Economic assessment of abemaciclib for the adjuvant treatment of luminal HER2- breast cancer from the perspective of the Spanish health system.

Introduction: Abemaciclib is an oral inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6). Data from the clinical trial monarchE (2023) showed improved survival from invasive disease. The aim of the present article was to conduct an economic assessment of adjuvant treatment with abemaciclib in women with luminal, HER2- and node-positive breast cancer.

Methods: A Markov model was constructed with four mutually exclusive health states (disease-free, local recurrence, distal recurrence and death). Analyses were based on the clinical trial monarchE which compared an intervention group (abemaciclib + hormone therapy [HT]) with HT alone. The effectiveness measure used was quality-adjusted life years (QALY), with unit costs and utilities being obtained from existing literature. The incremental cost-utility ratio (ICUR) was used to compare the two treatment strategies.

Results: Total costs were €98,765 and €17,935 for the abemaciclib plus HT group and the HT alone group, respectively. The health outcome was 10.076QALY for the intervention group and 9.495QALY for the control group, with the ICUR being€139,173/QALY.

Conclusion: Despite the significant gains of abemaciclib as adjuvant treatment in terms of progression-free survival, this treatment is not cost-effective for the Spanish National Health System at published prices. It may be cost-effective with an appropriate discount on the official price.