Safety analysis set consisted of all participants who received at least one infusion of study medication (including partial infusions). A TEAE was defined as an untoward medical occurrence reported by the participant or investigator following administration of at least one dose of AAB-003.

Safety analysis set consisted of all participants who received at least one infusion of study medication (including partial infusions). Laboratory test parameters included hematology, coagulation, liver function, renal function, electrolytes, clinical chemistry, and urinalysis (dipstick and microscopy).

Criteria for potential clinical concern in vital signs included: supine/sitting pulse rate of less than (<) 40 or more than (>) 120 beats per minute (bpm), and standing pulse rate of <40 or >140 bpm; systolic blood pressure (SBP) of more than or equal to (>=)30 millimeters of mercury (mm Hg) change from baseline in same posture and <90 mm Hg; diastolic blood pressure (DBP) >=20 mm Hg change from baseline in same posture and <50 mm Hg. Only supine vital signs were planned for this study. Unplanned sitting vital signs were collected only in the 8/mg and placebo groups and also reported.

Safety analysis set consisted of all participants who received at least one infusion of study medication (including partial infusions).

Safety analysis set consisted of all participants who received at least one infusion of study medication (including partial infusions). A full physical examination consisted of abdomen, genitourinary, cardiovascular systems, lungs, lymph nodes, mouth, musculoskeletal, general, skin, extremities, head, ears, eyes, nose, throat and thyroid.

The neurological examination was done to the extent needed to assess the participant for any potential changes in neurological status, as determined by the investigator. The minimum items assessed were level of consciousness, speech, cranial nerves, motor, sensory, coordination, gait, and tendon reflexes.

Safety analysis set consisted of all participants who received at least one infusion of study medication (including partial infusions). n = number of evaluable participants at the corresponding time point.

Pharmacokinetic (PK) Analysis Set consisted of all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment.

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

PK Analysis Set consisted of all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment.

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

PK Analysis Set consisted of all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

Evaluable participants in the PK analysis set (all randomized participants who received at least one infusion of study medication and have at least one post-dose PK parameter assessment).

The C-SSRS assessed whether the participant experienced the following: completed suicide (1), suicide attempt (2) (response of "Yes" on "actual attempt"), preparatory acts toward imminent suicidal behavior (3)("Yes" on "preparatory acts or behavior"), suicidal ideation (4) ("Yes" on "wish to be dead", "non-specific active suicidal thoughts", "active suicidal ideation with methods without intent to act or some intent to act, without specific plan or with specific plan and intent), any suicidal behavior or ideation, self-injurious behavior (7)("Yes" on "Has participant engaged in non-suicidal self-injurious behavior").

Safety Analysis Set included all participants who received at least one infusion of study medication (including partial infusions).

Brain MRIs were collected during the course of study to assess for any potential drug-related changes that might have constituted a safety concern for study participants. Findings suggestive of either vasogenic edema (VE) or intracranial hemorrhage represented adverse events of special circumstance and were to be reported immediately.

Safety Analysis Set included all participants who received an infusion of study medication (including partial infusions).

VE of the brain, identified via MRI, was identified as an adverse event of special circumstance.

Safety Analysis Set included all participants who received an infusion of study medication, including partial infusions. n = number of evaluable participants at the corresponding timeframe.

Criteria for ECG values of potential clinical concern are: interval between the start of the ECG P wave and the start of the QRS complex corresponding to the time between onset of atrial depolarization and onset of ventricular depolarization (PR): >= 300 milliseconds (msec), and >=25% increase when baseline >=200 msec/ >=50% increase when baseline less than or equal to (<=) 200 msec; time from ECG Q wave to the end of S wave corresponding to ventricular depolarization (QRS): >=200 msec, and >=25% increase when baseline >100 msec/ >=50% increase when baseline <=100 msec; QTc using Fridericia's formula (QTcF) interval: 450 to <480 msec, >=480 msec; QTcF change from baseline: 30 to <60 msec, and >=60 msec.

Safety Analysis Set included all participants who received an infusion of study medication (including partial infusions).

Human serum anti-drug antibodies (ADA) samples were analyzed for the presence or absence of anti-AAB-003 antibodies by enzyme-linked immunosorbent assay (ELISA) method

All participants who received an infusion of study medication. n = number of evaluable participants at the corresponding timeframe.

The ADAS-cog 70 Point is a structured scale (approximately 40 min to complete) that evaluates memory, orientation, attention, reasoning, language and constructional praxis. This study used the 11-item cognitive subscale of the ADAS-Cog with scores ranging from 0 to 70 points; higher scores indicated greater cognitive impairment.

All participants who were randomized to a treatment and received at least one infusion of study medication. n = number of evaluable participants at the corresponding timeframe.

The DAD is a functional assessment based on an interview with the caregiver that takes approximately 20 min to administer and it is comprised of 40 items, 17 related to self-care and 23 items involving instrumental activities of daily living. The DAD is scored from 0 to 100 (higher scores indicate better functioning).

All participants who were randomized to a treatment and received at least one infusion of study medication. n = number of evaluable participants at the corresponding timeframe.

