Taxane-containing Neoadjuvant Chemotherapy Research Articles

Abstract PO4-02-04: Overall survival and disease recurrence rates in patients with invasive lobular breast cancer of the PenelopeB cohort

Abstract Background: In the PENELOPEB trial, the addition of 1-year of cyclin-dependent kinase 4/6 (CDK4/6) inhibitor palbociclib to standard endocrine therapy (ET) for women with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) early breast cancer at high risk of recurrence after neoadjuvant chemotherapy (NACT) did not improve invasive disease-free survival (iDFS) or overall survival (OS) in the main study analysis. Invasive lobular breast cancer (ILC) accounts for ~15% of all breast cancers (BC) and represents an underinvestigated subtype of BC with typically less sensitivity to (neo)adjuvant chemotherapy, and poor distant disease-free survival (DDFS) irrespective of response to NACT. Here, we report the post-hoc analysis results of iDFS, DDFS and OS in pre- and postmenopausal women enrolled on PENELOPEB and with ILC. Methods: Patients with HR+/HER2-negative BC without pathological complete response (pCR) after taxane-containing NACT and at high risk of relapse (CPS-EG score ≥3, or 2 and ypN+) were randomized (1:1) to receive 13 cycles of palbociclib 125mg daily or placebo on days 1-21 of a 28-day cycle in addition to standard ET with tamoxifen (TAM) +/- gonadotropin-releasing hormone analogue (GnRHa) or aromatase inhibitor (AI) +/- GnRH. Randomization was stratified by nodal status at surgery, age at first diagnosis (< 50 vs. ≥50 years), Ki-67, region, and CPS-EG score. ILC diagnosis was locally assessed and reported by the investigators on the pathology case report form. The primary objective of this post-hoc analysis was to evaluate iDFS, DDFS and OS by treatment arm in patients with high risk ILC. Results: A total of 1,250 patients were randomized, of whom 110 had ILC and were nearly uniformly distributed between both treatment arms (palbociclib n=58 vs. placebo n=52), with a higher proportion of postmenopausal women (58.6% in the palbociclib arm vs. 53.8% in the placebo arm) compared to premenopausal women (41.4% in the palbociclib arm vs. 46.2% in placebo arm). There was no difference in the distribution of AI/TAM use between the treatment arms. An estimated absolute 3-year-iDFS difference of 18.3% with palbociclib compared to placebo (iDFS 88.4% [95% CI 76.0-94.6] vs. 70.1% [95% CI 55.3-80.7]) with a HR of 0.66 [95% CI 0.27 – 1.61, log-rank p=0.354]) was observed. A comparable 3-year-DDFS difference of 16.3% was observed. An estimated 3-year-OS difference of 16.4% (98.0% [95% CI 86.6 – 99.7] vs. 81.6% [95% CI 67.5 – 90.0]) with a hazard ratio (HR) of 0.27 (95% CI 0.05 – 1.43, log-rank p=0.108) was observed. Out of 12 observed deaths (n=2 palbociclib vs. n=10 placebo), 11 (in placebo arm) were related to metastasic BC. Conclusions: In this post-hoc analysis, a trend towards improvement in OS and a trend in favor of iDFS and DDFS for the addition of palbociclib to ET was observed among women with HR+/HER2- ILC at high risk of recurrence after NACT, but these differences were not statistically significant. This could represent a valuable treatment option for patients with high risk ILC. Due to the small sample size of the ILC subgroup, further follow-up evaluation is necessary. Moreover, analyses in the ILC subgroup from other adjuvant CDK4/6 inhibitor trials could substantiate these findings. Table. Overall survival and disease recurrence rates in patients with invasive lobular breast cancer of the PenelopeB cohort Results of iDFS, DDFS and OS. Citation Format: Hervé Bonnefoi, Frederik Marmé, Miguel Martín, Michael Untch, Sung-Bae Kim, Harry Bear, Nicole McCarthy, Karen Gelmon, José Ángel García-Sáenz, Catherine M. Kelly, Toralf Reimer, Zhe Zhang, Masakazu Toi, Hope Rugo, Michael Gnant, Andreas Makris, Nader Hirmas, Valentina Nekljudova, Johannes Holtschmidt, Sibylle Loibl. Overall survival and disease recurrence rates in patients with invasive lobular breast cancer of the PenelopeB cohort [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-02-04.

Abstract PD2-04: Molecular plasticity of luminal breast cancer and response to CDK 4/6 inhibition - The biomarker program of the PENELOPE-B trial investigating post-neoadjuvant palbociclib

