August 7, 2014

Chemosensitivity Predicted by BluePrint 80-Gene Functional Subtype and MammaPrint in the Prospective Neoadjuvant Breast Registry Symphony Trial (NBRST)

PUBLICATION: 
Annals of Surgical Oncology; October 2014, Volume 21, Issue 10; pp 3261–3267.

AUTHORS: 
Pat Whitworth, MD; Lisette Stork-Sloots, MSc; Femke A. de Snoo, MD, PhD; Paul Richards, MD; Michael Rotkis, MD; Jennifer Beatty, DO; Angela Mislowsky, MD; James V. Pellicane, MD; Bichlien Nguyen, MD; Laura Lee, MD; Charles Nash, MD; Mark Gittleman, MD; Stephanie Akbari, MD; and Peter D. Beitsch, MD

ABSTRACT: 
Purpose: The purpose of the NBRST study is to compare a multigene classifier to conventional immunohistochemistry (IHC)/fluorescence in situ hybridization (FISH) subtyping to predict chemosensitivity as defined by pathological complete response (pCR) or endocrine sensitivity as defined by partial response.

Methods: The study includes women with histologically proven breast cancer, who will receive neoadjuvant chemotherapy (NCT) or neoadjuvant endocrine therapy. BluePrint in combination with MammaPrint classifies patients into four molecular subgroups: Luminal A, Luminal B, HER2, and Basal.

Results: A total of 426 patients had definitive surgery. Thirty-seven of 211 (18 %) IHC/FISH hormone receptor (HR)+/HER2− patients were reclassified by Blueprint as Basal (n = 35) or HER2 (n = 2). Fifty-three of 123 (43 %) IHC/FISH HER2+ patients were reclassified as Luminal (n = 36) or Basal (n = 17). Four of 92 (4 %) IHC/FISH triple-negative (TN) patients were reclassified as Luminal (n = 2) or HER2 (n = 2). NCT pCR rates were 2 % in Luminal A and 7 % Luminal B patients versus 10 % pCR in IHC/FISH HR+/HER2− patients. The NCT pCR rate was 53 % in BluePrint HER2 patients. This is significantly superior (p = 0.047) to the pCR rate in IHC/FISH HER2+ patients (38 %). The pCR rate of 36 of 75 IHC/FISH HER2+/HR+ patients reclassified as BPLuminal is 3 %. NCT pCR for BluePrint Basal patients was 49 of 140 (35 %), comparable to the 34 of 92 pCR rate (37 %) in IHC/FISH TN patients.

Read more: NBRST Trial (Molecular Subtypes)_Whitworth P et al_AnnSurgOnc_2014