Reinholz, Monica M.

11095 Background: Biologic characterization of CTCs is increasingly important in determining metastatic breast cancer (MBC) patient (pt) prognosis and treatment prediction. Combined preliminary results from two earlier metastatic BC NCCTG trials, N0234 & N0336, suggested that the change in CTC mammaglobin (MGB1) gene expression between baseline and two cycles of chemotherapy predicted tumor response (p=0.04). The objectives of this study were to 1) determine CTC gene expression of CK19 and MGB1 before, during, and after treatment in N0436 & N0437 and 2) determine associations between baseline and post-treatment gene expression and treatment response. Methods: CTCs were enriched using CD45-depletion from ∼10ml EDTA blood obtained from metastatic BC pts before, after two cycles, and at end of treatment with either first/second-line irinotecan plus cetuximab (N0436) or first-line paclitaxel poliglumex and capecitabine (N0437). CK19 and MGB1 mRNA levels were determined using quantitative RT-PCR in baseline and serial CTC samples of up to 19 pts from N0436 and 40 pts from N0437. The relative gene expressions were normalized to β2-microglobulin and calibrated to healthy blood using the 2-ΔΔCt algorithm; a value of 2 was defined as positive for the respective marker. Results: CK19+ mRNA was detected in 58% of baseline samples from N0436 (11/19) and N0437 (23/40). MGB1+ mRNA was detected in 32% (6/19) and 38% (15/40) of N0436 and N0437 baseline samples, respectively. CK19+ mRNA was detected in 50% (7/14) and 56% (29/52) of N0436 and N0437 serial CTC samples, respectively. MGB1+ mRNA was detected in 29% (4/14) and 27% (14/52) of N0436 and N0437 serial CTC samples, respectively. Of the 66 serial samples, 27% of samples (18/66) had turned positive from baseline for CK19 or MGB1. CK19 mRNA was detected in 85% (33/39) of MGB1+ mRNA samples but their baseline mRNA levels were not correlated. Conclusions: CK19 mRNA was detected in MBC pts with similar frequencies to the CellSearch imaging system. CK19 was detected at a higher frequency than MGB1. In the majority of cases, MGB1 was co-expressed with CK19. Associations between gene expression and treatment response using Chi-Squared analyses and Cox regression models will be presented. No significant financial relationships to disclose.

539 Background: An increased baseline sHER-2 concentration is an indicator of poor prognosis in the metastatic and adjuvant settings of HER-2+BC. This study evaluated the levels of sHER-2 during treatment and at time of recurrence in N9831. Methods: Aims were to describe sHER-2 levels during treatment and at time of recurrence in patients (pts) randomized to Arms A (standard chemotherapy) and C (standard chemotherapy with concurrent trastuzumab). Baseline serum samples of 1506 pts from both arms along with 86 recurrence serum samples were analyzed for sHER-2 (ng/mL). In addition, 556 serial samples were obtained in 148 patients over the treatment period. Median follow up was 4.5 years. Statistical methods included repeated measures linear models, Wilcoxon rank sum tests, and Cox regression models. Results: Analyzing serial sHER-2 levels during treatment, mean log sHER-2 remained constant in Arm C (estimated slope = 0.004, p = 0.44) while the estimated increase per month was 0.026 (on log e scale) for Arm A (p = 0.0003). Based on the linear model at 18 months, the mean log sHER-2 was 2.98 (95% CI: 2.87–3.09) and 2.55 (95% CI: 2.40–2.70) for Arms A and C, respectively. Among pts with disease recurrence, sHER-2 levels increased in Arm A from baseline to time of recurrence (mean = 72.9, median = 1.7, p =0.005) while sHER-2 levels remained unchanged in Arm C (mean = 9.2, median = -0.9, p = 0.65). While all 86 recurrence patients had baseline sHER2 levels <50, 24% (15/63) of Arm A patients had very high recurrence sHER-2 levels (≥50) as compared to 9% (2/23) on Arm C (p=0.10). Patients with recurrence sHER-2 levels ≥15 had shorter survival time following recurrence with 3 year overall survival of 51% compared to 76% for the <15 sHER-2 group (HR = 2.77; 95% CI: 1.20–6.43, p = 0.02). Conclusions: Based on serial specimens during treatment, the concurrent trastuzumab arm (C) had constant sHER-2 levels, whereas the standard chemotherapy arm (A) had increasing sHER-2 levels. In arm A, recurrence sHER-2 levels increased significantly from baseline while recurrence sHER-2 levels did not change in arm C. Additionally, pts with high sHER-2 levels at recurrence had shorter overall survival following recurrence. Partial support: CA25224, CA114740 , Genentech, Siemens, and the BCRF. [Table: see text]

