Safety, Radiation Dosimetry, Biokinetics, and Effectiveness of [18F]MK3328 (MK-3328-001)

Merck Sharp & Dohme LLC19 enrolled

Overview

This study will estimate the radiochemical and radiation safety and assess the efficacy of \[18F\]MK-3328, a novel positron emission tomography (PET) tracer. The study safety hypotheses will test whether \[18F\]MK-3328 is sufficiently safe and well-tolerated, based on an assessment of clinical and laboratory evaluations and adverse experiences in healthy participants, including healthy elderly (HE) participants, and Alzheimer's disease (AD) participants, to permit continued investigation. The study efficacy hypothesis will test whether \[18F\]MK-3328 can discriminate between AD participants and cognitively normal elderly control participants based on tracer volume of distribution, or one of its surrogates, in brain posterior cingulate gyrus.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Enrollment

Conditions

Alzheimer's Disease

Interventions

Eligibility

Sex: ALLMin age: 50 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: Part I: * Participant is male or female of non-reproductive potential between 50 and 65 years old. * Participant is less than 6'5" tall * Participant is in good health * Participant has been a non-smoker for at least 10 years Parts II and III: * Male or female of non-reproductive potential at least 55 years of age * Participant is cognitively normal (HE participants), or has probable mild-to moderate AD (AD participants) * Participant is willing to have an arterial catheter placed in the radial artery (Part II only) Exclusion Criteria: Part I: * Participant has a history of stroke, seizures, or neurological disorder * Participant has or has a history of any disease or condition, or takes any medication that would interfere with assessment of the tracer or make participation unsafe or unduly uncomfortable Parts II and III: * Participant has a history or current evidence of any neurological or neurodegenerative disorder other than AD that is associated with altered cognition * Participant has or has a history of any disease or condition, or takes any medication that would interfere with assessment of the tracer or make participation unsafe or unduly uncomfortable * Participant is living in a nursing home or skilled nursing facility

Outcomes

Primary Outcomes

Number of Participants With an Adverse Event (AE)

An AE is any unfavorable and unintended change in the structure, function or chemistry of the body temporally associated with study drug administration, whether or not considered related to the study drug.

Time frame: Up to 14 days after last dose

Number of Participants Who Discontinued Study Due to an AE

Time frame: Up to 14 days after last dose

Effective Dose of [18F]MK-3328

Using PET whole body images acquired after dosing, regions of interest (ROIs) were drawn in all organs showing visible \[18F\]MK-3328 accumulation. Time activity curves (TACs) showing total \[18F\]MK-3328 retention as a function of time were determined for each organ. Residence times were calculated from the area under each organ TAC. Radiation exposure of the body and critical organs was calculated from the \[18F\]MK-3328 residence times using OLINDA (Organ Level Internal Dose Assessment) software. For each organ, the equivalent dose, which is the absorbed radiation dose weighted for the degree of the biological effect of different types of radiation, was calculated. The total radiation exposure to the body is expressed as the effective dose, which is the sum of the equivalent doses in each organ multiplied by a weighting factor for the type of tissue exposed. Effective dose is the primary surrogate for radiation risk. The unit of effective dose is the Sievert (Sv).

Time frame: Up to approximately 6 hours post dose

Organ Effective Dose of [18F]MK-3328

Using PET whole body images acquired after dosing, ROIs were drawn in all organs showing visible \[18F\]MK-3328 accumulation. TACs showing total \[18F\]MK-3328 retention as a function of time were determined for each organ. Residence times were calculated from the area under each organ TAC. Radiation exposure of the body and critical organs was calculated from the \[18F\]MK-3328 residence times using OLINDA software. For each organ, the equivalent dose, which is the absorbed radiation dose weighted for the degree of the biological effect of different types of radiation, was calculated. The organ effective dose is the equivalent dose in each organ multiplied by a weighting factor for the type of tissue exposed. The unit of organ effective dose is Sv.

Time frame: Up to approximately 6 hours post dose

Mean Brain Cortical [18F]MK-3328 Standard Uptake Value Ratio (SUVR) in AD Participants and HE Participants

Using PET brain images acquired after dosing, regions of interest (ROIs) were drawn in identified brain areas. The ROIs were projected onto all frames of the dynamic PET scans in order to generate \[18F\]MK-3328 tissue TACs. SUVR is calculated as the ratio of the average \[18F\]MK-3328 uptake over 60-90 minutes post dose in the target brain region and the cerebellum. Cortical SUVR is reported, which is a mean SUVR derived from SUVR from multiple brain regions (frontal cortex, parietal cortex, anterior cingulate gyrus, posterior cingulate gyrus, temporal cortex, lateral temporal cortex and occipital cortices).

Time frame: 60-90 minutes post dose

Least Squares (LS) Mean [18F]MK-3328 SUVR in Brain Posterior Cingulate Gyrus in AD Participants and HE Participants

Using PET brain images acquired after the second dose of \[18F\]MK-3328, regions of interest (ROIs) were drawn in identified brain areas. The ROIs were projected onto all frames of the dynamic PET scans in order to generate \[18F\]MK-3328 tissue TACs. Posterior cingulate gyrus SUVR was calculated as the ratio of the average \[18F\]MK-3328 uptake over 60-90 minutes post dose in the target brain region and the cerebellum.

Time frame: 60-90 minutes after second dose