Abstract Background: Molecular plasticity of breast cancer is crucial for the development of therapy-resistant disease. In this investigation, we studied changes in molecular signatures between pretherapeutic (pre-Tx) and post-therapeutic (post-NACT) tumor samples from patients included in the PENELOPE-B (NCT01864746) trial. The phase III PENELOPE-B study did not show a significant benefit from palbociclib in women with centrally confirmed HR+, HER2- primary breast cancer without a pathological complete response after taxane-containing neoadjuvant chemotherapy (NACT) and at high-risk of relapse (CPS-EG score ≥3 or 2 and ypN+) (Loibl et al. JCO 2021). However, first translational investigations showed that a small number of patients with a luminal-B tumor subtype, based on absolute intrinsic molecular subtyping (AIMS, Paquet & Hallet, JNCI 2014) subtyping after NACT, had a numerical benefit from post-NACT palbociclib. We have therefore extended the analysis and included a cohort of paired pre-Tx and post-NACT samples. Methods: We investigated gene expression in pre-Tx (n=259) tumor tissue samples using the HTG EdgeSeq Oncology Biomarker Panel including 2549 genes (HTG Molecular Diagnostics Inc.); for the same patients the same panel on post-NACT residual tumor samples were available. The paired samples were selected based on a case-cohort approach. Based on 91 genes of this panel, the AIMS subtype was calculated. In addition, we performed exploratory biomarker analyses to identify genes and gene signatures with prognostic and predictive relevance. After completion of NACT, PENELOPE-B patients were randomized to palbociclib versus placebo in addition to standard endocrine therapy. Results: The prevalence of AIMS subtypes, in particular LumA vs LumB, changed in pre-Tx and post-NACT tumors. In the pre-Tx samples, 115 (44%) and 123 (47%) of tumors had LumA and LumB subtypes, respectively, as expected from a high-risk cohort. However, in the post-NACT samples, LumA tumors were predominant (n=183, 71%) over LumB (n=30; 12%). 78 (30%) and 6 (2%) tumors switched their subtype from LumB to LumA and LumA to LumB, respectively. For further analyses, we compared the groups of low proliferating (LumA and NormL) and high proliferating subtypes (LumB, BasalL and HER2E). In bivariable Cox regression analysis, the grouped pre-Tx and post-NACT AIMS subtypes were independent prognostic factors for iDFS: HR=1.85 (1.16-2.98, p=0.011) for pre-Tx LumB/BasalL/HER2E vs LumA/NormL and HR=2.18 (1.24-3.84, p=0.007) for post-NACT. Similar results were found when adjusted for prognostic clinical factors and for DDFS and OS endpoints although the pre-Tx subtype did not reach significance. These and further Cox models investigating interaction effects show that patients with tumors developing from high (pre-Tx) to low proliferation (post-NACT) had a higher iDFS risk compared to stable low proliferating tumors but a lower iDFS risk compared to stable high proliferating tumors. Neither in the pre-Tx LumB/BasalL/HER2E nor in the pre-Tx LumA/NormL subgroup a benefit from palbociclib was observed. Based on the results of the AIMS subtyping, we extended the exploratory analysis to identify genes that might be involved in the prognostic and predictive effects as well as genes driving the subtype switch. The analysis is ongoing and the relevant genes will be presented at the conference. Conclusions: Our findings show that the switch from high-risk molecular subtypes (in particular LumB) to low-risk subtypes (in particular LumA) is common in neoadjuvant therapy of luminal tumors. The adaptation of luminal high-risk tumors to therapy-induced stress is crucial for the clinical outcome and the results suggest that molecular defined tumor subtypes might not be as stable as originally thought. Citation Format: Carsten Denkert, Frederik Marmé, Miguel Martin, Michael Untch, Hervé Bonnefoi, Sung-Bae Kim, Harry Bear, Agnieszka Witkiewicz, Seock-Ah Im, Angela DeMichele, Laura Van’t Veer, Nicole McCarthy, Thorsten Stiewe, Karen A. Gelmon, José A. García-Sáenz, Catherine M. Kelly, Toralf Reimer, Erik Knudsen, Nicholas Turner, Federico Rojo, Peter A. Fasching, Julia Teply-Szymanski, Yuan Liu, Masakazu Toi, Hope S. Rugo, Michael Gnant, Andreas Makris, Bärbel Felder, Karsten Weber, Sibylle Loibl. Molecular plasticity of luminal breast cancer and response to CDK 4/6 inhibition - The biomarker program of the PENELOPE-B trial investigating post-neoadjuvant palbociclib [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD2-04.

Abstract GS1-02: Phase III study of palbociclib combined with endocrine therapy (ET) in patients with hormone-receptor-positive (HR+), HER2-negative primary breast cancerand with high relapse risk after neoadjuvant chemotherapy (NACT): First results from PENELOPE-B

Abstract Background: About one third of patients with hormone-receptor-positive (HR+), HER2- primary breast cancer with residual invasive disease after neoadjuvant chemotherapy will relapse despite adjuvant endocrine therapy. The risk of relapse can be assessed more accurately using the CPS-EG scoring system (Mittendorf et al. JCO 2011). Therapeutic inhibition of cyclin-dependent kinase 4 and 6 (CDK 4/6) by palbociclib combined with endocrine therapy demonstrated highly relevant efficacy in metastatic breast cancer. Thus, we hypothesize that palbociclib may also be active in these high-risk patients with primary breast cancer. Methods: PENELOPE-B (NCT01864746) is a double-blind, placebo-controlled, phase III study in women with centrally confirmed HR+, HER2- primary breast cancer without a pathological complete response after taxane-containing neoadjuvant chemotherapy and at high-risk of relapse (CPS-EG score ≥3 or 2 and ypN+). After completion of neoadjuvant chemotherapy and locoregional therapy, patients were randomized (1:1) to receive 13 cycles of palbociclib 125mg daily or placebo on days 1-21 in a 28d cycle in addition to standard endocrine therapy. Randomization was stratified by lymph node status (at surgery), age, Ki-67, global region, and CPS-EG score. Primary endpoint is invasive disease-free survival (iDFS). Final analysis was planned after 290 iDFS events with efficacy boundary p<0.0463 due to 2 interim analyses. Main secondary endpoints include iDFS excluding second primary invasive non-breast cancers, overall survival, and safety. Results: A total of 1250 patients were randomized between 2/2014 and 12/2017. Median age was 49.7 years [range 19-79]; 96.8% had residual disease in the breast, 94.6% were ypN+; G3 was reported in 47.4%, Ki-67 >15% in 27.7 %; 54.7% of patients had risk status CPS-EG score ≥3. 1118 patients (89%) completed at least 7 cycles of therapy. 50.1% of patients received aromatase inhibitor (AI), 49.8% tamoxifen, 6.6% AI + gonadotropin-releasing hormone (GnRH) and 9.7% tamoxifen + GnRH. Most common related serious adverse events (SAEs) were infections and vascular disorders. 8 fatal SAEs were reported. Conclusions: PENELOPE-B evaluates the effect of palbociclib for 1 year compared to placebo in addition to endocrine therapy in high-risk primary breast cancer patients. The database was locked with 308 events on September 25th 2020. After breaking the blind for analysis, top line results will be available as of mid October 2020. Results of the final iDFS analysis will be presented at the meeting. Citation Format: Sibylle Loibl, Frederik Marmé, Miguel Martin, Michael Untch, Hervé Bonnefoi, Sung-Bae Kim, Harry Bear, Nicole Mc Carthy, Mireia Melé Olivé, Karen Gelmon, José García Sáenz, Catherine M Kelly, Toralf Reimer, Masakazu Toi, Hope S Rugo, Sabine Seiler, Valentina Nekljudova, Carsten Denkert, Michael Gnant, Andreas Makris, Nicole Burchardi, Gunter von Minckwitz. Phase III study of palbociclib combined with endocrine therapy (ET) in patients with hormone-receptor-positive (HR+), HER2-negative primary breast cancerand with high relapse risk after neoadjuvant chemotherapy (NACT): First results from PENELOPE-B [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS1-02.

