The NPI is a retrospective interview covering 12 neuropsychiatric symptom domains and is used to evaluate psychopathology, neuropsychiatric manifestations, and caregiver distress. The Agitation/Aggression domain was designed to collect information on the behavioral aspects of agitation/aggression in participants with probable Alzheimer's Disease (AD) and clinically meaningful agitation secondary to AD. Each NPI domain is rated by the caregiver for symptom frequency and severity. Symptom frequency is rated as: 1, occasionally; 2, often; 3, frequently; 4, very frequently. Symptom severity is rated as: 1, mild; 2, moderate; 3, marked. The total domain score is calculated as the frequency score multiplied by the severity score and thus ranges from 1 to 12. A higher score represents worsening symptoms. Change from Baseline is calculated as the post-Baseline score minus the Baseline score. Data are reported for only those participants contributing data to the analysis.

Stage 1 modified Intent-to-Treat (mITT) Population: all participants randomized in Stage 1 who had at least one post-Baseline NPI agitation/aggression score in Stage 1. Stage 2 mITT Population: all placebo non-responders from Stage 1 who were re-randomized in Stage 2 and had at least one post-Week 4 NPI agitation/aggression score in Stage 2

Treatment-emergent adverse events (TEAEs) are defined as AEs that first occurred, or worsened, after the first dose of study medication and within 30 days after the permanent discontinuation of the study medication (first dose date ≤ AE start date ≤ date of last dose + 30 days)

Safety Population: all randomized participants who received at least one dose of study treatment

The NPI is a retrospective interview covering 12 neuropsychiatric symptom domains and is used to evaluate psychopathology, neuropsychiatric manifestations, and caregiver distress. Each NPI domain is rated by the caregiver for symptom frequency and severity. Symptom frequency is rated as: 1, occasionally; 2, often; 3, frequently; 4, very frequently. Symptom severity is rated as: 1, mild; 2, moderate; 3, marked. The total domain score is calculated as the frequency score multiplied by the severity score and thus ranges from 1 to 12. The total score is calculated as a sum of all 12 domain scores and thus ranges from 12 to 144. A higher score represents worsening symptoms. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Population. Data are reported for only those participants contributing data to the analysis.

The NPI is a retrospective interview covering 12 neuropsychiatric symptom domains and is used to evaluate psychopathology, neuropsychiatric manifestations, and caregiver distress. Each NPI domain is rated by the caregiver for symptom frequency and severity. Symptom frequency is rated as: 1, occasionally; 2, often; 3, frequently; 4, very frequently. Symptom severity is rated as: 1, mild; 2, moderate; 3, marked. The total domain score is calculated as the frequency score multiplied by the severity score and thus ranges from 1 to 12. A higher score represents worsening symptoms. Change from Baseline is calculated as the post-Baseline score minus the Baseline score. Sleep/nighttime behavior disorders = S/NB disorders.

Stage 1 and Stage 2 mITT Population. Data are reported for only those participants contributing data to the analysis.

