99P Cost effectiveness of pembrolizumab in combination with chemotherapy as neoadjuvant therapy and continued as a single agent as adjuvant therapy for high-risk early-stage TNBC in the United States

Abstract

This analysis evaluated the cost effectiveness of pembrolizumab in combination with chemotherapy as neoadjuvant treatment and continued as a single agent as adjuvant treatment after surgery compared with neoadjuvant chemotherapy for patients with high-risk early-stage triple-negative breast cancer (eTNBC). The analysis was conducted from a US third-party public healthcare payer perspective. A multi-state transition model including four mutually exclusive health states: event-free, locoregional recurrence, distant metastasis, and death was developed to simulate patients’ disease course over lifetime. Efficacy and safety data were derived from the KEYNOTE-522 randomized clinical trial. The model Quality-adjusted life-years (QALYs) were calculated based on EuroQoL-5 Dimensions (EQ-5D) utility data collected in the trial. Costs ($US, in 2021 values) for drug acquisition/administration, adverse events, disease management and subsequent therapies were included. Costs and outcomes were discounted at 3% per year. A series of deterministic and probabilistic sensitivity analyses were performed to test the robustness of the results. In the base-case scenario, pembrolizumab plus chemotherapy followed by pembrolizumab resulted in an expected gain of 3.37 life-years (LYs) and 2.90 QALYs and an incremental cost of $US79,046 compared with chemotherapy alone. The incremental cost per QALY gain was $US27,285/QALY and the incremental cost per LY gain was $US23,489/LY, which were lower than all cost-effectiveness thresholds cited in the literature. Sensitivity analyses showed the results to be robust over plausible values of key model inputs. Compared with neoadjuvant chemotherapy, pembrolizumab in combination with chemotherapy as neoadjuvant treatment and continued as a single agent as adjuvant treatment after surgery is projected to be a cost-effective option for high-risk eTNBC in the US.