Novartis announced compelling new data from the Phase III NATALEE trial demonstrating that Kisqali (ribociclib) plus endocrine therapy delivers enhanced benefits for younger patients with early breast cancer, with pre-menopausal patients experiencing a 33% reduction in relative risk of invasive disease at one-year post-treatment analysis. The findings were presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting.
Stronger Efficacy in Younger Patients
The subgroup analysis, conducted at a median follow-up of 44.2 months, evaluated efficacy and safety across age and menopausal status in patients with stage II and III hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) early breast cancer at high risk of recurrence. Results showed that patients receiving Kisqali continued to see consistent reductions in risk of recurrence across all efficacy measures, regardless of age and menopausal status.
Notably, pre-menopausal and younger patients, who often present with more aggressive disease characteristics, experienced greater reductions in risk of recurrence and fewer treatment discontinuations due to adverse events than post-menopausal patients.
"As the incidence of early onset breast cancer increases, it is encouraging to see that ribociclib continues to deliver durable risk reduction for a broad population of patients with EBC, including younger patients," said Dr. Kevin Kalinsky, Division Director of Medical Oncology and Director of the Glenn Family Breast Center at Winship Cancer Institute of Emory University. "Coupled with the lower rates of discontinuation due to AEs seen in this subgroup, these data reinforce the benefit of three-year adjuvant treatment with ribociclib as a well-tolerated intervention for patients seeking to reduce the likelihood of their cancer coming back."
Addressing Health Disparities
A separate real-world analysis presented at ASCO revealed concerning disparities in breast cancer outcomes. The study examined early breast cancer patients who met NATALEE trial eligibility criteria and received endocrine therapy monotherapy, finding that Black patients were more likely to be younger, pre-menopausal, have stage III tumors, and have more extensive nodal involvement than white patients.
After adjusting for these factors, Black patients also demonstrated worse recurrence-free survival, distant disease-free survival, and overall survival than their white counterparts. These findings reinforce the critical need to improve care for Black patients with the addition of a CDK4/6 inhibitor to their adjuvant treatment.
Expanding Access Through Clinical Research
Novartis is continuing to build evidence for Kisqali across diverse patient populations. The company presented trial design details at ASCO for the Adjuvant WIDER study, which is enrolling patients that closely reflect the population seen in clinical practice, including more patients from racial and ethnic minority groups.
"There is an undeniable and urgent need to improve outcomes for vulnerable patient populations, including younger and Black patients, who often face more aggressive forms of breast cancer and remain at high risk of recurrence," said Reshema Kemps-Polanco, Executive Vice President and Chief Commercial Officer, Novartis US. "With Kisqali, we have the opportunity to reduce the risk of recurrence for these patients with early breast cancer, while we continue to offer significant survival benefit to patients living with metastatic disease."
Clinical Context and Regulatory Status
The NATALEE trial is a global Phase III multi-center, randomized, open-label study evaluating Kisqali with endocrine therapy as adjuvant treatment versus endocrine therapy alone in patients with stage II and III HR+/HER2- early breast cancer. The trial enrolled 5,101 adult patients across 20 countries, with the primary endpoint being invasive disease-free survival.
Kisqali has been approved as a treatment for breast cancer by regulatory authorities in 99 countries worldwide, including the U.S. FDA and the European Commission. In the United States, Kisqali is indicated in combination with an aromatase inhibitor as adjuvant treatment for adults with HR+/HER2- stage II and III early breast cancer at high risk of recurrence.
In early breast cancer, ribociclib is the only CDK4/6 inhibitor recommended by the NCCN Guidelines for breast cancer for both all node-positive disease as well as for patients with no nodal involvement with high-risk disease characteristics. The drug has consistently demonstrated statistically significant overall survival benefit across three Phase III trials in metastatic breast cancer.
