Abstract P6-05-35: Cost-effectiveness of CDK4/6 inhibitors in the first-line treatment of HR+/HER2- metastatic breast cancer in postmenopausal women in Panama

Abstract Background: 4/6 kinase-dependent cyclin inhibitors have been approved for use in combination with first-line aromatase inhibitors in patients with hormone-sensitive, Her 2neu negative metastatic breast cancer. These agents have significantly improved progression-free survival compared to monotherapy aromatase inhibitors. The purpose of this study was to evaluate the cost-evaluation of each of these new agents (palbociclib, ribociclib, and abemaciclib) in the first line in Panama with the perspective of the National Oncological Institute. Methods: A partition survival analysis was carried out that includes three states (free of progression, progression, and death) with cycles of one month and a time horizon of 7.5 years. The efficacy data were taken from pivotal clinical trials, and the costs were estimated locally. A deterministic and probabilistic sensitivity analysis of the Monte Carlo was performed. Results; According to the base case, the update of each of these strategies involved an increase of USD 355,184 per additional QALY for ribociclib with Letrozole compared to Letrozole; USD 944,148/additional QALY for Palbociclib plus Letrozole; and USD 223,956 for Abemaciclib plus Letrozole, when compared with Letrozole, all above the availability threshold to pay 50,000/QALY. Conclusion: Despite the improvement in progression-free survival, none of the strategies have proved cost-effectiveness in our setting. Price negotiations, cost reduction, and risk-sharing agreements between pharmaceutical companies and payers might improve access to new drugs in countries with limited resources. Citation Format: Omar O. Castillo-Fernandez, Maria Lim, Lilian Montano. Cost-effectiveness of CDK4/6 inhibitors in the first-line treatment of HR+/HER2- metastatic breast cancer in postmenopausal women in Panama. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-05-35.