OBJECTIVES: Valoctocogene roxaparvovec (ValRox) is a gene therapy for hemophilia A. The aim of this study was to assess the cost-effectiveness of ValRox compared with emicizumab, in hemophilia A patients without inhibitors eligible for factor prophylaxis. As emicizumab has an annual acquisition cost exceeding $600,000 in the US, we highlight in this assessment a scenario where the cost savings of ValRox were capped using an annual $150,000/quality-adjusted life-years (QALYs) willingness to pay (WTP) threshold.

METHODS: We developed a semi-Markov model to simulate a cohort of hemophilia A patients’ costs and health outcomes (expressed in QALYs) from a healthcare sector perspective across a lifetime time horizon. The model structure was based on Pettersson scores (PS) where bleed rates determined transitions across PS. Factor VIII (FVIII) level projections and interventional durability were extrapolated using evidence from clinical trials, with all patients switched to emicizumab when FVIII levels fall below 1%. ValRox was associated with a small evidence based utility gain. The incremental cost per QALY gained and cost per bleed averted were the primary outcomes of interest. Scenario analyses followed the “High-Impact Single and Short-Term Therapies” framework developed by ICER. To explore model uncertainty, we performed deterministic and probabilistic sensitivity analysis.

RESULTS: ValRox priced at $2.8M was associated with a lifetime QALY gain of 0.1 and cost savings of $3.9 million in a conventional model. When we capped the cost offset attributed to emicizumab displacement at $150,000/year, the cost-effectiveness ratio rose to $8.2million/QALY. At a WTP of $150,000 per QALY, the value-based price using the $150,000 cost cap was $1,971,000.

CONCLUSIONS: This is the first model comparing the cost-effectiveness of ValRox versus emicizumab. The $150,000 per year cost cap was influential in projecting the cost-effectiveness of ValRox.