Cost-Effectiveness Analysis of Ribociclib Versus Abemaciclib in the First-Line (1L) Treatment of Postmenopausal Women With HR+/HER2- Advanced Breast Cancer (ABC)

OBJECTIVES: Ribociclib is the only cyclin-dependent kinase 4/6 inhibitor to demonstrate a statistically significant overall survival (OS) benefit in 1L ABC (MONALEESA-2). While palbociclib (PALOMA-2) failed to show OS benefit, data for abemaciclib (MONARCH-3) is pending and thus far not statistically significant. This study evaluated cost-effectiveness of ribociclib versus abemaciclib (utilizing latest clinical data) in 1L treatment of postmenopausal women with HR+/HER2− ABC from the UK National Health Service perspective.

METHODS: A three-state (progression-free, progressed disease, and death) partitioned survival model with 1-month cycle length was developed. Hazard ratios (HRs) for ribociclib plus AI versus AI were derived using a matching-adjusted indirect comparison to adjust for differences in patient characteristics between MONALEESA-2 and MONARCH-3. For abemaciclib plus AI versus AI, HRs were derived using conventional indirect treatment comparison. Cost inputs included drug acquisition, disease monitoring, subsequent therapies, and adverse event costs. Utility values were derived from trial data and published literature. Costs and effects were discounted at 3.5% per year over a lifetime horizon of 40 years. One-way and probabilistic sensitivity analyses were also performed.

RESULTS: At list price, total discounted costs of treatment with ribociclib and abemaciclib were £134,012 and £148,482, respectively. Total discounted quality-adjusted life years (QALYs) for treatment with ribociclib were 5.471 vs. 5.101 for abemaciclib. Ribociclib was estimated to be both cost-saving (−£14,470) and more effective (+0.370 QALYs) than abemaciclib and was the dominant treatment. Probability of ribociclib being cost-effective versus abemaciclib at £30,000 per QALY was 94%. Ribociclib remained cost-effective (versus abemaciclib) when HRs, utilities, ribociclib drug cost, and health state costs were varied.

CONCLUSIONS: Ribociclib is both a cost-saving and cost-effective option versus abemaciclib in 1L treatment of HR+/HER2– ABC. The key driver of cost savings were lower acquisition costs of ribociclib.