HER2-positive Inflammatory Breast Cancer Research Articles

Abstract PO5-01-03: Neoadjuvant HER2-targeted regimens with or without anthracyclines for HER2-positive inflammatory breast cancer (IBC): a multicenter retrospective study

Abstract Background Previous randomized clinical trials have shown no significant benefit with the addition of anthracyclines to neoadjuvant treatment for HER2-positive breast cancer. However, these studies did not focus on inflammatory breast cancer (IBC), or a small minority of patients on these trials. The study aims to compare pathologic complete response rates with and without anthracyclines in HER2-positive IBC. Methods We reviewed patients diagnosed with Stage III HER2-positive IBC who underwent neoadjuvant therapy and modified radical mastectomy at MD Anderson Cancer Center and Dana-Farber Cancer Institute between 2014 and 2021. Patients received either docetaxel/trastuzumab/pertuzumab-doxorubicin/cyclophosphamide (THP-AC) or docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP). The primary outcome was pathologic complete response (pCR) rate, defined as ypTisT0/N0. Secondary outcomes included 2-year event-free survival (EFS) and overall survival (OS). Univariate and multivariable analyses were performed with adjustments for clinically relevant covariates. Results Ninety-nine patients were included in the analysis. Thirty-nine patients received TCHP and 60 received THP-AC. The median follow-up time was 3.02 years. Three patients had disease progression during neoadjuvant therapy. pCR rates did not differ between the two regimens (48.7% TCHP vs. 51.7% THP-AC; p = 0.774). Patient’s baseline characteristics did not significantly affect the pCR rate, except for age. A multivariable logistic regression model adjusted for age and estrogen receptor (ER) status did not show a significant association between pCR and regimen (odds ratio 1.232, 95% CI 0.537–2.829 for THP-AC vs. TCHP, p = 0.623). The 2-year EFS rates for TCHP and THP-AC were 57% and 74%, respectively. In univariate analysis, patients who received THP-AC had better EFS than patients who received TCHP (hazard ratio [HR] 0.423, 95% CI 0.214–0.835, p = 0.013). The EFS benefit of THP-AC remained statistically significant after adjusting for age and type of adjuvant therapy in the final reduced multivariable Cox model (HR 0.441, 95% CI 0.220–0.882, p = 0.021). Univariate analysis did not show a significant association between EFS and other baseline covariates (body mass index, race, N and M category, nuclear grade, ER status, and HER2-targeted therapy). OS did not differ between the THP-AC and TCHP groups (HR 0.419, 95% CI 0.122–1.440, p = 0.167). Conclusions The present analysis revealed that a non–anthracycline-containing regimen in HER2-positive IBC patients had no significant difference in pCR rates but was associated with lower 2-year EFS when compared to an anthracycline-containing regimen. However, OS was similar. Limitations of the study include a small sample size, lack of temporal analysis, and retrospective design with its possible selection bias. Further investigation of the optimal neoadjuvant regimen for patients with HER2-positive IBC is warranted. Citation Format: Toshiaki Iwase, Sridhar Nithya, Megumi Kai, Jie Willey, Wenli Dong, Yu Shen, Savitri Krishnamurthy, Anthony Lucci, H. T. Carisa Le-Petross, Azadeh Nasrazadani, Sadia Saleem, Rachel Layman, Vicente Valero, Debu Tripathy, Wendy Woodward, Yee Chung Cheng, Faina Nakhlis, Jennifer Bellon, Filipa Lynce, Naoto Ueno. Neoadjuvant HER2-targeted regimens with or without anthracyclines for HER2-positive inflammatory breast cancer (IBC): a multicenter retrospective study [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 PO5-01-03.

