Chimerism Testing for Patients With Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation: A Cost-Utility Analysis

OBJECTIVES: Patients with acute myeloid leukemia (AML) face elevated relapse and mortality risk following allogeneic hematopoietic stem cell transplantation, but early identification of high-risk patients provides the opportunity for preventative interventions. Routine post-transplant monitoring with multiparameter flow cytometry (MFC) is recommended to detect measurable residual disease, a strong indicator of relapse risk, and more sensitive tests for mixed chimerism may supplement MFC. We evaluated the cost-effectiveness of post-transplant monitoring with a novel chimerism assay panel in parallel with MFC for the identification of AML patients with high relapse risk compared to standard MFC alone.

METHODS: A Markov model was developed to project the health outcomes (quality-adjusted life-years [QALYs]), economic costs (in 2022 US dollars), and incremental cost-effectiveness ratio (ICER) of parallel chimerism and MFC testing compared to MFC alone over 36 months. Each strategy was associated with unique test characteristics, and a proportion of identified high-risk patients were assumed to receive pre-emptive treatment to prevent relapse. We employed a healthcare payer perspective and discounted costs and outcomes at 3% per year. One-way, probabilistic, and scenario analyses were conducted to explore the range of potential outcomes considering the uncertainty in the current evidence.

RESULTS: At the assumed cost of $1,500 per chimerism test, parallel testing demonstrated modest clinical benefit with additional costs compared to standard MFC alone, but the ICER exceeded $1.65 million per QALY gained. The estimated value-based price for the chimerism assay was $1,030 per test, and the development of more effective preventative interventions would increase the value of chimerism testing.

CONCLUSIONS: Parallel chimerism and MFC testing would provide marginal benefits for post-transplant AML patients at increased costs and would not be cost-effective given current test characteristics and treatment options, but future advancements in pre-emptive therapies may increase the value of the chimerism assay panel in post-transplant monitoring.