A Clinical Study of MK-2214 in People With Early Alzheimer's Disease (MK-2214-004)

Participants will have tau PET imaging to assess tau pathology. Tau is a protein that accumulates in AD & damages brain cells. SUVr is SUV in the region of interest divided by SUV in a reference region (cerebellum). The change from baseline in tau PET SUVr will be reported.

An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants who experience one or more AEs will be reported.

An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants who discontinue study intervention due to an AE will be reported.

The CDR-SB is used for cognitive assessment in people with AD. The CDR is a clinical scale that describes 5 degrees of impairment in performance on each of 6 categories of function including memory, orientation, judgment and problem solving, community affairs, home and hobbies, and personal care. The ratings of degree of impairment obtained on each of the 6 categories of function are synthesized into 1 global rating of dementia CDR score ranging from 0 (normal) to 3 (severe). A total score is calculated as the sum of the category scores, with a range of 0 (normal) to 18 (severe). Higher scores indicate more impairment. The change from baseline in CDR-SB total score will be reported.

Participants will have tau PET imaging to assess tau pathology. Tau is a protein that accumulates in AD & damages brain cells. SUVr is SUV in the region of interest, divided by SUV in a reference region (cerebellum). Braak staging ranges from Braak I to VI. Description for Braak III includes amygdala, parahippocampal gyrus, fusiform gyrus, & lingual gyrus, and Braak IV includes insula, inferior temporal, lateral temporal, posterior cingulate, & inferior parietal. The composite tau PET SUVr is a weighted average of tau PET SUVr values obtained from multiple brain regions, with weights being the percentage volume of each region within the composite. The change from baseline in composite tau PET SUVr in Braak regions III and IV will be reported.

Participants will have tau PET imaging to assess tau pathology. Tau is a protein that accumulates in AD & damages brain cells. SUVr is SUV in the region of interest, divided by SUV in a reference region (cerebellum). The composite tau PET SUVr is a weighted average of tau PET SUVr values obtained from multiple brain regions, with weights being the percentage volume of each region within the composite. The change from baseline in composite tau PET SUVr will be reported.

Participants will have tau PET imaging to assess tau (protein that accumulates in AD & damages brain cells) pathology. SUVr is SUV in the region of interest, divided by SUV in a reference region (cerebellum). Braak staging ranges from I-VI (Braak I (transentorhinal); II (entorhinal & hippocampus); III (amygdala, parahippocampal gyrus, fusiform gyrus, & lingual gyrus); IV (insula, inferior temporal, lateral temporal, posterior cingulate, & inferior parietal); V (orbitofrontal, superior temporal, inferior frontal, cuneus, anterior cingulate, supramarginal gyrus, lateral occipital, precuneus, superior parietal, superior frontal, & rostro medial frontal); VI (paracentral, postcentral, precentral, & pericalcarine)). Composite tau PET SUVr is weighted average of tau PET SUVr values from multiple brain regions, with weights being percentage volume of each region. The change from baseline in composite tau PET SUVr in Braak region I to IV will be reported.

The ADAS-Cog13 is a structured scale that evaluates memory (word recall, delayed word recall, and word recognition), reasoning (following commands), language (naming, comprehension), orientation, ideational praxis (placing letter in envelope) and constructional praxis (copying geometric designs). In addition, ratings of spoken language, language comprehension, word finding difficulty, ability to remember test instructions, and number cancellation will be obtained. Per protocol, score range will be from 0 (no impairment) to 85 (maximum impairment) points. Higher scores indicate more impairment. The change from baseline in ADAS-Cog13 total score will be reported.

ADCS-ADL-MCI evaluates the ability of individuals to perform various daily activities including basic activities of daily living (BADL; personal care tasks like bathing, dressing and eating) and instrumental activities of daily living (IADL; complex tasks such as managing finances, preparing meals, using telephone) administered through caregiver or family member to access severity of cognitive decline in the past 4 weeks. Each item is scored on a scale of 0 (unable to do) to 2 (independent). The total score is calculated by summing scores of all items and ranges from 0 (poor functioning) to 68 (better functioning). Higher scores indicate better functional ability. The change from baseline in ADCS-ADL-MCI total score will be reported.

The modified iADRS is a composite tool to measure cognition and function. The modified iADRS is a linear combination of total scores from the ADAS-Cog and the ADCS-ADL-MCI. The modified iADRS composite score is calculated by subtracting the ADAS-Cog13 score from 85 and then adding the ADCS-ADL-MCI score. Composite score ranges from 0 (maximum impairment) to 144 (greater independent, healthy functioning and cognition). Lower scores indicate more impairment. The change from baseline in modified iADRS total score will be reported.