Abstract PO3-20-06: TRUDI: A phase II study of neoadjuvant TRastuzumab derUxtecan and Durvalumab for stage III HER2-expressing Inflammatory breast cancer

Abstract Background: Despite being a rare presentation of breast cancer, inflammatory breast cancer (IBC) is responsible for up to 10% of all breast cancer-related deaths. Most IBCs express HER2, with up to 40% of all IBCs being HER2-positive and 40% being HER2-low. Additionally, IBC more often exhibits PD-L1 expression compared to non-IBC, suggesting a preeminent role for immune evasion in the development and progression of IBC. No systemic treatment approaches have been yet developed specifically for IBC, and standard treatments commonly lead to poor outcomes. Trastuzumab deruxtecan (T-DXd) is an anti-HER2 antibody-drug conjugate currently approved for patients with pretreated HER2-positive and HER2-low metastatic breast cancer. Early-phase data highlighted the safety and potential synergy of combining T-DXd with the immune checkpoint inhibitor durvalumab. The aim of TRUDI is to evaluate the clinical activity and safety of neoadjuvant T-DXd with durvalumab among patients with HER2-expressing IBC. Trial Design: TRUDI is an ongoing, open label, multicenter, two cohort investigator-initiated phase II neoadjuvant trial for patients with stage III HER2-expressing IBC. The trial was activated in May 2023, with enrollment ongoing. Eligible participants are women and men with previously untreated, stage III (T4d, any N) breast cancer, clinically determined to be IBC. Patients will be included in two cohorts, depending on the locally determined HER2 status (with any hormone receptor [HR] status): Cohort 1 (n=36) for patients with HER2-positive disease (HER2 IHC 3+ or 2+/ISH amplified); Cohort 2 (n=27) for patients with HER2-low disease (HER2 IHC 1+ or 2+/ISH not amplified). Patients will receive eight cycles of T-DXd (5.4 mg/kg IV every 21 days) combined with durvalumab (1125 mg IV every 21 days), followed by modified radical mastectomy and post-mastectomy radiation. Post-surgical systemic treatment will follow local standards. Tumor tissue will be collected at baseline, cycle 1 day 8, and at surgery; blood will be collected at baseline, cycle 4 day 1, cycle 7 day 1 and at surgery; stool will be collected at baseline, after 3-6 weeks of treatment and surgery. The primary endpoint is pathologic complete response (pCR; ypT0/Tis ypN0). Patients in each cohort will be enrolled based upon Simon two-stage designs: in Cohort 1, if ≥8/20 patients with HER2-positive IBC experience pCR then a total of 36 patients will be enrolled. In Cohort 2, if ≥1/18 patients with HER2-low IBC experience pCR then a total of 27 patients will be enrolled. Secondary endpoints include the residual cancer burden at surgery, event free survival, distant progression or distant disease-free survival, as well as safety of the regimen. Exploratory objectives will investigate biomarker analyses on tissue, blood, and microbiome to explore the association of HER2 expression, immune variables, and stool composition on the efficacy of T-DXd with durvalumab among patient with HER2-expressing IBC. To our knowledge, this is the first and only ongoing study testing the combination of an anti-HER2 antibody-drug conjugate with immunotherapy for the neoadjuvant treatment of patients with IBC. Clinical trial information: NCT05795101. Citation Format: Paolo Tarantino, Samuel Niman, Antonio Giordano, Faina Nakhlis, Jennifer Bellon, Wendy Woodward, Azadeh Nasrazadani, Sadia Saleem, Anthony Lucci, Michelle DeMeo, Naoto Ueno, Sara Tolaney, Vicente Valero, Meredith Regan, Rachel Layman, Filipa Lynce. TRUDI: A phase II study of neoadjuvant TRastuzumab derUxtecan and Durvalumab for stage III HER2-expressing Inflammatory breast cancer [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 PO3-20-06.

