258P - Cost-effectiveness of neoadjuvant pembrolizumab plus chemotherapy followed by adjuvant pembrolizumab for high-risk early-stage triple-negative breast cancer in Colombia

Background

In Colombia, 15,509 new cases of breast cancer (BC) were diagnosed in 2020. Furthermore, BC was the leading cause of cancer deaths. Triple-negative breast cancer (TNBC) is an aggressive subtype that represents 15-20% of BC. The KEYNOTE-522 (KN522) trial showed that neoadjuvant pembrolizumab + chemotherapy followed by adjuvant pembrolizumab significantly improved pathological complete response and event-free survival when compared to neoadjuvant placebo + chemotherapy followed by adjuvant placebo in patients with high-risk early stage TNBC (eTNBC). This study evaluated the cost-effectiveness of neoadjuvant pembrolizumab + chemotherapy [paclitaxel + carboplatin followed by anthracycline + cyclophosphamide] plus adjuvant pembrolizumab versus neoadjuvant chemotherapy in high-risk eTNBC, from a third payer perspective in Colombia.

Methods

A Markov cohort model was developed with four mutually exclusive health states: event-free, locoregional recurrence, distant metastasis, and death, to simulate patients’ lifetime disease course based on the efficacy and safety data from KN522. Outcomes and costs were discounted at 3% annually. Time on treatment was estimated using observed Kaplan-Meier curves from KN522. Utility inputs were derived from EuroQoL-five-dimension questionnaire in KN522. Costs for initial and subsequent therapies, disease and adverse events management, and terminal care were estimated using drug and healthcare public lists prices of Colombia.

Results

Over a 51-year time horizon, patients receiving pembrolizumab + chemotherapy accrued an additional 2.39 life-years (LYs) and 2.19 quality-adjusted life-years (QALYs) compared to neoadjuvant chemotherapy. The resulting incremental cost-effectiveness ratios (ICER) were COP 65,159,259/LY and COP 71,172,546/QALY, which were lower than the willingness-to-pay threshold of COP 85,093,272 in Colombia (based on 3-GDP per capita).

Conclusions

Neoadjuvant pembrolizumab + chemotherapy followed by adjuvant pembrolizumab is a cost-effective treatment versus neoadjuvant chemotherapy for high-risk eTNBC in Colombia, constituting a novel and key therapy option for those patients.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

MSD Colombia.

Funding

MSD Colombia.

Disclosure

R. Brugés Maya: Financial Interests, Personal, Advisory Board, Advisory board neoadyuvant therapy in breast cancer triple negative: MSD; Non-Financial Interests, Advisory Role, Advisory in triple-negative breast cancer: MSD; Non-Financial Interests, Leadership Role, President of Asociacion Colombiana de Hematologia y Oncologia: ACHO. J.C. Urrego: Financial Interests, Personal, Full or part-time Employment, MSD Employee HTA - Market Access: MSD Colombia. C. Marrugo: Financial Interests, Personal, Full or part-time Employment, Market Access Manager: MSD Colombia. V. Wurcel: Financial Interests, Personal, Full or part-time Employment: MSD; Financial Interests, Personal, Stocks/Shares: MSD. M. Huang: Other, Full time employee: Merck & CO., Inc. A. Haiderali: Financial Interests, Institutional, Full or part-time Employment: Merck & Co., Inc. All other authors have declared no conflicts of interest.