EXOSOMAL MICRO-RNA - POTENTIAL PREDICTIVE MARKER OF BREAST CANCER NEOADJUVANT THERAPY EFFECT

Neoadjuvant systemic treatment of patients with breast cancer (BC) may include neoadjuvant chemotherapy (NHT), neoadjuvant hormone therapy (NGT), neoadjuvant targeted therapy. The type of systemic therapy is determined by the level of expression of estrogen/progesterone receptors, HER2, i.e. immunohistochemical characteristic of the disease. In this article, we evaluated the predictive value of the profile of plasma exosomal microRNA, assessing the immediate efficacy of NHT, which included taxanes. Obtained results revealed a correlation between the level of concentration of several miRNA molecules in circulating exosomes and the effect of NHT. Furthermore, the index calculated as the ratio of miR-34a and miR-451 concentrations, allowеd to predict the effect of taxanecontaining NHT. The results confirm the assumption on the predictive significance of exosomal miRNA. Further research is needed to confirm the validity of a new method of prediction of the NHT efficacy in breast cancer.

Abstract S1-07: A phase III trial of adjuvant capecitabine in breast cancer patients with HER2-negative pathologic residual invasive disease after neoadjuvant chemotherapy (CREATE-X, JBCRG-04)

Abstract Background Patients (pts) with pathologic residual invasive disease after neoadjuvant chemotherapy (NAC) have an intermediate or high-risk for relapse. It is not clear whether further systemic chemotherapy is beneficial for these pts. CREATE-X is a multicenter open-label randomized phase III trial evaluating this major clinical issue using capecitabine (X) in pts without pCR after NAC (UMIN000000843). We have shown previously that the addition of 8 cycles of X to standard adjuvant therapy is feasible and well tolerated (Ohtani S, et al. SABCS2013#P3-12-03). We report the first efficacy results from a pre-planned interim analysis after 2-year follow-up. Methods Pts with HER2-negative residual invasive cancer after anthracycline- and/or taxane-containing NAC were randomized to standard treatment (RT, hormone therapy (HT) as appropriate) with or without 8 cycles of X (1250 mg/m2 bid, days1–14,q3w). Pts with hormone receptor (HR)-positive disease received HT either with or after X, according to each center's prespecified standard practice. The primary endpoint was disease-free survival (DFS). Secondary endpoints included overall survival (OS), safety, and cost-effectiveness. It was originally planned to enroll 450 pts in each arm in order to detect a HR 0.74 improvement in the X arm with 80% power and a two-sided 5% significance level. We planned one interim analysis of DFS at 2-years after all pts enrolled using Lan-DeMets alpha spending function method (O'Brein-Fleming type). Results Between Feb 2007 and Jul 2012, 910 pts were randomized, with 455 pts to receive X. The full analysis consisted of 902 pts who matched the inclusion criteria. Baseline characteristics were well balanced. The median age was 48 years in both arms; 63.5% were HR-positive. In the investigational arm, HT was given with X concurrently in 200 pts and after X in 24 pts. The relative dose intensity of X was 78.8%. At the time of the interim analysis, DFS events were confirmed in 81 (18.8%) in the investigational arm and 109 (24.7%) in the standard arm, and OS events were 28 (6.5%) and 41 (9.3%), respectively. On Kaplan-Meier analysis, 2-year DFS was 87.3% for the arm with X and 80.5% for no X (HR:0.688, 98.66%CI: 0.479-0.989, log-rank P=0.001). The tendency for improvement of OS by adding X was also confirmed; 2-year OS was 96.2% and 93.9%, respectively (HR: 0.658, 95%CI: 0.407-1.065, log-rank P=0.086). In the experimental arm with X, grade 3/4 toxicities included HFS (11%), neutropenia (9%), diarrhea (3%), and fatigue (1%); all were controllable. No SAE was related to X administration. Because the study met the primary endpoint, an independent data monitoring committee recommended discontinuation of the study. Conclusions: The clinical utility of X in the adjuvant setting for breast cancer pts has been proven to improve the prognosis based on the pathological response-guided strategy. Tolerability was consistent with the established safety profile of X in mBC. The benefit to risk balance of the addition of 8 cycles of X to standard adjuvant therapy seems to be satisfied. This evidence might allow the development of personalized individualized treatment based on the response to primary systemic therapy. Citation Format: Toi M, Lee S-J, Lee ES, Ohtani S, Im Y-H, Im S-A, Park B-W, Kim S-B, Yanagita Y, Takao S, Ohno S, Aogi K, Iwata H, Kim A, Sasano H, Yokota I, Ohashi Y, Masuda N. A phase III trial of adjuvant capecitabine in breast cancer patients with HER2-negative pathologic residual invasive disease after neoadjuvant chemotherapy (CREATE-X, JBCRG-04). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S1-07.

