Cost-effectiveness analysis of ribociclib versus palbociclib in the first-line treatment of HR+/HER2– advanced or metastatic breast cancer in Spain

Elena Galve-Calvo,1 Eva González-Haba,2 Joana Gostkorzewicz,3 Irene Martínez,4 Alejandro Pérez-Mitru4 1Medical Oncology Service, Basurto University Hospital, Bilbao, Spain; 2Pharmacy Department, Hospital Universitario Gregorio Marañón, Madrid, Spain; 3Novartis Farmacéutica, S.A., Health Economics and Outcomes Research, Madrid, Spain; 4Oblikue Consulting, Barcelona, Spain Purpose: The aim of this study was to evaluate the cost-effectiveness of ribociclib compared to palbociclib, both in combination with letrozole, in the first-line treatment of postmenopausal women with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2–) advanced or metastatic breast cancer (ABC) from the perspective of the Spanish National Health System (NHS).Patients and methods: Disease progression was simulated with a partitioned survival model developed from the parameterization and extrapolation of survival curves of postmenopausal women with HR+/HER2– ABC from clinical trials with ribociclib or palbociclib, both in combination with letrozole. The model was structured on the basis of three health states (progression-free, progressed disease, and death), with a 1-month cycle length and inclusion of subsequent treatments administered for disease progression, over a time horizon of 15 years. Clinical, economic, and quality of life parameters were drawn from clinical trials and the literature. The use of resources and clinical practice in the Spanish setting was validated by a panel of experts. The Spanish NHS perspective was adopted, taking into account exclusively direct health costs from 2017 expressed in Euros. Drug prices used were the reported ex-factory prices. Uncertainty of the parameters and robustness of the results were evaluated using deterministic and probabilistic sensitivity analyses (2,000 iterations).Results: This cost-effectiveness analysis showed a greater benefit (0.437 and 0.285 life-years gained [LYGs] and quality-adjusted life years [QALYs] gained, respectively) and a slightly higher cost (€439.86) for ribociclib+letrozole compared to palbociclib+letrozole. The resulting incremental cost-effectiveness and cost-utility ratios were €1,007.69 per LYG and €1,543.62 per QALY gained, respectively. The results of the multiple sensitivity analyses showed limited dispersion of the outcomes, thus corroborating their robustness.Conclusion: From the NHS perspective, considering the most commonly established willingness-to-pay thresholds in the Spanish setting, ribociclib+letrozole would represent a cost-effective therapeutic option compared to palbociclib+letrozole in the first-line treatment of HR+/HER2– ABC in postmenopausal women. Keywords: economic evaluation, CDK4/6 inhibitors, breast cancer, payers’ perspective