ADAPTcycle: Adjuvant dynamic marker-adjusted personalized therapy (ADAPT) comparing endocrine therapy plus ribociclib versus chemotherapy in intermediate-risk HR+/HER2- early breast cancer (EBC).

Abstract

TPS601 Background: The WSG ADAPT trial program represents the concept of individualization of (neo)-adjuvant decision-making in EBC in a subtype-specific manner. The first WSG ADAPT umbrella trial aimed to establish early predictive molecular surrogate markers for response after a short 3-week induction treatment. The goals of the WSG ADAPT trial program are early response assessment and subtype-specific therapy tailoring to those patients who are most likely to benefit. Methods: WSG-ADAPTcycle is a prospective, multi-center, interventional, two-arm, open-label, (neo)adjuvant, non-blinded, randomized, controlled phase III trial (NCT04055493). It investigates whether patients (pts.) with HR+/HER2- EBC identified during screening as intermediate risk (based on Oncotype DX and response to 3 weeks of preoperative endocrine therapy [ET]) derive additional benefit from 2 years of the CDK4/6 inhibitor ribociclib combined with ET compared to chemotherapy (CT) (followed by standard ET). Co-primary endpoints are disease-free survival (DFS) and distant DFS. It is planned to screen 5600 pts and to randomize 1670 pts in a 3:2 ratio (ribociclib + ET/CT). Study start was in July 2019 (80 sites, enrollment period 36 months) and until date of submission, 180 pts. have been screened and 40 randomized. Pts with HR+/HER2- EBC with clinically enhanced risk (cT2-4 or Ki67 20% or G3 or cN+) are eligible if they fulfill the ADAPT intermediate-risk group criteria: either Recurrence Score (RS) ≤25 and Ki67postendocrine>10%, RS >25 and Ki67postendocrine<10% in p/cN0-1 pts, or RS ≤25 and Ki67postendocrine<10% in c/pN2-3 pts. Treatment duration is 2 years for the ribociclib + ET (premenopausal: AI + GnRH) arm and 16-24 weeks for the CT arm; treatment is possible either in the neoadjuvant (ET + ribociclib duration 16 – 32 weeks) or adjuvant setting. ePROs are collected using CANKADO; ECG monitoring is performed using a novel cardiology-supported CANKADO-based eHealth method. Translational analyses: Exploratory tissue biomarker research will be conducted to assess alterations in molecular markers. In addition, ctDNA/ctRNA from optional blood samples will be assessed for mutations and gene expression. Conclusions: ADAPTcycle seeks to evaluate whether endocrine-based therapy with ET and a CDK 4/6 inhibitor is superior to CT followed by ET in patients with luminal EBC who may be undertreated with ET alone (based on either lack of endocrine responsiveness or high tumor burden). Clinical trial information: 2018-003749-40 .