e11527 Background: 118 Her2 positive invasive carcinomas were retested centrally at the Mayo Clinic for Her2 status confirmation prior to inclusion in Mayo Clinic Cancer Research Consortium study RC0639 phase II study of cardiac safety and tolerability of adjuvant chemotherapy plus trastuzumab with lapatinib for resected Her2+ breast cancer (MCCRC RC0639). Methods: Central confirmatory methods were immunohistochemical (IHC) Dako HercepTest on a Dako Autostainer using the manufacturer's recommendations and HercepTest kit epitrope retrieval kit and fluorescent in situ hybridization (FISH) using Vysis PathVysion probe kit. Test results are interpreted using ASCO/CAP guidelines (IHC >30%, Her2:CEP 17 ratio >2.2). Results: There is local and central test 3+ IHC concordance in 48 of 53 tumors (agreement 90.6%) and FISH amplification in 29 of 33 tumors (agreement 87.9%), improved or similar results using identical methods to results in NCCTG N9831 adjuvant trial (n=1063, 81.6% IHC; n=813, 88.1% FISH). Of 92 centrally tested 3+ IHC positive tumors, 88 (95.7%) were FISH amplified. 5 centrally tested patients interpreted as Her2 positive by pre-ASCO/CAP guidelines (IHC >10%; HER2:CEP17 ratio >2) are Her2 ineligible using ASCO/CAP guidelines. IHC not confirmed centrally was reviewed by a second pathologist in 16 of 118 specimens. IHC concordance between two central pathologists was 10/16 (62.5%) in negative or equivocal (≤30% IHC staining) specimens; 7/10 (70%) with two reader agreement were FISH amplified and 4/6 (66%) with disagreement were FISH amplified. Conclusions: Concordance in IHC and FISH results between local and central labs is similar or improved since N9831. New ASCO/CAP Her2 testing guidelines change eligibility based on Her2 status in 4.2 % of patients. Equivocal IHC results falling between pre- and post- ASCO/CAP IHC positive thresholds (>10% and <30% IHC strong staining) are only partially resolved by repeat IHC review and/or FISH testing. No significant financial relationships to disclose.

1083 Background: Pixantrone (Pix) is a novel aza-anthracenedione with structural similarities to mitoxantrone and promising activity against non-Hodgkin’s lymphoma. Due to the lack of iron binding it is theorized to exhibit less cardiotoxicity than the anthracyclines. Methods: N1031 is a phase II RCT of 2 schedules of Pix, in pts with MBC. Group A pts received 180mg/m2 IV q3 wks, and group B pts 85mg/m2 IV on days 1, 8, 15 q4 wks. Eligibility included prior exposure to anthracyclines and/or taxanes, and 1 to 3 regiments in the metastatic setting (minimum of 2 if no prior adjuvant therapy given). Due to lack of long term cardiac safety data no more than 12 cycles were allowed. Frequent cardiac imaging was performed per protocol. Primary endpoint was RR and secondary endpoints included PFS, OS, safety, and QOL. Planned sample size was 25 pts per group. Results: In total 46 pts were evaluable (23 per group), mean age 55.5 yrs (range 38-79), 37% PS 0, 52% PS 1, and 11% PS 2. 80% of pts had prior exposure to doxorubicin, 72% had prior (neo)-adjuvant therapy, 76% were ER+ and 57% received prior HT. Number of prior metastatic regiments was: 1 (28%), 2 (61%) and 3 (11%). Most common adverse events (%) of any grade were: alopecia (74), anemia (74), fatigue (85), nausea (67), ANC decrease (87), and skin disorder (41). Grade 3-4 adverse events (%) at least possibly attributed to Pix and occurring in at least 2 pts were: ANC decrease (57), fatigue (9), increased AST (4%). One pt from each group (4%) had a grade 3 decrease in EF. There were no major differences between the two groups except for more oral mucositis in group A (35% vs 4%). Median number of cycles was 3 in group A (range 1-12) and 2 in group B (range 1-8). There was only 1 confirmed tumor response per group (4%,95% CI: 0.1-22%) prompting early termination of the trial. The median PFS was 2.7 mo (95% CI: 1.8-3.8), and the median OS was 8.9 mo (95% CI: 7.5-N/A). Conclusions: Pixantrone has insufficient activity in patients with MBC exposed to prior anthracyclines and/or taxanes. Adverse events were similar to prior experience with Pix. There were no major differences between the 2 schedules of administration. There was no significant cardiac toxicity seen in this trial. Correlative studies are underway.