Clinical outcomes of de novo metastatic HER2-positive inflammatory breast cancer

Inflammatory breast cancer (IBC) is a rare, aggressive form of breast cancer that presents as de novo metastatic disease in 20–30% of cases, with one-third of cases demonstrating HER2-positivity. There has been limited investigation into locoregional therapy utilization following HER2-directed systemic therapy for these patients, and their locoregional progression or recurrence (LRPR) and survival outcomes. Patients with de novo HER2-positive metastatic IBC (mIBC) were identified from an IRB-approved IBC registry at Dana-Farber Cancer Institute. Clinical, pathology, and treatment data were abstracted. Rates of LRPR, progression-free survival (PFS), overall survival (OS), and pathologic complete response (pCR) were determined. Seventy-eight patients diagnosed between 1998 and 2019 were identified. First-line systemic therapy comprised chemotherapy for most patients (97.4%) and HER2-directed therapy for all patients (trastuzumab [47.4%]; trastuzumab+pertuzumab [51.3%]; or trastuzumab emtansine [1.3%]). At a median follow-up of 2.7 years, the median PFS was 1.0 year, and the median OS was 4.6 years. The 1- and 2-year cumulative incidence of LRPR was 20.7% and 29.0%, respectively. Mastectomy was performed after systemic therapy in 41/78 patients (52.6%); 10 had a pCR (24.4%) and all were alive at last follow-up (1.3–8.9 years after surgery). Among 56 patients who were alive and LRPR-free at one year, 10 developed LRPR (surgery group = 1; no-surgery group = 9). In conclusion, patients with de novo HER2-positive mIBC who undergo surgery have favorable outcomes. More than half of patients received systemic and local therapy with good locoregional control and prolonged survival, suggesting a potential role for local therapy.

HER2/positive and HER2/low in inflammatory breast cancer recurrence.

This study aimed to investigate the impact of HER2-low on the risk of recurrence in individuals with inflammatory breast cancer (IBC). 60 females with HER2-low and HER2-positive IBC underwent surgery between July 2020 and July 2022. Patients were divided into three groups of 20 patients: (1) HRplus/HER2-, (2) HRplus/HERplus, and (3) HR-/HER2plus. All patients underwent chemotherapy in adjuvant mode, following this scheme: TCH=docetaxel and carboplatin plus Herceptin (HER2 target - 4 mg/kg as the loading dose and 6 mg/kg as subsequent doses throughout every 21 days, entire 52 weeks of Herceptin therapy). HRplus/HERplus group had an OS of 76.9% compared with 77.0% in the group with the HRplus/HER2plus subtype and 74.4% in the HR-/HER2plus group. Moreover, recurrence-free survival was 19.1% for the HRplus/HER2- group, 21.3% for the HRplus/HERplus group, and 11.7% for the HR-/HER2plus group. In our study, patients with HER2-low IBC could acquire a perfect response with preliminary systemic therapy, without disease progression or with stable disease on target alone. Further examination is important to decide on the most effective treatment regimens, in addition to mixing chemotherapy with HER2-low-focused on agents.

HER2-Positive Inflammatory Breast Cancer Challenges of Clinical Practices

HER2-positive inflammatory breast cancer (IBC) is associated with poor overall survival. Targeted therapies have led to improved outcomes. IBC is underrepresented in clinical trials due to its rareness. This case reports a 52-year-old woman diagnosed with IBC of 119x89mm, axillar node-positive, hormone receptor-negative, HER2 positive. The patient underwent neoadjuvant chemotherapy with dual HER2 blockage. Mastectomy histology showed pathological complete response. After two cycles of adjuvant trastuzumab, the patient developed asymptomatic cardiotoxicity leading to the therapeutic suspension. Early recurrence and persisting cardiac alterations prevented treatment with anti-HER2 therapy. At the time of brain recurrence, with cardio-oncology collaboration, it was possible to start TDM-1, with a reduction of 71% of brain lesions size, after two cycles. This case highlights the effectiveness of anti-HER therapy in IBC and the importance of multidisciplinary discussion in treatment choice and toxicity management.

Early on-treatment transcriptional profiling as a tool for improving pathological response prediction in HER2-positive inflammatory breast cancer.

