OBJECTIVE: To examine potential cost-effectiveness of Alzheimer’s disease-modifying therapies (DMTs) of different treatment durations.

BACKGROUND: Clinical trial results suggest the disease-modifying impact of a new class of anti-amyloid monoclonal antibodies. Optimal treatment duration is uncertain due to limited follow-up in clinical trials. A recent economic analysis of the first such agent approved questioned the economic value of treatments that slow progression of early symptomatic Alzheimer’s disease (AD) to more advanced states. Results were highly sensitive to therapy costs, which would likely be substantially influenced by treatment duration.

METHODS: We constructed a population-based Markov state-transition simulation model to calculate the cost-effectiveness of hypothetical DMTs. Base-case assumptions were similar to those in the Institute for Clinical and Economic Review evaluation of aducanumab, including a healthcare system perspective and patient lifetime time horizon. We assumed greater treatment efficacy (30% slowing of progression from mild cognitive impairment and from mild AD states), consistent with benefits anticipated from DMTs currently under evaluation. The impact of different treatment durations and therapy costs were examined.

RESULTS: A hypothetical DMT used continuously until patients progress to severe AD had an incremental cost-effectiveness ratio (ICER) ranging from $297K/QALY to $586K/QALY as annual treatment cost varied from $28K to $56K, based on the original and subsequently reduced prices set by one manufacturer. A hypothetical DMT with similar efficacy but used for only 18 months yielded ICERs from $89K to $173K/QALY. Use of a diagnostic test (cost $4000) to identify 40% of patients who could discontinue treatment due to amyloid negativity at 6 months reduced total treatment costs by 25% and yielded ICERs from $77K/QALY to $139K/QALY. Results were sensitive to mean age, efficacy assumptions and treatment cost.

CONCLUSIONS: Efficacious Alzheimer’s DMTs used for limited durations or until amyloid plaque clearance have potential to deliver value consistent with accepted cost-effectiveness thresholds.