Primary efficacy analyses of NeoRHEA, neoadjuvant biomarker research study of palbociclib combined with endocrine therapy in estrogen receptor positive/HER2 negative breast cancer.

Authors

null

Elisa Agostinetto

Université Libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), Institut Jules Bordet, Academic Trials Promoting Team (ATPT), Brussels, Belgium

Elisa Agostinetto , Andreas Papagiannis , Frederic Cailleux , Mariana Brandão , Alexandra Stanciu , Denis Larsimont , Isabelle Veys , Marianne Paesmans , Tatiana Besse-Hammer , Ahmad Awada , Martine J. Piccart-Gebhart , Christos Sotiriou , Lieveke Ameye , Patrick Neven , Francois P. Duhoux , Peter Vuylsteke , Michail Ignatiadis

Organizations

Université Libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), Institut Jules Bordet, Academic Trials Promoting Team (ATPT), Brussels, Belgium, Institut Jules Bordet and l’Université Libre de Bruxelles (U.L.B.), Brussel, Belgium, Institut Jules Bordet, Bruxelles, Belgium, Jules Bordet Institute, Brussels, Belgium, Institut Jules Bordet and l’Université Libre de Bruxelles (U.L.B.), Bruxelles, Belgium, Institut Jules Bordet, Brussels, Belgium, Data Centre, Institut Jules Bordet-Université Libre de Bruxelles (ULB), Brussels, Belgium, CHU Brugmann, Brussels, Belgium, Jules Bordet Institute, Université Libre de Bruxelles, Brussels, Belgium, Université Libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), Institut Jules Bordet, Brussels, Belgium, UZ Gasthuisberg - Leuven Cancer Institute, Leuven, Belgium, Cliniques Universitaires Saint-Luc, Brussels, Belgium, Department of Medical Oncology, UCLouvain, CHU UCL Namur, site Sainte-Elisabeth, Namur, Belgium, Department of Medical Oncology and Academic Trials Promoting Team, Institut Jules Bordet and l’Université Libre de Bruxelles (U.L.B.), Brussels, Belgium

Research Funding

Pharmaceutical/Biotech Company
Pfizer, Fondation Contre le Cancer

Background: CDK4/6 inhibitors (CDK4/6i) and endocrine therapy (ET) are standard of care in the treatment of estrogen receptor (ER) positive, HER2-negative (ER+/HER2-) advanced breast cancer (BC). We tested palbociclib + ET as neoadjuvant therapy to identify baseline biomarkers of no response. Methods: NeoRHEA (NCT03065621) was a phase II, single arm trial evaluating 4 months of neoadjuvant palbociclib and ET in pre- or post-menopausal women with ER+/HER2- early BC. The primary objective was to identify biomarkers of no response by locally-assessed ultrasound (US) using RNA-seq on baseline (pretreatment) tumor biopsies. No response to treatment was defined as stable or progressive disease (SD or PD) at post-treatment US based on WHO criteria. Secondary endpoints included residual cancer burden (RCB) of 3 and absence of complete cell cycle arrest (CCCA) defined as Ki67 by immunohistochemistry (IHC) > 2.7% at surgery. We evaluated baseline clinicopathological characteristics, RNA-seq derived PAM50 subtypes and mRNA expression of ESR1, Ki67, CCNE1, RB1 and CDK6 single genes according to US response and CCCA. We also performed gene set enrichment analysis (GSEA) for 50 gene sets related to cancer hallmarks according to US response and CCCA. Results: 73 of 100 patients enrolled had baseline frozen tumors with enough cellularity and successful RNA-sequencing performed. Among the 73 patients, 70% were post-menopausal, 84% had cT2 and 70% cN0 tumors, 75% had invasive ductal carcinoma and 66% had histological grade 2 tumors. RNA-seq derived PAM50 subtypes were Luminal A, Luminal B, and non-Luminal in 56%, 36% and 8% of patients, respectively. Among the 73 patients, 31 (42%) had absence of US response (28 and 3 patients had stable and progressive disease by US, respectively) and 23 (31%) had RCB 3 tumors. Fifty-three of 73 patients had Ki67 by IHC available at surgery out of whom, 14 (26%) had absence of CCCA. Neither baseline clinicopathological characteristics nor PAM50 subtypes nor expression of ESR1, Ki67, CCNE1 and RB1 were associated with absence of US response or absence of CCCA. Interestingly, we observed higher baseline mRNA expression of CDK6 in patients with absence of US response (p = 0.039) or those with no CCCA (p = 0.004). We observed an enrichment in inflammatory / IFN-γ response and proliferation-related, G2M checkpoint gene sets in patients with US response (NES: 2.06, 2.30, 1.47; FDR: 7.04e-9, 5.48e-17, 0.0193 respectively) and an enrichment in early estrogen response gene set in patients with absence of US response (NES: -1.78, FDR: 0.0006). No signaling pathway was enriched in patients without CCCA. Conclusions: High pre-treatment mRNA expression of the CDK6 gene was associated with no US response or absence of CCCA in patients treated with neoadjuvant palbociclib and ET. Independent validation is needed. Clinical trial information: NCT03065621.

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Abstract Details

Meeting

2023 ASCO Annual Meeting

Session Type

Poster Discussion Session

Session Title

Breast Cancer—Local/Regional/Adjuvant

Track

Breast Cancer

Sub Track

Neoadjuvant Therapy

Clinical Trial Registration Number

NCT03065621

Citation

J Clin Oncol 41, 2023 (suppl 16; abstr 522)

DOI

10.1200/JCO.2023.41.16_suppl.522

Abstract #

522

Poster Bd #

352

Abstract Disclosures