Background:Inflammatory breast cancer (IBC) is a rare and understudied disease, with 40% of cases presenting with human epidermal growth factor receptor 2 (HER2)-positive subtype. The goals of this study were to (i) assess the pathologic complete response (pCR) rate of short-term neoadjuvant dual-HER2-blockade and paclitaxel, (ii) contrast baseline and on-treatment transcriptional profiles of IBC tumor biopsies associated with pCR, and (iii) identify biological pathways that may explain the effect of neoadjuvant therapy on tumor response.Patients and Methods:A single-arm phase II trial of neoadjuvant trastuzumab (H), pertuzumab (P), and paclitaxel for 16 weeks was completed among patients with newly diagnosed HER2-positive IBC. Fresh-frozen tumor biopsies were obtained pretreatment (D1) and 8 days later (D8), following a single dose of HP, prior to adding paclitaxel. We performed RNA-sequencing on D1 and D8 tumor biopsies, identified genes associated with pCR using differential gene expression analysis, identified pathways associated with pCR using gene set enrichment and gene expression deconvolution methods, and compared the pCR predictive value of principal components derived from gene expression profiles by calculating and area under the curve for D1 and D8 subsets.Results:Twenty-three participants were enrolled, of whom 21 completed surgery following neoadjuvant therapy. Paired longitudinal fresh-frozen tumor samples (D1 and D8) were obtained from all patients. Among the 21 patients who underwent surgery, the pCR and the 4-year disease-free survival were 48% (90% CI 0.29–0.67) and 90% (95% CI 66–97%), respectively. The transcriptional profile of D8 biopsies was found to be more predictive of pCR (AUC = 0.91, 95% CI: 0.7993–1) than the D1 biopsies (AUC = 0.79, 95% CI: 0.5905–0.9822).Conclusions:In patients with HER2-positive IBC treated with neoadjuvant HP and paclitaxel for 16 weeks, gene expression patterns of tumor biopsies measured 1 week after treatment initiation not only offered different biological information but importantly served as a better predictor of pCR than baseline transcriptional analysis.Trial Registration:ClinicalTrials.gov identifier: NCT01796197 (https://clinicaltrials.gov/ct2/show/NCT01796197); registered on February 21, 2013.

Abstract PS10-34: Clinical outcomes in de novo metastatic HER2-positive inflammatory breast cancer