Abstract P1-12-04: A phase 2 study of eribulin in breast cancer not achieving a pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC)

Abstract Background: Residual breast cancer after NAC is associated with a high risk of recurrence. Little evidence supports the use of further chemotherapy in this setting. Eribulin, an inhibitor of microtubule dynamics, demonstrated a survival advantage in patients with metastatic breast cancer who had progressed after previous anthracycline and taxane therapy. This phase 2 trial assessed the efficacy of eribulin (2-yr disease-free survival) administered postoperatively to breast cancer pts not achieving a pCR following standard NAC. Methods: Women with invasive breast cancer (stage T1-4b, N0-2, M0 at diagnosis) and evidence of residual cancer (>5 mm) in the breast or axillary lymph nodes (LN) following ≥4 cycles of standard anthracycline and/or taxane-containing NAC were eligible. Additional eligibility criteria: age ≥18 yrs, peripheral neuropathy < 1, adequate hematologic, hepatic, and renal function. 3 groups were studied: Cohort A-triple negative (TN), Cohort B-HR+/HER2-, Cohort C-HER2+. After recovery from definitive surgery, all pts received eribulin mesylate 1.4mg/m2 IV on days 1 and 8 every 21 days for 6 cycles. Cohort C pts also received trastuzumab 6mg/kg IV day 1 every 21 days for a total of 1 yr from start of NAC. Adjuvant hormonal therapy and loco-regional radiotherapy were administered per institutional guidelines. We hypothesized post-operative eribulin would result in a 40% increase over the reported 40% 2 yr DFS for TN, and a 15% increase over the reported 80% 2 yr DFS for HR+/HER2- pts who did not achieve pCR following standard NAC. Results: 127 pts were enrolled (54, Cohort A; 42, Cohort B; 31, Cohort C). Pts on Cohort C continue with study treatment. Here, we present the results of 95 pts treated on Cohorts A and B. Median age-52 yrs (range, 27-74). 87 pts (92%) had invasive ductal adenocarcinoma, 6 (6%) invasive lobular, 1 (1%) mucinous, and 1 (1 %) unknown; 34 pts (36%) had T3 or T4 tumors and 65 (68%) had N1-2 disease at diagnosis. NAC with anthracyclines was administered to 74 pts (78%), taxanes to 88 (93%), and 72 (76%) received both. 71 pts (75%) had mastectomies, 24 (25%) had breast conserving surgery. Median residual tumor was 17.5 mm (range 0.1 to 80); 60 pts (63%) were LN+. 78 pts (81%) completed the planned 6 cycles of eribulin. Adjuvant radiation was administered in 28 pts (30%). 3 pts discontinued treatment due to toxicity (1 each with G3 neutropenia, G3 nausea, and unknown grade neuropathy). The most common treatment-related G3/4 adverse events were neutropenia [29 pts (31%)] and leukopenia [10 pts (11%)]. 3 pts (3%) had G3/4 febrile neutropenia and 2 pts (2%) had G3/4 neuropathy. Growth factors were administered to 22 pts (24%). There were no treatment-related deaths. With a median follow up of 19.2 and 14.9 months for Cohorts A and B respectively, the 2 yr DFS probabilities calculated from date of surgery were 61.1 % (95% CI-41.2-76.0) for Cohort A; 82.2% (95% CI-60.2-92.7) for Cohort B. Conclusions: The addition of eribulin is safe and feasible in pts who do not achieve pCR following anthracycline and/or taxane based NAC. At a median follow up of 19.2 months, a statistically significant improvement in the estimated 2 yr DFS was evident in the TN (Cohort A) pts. Citation Format: Yardley DA, Peacock N, Shroff S, Molthrop, Jr DC, Anz B, Daniel BR, Young RR, Weaver R, Harwin W, Webb CD, Ward P, Shastry M, DeBusk LM, Midha R, Hainsworth JD, Burris III HA. A phase 2 study of eribulin in breast cancer not achieving a pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-12-04.

Breast Cancer: Influence of Taxanes on Response Assessment with Dynamic Contrast-enhanced MR Imaging.

