The Value of Positron Emission Tomography for Confirmation of Alzheimer’s Disease in the Era of Amyloid-Targeting Therapies

Objectives Amyloid-targeting therapies for Alzheimer’s disease (AD), such as lecanemab, target and reduce brain β-amyloid plaques. To initiate therapy accurately, confirming the presence of brain β-amyloid plaques is necessary. This research investigated the added value and cost-effectiveness of 18F-flutemetamol positron emission tomography (PET) in the United States. Methods A cost-effectiveness model was developed to evaluate the differential diagnostic accuracy for AD and associated clinical and economic outcomes between 18F-flutemetamol PET imaging and cerebrospinal fluid (CSF) testing. The model simulates the impact of the diagnostic modality choice in a hypothetical patient cohort with mild cognitive impairment or suspected AD and aged 40 to 79 years for eligibility to receive Amyloid-targeting therapy. Results The use of 18F-flutemetamol PET to diagnose AD results in an additional 14% of patients correctly identified versus CSF testing. Furthermore, the use of 18F-flutemetamol PET leads to fewer patients expected to progress to moderate/severe AD (6.83% vs 6.91%) and is associated with decreased mortality (36.88% vs 37.06%). Over a patient’s lifetime, 18F-flutemetamol PET contributes an additional 0.02 discounted quality-adjusted life years compared with CSF (4.91 vs 4.89) with an incremental discounted cost of $1405. This translates to a cost of $73 872 per quality-adjusted life year gained. Conclusions Compared with CSF testing, 18F-flutemetamol PET imaging is less invasive, leading to more patients being correctly diagnosed and targeted for appropriate therapy, which has a downstream impact on disease progression and mortality. The model suggests that 18F-flutemetamol PET is a cost-effective diagnostic modality for US payers.