Cost-effectiveness of ribociclib versus palbociclib in combination with an aromatase inhibitor as first-line treatment of postmenopausal women with HR+/HER2- advanced breast cancer: analysis based on final OS results of MONALEESA-2 and PALOMA-2.

Background and AimsCombination of a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor and an aromatase inhibitor is the standard of care first-line (1L) treatment of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC). Updated clinical data have become available from the MONALEESA-2 and PALOMA-2 trials for ribociclib and palbociclib, respectively. This analysis with updated data assessed the cost-effectiveness of ribociclib versus palbociclib, both in combination with letrozole, in the setting of 1L therapy of postmenopausal women with HR+/HER2- ABC, from a United Kingdom (UK) National Health Service perspective.MethodsA three state (progression-free, progressed disease, and death) partitioned survival model with a 1-month cycle was developed. Clinical data were derived from MONALEESA-2 (NCT01958021) and PALOMA-2 (NCT01740427). Treatment effect was modelled using hazard ratios (HRs) for progression-free survival and overall survival derived through a matched-adjusted indirect comparison. Trial data and published literature were used to derive utility values. Cost inputs included drug acquisition, disease monitoring, subsequent therapies, and adverse events. Costs and outcomes were discounted by 3.5%, over a 40-year lifetime horizon. One-way and probabilistic sensitivity analyses were performed.ResultsRibociclib dominated palbociclib, and was both overall cost saving (-£3,273) and more effective (+1.251 quality-adjusted life years [QALYs]). Ribociclib total drug costs were £17,156 lower than palbociclib. At a £30,000 per QALY willingness-to-pay threshold, the probability of ribociclib being cost-effective was almost 100%. Ribociclib remained cost-effective when varying HRs, utilities, drug cost, and health state costs.ConclusionsRibociclib is both cost-saving and cost-effective compared with palbociclib for the 1L treatment of postmenopausal women with HR+/HER2- ABC in the UK.