ESMO Congress 2026

Whether adding a CDK4/6 inhibitor after surgery improves disease-free survival in hormone receptor-positive, HER2-negative early breast cancer is a question NATALEE already answered on invasive disease-free survival: ribociclib 400 mg (3 weeks on / 1 week off for 36 months) plus a nonsteroidal aromatase inhibitor versus endocrine therapy alone, a broader population than monarchE, including some node-negative stage II disease. NEJM 2024 reported iDFS; OS was immature.^[2] The Annals of Oncology final analysis gave iDFS hazard ratio 0.749, 3-year rates 90.7% vs 87.6%.^[3] The protocol planned 5101 patients; the primary remains iDFS, OS secondary.^[1]

This meeting’s LBA25 is six-year overall survival, not a re-read of the 2024 iDFS. Floor post: 6-year OS 91.86% vs 89.73%, an absolute 2.1 percentage points (hazard ratio 0.809; 95% CI 0.661–0.989; nominal one-sided P=0.019). The absolute difference is small and the interval sits against 1: a descriptive OS signal, not a new primary. Strata, discontinuation and subsequent therapy wait on the oral.

The JAMA Oncology four-year update and ESMO Open five-year follow-up are earlier published snapshots, not this six-year OS. The two sets of numbers are not one new claim that patients both relapse less and live longer, unless the slides use the same analysis set. monarchE (abemaciclib) is another trial in another population; this page does not make that indirect comparison.