New IPECAD Open-Source Model Framework for the Health Technology Assessment of Early Alzheimer's Disease Treatment:...

Area of Science:

• Health economics
• Pharmacoeconomics
• Alzheimer's disease research

Background:

• Economic evaluations are crucial for Alzheimer's disease (AD) treatment reimbursement.
• Transparency and credibility in these evaluations are enhanced by open-source, cross-validatable models.
• The International Pharmaco-Economic Collaboration on Alzheimer's Disease (IPECAD) developed an open-source model framework (version 2) for early AD treatment economic evaluation.

Purpose of the Study:

• To describe the IPECAD open-source model framework (version 2).
• To utilize the model for cross-validation against existing economic models.
• To perform uncertainty analyses relevant to early AD treatment evaluations.

Main Methods:

• Developed a cohort state-transition model replicating a reference model for internal validity.
• Implemented features from Institute for Clinical and Economic Review (ICER) and Alzheimer's Disease Archimedes Condition-Event Simulator (AD-ACE) models for cross-validation.
• Conducted uncertainty analyses on efficacy outcomes, disease progression, treatment waning, and stopping rules. The model is available as R code, spreadsheet, and web version.

Main Results:

• The IPECAD model yielded smaller incremental life-years, QALY gains, and cost savings compared to ICER (21-31% less) and AD-ACE (36-56% less) models.
• IPECAD model results showed particular sensitivity to assumptions regarding treatment effect waning, stopping rules, and the choice of efficacy outcome from trials.

Conclusions:

• The IPECAD open-source model framework enables cross-validation of Health Technology Assessment submission models.
• It facilitates additional uncertainty analyses, promoting open science in AD decision modeling.
• The framework supports informed reimbursement decisions for new Alzheimer's disease treatments.