Abstract Background: Advances in HER2-directed therapy have significantly improved survival in HER2+ metastatic breast cancer. Approximately 30% of de novo metastatic inflammatory breast cancer (mIBC) is HER2+, though there has been limited IBC representation in clinical trials evaluating the role of HER2-directed agents as first-line metastatic therapy. Elevated rates of locoregional progression or recurrence (LRPR) with systemic therapy alone also raise the question of whether trimodality therapy (TMT) may improve outcomes in IBC patients (pts) with limited metastatic disease, particularly in the setting of increasingly effective anti-HER2 therapy. Methods: Pts diagnosed with de novo HER2+ mIBC were identified from an IRB-approved IBC registry at Dana-Farber Cancer Institute. Clinical, pathology and treatment data were manually abstracted by chart review. Progression-free survival (PFS) was defined as time from IBC diagnosis to LRPR, distant progression/relapse or death (in the absence of event, censored at date of last follow-up). Overall survival (OS) was defined as time from IBC diagnosis to death from any cause or censored at date last known alive. For pts who underwent surgery of the primary tumor, pathologic complete response (pCR) was defined as no residual invasive carcinoma in the breast and axilla and survival was estimated from date of surgery. Median PFS and OS were estimated by Kaplan-Meier method; cumulative incidence of CNS metastasis and LRPR were estimated with death as competing risk. Results: 78 pts diagnosed between 1998-2019 with de novo HER2+ mIBC (41 hormone receptor (HR)-positive; 37 HR-negative) were identified. Median age at diagnosis was 53 years (yr; range: 24-91). Sites of metastatic disease at presentation included bone only (n=12), lymph node/contralateral chest wall only (n=17), bone and lymph node (n=5), visceral (n=40) and CNS with extracranial disease (n=4). As initial HER2-directed therapy, 37 pts received trastuzumab (H), 40 H plus pertuzumab and 1 T-DM1. At a median follow-up of 2.7 yr in the overall cohort, median PFS was 1.0 yr (IQR: 0.5-2.8 yr; 60 events) and median OS was 4.6 yr (IQR: 2.9-8.7 yr; 39 deaths). 34 pts had CNS metastasis with a cumulative incidence of 20% and 28% at 1 and 2 yr, respectively. LRPR developed in 26 pts, of which 16 occurred within 12 months (mo) of diagnosis. Cumulative incidence of LRPR at 1 and 2 yr was 21% and 29%, respectively. In 41 pts (53%), mastectomy was performed after receipt of systemic therapy. Median time from IBC diagnosis to surgery was 7.5 mo (IQR: 6.0-9.9 mo). Radiation was administered in 33 pts, 3 pre- and 30 post-mastectomy. Median OS from surgery was 5.2 yr (IQR: 3.1-8.4 yr). 9/41 pts (22%) achieved pCR; all pCR pts were alive at 1.3-8.9 yr since surgery. To investigate the value of therapy for locoregional control, a landmark analysis was performed in the subset of pts alive and LRPR free at 12 mo from diagnosis (n=56). 27 had surgery within 12 mo from diagnosis and 29 did not. LRPR occurred in 10/56; 9 were among pts who did not undergo surgery. Cumulative LRPR incidence at 1 and 2 yr since the 12 mo landmark was 21% and 29%, respectively, in pts who did not undergo surgery, and 0% at both time points in pts who had surgery (1 LRPR at 8 yr). Conclusion: Long-term outcomes in de novo HER2+ mIBC are overall similar to those reported in metastatic HER2+ non-IBC. More than half of pts underwent systemic and local therapy with good locoregional control and prolonged survival, suggesting a potential role for aggressive local therapy in this mIBC subset with favorable prognosis and effective systemic therapy. The high incidence of early CNS involvement in de novo HER2+ mIBC prompted us to explore this group in detail (Warren SABCS 2020 abstract). Larger studies are needed to better understand the effectiveness of TMT in HER2+ mIBC, highlighting the importance of collaborative research efforts in this rare subset. Citation Format: Ana C. Garrido-Castro, Samuel M. Niman, Marie Claire Remolano, Jennifer M. Rosenbluth, Caroline Block, Laura E. Warren, Jennifer Bellon, Beth T. Harrison, Faina Nakhlis, Meredith Regan, Beth Overmoyer. Clinical outcomes in de novo metastatic HER2-positive inflammatory breast cancer [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 PS10-34.

Lapatinib inhibits doxorubicin induced migration of HER2-positive breast cancer cells.

Inflammatory breast cancer (IBC) is an uncommon and highly aggressive form of breast cancer. The disease is characterized by rapid progression with approximately 50% of IBC patients to have human epidermal growth factor receptor 2 (HER2) amplification. HER2-positive IBC is associated with unfavourable prognosis and increased risk of brain metastasis. Ironically, HER2-positive metastatic breast cancer is still prevalent where therapeutic targeting of HER2-receptor is well developed. In addition, the ability to accurately predict the risk of metastatic potential in these cells poses a substantial challenge. Lapatinib (Lap), a dual kinase inhibitor of HER2 and epidermal growth factor receptor is used in the treatment of advanced HER-2 positive breast cancers and is currently being evaluated in the adjuvant setting. In this study, we report the effectiveness of Lap in the suppression of low-dose response to doxorubicin (Dox) in HER2-positive SKBR3 cells. Upon treatment of SKBR3 cells with 0.1µM of Dox, the cell viability was significantly increased as compared to the human mammary fibroblasts, and triple-negative human breast cancer MDA-MB-231 cells. Interestingly, the effect of 0.1µM Dox revealed morphological changes consistent with a significant increase in the formation of prominent F-actin filaments and mitochondrial spread compared with the control SKBR3 cells. Furthermore, an enhanced migration was also evident in these cells. However, a combinational dose of 0.1µM Dox + 5µM Lap suppressed the observed phenotypic changes in the 0.1µM Dox treated SKBR3 cells. There was a significant difference in the prominent F-actin filaments and the mitochondrial spread compared with the 0.1µM Dox versus combination regimen of 0.1µM Dox + 5µM Lap. In addition, the combinational therapy showed a decrease in the percentage of wound closure when compared to the control. Hence, the combinational therapy in which Lap suppresses the low-dose effect of Dox in SKBR3 cells may provide an effective intervention strategy for reducing the risk of metastasis in HER2-positive breast cancers.

