Harris, Lyndsay N.

Purpose To provide recommendations on the appropriate use of breast tumor biomarker assay results to guide decisions on systemic therapy for metastatic breast cancer. Methods A literature search and prospectively defined study selection identified systematic reviews, meta-analyses, randomized controlled trials (RCTs), prospective–retrospective studies, and prospective comparative observational studies published from 2006 through September 2014. Results The literature search revealed 17 articles that met criteria for further review: 11 studies reporting discordances between primary tumors and metastases in expression of hormone receptors or human epidermal growth factor receptor 2 (HER2), one RCT that addressed the use of a biomarker to decide whether to change or continue a treatment regimen, and five prospective–retrospective studies that evaluated the clinical utility of biomarkers. Recommendations In patients with accessible metastases, biopsy for confirmation of disease process and retesting of estrogen receptor, progesterone receptor, and HER2 status should be offered, but evidence is lacking to determine whether changing anticancer treatment on the basis of change in receptor status affects clinical outcomes. With discordance of results between primary and metastatic tissues, the Panel consensus is to use preferentially the estrogen receptor, progesterone receptor, and HER2 status of the metastasis to direct therapy if supported by the clinical scenario and patient's goals for care. Carcinoembryonic antigen, cancer antigen 15-3, and cancer antigen 27-29 may be used as adjunctive assessments, but not alone, to contribute to decisions regarding therapy. Recommendations for tumor rebiopsy and use of circulating tumor markers are based on clinical experience and Panel informal consensus in the absence of studies designed to evaluate the clinical utility of the markers. As such, it is also reasonable for clinicians to not use these markers as adjunctive assessments.

Abstract Background: CTCs are associated with clinical outcomes in metastatic breast cancer irrespective of ER/PR/HER2 status. Some data support the prognostic relevance of serial CTC enumeration relative to adjuvant chemotherapy in early stage breast cancer. However, data from a large scale study focused on HER2 directed therapy for HER2+ disease have been lacking. We therefore sought to prospectively evaluate the effect of trastuzumab +/- lapatinib on CTCs and assess the prognostic/predictive value of CTC monitoring in HER2+ early stage breast cancer patients (pts). Methods: The Adjuvant Lapatinib and/or Trastuzumab Treatment Optimisation (ALTTO; NCT00490139) Trial is an international, randomized, open-label phase III study of two targeted agents for HER2+ breast cancer. From June 2007 to July 2011, 8381 pts were randomised from 946 sites in 44 countries to 1 of 4 arms with sequential or concurrent chemotherapy: (i) 52 wks of trastuzumab (T); (ii) 52 wks of oral lapatinib (L); (iii) 12 or 18 wks of T followed by a washout and then 34 or 38 wks of L; or (iv) 52 wks of L+T. 540 (6%) pts provided optional informed consent and up to 30 mL peripheral blood suitable for CTC analyses at baseline with additional collections at 13 or 19 wks, 52 wks, 18 mos, 24 mos, and recurrence. CTC analyses are being conducted in three laboratories (Mayo Clinic Rochester, n=431; Institut Jules Bordet and University of Munich, n=109). 2-3 x 10 mL CellSave™ samples are pooled and processed at each time point for CTC enumeration and HER2 expression using the immunomagnetic/immunofluorescence assay (CellSearch™). A round-robin concordance project was done between Mayo Clinic Rochester and Institut Jules Bordet before embarking on the primary correlative work. Results: At baseline, 20% pts had detectable (i.e., ≥1) EpCAM+/CK+/DAPI+/CD45- CTCs, and 16% pts had detectable EpCAM+/CK+/DAPI+/CD45-/HER2+ CTCs. Correlative analyses with clinical outcome are ongoing with plans for completion by Fall 2014. Conclusions: CTCs were detected in 20% of pts with HER2+ early stage breast cancer. This is similar to the frequency of detection in mixed early stage breast cancer populations relative to ER/PR and HER2 status. Concordance of enumeration and HER2 assessments between the two experienced laboratories, and correlation between disease free survival and CTC findings (from serial samples collected at baseline, during the course of HER2 directed therapy, and at set intervals of follow-up) will be reported. Citation Format: Minetta C Liu, Brigitte Rack, Amylou C Dueck, David W Hillman, Michael B Campion, Monica M Reinholz, Kevin C Halling, Christos Sotiriou, Françoise Rothé, Marion Maetens, Ghizlane Rouas, Wolfgang Janni, Antonio C Wolff, Lyndsay N Harris, Julie R Gralow, Kathleen I Pritchard, Susan Ellard, Nguyet A Le-Lindqwister, Frances Boyle, Evandro De Azambuja, Martine J Piccart-Gebhart, Michail Ignatiadis, Edith A Perez. Circulating tumor cell (CTC) enumeration and HER2 assessment as predictors of breast cancer outcomes in the ALTTO (BIG 2-06, Alliance N063D) Trial [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-01-01.