To prospectively investigate the influence of taxane-containing neoadjuvant chemotherapy (T-NACT) versus non-taxane-containing NACT (NT-NACT) on the contrast material enhancement of breast cancers, benign enhancing lesions (BELs), and background parenchymal enhancement (BPE) at dynamic contrast-enhanced magnetic resonance (MR) imaging. This institutional review board-approved study was performed in 62 patients with invasive breast cancer who underwent multiagent NACT with (n = 49) or without (n = 13) taxanes between 2008 and 2011. Written informed consent was obtained. Patients underwent dynamic contrast-enhanced MR imaging according to a standardized protocol before and 2 weeks after completing NACT. The percentage reduction of enhancement of breast cancers, BELs, and BPEs was calculated for patients undergoing NT-NACT versus those undergoing T-NACT. Final surgical pathologic results served as standard of reference. Changes in mean enhancement of breast cancers, BELs, and BPEs between the regimens were compared by using the Student t test for unpaired samples; for intraindividual comparison, the Student t test for paired samples was used. Similar rates of complete pathologic response were observed after T-NACT and NT-NACT (28 [57.2%] of 49 vs eight [61.5%] of 13). T-NACT was associated with an almost complete suppression of enhancement in not only breast cancers but also BELs and BPE in the same patients, with an average reduction of enhancement of -89.9% ± 9.3, -90.2% ± 11.8, and -91.2% ± 7.5, respectively. After T-NACT, cancers with partial (n = 21) or complete (n = 28) pathologic response exhibited a similar reduction of enhancement (-81.8% ± 17.5 vs -93.9% ± 2.3; P = .22). The reduction of enhancement of cancers after NT-NACT was significantly less pronounced than that after T-NACT (-41.1% ± 22.8 vs 88.1% ± 13.9; P < .0001), and effects on enhancement of BELs and BPE were significantly less pronounced compared with effects on enhancement of cancers in the same women (P < .0001). MR imaging led to an overestimation of response (yielded false-negative results for residual disease) in 66.7% (14 of 21) of patients after T-NACT, versus in 20% (one of five) of patients after NT-NACT. The reduction of enhancement observed in breast cancers after T-NACT is, in part, unrelated to their oncologic response. MR imaging-detectable effects of taxanes represent a combination of specific antimitotic and nonspecific antiangiogenic effects. This impacts the accuracy with which dynamic contrast-enhanced MR imaging helps predict complete pathologic response to T-NACT. (©) RSNA, 2015 Online supplemental material is available for this article.

β3-tubulin is a good predictor of sensitivity to taxane-based neoadjuvant chemotherapy in primary breast cancer.

The objective of this study was to explore the relationship between β3-tubulin expression and sensitivity to taxane-based neoadjuvant chemotherapy in primary breast cancer patients. A total of 48 local advanced breast cancer patients that received taxane-containing neoadjuvant chemotherapy were studied. The levels of β3-tubulin expression were tested by immunohistochemistry before chemotherapy and at the end of cycles 2, 4 and 6. The correlation between the efficacy of the chemotherapy and β3-tubulin expression and changes in β3-tubulin expression over the course of chemotherapy was examined. β3-tubulin protein expression before chemotherapy was significantly and negatively correlated with the response rate. The overall response rate was 31.8% in the high β3-tubulin expression group, whereas it was 84.6% in the low β3-tubulin expression group. At the end of cycles 2, 4 and 6 during the treatment course, the average expression rates of β3-tubulin were showed an increasing trend with β3-tubulin expression level at the end of cycle 4 being significantly different from that before chemotherapy. Nine patients that had a low β3-tubulin expression level preneoadjuvant chemotherapy changed to a high β3-tubulin expression level postneoadjuvant chemotherapy, and they had lower response rate than patients with consistent low. In conclusion, β3-tubulin is a good predictor of chemosensitivity to taxane for breast cancer, and the change of its expression level during chemotherapy may be an important cause of secondary resistance to taxane. Detection of β3-tubulin expression before and throughout the chemotherapy will help with selection of the chemotherapy treatment plan.

Phase II Trial of Neoadjuvant Weekly Nanoparticle Albumin-Bound Paclitaxel, Carboplatin, and Biweekly Bevacizumab Therapy in Women With Clinical Stage II or III HER2-Negative Breast Cancer

BackgroundWe hypothesized that adding bevacizumab to neoadjuvant chemotherapy (NCT) with nab-P and carboplatin would increase the rates of pCR in BC patients and that early changes in tumor vascularity imaged by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) would predict pCR. MethodsThirty-three women with clinical stage II or III HER2-negative BC received nab-P 100 mg/m2 and carboplatin area under the curve = 2 on days 1, 8, and 15 in combination with bevacizumab 10 mg/kg on days 1 and 15 administered every 28 days. ResultsSix patients (18%) achieved pCR, all pCRs occurred in triple-negative BC (TNBC) (pCR = 50% for TNBC). At the end of cycle 2, the changes in relative angiogenic volume were significantly different between responders and nonresponders (P = .001). The major toxicity of this NCT was myelosuppression. ConclusionNCT with weekly nab-P, carboplatin, and biweekly bevacizumab resulted in a pCR rate that was neither superior to the historical data with anthracycline- or taxane-containing NCT nor to carboplatin and taxane combinations in patients with HER2-negative BC. In patients with TNBC, the observed pCR rate was 50%. The early changes in the relative angiogenic volume imaged by DCE-MRI could predict pCR.

Abstract OT2-6-11: PENELOPE: Phase III study evaluating palbociclib (PD-0332991), a cyclin-dependent kinase (CDK) 4/6 inhibitor in patients with hormone-receptor-positive, HER2-normal primary breast cancer with high relapse risk after neoadjuvant chemotherapy (GBG-78/BIG1-13)

