Economic evaluation of work productivity gains associated with ribociclib (RIB) in hormone receptor–positive/human epidermal growth factor receptor 2–negative (HR+/HER2−) early breast cancer (EBC) in the United States.

e23117 Background: Despite treatment with standard-of-care adjuvant endocrine therapy, many patients with HR+/HER2− EBC continue to experience recurrences, most of which are distant. Recurrences can lead to extensive costs, including indirect costs associated with the loss of income due to reduction or complete loss in the ability to work. The cyclin-dependent kinase 4/6 inhibitor RIB + an aromatase inhibitor (AI) was FDA-approved in Sept 2024 to reduce risk of recurrence among patients with HR+/HER2− disease (stage II and III at high risk of recurrence). At a 44.2 mo median follow-up of NATALEE, with all patients off RIB, RIB + a nonsteroidal AI (NSAI) vs NSAI significantly improved invasive disease-free survival (iDFS; HR, 0.715 [0.609-0.840]) with a 4y landmark Δ of 4.9%. This analysis assessed long-term work productivity gains of treating patients with HR+/HER2− EBC with RIB+NSAI vs NSAI from a US societal perspective. Methods: A Markov model was developed to estimate the distribution of being in 4 health states (invasive disease-free [IDF], locoregional recurrence [LR], distant recurrence [DR], and death) for patients with HR+/HER2− EBC treated with RIB+NSAI vs NSAI over a lifetime horizon. Efficacy data were modeled using patient-level iDFS data from the NATALEE trial up to 4.5y (median follow up: 44.2 mo) using Kaplan Meier (KM) method and parametric extrapolation of the KM curves afterward. Other clinical data were obtained from literature. Data on age- and gender-adjusted employment rates, wages, and number of workdays lost in each health state were obtained from published literature and applied to the distribution of patients across each health state. Work productivity-related indirect cost across health states was estimated until the cohort reached 65y, retirement age assumed for the base-case. All cost inputs were in 2024 USD. Work productivity was estimated at individual pt and US population levels. Scenario analyses to test alternative assumptions were conducted. Results: Patients receiving RIB+NSAI on average spent more time in IDF and less time in LR and DR states vs those receiving NSAI alone. A pt receiving RIB+NSAI was estimated to have more lifetime earnings ($494,317) vs those receiving NSAI ($482,581), with the work-related productivity gain from the addition of RIB estimated at $11,736 per patient. At the US population level, the total lifetime work productivity gains for the estimated 54,257 patients receiving the addition of RIB to NSAI in 2024 were projected to be $637.7 million. Conclusions: The addition of RIB to NSAI in the adjuvant treatment of HR+/HER2− EBC not only improves iDFS but can also yield substantial work productivity gains for individual patients with HR+/HER2− EBC and for society as a whole.