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Title: RIBOLARIS: ribociclib in neoadjuvant and adjuvant settings for high-risk HR+ breast cancer — a paradigm shift
Type: B (clinical / real-world)
Tags: ribociclib, CDK4/6, HR+ breast cancer, neoadjuvant, adjuvant, RIBOLARIS
PMID: 42602220
DOI: 10.1177/17588359261467380
Journal: Therapeutic Advances in Medical Oncology (2026)
Category: Oncology

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⚖️ Transparency notice: this article was written with AI assistance and reviewed by the author, a medical oncologist.

Trial design

RIBOLARIS is a phase II trial (Cottu, SOLTI/Institut Curie, Ther Adv Med Oncol 2026) evaluating ribociclib + endocrine therapy in both phases — neoadjuvant (pre-surgery) and adjuvant — in clinically high-risk HR+/HER2- breast cancer (node-positive, grade 3, or high genomic risk). The premise: if CDK4/6i works in the adjuvant setting (NATALEE already showed this in a broad population), can the benefit be intensified by extending it to the neoadjuvant phase as well? [PMID 42602220]

Why it matters

1. Neoadjuvant use of CDK4/6i is a little-explored territory. Most adjuvant data (NATALEE, monarchE) are post-surgery. Administering ribociclib before surgery allows measurement of early tumor response (dynamic biomarkers) and not just long-term iDFS.
2. “Clinically high-risk” population — not just by genomic RS, but by stage/grade. This is closer to real-world clinical decision-making than isolated RS cutoffs.
3. SOLTI (Spain) leads recruitment — relevant for your COG/A Coruña setting if the trial opens national arms.

Critical reading

• It is a trial design paper, not results (rationale + trial design). No efficacy data yet — only the hypothesis and architecture.
• Risk of overtreatment: neoadjuvant CDK4/6i + endocrine therapy could delay surgery or complicate pathological assessment if the response is partial.
• Comparator: depends on the control arm (neoadjuvant endocrine therapy alone? standard QT?). The design paper should clarify — see full methods.
• Connects with the CDK4/6i and menopause post (ID 59): here the question is not whether CDK4/6i works, but when in the continuum (neoadjuvant vs adjuvant) and in which risk subgroup.

💡 Implications for clinical practice

RIBOLARIS points to a clear trend: CDK4/6i as the backbone of the entire continuum, not just adjuvant. If neoadjuvant results are positive, it changes how we approach the sequence in high-risk HR+ disease. For now: monitor, do not change practice.

Reference: Cottu P, et al. Ther Adv Med Oncol. 2026;18:17588359261467380. doi:10.1177/17588359261467380. PMID: 42602220.

— This analysis was generated by ANGIE (Always Next to Guide, Inspire and Empower), an artificial intelligence system with SOUL profiles, designed by Dr. Javier Pumares Pérez.

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