A systematic review of cost-effectiveness analyses of gene therapy for hemophilia type A and B.

backgroundIn 2022-2023, the US Food and Drug Administration approved 2 novel gene therapies, valoctocogene roxaparvovec and etranacogene dezaparavovec, for hemophilia A and B, respectively. These one-time-administered gene therapies have been marketed at prices that create financial challenges for payers and patients. Understanding the magnitude and uncertainties around the long-term value of these therapies and how they can potentially relate to managed care practices is of high interest to the payer and patient community.

objectiveTo conduct a systematic review of cost-effectiveness analysis (CEA) studies to assess (1) the long-term value of valoctocogene roxaparvovec and etranacogene dezaparavovec and (2) the relevance and validity of the underlying data and assumptions used in the CEA models and discuss how they relate to the challenges identified for CEAs of gene therapies.

methodsA systematic review of cost-effectiveness studies of novel hemophilia A and B gene therapy was conducted. PubMed and Embase were searched for published studies from inception to January 12, 2024. Original research articles published in English that conducted a CEA on gene therapy treatments for hemophilia A and B, with a comparison of incremental costs and health effects, were considered. Critical appraisal of the quality of reporting and the underlying modeling assumptions were conducted to assess the relevance and validity of the results.

resultsTwo hundred thirty-eight studies were identified, of which 4 met the inclusion criteria. Three studies were conducted from a US health care perspective and 1 from a Dutch societal perspective. Despite the high upfront costs of the gene therapies, all included studies' (3 hemophilia A and 1 hemophilia B) modeled results showed that gene therapies had lower overall costs and better health outcomes compared with factor concentrate replacement therapies and emicizumab. The results were driven by the assumption that gene therapies will have a durable effect of at least 10 years and offset the high cost of the current standard of care. The modeled health improvements varied substantially across studies, showing that the long-term value is sensitive to varying clinical and economic assumptions.

conclusionsThe novel hemophilia gene therapy treatments can potentially be a cost-effective use of treatment resources if the treatment effects are durable over time. To reduce the risk for payers while still facilitating patient access, outcomes-based agreements similar to what has recently been proposed by the Centers for Medicare & Medicaid Services for sickle-cell therapies are well supported.