Abstract Purpose: This study investigated the association between tumor MYC protein expression and disease-free survival (DFS) of patients randomized to receive chemotherapy alone (Arm A) or chemotherapy with sequential (Arm B) or concurrent trastuzumab (Arm C) in the N9831 (Alliance) adjuvant HER2+ trastuzumab breast cancer trial. Experimental Design: This analysis included 1,736 patients randomized to Arms A, B, and C on N9831. Nuclear MYC protein expression was determined in tissue microarray sections containing three biopsies per patient or whole tissue sections using standard immunohistochemistry (clone 9E10). A tumor was considered positive for MYC protein overexpression (MYC+) if the nuclear 3+ staining percentage was more than 30%. Results: Five hundred and seventy-four (33%) tumors were MYC+. MYC+ was associated with hormone receptor positivity (χ2, P = 0.006), tumors 2 cm or more (χ2, P = 0.02), and a higher rate of nodal positivity (χ2, P < 0.001). HRs for DFS (median follow-up: 6.1 years) for Arm C versus A were 0.52 (P = 0.006) and 0.65 (P = 0.006) for patients with MYC+ and MYC− tumors, respectively (Pinteraction = 0.40). For Arm B versus A, HRs for patients with MYC+ and MYC− tumors were 0.79 (P = 0.21) and 0.74 (P = 0.04), respectively (Pinteraction = 0.71). For Arm C versus B, HRs for patients with MYC+ and MYC− tumors were 0.56 (P = 0.02) and 0.89 (P = 0.49), respectively (Pinteraction = 0.17). Conclusions: Our data do not support an impact of tumor MYC protein expression on differential benefit from adjuvant trastuzumab. Clin Cancer Res; 19(20); 5798–807. ©2013 AACR.

Purpose It has been suggested that PTEN, a negative regulator of PI3K/AKT signaling, is involved in tumor sensitivity to trastuzumab. We investigated the association between tumor PTEN protein expression and disease-free survival (DFS) of patients randomly assigned to receive chemotherapy alone (arm A) or chemotherapy with sequential (arm B) or concurrent trastuzumab (arm C) in the phase III early-stage human epidermal growth factor receptor 2 (HER2) –positive trial—North Central Cancer Treatment Group (NCCTG) N9831. Patients and Methods The intensity and percentage of invasive cells with cytoplasmic PTEN staining were determined in tissue microarray sections containing three cores per block (n = 1,286) or in whole tissue sections (WS; n = 516) by using standard immunohistochemistry (138G6 monoclonal antibody). Tumors were considered positive for PTEN (PTEN-positive) if any core or WS had any invasive cells with ≥ 1+ staining. Median follow-up was 6.0 years. Results Of 1,802 patients included in this analysis (of 3,505 patients registered to N9831), 1,342 (74%) had PTEN-positive tumors. PTEN positivity was associated with hormone receptor negativity (χ2 P < .001) and nodal positivity (χ2 P = .04). PTEN did not have an impact on DFS within the various arms. Comparing DFS of arm C to arm A, patients with PTEN-positive and PTEN-negative tumors had hazard ratios (HRs) of 0.65 (P = .003) and 0.47 (P = .005), respectively (interaction P = .16). For arm B versus arm A, patients with PTEN-positive and PTEN-negative tumors had HRs of 0.70 (P = .009) and 0.85 (P = .44), respectively (interaction P = .47). Conclusion In contrast to selected preclinical and limited clinical studies suggesting a decrease in trastuzumab sensitivity in patients with PTEN-negative tumors, our data show benefit of adjuvant trastuzumab for patients with HER2-positive breast cancer, independent of tumor PTEN status.

Purpose Findings from the human epidermal growth factor receptor 2 (HER2) –positive National Surgical Adjuvant Breast and Bowel Project (NSABP) B31 trial suggested that MYC/HER2 coamplification (> 5.0 copies/nucleus) was associated with additional benefit from adjuvant trastuzumab in patients with early-stage breast cancer. To further explore this relationship, we investigated associations between MYC amplification and disease-free survival (DFS) in a similar adjuvant trastuzumab HER2-positive breast cancer trial—North Central Cancer Treatment Group (NCCTG) N9831. Patients and Methods This analysis included 799 patients randomly assigned to receive chemotherapy alone or with concurrent trastuzumab on N9831. Fluorescence in situ hybridization (FISH) was performed by using a dual-probe mixture for MYC and centromere 8 (MYC:CEP8) on tissue microarrays. MYC amplification was prespecified as MYC:CEP8 ratio > 2.2 or average MYC copies/nucleus > 5.0. Exploratory variables included polysomy 8. Results In comparing DFS (median follow-up, 4.0 years) between treatments, patients with MYC:CEP8 ratio ≤ 2.2 (n = 618; 77%) and > 2.2 (n = 181; 23%) had hazard ratios (HRs) of 0.46 (P < .001) and 0.67 (P = .33), respectively (interaction P = .38). Patients with MYC copies/nucleus ≤ 5.0 (n = 534; 67%) and > 5.0 (n = 265; 33%) had HRs of 0.52 (P = .002) and 0.48 (P = .02), respectively (interaction P = .94). Patients with MYC:CEP8 ratio < 1.3 with normal chromosome 8 copy number (n = 141; 18%) and ≥ 1.3 or < 1.3 with polysomy 8 (n = 658; 82%) had HRs of 0.66 (P = .28) and 0.44 (P < .001), respectively (interaction P = .23). Patients with MYC copies/nucleus < 2.5 (n = 130; 16%) and ≥ 2.5 (n = 669; 84%) had HRs of 1.07 (P = .87) and 0.42 (P < .001), respectively (interaction P = .05). Conclusion We did not confirm the B31 association between MYC amplification and additional trastuzumab benefit. Exploratory analyses revealed potential associations between alternative MYC/chromosome 8 copy number alterations and differential benefit of adjuvant trastuzumab.

