Cost Effectiveness of Zanubrutinib Versus Ibrutinib in Relapsed or Refractory Chronic Lymphocytic Leukemia

Background While the efficacy and safety of zanubrutinib have been established in relapsed or refractory chronic lymphocytic leukemia, the evidence on cost effectiveness is still lacking. Objective We aimed to evaluate the cost effectiveness of zanubrutinib versus ibrutinib in relapsed or refractory chronic lymphocytic leukemia from the commercial payer perspective in the USA. Methods A partitioned survival model was developed based on survival curves from the phase III ALPINE trial. We reconstructed patient-level data for each curve and conducted a parametric estimation to incorporate long-term clinical outcomes and treatment costs into the model. Medical costs and utilities were obtained from public data and previous cost-effectiveness studies. A discount rate of 3.0% per annum was applied and costs were adjusted to 2023 US dollars. The incremental cost-effectiveness ratio was calculated by dividing the incremental costs of zanubrutinib over ibrutinib by the incremental life-years or quality-adjusted life-years. Deterministic and probabilistic sensitivity analyses were performed to examine the robustness of the results. Results Over a 10-year analysis period, the incremental cost-effectiveness ratio of zanubrutinib versus ibrutinib was $91,260 per life-year gained and $120,634 per quality-adjusted life-year gained, making it cost effective within a threshold of $150,000 per quality-adjusted life-year gained. The incremental cost-effectiveness ratio was most sensitive to drug acquisition costs and progression-free survival distributions, and the probability of zanubrutinib being cost effective was approximately 52.8%, with a 30.0% likelihood of dominance. Conclusions Zanubrutinib is likely to be cost effective versus ibrutinib in relapsed or refractory chronic lymphocytic leukemia in the USA, but the high threshold should be noted. Our findings may provide a basis for pricing strategy and reimbursement decisions for zanubrutinib.