Open Label Extension Study Evaluating Safety and Tolerability of AAB-003 (PF-05236812) in Subject With Mild to Moderate Alzheimer's Disease

An AE was any untoward medical occurrence in a participant who received study drug. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent are events between first dose of study drug and up to 28 days after last dose that were absent before treatment or that worsened relative to pre-treatment state. AEs included both SAEs and non-SAEs.

The following laboratory parameters were analyzed: hematology (hemoglobin, hematocrit, red blood cell [RBC] count, RBC morphology, platelet count, white blood cell [WBC] count, total neutrophils, eosinophils, monocytes, basophils, lymphocytes); blood chemistry (blood urea nitrogen [BUN], creatinine, glucose, calcium, sodium, potassium, chloride, total bicarbonate, aspartate aminotransferase [AST], alanine aminotransferase [ALT], total bilirubin, alkaline phosphatase, uric acid, albumin, and total protein; urinalysis (pH, glucose, protein, blood, ketones, nitrites, leukocyte esterase, microscopy [if urine dipstick was positive for blood, protein, nitrites or leukocyte esterase]); others (coagulation panel, circulating immune complex, and complement activation).

Vital signs assessment included pulse rate and blood pressure. Criteria for vital sign values meeting potential clinical concern included: supine/sitting pulse rate <40 or >120 beats per minute (bpm); standing pulse rate <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 or SBP <90 mm Hg, diastolic blood pressure (DBP) >=20 mmHg change from baseline in same posture or DBP <50 mm Hg.

ECG parameters included PR interval, QRS interval, and QT interval. Criteria for ECG changes meeting potential clinical concern included: PR interval >=300 milliseconds (msec) or >=25% increase when baseline is >200 msec and >=50% increase when baseline is less than or equal to (<=)200 msec; QRS interval >=200 msec or >=50% increase from baseline when baseline is less than or equal to 100 msec and >=25% increase when baseline is >100 msec; and QTcF >=450 msec or >=30 msec increase.

A full physical examination consisted of an examination of the abdomen, genitourinary and cardiovascular systems, lungs, lymph nodes, mouth, musculoskeletal and neurological systems, skin, extremities, head, ears, eyes, nose, throat and thyroid gland. Criteria for abnormal physical findings was based on the investigator's discretion and any new physical examination findings were documented as AEs. Only sites with at least 1 participant abnormality are reported.

Neurological examinations were done to the extent needed to assess the subject for any potential changes in neurological status, as determined by the investigator. Examinations included level of consciousness, speech, cranial nerves, motor, sensory, coordination, gait, and tendon reflexes. Only tests with at least 1 participant abnormality are reported.

The C-SSRS captures the occurrence, severity, and frequency of suicide-related thoughts and behaviors during the assessment period. C-SSRS assesses whether participant experienced the following: completed suicide; suicide attempt; preparatory acts towards imminent suicidal behavior; suicidal ideation; self-injurious behavior, no suicidal intent. The results presented are the number of participants with completed suicide or non-fatal suicide events or behaviors. Worsening of suicidal ideation was an increase in severity of suicidal ideation from baseline.

Brain MRIs were collected to assess for potential drug-related changes that might have constituted a safety concern. Findings suggestive of either vasogenic edema or intracranial hemorrhage were to be reported as AEs of special circumstance.

Number of participants with positive sample(s) in the ADA assay and in the neutralizing anti-drug antibodies (NAb) assay. An endpoint titer >=6.64 corresponded to positive ADA category value. The number of participants who tested positive on 1 or more occasions is reported.

ADAS-Cog is a structured scale that evaluates memory, orientation, attention, reasoning, language and constructional praxis. The ADAS-Cog comprises 11 items that are summed to a total score ranging from 0 to 70, with higher scores indicate greater cognitive impairment.

The DAD is a functional assessment comprised of 40 items (17 items related to self-care and 23 items involving instrumental activities of daily living). The DAD assessment is scored from 0 to 100; higher scores indicate better function.

The NPI is an instrument used to assess changes of behavior that have appeared in a defined period of time in subjects with Alzheimer's Disease and other dementias. Twelve behavioral areas are assessed: 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. Severity (1=Mild to 3=Severe), frequency (1=occasionally to 4=very frequently) scales recorded for each domain; frequency*severity=each domain score (range 0-12). Total score=sum of each domain score (range 0-144); higher score=greater behavioral disturbances; negative change score from baseline=improvement.

The CDR scale is a 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. The CDR-SB scale is obtained by summing the ratings in each of the 6 categories, ranging from 0 to 18. Higher scores indicate greater disease severity.

The MMSE is a brief 30-point questionnaire test that is used to assess cognition. Scores range from 0 to 30, with higher scores indicating better cognitive state.