) of each item. Clinician rating of clinical impression is a severity rating (0 to 3) based on all available clinical and interview information. For this endpoint, the caregiver distress will be analyzed for the agitation and aggression domains. Caregiver distress is rated on a scale from 0 to 5 with a total score range of 0 to 10 across the 2 domains. Higher scores indicate greater caregiver distress.