149907-156

Analytical validation of Bond Oracle HER2 IHC system for identifying low to intermediate HER2-expressing breast cancer in NeuVax PRESENT phase III clinical trial.

Subcategory: 
Category: 
Breast Cancer—HER2/ER
Session Type and Session Title: 
This abstract will not be presented at the 2015 ASCO Annual Meeting but has been published in conjunction with the meeting.
Abstract Number: 

e11609

Citation: 
J Clin Oncol 33, 2015 (suppl; abstr e11609)
Author(s): 
Amit K Jain, Sonia Kumar, Gavin S. Choy, Desiree Hollemon, Elizabeth Ann Mittendorf; Leica Biosystems, Danvers, MA; Astex Pharmaceuticals Inc, Burlingame, CA; Galena Biopharma, Portland, OR; The University of Texas MD Anderson Cancer Center, Houston, TX

Abstract Disclosures

Abstract: 

Background: Current therapies targeting HER2 neuprotein expression are effective for breast tumors (CaB) with high expression levels (IHC 3+). However, most breast tumours exhibit low to intermediate expression of HER2 (IHC 1+/2+). Nelipepimut-S (NeuVax; Galena Biopharma) is a cancer vaccine that generates a specific immune response to E75, a HER2 peptide. The ongoing Phase 3 trial (PRESENT) is evaluating NeuVax to prevent CaB recurrence in HER2 low or intermediate patients. Given the importance of identifying eligible patients, the Bond Oracle HER2 IHC System (Leica Biosystems) is currently being validated to reliably discriminate IHC HER2 0, 1+, and 2+, expression levels by correlating to independent analytical measures of HER2 expression Methods: HER2 receptor load was determined via flow cytometry for three immortalized CaB cell lines with various levels of HER2 expression (MDA-MB-453 [2+], MDA-MB-175 [1+], and MDA-MB-231 [0]). In parallel, FFPE cell blocks were generated for each cell line and sectioned for HER2 IHC. Quantitative Western Blots was performed to measure HER2 protein quantity. The measured receptor loads and quantitation by Western Blots were correlated to HER2 IHC scores of 0, 1+, and 2+. Results: See Table. Conclusions: These data demonstrate a direct correlation between cell line receptor load, quantitative measure of HER2 protein, and IHC score. The ability to discriminate HER2 protein expression at the low and intermediate levels in CaB will identify patients for new treatments in development such as NeuVax. Specifically, the validation of the Bond Oracle HER2 IHC System to distinguish IHC 0, 1+, and 2+ expressions supports its use as a companion diagnostic.

Analytical data demonstrating correlation of IHC results with HER2 receptor load and quantitative measurement of HER2 protein.

Cell lineBond Oracle
HER2 expression
by IHC
HER2 receptor
load per cell by
Flow Cytometry (x104 )
HER2 protein
measurement by
Quantitative Western
Blot (Chemiluminescence) x104
MDA-MB-4532+9.0 5.8
MDA-MB-1751+5.4 2.7
MDA-MB-23100.8 0.7