The NPI is an instrument used to assess changes of behavior that have appeared in a defined period of time in participants with Alzheimer's disease (AD) and other dementias. Twelve (12) behavioral areas are assessed in the NPI - delusions, apathy, hallucinations, disinhibition, agitation, irritability, depression, aberrant motor behavior, anxiety, nighttime behaviors, euphoria, appetite, and eating changes. The NPI score is based on frequency and severity of specific behaviors within these categories as reported by the caregiver. A separate caregiver distress score may also be included. The NPI ranges from 0 to 144 (higher scores indicate greater psychopathology).

All participants who were randomized to a treatment and received at least one infusion of study medication. n = number of evaluable participants at the corresponding timeframe.

The CDR scale is a clinician-rated dementia staging instrument that tracks the progression of cognitive impairment in the following 6 categories - memory, orientation, judgment and problem solving, involvement in community affairs, home and hobbies, and personal care based on the CDR interview. The CDR is based on discussions between the clinician with the participant and caregiver using a structured format. A global CDR score is established by clinical scoring rules with values of 0 (no dementia), 0.5 (questionable dementia), 1 (mild dementia), 2 (moderate dementia), and 3 (severe dementia). A more quantitative version of the CDR scale is obtained by summing up the ratings in each of the 6 categories to provide the (CDR-SB). The CDR-SB scale ranges from 0 to 18 where higher score indicates severe dementia.

All participants who were randomized to a treatment and received at least one infusion of study medication. n = number of evaluable participants at the corresponding timeframe.

The MMSE is a brief 30-point questionnaire test that is used to assess cognition. It is commonly used to screen for dementia. In the time span of about 10 min, it samples various functions, including arithmetic, memory and orientation. Scores range from 0 to 30 (higher scores indicate less impairment) and participants with scores of 16 to 26 were eligible.

All participants who were randomized to a treatment and received at least one infusion of study medication. n = number of evaluable participants at the corresponding timeframe.

Participants enrolled in the 2, 4 and 8 mg/kg cohorts participated in an optional CSF collection. Participants enrolled in the maximum tolerated dose (MTD) cohort were mandatorily collected for CSF.

All randomized and treated participants in the 2, 4 and 8 mg/kg cohorts who consented to the collection of CSF samples.

The CSF analysis set consisted of participants in the AAB-003 8 mg/kg cohort who had provided sufficient CSF samples at Baseline and Week 32 to allow for assaying of both samples, and who had no occurrence of VE.

The CSF analysis set consisted of participants in the AAB-003 8 mg/kg cohort who had provided sufficient CSF samples at Baseline and Week 32 to allow for assaying of both samples, and who had no occurrence of VE.

The CSF analysis set consisted of participants in the AAB-003 8 mg/kg cohort who had provided sufficient CSF samples at Baseline and Week 32 to allow for assaying of both samples, and who had no occurrence of VE.

The CSF analysis set consisted of participants in the AAB-003 8 mg/kg cohort who had provided sufficient CSF samples at Baseline and Week 32 to allow for assaying of both samples, and who had no occurrence of VE.

The CSF analysis set consisted of participants in the AAB-003 8 mg/kg cohort who had provided sufficient CSF samples at Baseline and Week 32 to allow for assaying of both samples, and who had no occurrence of VE.

The CSF analysis set consisted of participants in the AAB-003 8 mg/kg cohort who had provided sufficient CSF samples at Baseline and Week 32 to allow for assaying of both samples, and who had no occurrence of VE.

The CSF analysis set consisted of participants in the AAB-003 8 mg/kg cohort who had provided sufficient CSF samples at Baseline and Week 32 to allow for assaying of both samples, and who had no occurrence of VE.

The CSF analysis set consisted of participants in the AAB-003 8 mg/kg cohort who had provided sufficient CSF samples at Baseline and Week 32 to allow for assaying of both samples, and who had no occurrence of VE.

All randomized participants who received at least one infusion of study medication and have at least one postdose pharmacodynamic (PD) parameter assessment. n = number of evaluable participants at the corresponding timeframe.

All randomized participants who received at least one infusion of study medication, had a Baseline PD parameter assessment and at least one post-dose PD parameter assessment. n = number of evaluable participants at the corresponding timeframe.

All randomized participants who received at least one infusion of study medication, had a Baseline PD parameter assessment, at least one post-dose PD parameter assessment, and who had available data for AUClast.

All randomized participants who received at least one infusion of study medication, had a Baseline PD parameter assessment, at least one post-dose PD parameter assessment, and who had available data for AUCinf. No participants had available data for AUCinf in AAB-003 8 mg/kg and Placebo Groups.

All randomized participants who received at least one infusion of study medication, had a Baseline PD parameter assessment, and at least one post-dose PD parameter assessment. n = number of evaluable participants at the corresponding timeframe.

All randomized participants who received at least one infusion of study medication, had a Baseline PD parameter assessment, at least one post-dose PD parameter assessment, and who had available data for t1/2. No participants had available data for t1/2 in AAB-003 8 mg/kg and Placebo Groups.