Aditya Bardia, MD, Massachusetts General Hospital, Boston, discusses results from a subgroup analysis of the phase 3 NATALEE study comparing invasive disease-free survival (iDFS) across a broad range of patients with HR-positive, HER2-Negative early breast cancer treated with ribociclib plus a nonsteroidal aromatase inhibitor.

Results demonstrated the iDFS benefit seen with ribociclib in the intent-to-treat population was maintained across the subgroups, further supporting the use of ribociclib plus a nonsteroidal aromatase inhibitor in this patient population.

Dr Bardia presented these results at the 2023 ESMO Congress in Madrid, Spain.

Transcript:

Hello, I'm Aditya Bardia, Breast Medical Oncologist at Massachusetts General Hospital, Harvard Medical School, excited to be here at ESMO 2023. On behalf of the coauthors, I presented the results from the NATALEE trial looking at subgroups.

As a reminder, at ASCO 2023 we saw the results of the NATALEE trial presented by Dr Dennis Slamon [MD, PhD, David Geffen School of Medicine at University of California Los Angeles, California]  which demonstrated that the addition of ribociclib to nonsteroidal aromatase inhibitor (NSAI) reduced risk of recurrence as compared to aromatase inhibitor alone for patients with localized hormone receptor-positive breast cancer. Here at ESMO 2023 the subgroup results, focused on key clinical pathological characteristics, were presented.

The bottom line is that regardless of the subgroup: age, lymph node status, stage, menopausal status, or Ki-67 results, the benefit with ribociclib was maintained regardless of the subgroups, so hazard ratio about 0.75 consistently across different subgroups, so that's about 25% risk of disease recurrence for this patient population.

The study included both patient stage 2 and stage 3, and we saw similar hazard ratios, so both stage 2 and stage 3, similarly, lymph node positive, or negative, similar hazard ratios for menopausal status, for age. Finally for Ki-67, in this trial, Ki-67 was assessed locally and regardless of the Ki-67 level the benefit with ribociclib was maintained. The study also demonstrated what has been seen previously, which is that Ki-67 is prognostic but not predictive of benefit with the CDK4/6 inhibitor.

The study confirms that the benefit with ribociclib was not driven by any particular subgroup, it was maintained across all subgroups. The other important point to note is that if we look at the control arm, even patients with lymph node-negative disease have risk of recurrence, so it highlights we need better therapeutic strategies in this setting like escalation with ribociclib.

Overall, these results confirm ribociclib plus NSAI reduces risk of recurrence for patients with stage 2 and stage 3 hormone receptor-positive breast cancer, and if approved by the FDA would be a therapeutic option in this setting.

Source:

Bardia A, Hortobagyi GN, Lipatov O, et al. Invasive disease–free survival (iDFS) across key subgroups from the Phase III NATALEE study of ribociclib (RIB) + a nonsteroidal aromatase inhibitor (NSAI) in patients (pts) with HR+/HER2− early breast cancer (EBC). Presented at 2023 ESMO Annual Congress; October 20-24, 2023; Madrid, Spain. Abstract LBA23.