new research presented at the 2025 American Society of Clinical Oncology (ASCO) annual Meeting in CHICAGO,Illinois,suggests that the use of ribociclib (Kisqali) alongside a nonsteroidal aromatase inhibitor (NSAI) as an adjuvant treatment for patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2−) early breast cancer not only boosts invasive disease-free survival (iDFS) but also leads to notable gains in work productivity for patients and society.

The American Cancer Society estimates that over 300,000 women in the US woudl be diagnosed with breast cancer in 2024,resulting in approximately 42,000 deaths. HR+/HER2- is the most prevalent breast cancer subtype, accounting for about 70% of new diagnoses. Patients with this subtype face a higher risk of cancer recurrence, often in the form of incurable metastatic disease.

In September 2024, the FDA approved ribociclib in combination with an aromatase inhibitor for patients with stage II and III HR+/HER2- early breast cancer who are at high risk of recurrence. This approval was based on data from the phase 3 NATALEE trial (NCT03701334),a randomized,open-label study that demonstrated a important reduction in disease recurrence risk and a manageable safety profile.The trial involved over 1500 adult patients who were randomly assigned to receive either ribociclib (2 oral 200-mg doses) plus endocrine therapy (NSAI) or endocrine therapy alone.

After a median follow-up of 44.2 months, the combination of ribociclib and an NSAI significantly improved iDFS (HR, 0.715 [95% CI, 0.609-0.840]) compared to NSAI alone, with a 4-year landmark difference of about 4.9%. These findings prompted researchers to evaluate the long-term work productivity gains from a US societal perspective in patients with HR+/HER2− early breast cancer treated with the NATALEE trial’s regimens.

The study employed a Markov model to estimate the distribution of patients across four health states: invasive disease-free (IDF),locoregional recurrence (LR),distant recurrence (DR),and death. Efficacy data were modeled using patient-level iDFS data from the NATALEE trial for up to 4.5 years (median follow-up: 44.2 months). Data on age- and gender-adjusted employment rates, wages, and workdays lost in each health state were sourced from published literature and applied to the distribution of patients across these states. Work productivity-related indirect costs were estimated until the patients reached 65 years of age.

Results indicated that patients treated with ribociclib and an NSAI spent more time in the IDF state and less time in the LR and DR states compared to those receiving NSAI alone. Patients on the ribociclib combination were estimated to have approximately $11,736 more in lifetime earnings, with individual lifetime earnings estimated at $494,317 versus $482,581 for those on NSAI alone. At the US population level, total lifetime work productivity gains for the estimated 54,257 patients receiving ribociclib in 2024 were projected to be $637.7 million.

These results highlight the importance of considering both clinical efficacy and broader societal impacts when assessing new cancer treatments, demonstrating that improved health outcomes can directly enhance economic productivity and overall well-being. The benefits of ribociclib and an NSAI extend beyond individual patient gains, underscoring the value of therapies that prolong and improve life.

“Improved health outcomes can directly enhance economic productivity and overall well-being.”

Understanding Ribociclib and Breast Cancer