The NPI is a retrospective interview covering 12 neuropsychiatric symptom domains and is used to evaluate psychopathology, neuropsychiatric manifestations, and caregiver distress. Each NPI domain is rated by the caregiver for symptom frequency and severity. Symptom frequency is rated as: 1, occasionally; 2, often; 3, frequently; 4, very frequently. Symptom severity is rated as: 1, mild; 2, moderate; 3, marked. The total domain score is calculated as the frequency score multiplied by the severity score and thus ranges from 1 to 12. The NPI4D score is the sum of the Agitation/Aggression, Irritability/Lability, Disinhibition, and Aberrant Motor Behavior domain scores, and thus ranges from 4 to 48. A higher score represents worsening symptoms. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The NPI is a retrospective interview covering 12 neuropsychiatric symptom domains and is used to evaluate psychopathology, neuropsychiatric manifestations, and caregiver distress. Each NPI domain is rated by the caregiver for symptom frequency and severity. Symptom frequency is rated as: 1, occasionally; 2, often; 3, frequently; 4, very frequently. Symptom severity is rated as: 1, mild; 2, moderate; 3, marked. The total domain score is calculated as the frequency score multiplied by the severity score and thus ranges from 1 to 12. The NPI4A score is the sum of the Agitation/Aggression, Irritability/Lability, Anxiety, and Aberrant Motor Behavior domain scores, and thus ranges from 4 to 48. A higher score represents worsening symptoms. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The NPI is a retrospective interview covering 12 neuropsychiatric symptom domains and is used to evaluate psychopathology, neuropsychiatric manifestations, and caregiver distress. For each domain, the caregiver is asked to rate how emotionally distressing they find the symptom behavior on the following scale: 0, not at all; 1, minimally; 2, mildly; 3, moderately; 4, severely; 5, very severely or extremely. The total NPI-CDS score is calculated as the sum of all 12 domain scores and thus ranges from 0 to 60. A higher score represents increased distress. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The NPI is a retrospective interview covering 12 neuropsychiatric symptom domains and is used to evaluate psychopathology, neuropsychiatric manifestations, and caregiver distress. For the Agitation/Aggression domain, the caregiver is asked to rate how emotionally distressing they find the symptom behavior on the following scale: 0, not at all; 1, minimally; 2, mildly; 3, moderately; 4, severely; 5, very severely or extremely. A higher score represents increased distress. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The NPI is a retrospective interview covering 12 neuropsychiatric symptom domains and is used to evaluate psychopathology, neuropsychiatric manifestations, and caregiver distress. For the NPI4D NPI-CDS score, the caregiver is asked to rate how emotionally distressing they find the symptom behavior (for the Agitation/Aggression, Irritability/Lability, Disinhibition, and Aberrant Motor Behavior domains) on the following scale: 0, not at all; 1, minimally; 2, mildly; 3, moderately; 4, severely; 5, very severely or extremely. The NPI4D NPI-CDS score ranges from 0 to 20. A higher score represents increased distress. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The NPI is a retrospective interview covering 12 neuropsychiatric symptom domains and is used to evaluate psychopathology, neuropsychiatric manifestations, and caregiver distress. For the NPI4A NPI-CDS score, the caregiver is asked to rate how emotionally distressing they find the symptom behavior (for the Agitation/Aggression, Irritability/Lability, Anxiety, and Aberrant Motor Behavior domains) on the following scale: 0, not at all; 1, minimally; 2, mildly; 3, moderately; 4, severely; 5, very severely or extremely. The NPI4A NPI-CDS score ranges from 0 to 20. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The CSI is a 13-question tool that is used to measure strain related to care provision and to identify families with potential caregiving concerns. There is at least one item for each of the following major domains: Employment, Financial, Physical, Social, and Time. A 0 (No) to 1 (Yes) scale is used for each of the 13 questions; thus the total score ranges from 0 to 13. Higher scores signify higher stress levels. Positive responses to 7 or more items on the index indicate a greater level of strain. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The CSDD is a 19-item interview specifically developed to assess the signs and symptoms of major depression in participants with dementia. Each of the 19 items is rated for severity on a scale of 0 to 2 (0, absent; 1, mild or intermittent; 2, severe). The total score is calculated as the sum of the item scores and thus ranges from 0 to 38. Higher scores signify more severe depression. Scores above 10 indicate probable major depression. Scores above 18 indicate definite major depression. Scores below 6, as a rule, are associated with the absence of significant depressive symptoms. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The MMSE is a brief test that is used to screen for cognitive impairment. The MMSE scale comprises 11 questions or simple tasks concerning orientation, memory, attention, and language to evaluate the participant's cognitive state. The anchor values are not consistent for each task. The MMSE total score is calculated by summing the item scores across all 11 tasks. A participant's total possible MMSE score ranges from 0 to 30 points. Higher scores indicate milder cognitive impairment. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The QoL-AD is a brief, 13-item measure designed specifically to obtain a rating of the participant's quality of life (QoL) from both the participant and the caregiver. It uses simple and straightforward language and responses and includes assessments of the individual's relationships with friends and family, concerns about finances, physical condition, mood, and an overall assessment of life quality. Caregivers complete the measure as a questionnaire about the participants' QoL, whereas participants complete it in interview format about their own QoL. Each of the 13 items is rated on a 4-point scale, with 1 indicating a poor QoL and 4 indicating an excellent QoL. Total scores range from 13 to 52, with a higher score indicating a better QoL. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The ADCS-ADL inventory measures basic activities of daily living such as dressing, conversation, eating, bathing, and grooming. The 19-item version, covering mainly basic ADL, is used to assess participants with more severe disabilities. The ADCS-ADL uses a scale from 0 to 54. Lower scores indicate declining ability. Change from Baseline is calculated as the post-Baseline value minus the Baseline value.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The NPI is a retrospective interview covering 12 neuropsychiatric symptom domains and is used to evaluate psychopathology, neuropsychiatric manifestations, and caregiver distress. The Agitation/Aggression domain was designed to collect information on the behavioral aspects of agitation/aggression in participants with probable AD and clinically meaningful agitation secondary to AD. Each NPI domain is rated by the caregiver for symptom frequency and severity. Symptom frequency is rated as: 1, occasionally; 2, often; 3, frequently; 4, very frequently. Symptom severity is rated as: 1, mild; 2, moderate; 3, marked. The total domain score is calculated as the frequency score multiplied by the severity score and thus ranges from 1 to 12. A higher score represents worsening symptoms. Change from Baseline is calculated as the post-Baseline score minus the Baseline score.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The intent of the ADCS version of the CGIC is to provide a means to reliably assess the global impression of change from Baseline in a clinical trial. The mADCS-CGIC is a modification of the ADCS-CGIC instrument that focuses specifically on agitation. The participant is asked to rate their impression of change from Baseline as: 1, marked improvement; 2, moderate improvement; 3, minimal improvement; 4, no change; 5, minimal worsening; 6, moderate worsening; 7, marked worsening. Baseline is defined as the last non-missing assessment prior to Stage 1 randomization.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The intent of the ADCS version of the CGIC is to provide a means to reliably assess the global impression of change from Baseline in a clinical trial. The mADCS-CGIC is a modification of the ADCS-CGIC instrument that focuses specifically on agitation. The participant is asked to rate their impression of change from Baseline as: 1, marked improvement; 2, moderate improvement; 3, minimal improvement; 4, no change; 5, minimal worsening; 6, moderate worsening; 7, marked worsening. For placebo non-responders re-randomized to AVP-923 or placebo at Stage 2, Baseline is defined as the last non-missing assessment prior to Stage 2 re-randomization.