Abstract Background: About one third of hormone-receptor (HR)-positive, HER2-normal breast cancer (BC) patients with residual disease after neoadjuvant chemotherapy (NACT) have a substantial risk of relapse. Those patients can be identified using validated clinical-pathologic stage–estrogen/grade (CPS-EG) scoring system. Palbociclib is an oral, highly selective inhibitor of CDK4/6 kinase activity that prevents cellular DNA synthesis by inhibiting cell cycle progression. Luminal tumors have been shown to be sensitive to palbociclib. In a phase 2 study, palbocilcib extended PFS in combination with letrozole as first-line hormonal treatment for advanced BC. In addition, it has shown single agent activity in patients with multiply relapsed hormone positive ABC. Methods: PENELOPE (NCT01864746) is a prospective, international, multicenter, randomized, double-blind, placebo-controlled, phase 3 study aiming to demonstrate that 1 year of adjuvant treatment with palbociclib, in addition to standard anti-hormonal therapy, provides a superior invasive disease-free survival (iDFS) and acceptable safety profile compared to placebo in women with HR-positive/HER2-normal early BC who did not obtain a pathological complete response (pCR) after taxane-containing NACT and are at high risk of relapse (CPS-EG score ≥3). After completion of NACT and adequate surgery and radiotherapy, 800 patients will receive standard adjuvant endocrine treatment (5years) and will be randomized (1:1) to 13 cycles of palbociclib 125mg daily or matching placebo on d1-21 in a 28d cycle. Randomization will be dynamic and patients will be stratified by histological lymph node status at surgery (ypN 0-1 vs ypN2-3), age at first diagnosis (&amp;lt; = 50 vs &amp;gt;50 yrs), Ki-67 (&amp;gt;15% vs &amp;lt; = 15%), pRB and cyclin D immunoreactive scores in residual tumor after NACT (&amp;lt; = 2 vs &amp;gt;2 points), global region of participating site (Eur vs N.America vs RoW). Patients will be followed until any invasive local, regional or distant recurrence, diagnosis of secondary malignancy, unacceptable toxicity, withdrawal of consent or study termination. Primary objective is to compare iDFS for palbociclib vs placebo. Secondary objectives are iDFS excluding second non-breast cancers, overall, distant disease-free and locoregional recurrence-free survival, iDFS per treatment arm in luminal-B tumors, compliance and safety, patient reported outcomes, health economics, correlations between drug exposure and efficacy/safety findings. Further objectives are translational and aim to identify scores/markers for their prognostic value and predictive information on efficacy/safety of palbociclib in this specific setting. Results: Recruitment is planned to start in Oct 2013 at 200-250 sites in 11 countries and continue for 3years. Conclusion: PENELOPE will study whether palbociclib is an effective treatment with a sufficiently favorable safety profile for patients with high risk of recurrence and high CPS-EG score after NACT. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT2-6-11.

Abstract P3-12-03: Adjuvant capecitabine in breast cancer patients with pathologic residual disease after neoadjuvant chemotherapy: First safety analysis of CREATE-X (JBCRG-04)

Abstract Background Patients (pts) without pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) have a poor prognosis compared with pts achieving a pCR with NAC. It is not clear whether further systemic chemotherapy is beneficial for pts with no pCR. CREATE-X (UMIN000000843) is an ongoing collaborative Korean (KRN)/Japanese (JPN) prospective multicenter open-label randomized phase III trial evaluating this clinical question using capecitabine (X) in pts with no pCR after NAC. We report first safety results, focusing on hand-foot syndrome (HFS), the timing of radiotherapy (RT) and hormone therapy (HT), and differences between KRN and JPN pts. Methods Pts with residual invasive cancer after anthracycline- and/or taxane-containing NAC were randomized to standard post-surgical treatment (RT, HT as appropriate) with or without 8 cycles of X (1250 mg/m2 bid, days 1–14 q3w). RT was given before or after X. Pts with hormone receptor (HR)-positive disease received HT either with or after X, according to each center's prespecified standard practice. After evaluation of the tolerability of 6 cycles of X in the first 50 pts, the independent data monitoring committee recommended extending X to 8 cycles. Results Between Feb 2007 and Jul 2012, 910 pts were enrolled (304 in Korea, 606 in Japan). At the time of data cut-off (May 20, 2013), data were available from 866 pts. Median age was 48 years in both arms. In the investigational arm, RT was given before X in 260 pts and after X in 33 pts; 73 pts received prophylactic vitamin B6 (VB6). In HR-positive pts HT was given with X in 200 pts and after X in 24 pts. The relative dose intensity of X was 85.7% in JPN pts and 95.2% in KRN pts. Grade (G) 3/4 neutropenia, HFS (G3 only), fatigue, and diarrhea were significantly (p&amp;lt;0.05) more common with X than no X. G3 HFS occurred in 11.1% of pts receiving X, and was significantly more common in JPN vs KRN pts (p = 0.016). No significant difference in HFS was observed between pts who received vs did not receive VB6 (p = 0.392). G3/4 alanine aminotransferase (ALT) abnormalities were significantly more common in pts receiving RT after vs before X (p&amp;lt;0.001) and in pts receiving HT after vs concurrently with X (p&amp;lt;0.001). n/N(%) Investigational armControl arm (n = 430)(n = 436)HR status Positive275/430(64)275/436(63)Negative141/430(33)143/436(33)Unknown14/430(3)18/436(4)G 3/4 toxicity Neutropenia36/385(9)5/326(2)Fatigue6/426(1)0/417(0)Diarrhea12/426(3)1/417(&amp;lt;1)HFS(G3)47/424(11)0 JPN40/296(14)0 KRN7/128(5)0 VB66/73(8)- No VB641/351(12)-ALT abnormality10/409(2)3/391(&amp;lt;1) with RT8/285(3)1/280(&amp;lt;1) X → RT8/31(26)- RT → X0/254(0)- without RT2/124(2)2/111(2) with HT2/214(1)1/267(&amp;lt;1) X + HT0/190(0)- X → HT2/24(8)- wothout HT8/195(4)2/124(2) Conclusions Addition of 8 cycles of X to standard adjuvant therapy is feasible and tolerable, resulting in a modest yet acceptable increase in toxicities. The timing of RT and HT administration relative to X influenced the incidence of adverse events. HFS was more common in JPN than KRN pts, although further investigation of the potential cause of this difference is required. These findings should be interpreted in light of efficacy data, expected in 2015. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-12-03.

