ASCO 2025: Ribociclib With NSAI in HR+/HER– Breast Cancer Improves iDFS, Yields Substantial Work Productivity Gains

Adding ribociclib (Kisqali; Novartis) in combination with a nonsteroidal aromatase inhibitor (NSAI) in the adjuvant treatment of patients with hormone receptor-positive (HR+)/human epidermal growth receptor 2-negative (HER2−) early breast cancer not only improves invasive disease-free survival (iDFS) but can also produce significant work productivity gains for both individual patients and society as a whole. These findings were presented at the 2025 American Society of Clinical Oncology Annual Meeting in Chicago, Illinois.¹

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Over 300,000 US women were estimated to be diagnosed with breast cancer in 2024 in the US, according to the American Cancer Society. Among these cases, about 42,000 deaths were estimated. HR+/HER2- is the most common subtype of breast cancer and accounts for approximately 70% of all new cases. In addition, patients with HR+/HER2– breast cancer are at higher risk of their cancer returning, often as incurable metastatic disease.²

Ribociclib, used in combination with an aromatase inhibitor in patients with stage II and III HR+/HER2– early breast cancer at high risk of recurrence, was approved by the FDA in September 2024.² The approval was based on positive data from the phase 3 NATALEE trial (NCT03701334)³, a multicenter, randomized, open-label study that demonstrated a clinically meaningful reduction in the risk of disease recurrence and well-tolerated safety. In this trial, over 1500 adult patients were randomly assigned to receive ribociclib (2 oral 200-mg doses) in combination with endocrine therapy (NSAI) or endocrine therapy alone.^2,3

At a 44.2-month median follow-up, ribociclib with an NSAI significantly improved iDFS (HR, 0.715 [95% CI, 0.609-0.840]) compared with NSAI alone, with a 4-year landmark difference of about 4.9%.^2,3 With these results suggesting that patients receiving the ribociclib combination therapy are less likely to have recurrent disease, the current study authors assessed, from a US societal perspective, the long-term work productivity gains in patients with HR+/HER2− early breast cancer treated with the NATALEE trial’s regimens.^1,2

For this study, a Markov model was developed to estimate the distribution of being in 4 different health states—invasive disease-free (IDF), locoregional recurrence (LR), distant recurrence (DR), and death—in patients with HR+/HER2– early breast cancer. Efficacy data were modeled using patient-level iDFS data from the NATALEE trial up to 4.5 years (median follow-up: 44.2 months). Additionally, 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 costs across health states were estimated until the cohort reached 65 years of age.¹

The findings demonstrated that patients who received treatment with ribociclib and an NSAI on average spent more time in IDF and less time in LR and DR states compared with those who received NSAI monotherapy. Additionally, a patient treated with the ribociclib combination was estimated to have more lifetime earnings (about $494,317) than those receiving NSAI ($482,581), with the work-related productivity gain from the addition of ribociclib estimated at about $11,736 per patient. Further, at the US population level, the total lifetime work productivity gains for the estimated 54,257 patients receiving the addition of ribociclib in 2024 were projected to be $637.7 million.¹

These data underscore the significance of considering both clinical efficacy and broader societal impacts when evaluating novel cancer treatments, demonstrating how improved health outcomes can directly contribute to enhanced economic productivity and overall well-being. In addition to improving gains for the individual patient, ribociclib and an NSAI have broader societal impacts, reinforcing the value of therapies that prolong and enhance life.¹

REFERENCES

1. Brufsky A, Sparano J, Tolaney S, et al. 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. J Clin Oncol. 2025;45(Number 16_suppl). doi:10.1200/JCO.2025.43.16_suppl.e23117

2. Gerlach A. FDA Approves Ribociclib in Combination With an Aromatase Inhibitor for HR+/HER2- Early Breast Cancer. Pharmacy Times. September 17, 2024. Accessed June 11, 2025. https://www.pharmacytimes.com/view/fda-approves-ribociclib-in-combination-with-an-aromatase-inhibitor-for-hr-her2--early-breast-cancer

3. A Trial to Evaluate Efficacy and Safety of Ribociclib With Endocrine Therapy as Adjuvant Treatment in Patients With HR+/​HER2- Early Breast Cancer (NATALEE). ClinicalTrials.gov Identifier: NCT03701334. Updated November 14, 2024. Accessed June 11, 2025. https://clinicaltrials.gov/study/NCT03701334