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

Abstract

Objectives: Amyloid-targeting therapies (ATTs) 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 (US).

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 (MCI) or suspected AD, aged 40-79 years for eligibility to receive ATT.

Results: The use of ¹⁸F-flutemetamol PET to diagnose AD results in an additional 14% of patients correctly identified vs CSF testing. Further, 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 (QALYs) compared to CSF (4.91 vs 4.89) with an incremental discounted cost of $1,405. This translates to a cost of $73,872 per QALY gained.

Conclusions: Compared to 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.