Cost-Effectiveness of Eltrombopag versus Romiplostim for the Treatment of Chronic Immune Thrombocytopenia in England and Wales

Objective: To evaluate the cost-effectiveness of eltrombopag compared with romiplostim as a treatment for chronic immune thrombocytopenia (cITP) in patients who are splenectomized or ineligible for splenectomy and are treatment refractory in England and Wales. Methods: A Markov cohort model in which patients were administered a sequence of treatments was used to predict long-term outcomes associated with each treatment. The model was informed by data from the eltrombopag clinical trial program and the available literature. The analysis was conducted from the perspective of the United Kingdom National Health Service, and a lifetime time horizon was used. Deterministic and probabilistic sensitivity analyses were performed. Results: Eltrombopag dominated romiplostim (i.e., eltrombopag was as effective as but less costly than romiplostim) in both splenectomized and non-splenectomized patients, assuming a class effect for the two treatments. Eltrombopag also dominated romiplostim in the majority of deterministic sensitivity analyses with the exception of when indirect efficacy estimates were incorporated into the model. In this analysis, eltrombopag no longer dominated romiplostim but remained cost-effective versus romiplostim at a willingness-to-pay threshold of £20,000 per quality-adjusted life-year (QALY). Probabilistic sensitivity analysis demonstrated that there was a 99% and 92% chance of eltrombopag being cost-effective at a cost-effectiveness threshold of £20,000/QALY in splenectomized and non-splenectomized patients, respectively. Conclusions: Results of this study demonstrate that eltrombopag is cost-effective when compared to romiplostim as a treatment for cITP, representing good value for the United Kingdom National Health Service.