FOXA1 expression after neoadjuvant chemotherapy is a prognostic marker in estrogen receptor-positive breast cancer

Recent studies have indicated that the response to chemotherapy and the prognostic impact of a pathological complete response (pCR) after neoadjuvant chemotherapy differ among breast cancer subtypes. Predictors of response to chemotherapy and prognostic factors for survival might be different in estrogen receptor (ER)-positive breast cancer. Women with Stage II to III ER-positive HER2-negative breast cancer treated with anthracycline and taxane-containing neoadjuvant chemotherapy between 2003 and 2011 were retrospectively analyzed. Expression of forkhead box A1 (FOXA1), B cell lymphoma 2 (BCL2) and microtubule-associated protein tau (MAPT) as well as ER, progesterone receptor, HER2 and Ki67 was examined by immunohistochemistry in pre- and post-treatment specimens. Factors predictive of response to neoadjuvant chemotherapy and distant disease-free survival were analyzed. Tumor grade was positively correlated with Ki67 expression. Expression levels of ER were positively correlated with expression levels of HER2, BCL2, FOXA1 and MAPT in pre-treatment tumors. The Ki67 labeling index was the only factor that was significantly associated with clinical response measured by the reduction of tumor volume and pCR. Lymph node status, expression of ER before neoadjuvant chemotherapy and expression of FOXA1 after neoadjuvant chemotherapy were significantly associated with distant disease-free survival, both by univariate and multivariate analyses. Patients with ER-positive HER2-negative breast cancer should be selected for neoadjuvant chemotherapy. FOXA1 expression could be a prognostic marker in ER-positive breast cancer.

Tau proteins expressions in advanced breast cancer and its significance in taxane-containing neoadjuvant chemotherapy

Tau is a microtubule-associated protein and expressed in normal breast epithelial cells and breast cancer. Tau expression in breast cancer may be important for chemotherapy optimization. This study is to investigate the expression of Tau in advanced breast cancer and its significance in taxane-containing neoadjuvant chemotherapy. Levels of Tau protein in advanced breast cancer were detected immunohistochemically. The chemotherapeutic efficacy indexes in Tau(-) group, which includes the remission rate, Miller-Payne pathological reactive grade, and pathologic complete response rate, were improved compared with that in Tau(+) group. There was difference in the efficacy indexes among ER+ subgroups but not among ER- patients. In addition, Tau expression was positively correlated (r = 0.32, P < 0.00). In multivariate analysis, when age, clinical stage, postoperative lymph node metastasis, ER, PR, HER2, Ki-67, TP53, or Tau status were included, postoperative lymph node metastasis and Tau-negative status were identified as independent predictors of pathologic complete response. In conclusion, negative Tau protein expression may be an effective predictor for taxane-containing neoadjuvant chemotherapy, especially in ER+ subgroups. Further study on the molecular mechanism and utility of Tau for individualizing adjuvant chemotherapy is warranted.

P4-03-03: Therapeutic Sensitivities of Mouse Models of Human Breast Cancer.

Abstract Genetically engineered mouse (GEM) models have provided a wealth of information regarding the genetic causes of cancer, but their utility for preclinical drug evaluation has not been well examined. Here we have used three mammary tumor GEM models that represent three human breast cancer subtypes and have evaluated their sensitivities to chemotherapy and to three biologically targeted agents. We have selected three mouse models that resemble human breast cancer subtypes based upon common gene expression profiles; Basal-like tumors are represented by the C3(1)-T-antigen (C3-TAg) model, Luminal B tumors are represented by the MMTV-Neu model, and the P53 null transplant T11 line represents the newly described Claudin-low breast tumor subtype. On each of these models we have tested the therapeutic efficacy of: four chemotherapeutics (doxorubicin, carboplatin, paclitaxel, and cyclophosphamide), two chemotherapy combinations (carboplatin/paclitaxel and doxorubicin/cyclophosphamide), and three biologically targeted agents (erlotinib, lapatinib, and ABT-888, alone and combined with selected chemotherapies). The results from individual models were as follows: The MMTV-Neu tumors were sensitive to the single-agent chemotherapeutics carboplatin and cyclophosphamide, and cyclophosphamide dramatically increased overall survival of the MMTV-Neu mice. The targeted agents lapatinib and erlotinib were extremely effective; lapatinib produced a near complete regression in every MMTV-Neu mouse tested and both compounds lead to greatly increased survival times. In the Claudin-low T11 line, the tumors were very sensitive to cyclophosphamide. Alone and in combination with doxorubicin, cyclophosphamide was the only chemotherapeutic able to successfully cause tumor regression in this model. None of the biological inhibitors were effective as single agents in these mice, nor were they effective in combination with chemotherapeutics other than cyclophosphamide In the C3-TAg basal-like model, carboplatin alone and in combination with other drugs caused volume reduction in some of the tumors. Erlotinib was able to cause volume reductions in a third of the treated C3-Tag tumors, which revealed a heterogeneity of response within this GEM strain. None of the single agent treatments significantly increased overall survival in these mice. Those combination treatments that were effective showed a range of responses from tumor regression to slowed progression. Finally, we closely examined the heterogeneous responses of the C3-Tag tumors to carboplatin/paclitaxel and performed expression profiling of sensitive and resistant tumors. We identified a gene signature from these treated mouse tumors that was able to predict pathological complete response of human patients receiving multiagent taxane-containing neoadjuvant chemotherapy regimens. These results show that genomically selected GEM models can recapitulate findings seen in human tumors (like lapatinib responsiveness in HER2+ tumors and carboplatin sensitivity in basal-like tumors) and that GEM models can potentially be used to develop biomarkers and to test new drug combinations prior to their being tested in humans. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-03-03.