Stage 2 mITT Population. Data are reported for only those participants contributing data to the analysis.

The PGI-C uses a 7-point scale to assess treatment response and to rate the global impression of clinical change in a participant's agitation. The participant is asked to rate their impression of change from Baseline as: 1, very much improved; 2, much improved; 3, minimally improved; 4, no change; 5, minimally worse; 6, much worse; 7, very much worse. Baseline is defined as the last non-missing assessment prior to Stage 1 randomization.

Stage 1 and Stage 2 mITT Populations. Data are reported for only those participants contributing data to the analysis.

The PGI-C uses a 7-point scale to assess treatment response and to rate the global impression of clinical change in a participant's agitation. The participant is asked to rate their impression of change from Baseline as: 1, very much improved; 2, much improved; 3, minimally improved; 4, no change; 5, minimally worse; 6, much worse; 7, very much worse. For placebo non-responders re-randomized to AVP-923 or placebo at Stage 2, Baseline is defined as the last non-missing assessment prior to Stage 2 re-randomization.

Only AVP-923/only placebo ITT Subset

Concomitant medications (CMs) are defined as non-study medications with a start date on or before the final study visit, and that were either ongoing at the end of the study or had a stop date on or after the date of first dose of study drug. Drugs for the treatment of AD (e.g., donepezil, rivastigmine, galantamine, memantine) were allowed when administered at stable dose for at least 2 months prior to randomization. Concomitant use of the following medications was allowed, provided the participant had been on a stable dose for at least 1 month prior to randomization and remained stable throughout the study: medications for agitation secondary to AD; medications for nighttime management of insomnia or behavioral disturbances that included short-acting benzodiazepines, a low dose of alprazolam up to 0.5 milligrams (mg)/day, and a low dose of trazodone up to 50 mg/day; hypnotics for the treatment of insomnia; and certain classes of antidepressants.

mITT Population: all participants randomized in Stage 1 who had at least one post-Baseline NPI Agitation/Aggression score in Stage 1, and all placebo non-responders from Stage 1 who are re-randomized in Stage 2 and had at least one post-Week 4 NPI Agitation/Aggression score in Stage 2. Only those participants who took CMs were analyzed.

Participants were allowed to receive oral lorazepam as rescue medication for the short-term treatment of symptoms of agitation, if deemed necessary by the investigator. Lorazepam was to be administered at doses up to 1.5 mg/day, and dosing was not to exceed 3 days in any 7-day period.

mITT Population