Economic value of ribociclib in early breast cancer in the United States

BACKGROUND: Many patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) early breast cancer (eBC) experience recurrence despite treatment with adjuvant endocrine therapy; recurrences bear a substantial cost and can impact life expectancy and quality of life. OBJECTIVE: To estimate the lifetime clinical and economic value of ribociclib for the treatment of patients with HR+/HER2- stage II/III eBC at high risk of recurrence including select node-negative and all node-positive patients. METHODS: A 4-state Markov model comparing ribociclib+nonsteroidal aromatase inhibitor (NSAI) with NSAI alone estimated the expected lifetime costs and effectiveness for patients with eBC (mean age = 53 years). High risk of recurrence in HR+/HER2- eBC was based on the NATALEE trial criteria: all node-positive and node-negative patients with tumor size larger than 5 cm or 2-5 cm with Grade 3 or Grade 2 and high genomic risk. Model outcomes included invasive disease-free survival (IDFS), locoregional recurrence (LR), distant recurrence (DR), overall survival, adjuvant treatment costs, adverse event costs, disease management costs by health state, and DR treatment costs. Patient-level IDFS for the first 4.5 years observed in the NATALEE trial was parametrically extrapolated thereafter. DR and LR progression risks and treatment utilization patterns were obtained from the literature. Model outputs included total costs, quality-adjusted life-years (QALYs), life-years (LYs), equal-value LYs (evLYs), and the incremental cost-effectiveness ratio (ICER) of ribociclib+NSAI vs NSAI when using IDFS as the effectiveness outcome. RESULTS: Ribociclib+NSAI improved IDFS (13.08 vs 11.09 years) and reduced DR (DR state = 1.28 vs 2.35 years), generating QALY gains of 0.68 (ribociclib+NSAI = 11.45; NSAI = 10.77), LY gains of 0.69 (ribociclib+NSAI = 14.98; NSAI = 14.29), and evLY gains of 0.75 (ribociclib+NSAI = 11.52; NSAI = 10.77). Total lifetime incremental costs were $52,385 (ribociclib+NSAI = $831,433; NSAI = $779,047). The ICER was $77,448/QALY, and the probability of ribociclib+NSAI being cost-effective was 68.5% at a willingness to pay of $150,000/QALY. CONCLUSIONS: Based on model estimation, ribociclib+NSAI is projected to be a cost-effective therapy in the United States vs NSAI alone by reducing the rate of high-cost metastatic recurrences and increasing QALYs.