Abstract Background: In 2007, the American Society of Clinical Oncology and College of American Pathologists (ASCO/CAP) recommended new guidelines to define HER2 positivity by immunohistochemistry (3+ IHC: uniform intense membrane staining of &gt;30% of invasive tumor cells) or fluorescent in situ hybridization (FISH+: HER2/CEP17 ratio &gt;2.2). The original criteria used for enrollment in the pivotal N9831 trial conducted from 2000-2005 were IHC&gt;10% (3+) or FISH ≥2.0.Purpose: To investigate the impact of the ASCO/CAP guidelines on patient (pt) eligibility and disease free survival (DFS) compared to the originally used FDA-approved definitions.Patients/Methods: This analysis included 2268 patients from the HER2+ N9831 adjuvant trastuzumab phase III trial. IHC was centrally performed at the Mayo Clinic using the DAKO HercepTest™ and was re-analyzed to determine the percent of tumor cells with 0, 1+, 2+, and 3+ staining intensities. DFS was compared between pts randomized to standard chemotherapy +/- concurrent trastuzumab (Arms A and C of the trial) within IHC/FISH subgroups using Cox proportional hazards regression stratified by hormone receptor and nodal status.Results: Based on 2268 pts, 83 pts (3.7%) were 3+ by FDA-approved guidelines but not 3+ by the ASCO/CAP guidelines. Among these pts, 77% (64/83) were FISH amplified centrally by ASCO/CAP guidelines. Only 1.5% (34/2268) of pts eligible under FDA-approved definitions from N9831 in this sample set would not meet the ASCO/CAP guidelines. In 1441 patients randomized to standard chemotherapy +/- concurrent trastuzumab, the exploratory DFS hazard ratio (HR) associated with trastuzumab in IHC/FISH subgroups were as follows: ASCO/CAP HER2+ HR=0.59 (95% CI: 0.47-0.75; p&lt;0.001); FDA-approved HER2+ HR=0.60 (95% CI: 0.47-0.75; p&lt;0.001); ASCO/CAP HER2 normal(not positive) HR=0.74 (95% CI: 0.35-1.57; p=0.43); and FDA-approved HER2 normal HR=0.53 (95% CI: 0.22-1.26; p=0.15).Conclusions: A small percentage (1.5%) of N9831 patients did not meet ASCO/CAP 2007 guidelines when applied retrospectively. Trastuzumab effect appeared similar for HER2+ patients regardless of ASCO/CAP or FDA-approved guidelines. Additional DFS analyses by IHC/FISH subgroups will be presented. We gratefully acknowledge support from the Breast Cancer Research Foundation, Genentech, and NIH CA25224 for this study. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 701.

Purpose We examined associations between tumor characteristics (human epidermal growth factor receptor 2 [HER2] protein expression, HER2 gene and chromosome 17 copy number, hormone receptor status) and disease-free survival (DFS) of patients in the N9831 adjuvant trastuzumab trial. Patients and Methods All patients (N = 1,888) underwent chemotherapy with doxorubicin and cyclophosphamide, followed by weekly paclitaxel with or without concurrent trastuzumab. HER2 status was determined by immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) at a central laboratory, Mayo Clinic, Rochester, MN. Patients with conflicting local positive HER2 expression results but normal central laboratory testing were included in the analyses (n = 103). Results Patients with HER2-positive tumors (IHC 3+, FISH HER2/centromere 17 ratio ≥ 2.0, or both) benefited from trastuzumab, with hazard ratios (HRs) of 0.46, 0.49, and 0.45, respectively (all P < .0001). Patients with HER2-amplified tumors with polysomic (p17) or normal (n17) chromosome 17 copy number also benefited from trastuzumab, with HRs of 0.52 and 0.37, respectively (P < .006). Patients who received chemotherapy alone and had HER2-amplified and p17 tumors had a longer DFS than those who had n17 (78% v 68%; P = .04), irrespective of hormone receptor status or tumor grade. Patients with HER2-normal tumors by central testing (n = 103) seemed to benefit from trastuzumab, but the difference was not statistically significant (HR, 0.51; P = .14). Patients with hormone receptor–positive or –negative tumors benefited from the addition of trastuzumab, with HRs of 0.42 (P = .005) and 0.60 (P = .0001), respectively. Conclusion These results confirm that IHC or FISH HER2 testing is appropriate for patient selection for adjuvant trastuzumab therapy. Trastuzumab benefit seemed independent of HER2/centromere 17 ratio and chromosome 17 copy number.