OBJECTIVES: Approaches to extrapolating treatment effects and valuing short- versus long-term benefits can differ between chronic progressive conditions requiring treatment early in the disease course, such as Alzheimer’s disease (AlzDis), and chronic conditions treated in more severe stages, such as atopic dermatitis (ADerm). This study contrasts economic evaluations in AlzDis and ADerm to illustrate how disease characteristics and extrapolation assumptions impact value assessments for two types of chronic conditions.

METHODS: We compared the Institute for Clinical and Economic Review’s (ICER’s) 2021 cost-effectiveness analyses for biologic therapies in moderate-to-severe ADerm and for aducanumab in early AlzDis. Emphasis was placed on comparing baseline populations, long-term progression, treatment effect extrapolation assumptions, treatment discontinuation assumptions, timing of quality-adjusted life-year (QALY) gains, and pricing benchmarks.

RESULTS: The ADerm population started treatment in a more severe state than the AlzDis population (baseline utility=0.60 vs. 0.68-0.73). While ADerm only improved over time (no progression), AlzDis progressed to more advanced states (lowest utility=0.31). The ADerm treatment effect (response) produced immediate QALY gains and persisted without waning for responders remaining on treatment. The AlzDis treatment effect (reduction in progression) was applied fully only in the baseline state, waned with progression, and stopped prior to treatment discontinuation. QALY gains in AlzDis accrued indirectly by slowing progression and extending survival and thus were delayed and discounted. Trial-based treatment discontinuation was extrapolated for ADerm but was not extrapolated for AlzDis. Age differences (ADerm=36.5 years; AlzDis=70 years) contributed primarily through higher competing mortality risks for AlzDis. ICER’s resulting benchmark prices at $100,000/QALY gained for ADerm biologic therapies ($24,400-$30,600/year) were higher than the benchmark price range for aducanumab for AlzDis ($1,650-$11,000/year).

CONCLUSIONS: Conventional value assessment approaches may inequitably value treatments for chronic progressive conditions requiring early, preventive treatment. Such conditions merit inclusion in ongoing discussions on augmented and/or risk-adjusted cost-effectiveness analysis.