Open-label Extension Study in Participants With Early Alzheimer's Disease

An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of a study intervention, whether or not considered related to the study intervention.

AESIs includes Infusion-related reactions, Amyloid related imaging abnormalities (ARIA) and cerebral macrohemorrhage.

A SAE is defined as any untoward medical occurrence that, at any dose, results in death and is life threatening requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability or incapacity, or is a birth defect or congenital anomaly.

Magnetic resonance imaging (MRIs) will be used to monitor for abnormalities in the brain such as brain swelling and/or brain bleeding, which are termed as ARIAs.

The CDR-SB score is a quantitative general index that provides more precision in participants with mild dementia. The CDR scale is a clinician-rated dementia staging system tracks the progression of cognitive impairment in 6 categories (memory, orientation, judgment, and problem solving, community affairs, home and hobbies, and personal care). Each category is scored on a 5- point scale in which 0=None, 0.5=Questionable, 1= Mild, 2=Moderate, and 3=Severe. The CDR-SB score is obtained by adding the ratings in each of the 6 categories and total score ranges from 0 to 18 with higher scores indicative of greater impairment.

The AD Assessment Scale-Cognitive subscale (ADAS-Cog14) is a 14-item version of the test that assesses immediate and delayed memory, confrontational naming, ability to follow commands, ideational and constructional praxis, orientation, language, and attention. The ADAS Cog-14 score ranges from 0 to 90 and higher scores indicate greater impairment.

The MMSE is a brief test used to screen for cognitive impairment. It is routinely used for estimating the severity of cognitive impairment and tracking cognitive changes in an individual over time. The MMSE assesses orientation (time and place), registration, attention and calculation, recent memory, language (naming, comprehension, and repetition), and constructional praxis (copying a figure). The MMSE score ranges from 0 to 30, with higher scores indicating better cognitive performance.

The AD Cooperative Study - Activities of Daily Living Scale for use in Mild Cognitive Impairment (ADCS-ADL-MCI). The ADCS-ADL for MCI is a 23-item scale that measures the competence of participants in basic and instrumental activities of daily living. Total scores on the ADCS-ADL-MCI range from 0 to 53 where lower scores indicates greater functional impairment.

The iADRS is a composite tool that measures both cognition and function. The iADRS combines scores from the ADAS-Cog-14 and the Alzheimer's Disease Cooperative Study-instrumental Activities of Daily Living (ADCS-iADL). The ADAS-Cog-14 is a 14-item version of the test that assesses immediate and delayed memory, confrontational naming, ability to follow commands, ideational and constructional praxis, orientation, language, and attention. The ADCS-iADL is a 23-item scale measuring basic and instrumental abilities in participants with mild to moderate AD. The iADRS score is then computed as the sum of the transformed ADAS-Cog14 and the ADCS-iADL with scores ranging from 0 to 144 and lower scores indicating worse performance.

The ADCOMS is a composite score comprising scores from the MMSE, ADAS-Cog14, and CDR-SB. It contains a total of 12 cognitive and functional items, including 4 items from the ADAS-Cog14, 2 items from the MMSE, and 6 items from the CDR-SB. The ADCOMS scores range from 0 to 1.97, with a higher score indicative of greater impairment.