Clinical and Pathological Features of Breast Cancer Associated with the Pathological Complete Response to Anthracycline-Based Neoadjuvant Chemotherapy

Objective: Patients with breast cancer with a pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) have a better prognosis than patients with residual disease. The aim of the current study was to identify predictors of pCR. Methods: This retrospective study included 388 patients treated with anthracycline-based NAC. Clinicopathological parameters were compared between the patients with and without pCR in breast and axilla. Results: Treatment consisted of FAC/FEC in 230 patients (59%), TAC in 39 (10%) patients and AC followed by docetaxel in 119 (31%). In all, 36 (9.3%) patients had pCR. In univariate analysis, age, tumor size, lymph node involvement, tumor grade (p = 0.077, n = 265), ER and HER-2 status (n = 213), lymphovascular invasion (LVI), type of chemotherapy and taxane-containing chemotherapy were associated with pCR. In multivariate analysis, ER negativity (p = 0.003), the absence of LVI (p = 0.009) and taxane-containing NAC (p = 0.026) were found to be significant indicators of pCR. Median follow-up time was 69 months. Progression-free survival was significantly improved in patients achieving pCR (p = 0.001). Conclusions: pCR is associated with a better outcome regardless of clinical and pathological parameters in breast cancer patients who receive NAC. The probability of pCR was higher in ER-negative, LVI-negative tumors and in patients treated with sequential taxane-containing chemotherapy.

Pathological complete response rates following different neoadjuvant chemotherapy regimens for operable breast cancer according to ER status, in two parallel, randomized phase II trials with an adaptive study design (ECTO II)

Sequential doxorubicin/paclitaxel (AT) followed by CMF treatment was shown to be an active neoadjuvant chemotherapy regimen in the first European Cooperative Trial in Operable Breast Cancer (ECTO I trial). The aim of the current study (ECTO II) is to assess the complete pathological response (pCR) rate following three different anthracycline and taxane-containing neoadjuvant chemotherapy regimens, with or without capecitabine (X). Patients with operable, invasive breast cancer > 2.0 cm in diameter, were randomized to AT→CMF, AT→CMX or AC→TX regimens in two parallel, randomized, open-label, phase II trials (within a single study) in patients with estrogen receptor negative (ER-) and estrogen receptor positive (ER+) diseases, respectively. Exemestane was delivered concomitantly with neoadjuvant chemotherapy in ER+ tumors. Achievement of pCR was more common in ER- than ER+ women (45.3 vs. 10.4%). Capecitabine was only associated with a higher frequency of pCR in ER+ patients receiving AT→CMX. Overall response rates (ORR) ranged from 88 to 97%, and this translated into high rates of breast-conserving surgery (67% of ER- patients and 72% of ER+ patients). All three regimens were well tolerated. Febrile neutropenia and gastrointestinal effects were the most common grade ≥ 3 adverse events. As expected, the ECTO II study showed higher pCR rates in patients with ER- disease. Substituting capecitabine for fluorouracil (± methotrexate) in anthracycline/taxane-containing regimens appeared to be beneficial only in ER+ tumors. Translational studies investigating interactions between therapeutic agents and tumor biology are warranted to refine patient selection and improve the results of neoadjuvant chemotherapy.

Activation of nuclear factor-κ B is linked to resistance to neoadjuvant chemotherapy in breast cancer patients

The nuclear factor (NF)-kappaB system is a promising anticancer target due to its role in oncogenesis and chemoresistance in preclinical models. To provide evidence in a clinical setting on the role of NF-kappaB in breast cancer, we aimed to study the value of basal NF-kappaB/p65 in predicting resistance to neoadjuvant chemotherapy, and to characterise the pharmacodynamic changes in NF-kappaB/p65 expression following chemotherapy in patients with locally advanced breast cancer. Pre- and post-chemotherapy tumour specimens from 51 breast cancer patients treated with anthracycline- and/or taxane-containing neoadjuvant chemotherapy were assayed by immunohistochemistry for NF-kappaB/p65 subcellular expression. We studied NF-kappaB/p65, a well-characterised member of the NF-kappaB family that undergoes nuclear translocation when NF-kappaB is activated. Activation of NF-kappaB (i.e. nuclear NF-kappaB/p65 staining in pre-therapy specimens) was linked to chemoresistance. Patients with NF-kappaB/p65 nuclear staining in pre-treatment samples had a 20% clinical response rate, while patients with undetected nuclear staining had a 91% response rate to chemotherapy (P = 0.002). Notably, four patients achieved a complete histological response and none of them had pre-treatment NF-kappaB/p65 nuclear staining. Moreover, the number of patients with NF-kappaB/p65 activation increased after chemotherapy exposure. It is concluded that NF-kappaB/p65 activation assayed by immunohistochemistry is a predictive factor of resistance to neoadjuvant chemotherapy in breast cancer patients. Moreover, NF-kappaB activation was inducible following chemotherapy in a proportion of breast cancer patients. These novel clinical findings strengthen the rationale for the use of NF-kappaB inhibitors to prevent or overcome chemoresistance in breast cancer.