260PD - Chemosensitivity predicted by MammaPrint and BluePrint in the prospective Neo-adjuvant Breast Registry Symphony Trial (NBRST)

Date 27 September 2014
Event ESMO 2014
Session Breast cancer, early stage
Topics Anti-Cancer Agents & Biologic Therapy
Breast Cancer, Early Stage
Personalised Medicine
Presenter Femke De Snoo
Citation Annals of Oncology (2014) 25 (suppl_4): iv85-iv109. 10.1093/annonc/mdu327
Authors F. De Snoo1, P. Whitworth2, L. Stork-Sloots3, P. Beitsch4
  • 1Medical Affairs, Agendia, 1098 XH - Amsterdam/NL
  • 2Department Of Surgery, Nashville Breast Center, Nashville/US
  • 3Medical Affairs, Agendia NV, 1098 XH - Amsterdam/NL
  • 4Department Of Surgery, Virginia Hospital Center, Dallas/US

Abstract

Aim

The aim of the NBRST study is to compare a multi-gene classifier to conventional IHC/FISH subtyping to predict chemosensitivity as defined by pathological complete response (pCR), or endocrine sensitivity as defined by partial response (PR).

Methods

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

Results

426 patients had definitive surgery. 37/211 (18%) IHC/FISH HR + /HER2- patients were re-classified by Blueprint as Basal (35) or HER2 (2). 53/123 (43%) IHC/FISH HER2+ patients were re-classified as Luminal (36) or Basal (17). 4/92 (4%) IHC/FISH triple negative (TN) patients were re-classified as Luminal (2) or HER2 (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 36/75 IHC/FISH HER2 + /HR+ patients re-classified as BPLuminal is 3%. NCT pCR for BluePrint Basal patients was 49/140 (35%), comparable to the 34/92 pCR rate (37%) in IHC/FISH TN patients.

Conclusions

BluePrint/MammaPrint molecular subtyping reclassifies 22% (94/426) of tumors, reassigning more responsive patients to the HER2 and Basal categories while reassigning less responsive patients to the Luminal category. These findings suggest that compared with IHC/FISH, BluePrint/MammaPrint more accurately identifies patients likely to respond (or not respond) to neo-adjuvant chemotherapy.

Disclosure

F. De Snoo: Employee of Agendia; L. Stork-Sloots: Employee of Agendia. All other authors have declared no conflicts of interest.