Abstract Background: Preclinical evidence indicates that increased insulin-like growth factor receptor-1 (IGF1R) signaling interferes with the action of trastuzumab suggesting a possible mechanism of trastuzumab resistance. Thus, we evaluated IGF1R prevalence, relationship with demographic data, and association with disease-free survival (DFS) of patients randomized to chemotherapy alone (Arm A) or chemotherapy with sequential (Arm B) or concurrent trastuzumab (Arm C) in the prospective phase III HER2+ adjuvant N9831 trial. Experimental Design: IGF1R protein expression was determined in tissue microarray sections (three cores per block; N = 1,197) or in whole tissue sections (WS; N = 537) using IHC (rabbit polyclonal antibody against IGF1R β-subunit). A tumor was considered positive (IGF1R+) if any core or WS had ≥1+ membrane staining in &gt;0% invasive cells. Median follow-up was 8.5 years. Results: Of 1,734 patients, 708 (41%) had IGF1R+ breast tumors. IGF1R+ was associated with younger age (median 48 vs. 51, P = 0.007), estrogen receptor/progesterone receptor positivity (78% vs. 35%, P &lt; 0.001), nodal positivity (89% vs. 83%, P &lt; 0.001), well/intermediate grade (34% vs. 24%, P &lt; 0.001), tumors ≥2 cm (72% vs. 67%, P = 0.02) but not associated with race or tumor histology. IGF1R did not affect DFS within arms. Between Arms A and C, patients with IGF1R+ and IGF1R− tumors had DFS HRs of 0.48 (P ≤ 0.001) and 0.68 (P = 0.009), respectively (Pinteraction = 0.17). Between Arms A and B, patients with IGF1R+ and IGF1R− tumors had DFS HRs of 0.83 (P = 0.25) and 0.69 (P = 0.01), respectively (Pinteraction = 0.42). Conclusions: In contrast to preclinical studies that suggest a decrease in trastuzumab sensitivity in IGF1R+ tumors, our adjuvant data show benefit of adding trastuzumab for patients with either IGF1R+ and IGF1R− breast tumors. Clin Cancer Res; 23(15); 4203–11. ©2016 AACR.

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.

Purpose To develop a genomic signature that predicts benefit from trastuzumab in human epidermal growth factor receptor 2–positive breast cancer. Patients and Methods DASL technology was used to quantify mRNA in samples from 1,282 patients enrolled onto the Combination Chemotherapy With or Without Trastuzumab in Treating Women With Breast Cancer (North Central Cancer Treatment Group N9831 [NCCTG-N9831]) adjuvant trastuzumab trial. Cox proportional hazard ratios (HRs), adjusted for significant clinicopathologic risk factors, were used to determine the association of each gene with relapse-free survival (RFS) for 433 patients who received chemotherapy alone (arm A) and 849 patients who received chemotherapy plus trastuzumab (arms B and C). Network and pathway analyses were used to identify key biologic processes linked to RFS. The signature was built by using a voting scheme. Results Network and functional ontology analyses suggested that increased RFS was linked to a subset of immune function genes. A voting scheme model was used to define immune gene enrichment based on the expression of any nine or more of 14 immune function genes at or above the 0.40 quantile for the population. This model was used to identify immune gene–enriched tumors in arm A and arms B and C. Immune gene enrichment was linked to increased RFS in arms B and C (HR, 0.35; 95% CI, 0.22 to 0.55; P < .001), whereas arm B and C patients who did not exhibit immune gene enrichment did not benefit from trastuzumab (HR, 0.89; 95% CI, 0.62 to 1.28; P = .53). Enriched immune function gene expression as defined by our predictive signature was not associated with increased RFS in arm A (HR, 0.90; 95% CI, 0.60 to 1.37; P = .64). Conclusion Increased expression of a subset of immune function genes may provide a means of predicting benefit from adjuvant trastuzumab.

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 &lt; 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.