Abstract P1-18-19: Phase II, open label, randomized, biomarker study of immune-mediated mechanism of action of neoadjuvant subcutaneous trastuzumab in patients with operable, locally advanced, or inflammatory HER2-positive breast cancer. ImmunHER trial on behalf of the Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC)

Abstract Background: Tumor-infiltrating lymphocytes (TILs) have been reported to be associated with increased therapeutic efficacy of trastuzumab/pertuzumab-based neoadjuvant therapy (NT) in patients (pts) with HER2-positive breast cancer (BC). Subcutaneous (SC) trastuzumab has non-inferior efficacy to intravenous (IV) administration, with a similar safety profile. Interestingly, SC trastuzumab has been observed to be more immunogenic than IV trastuzumab and act at different immunologic levels. Therefore, by modifying the modality of administration of trastuzumab, it could be possible to interfere with different immune pathways and exert a favorable immunomodulation in HER2-positive BC. Methods: In this non-comparative, phase II, neoadjuvant, randomized study, pts were eligible if they had previously untreated, histologically confirmed, locally advanced, inflammatory, or early-stage HER2-positive BC. Pts were treated with FEC (fluorouracil 500 mg/m2; epirubicin 75 mg/m2; cyclophosphamide 500 mg/m2) q21 × 3 cycles. Then, they were randomly assigned (1:1) to receive: docetaxel (75 mg/m2) plus pertuzumab (840 mg loading dose (LD), then 420 mg) plus IV trastuzumab (8 mg/kg LD, then 6 mg/kg) q21 × 4 cycles (arm A) or, docetaxel plus pertuzumab plus SC trastuzumab (fixed dose of 600 mg) q21 × 4 cycles (arm B). After surgery, pts received trastuzumab q21 × 14 cycles using the same formulation (SC or IV) of the preoperative phase. The primary endpoint was the rate of stromal TILs (sTILs) on residual disease after surgery. Tumor biopsy and posttreatment surgical samples were centrally analyzed for TILs. Blood samples were also collected during NT for tumor-specific lymphocyte cell activity analysis. Feasibility, efficacy and safety were also evaluated. ClinicalTrials.gov: NCT03144947. Results: Between November 2016 and September 2017, according to an adaptive Simon's two-stage optimal design, we enrolled 65 pts, of whom two were deemed ineligible for the study. Thus, 63 pts (31 in arm A and 32 in arm B) were assessed for the primary and secondary endpoints. The pathologic complete response (pCR; no invasive tumor in breast and axilla) rates were 64.5% (95% CI, 47-81) in arm A, and 59.4% (95% CI, 42-76) in arm B. The most common adverse events of grade 3 or higher were neutropenia (15 [48.4%] pts in arm A, and 11 [34.4%] in arm B), neurotoxicity (1 [3.2%], and 2 [6.2%], respectively), and diarrhea (1 [3.2%], and 1 [3.1%], respectively). There were no events of congestive heart failure. At surgery, 11 pts in arm A and 13 pts in arm B were evaluable for TIL analysis. The median value of sTILs (7.5%) on pre-treatment tumor biopsies was used as the cut-off value, and high sTIL levels were observed in 27.3% and in 46.1% of residual tumors after treatment arm A and B, respectively. There was a positive correlation between pretreatment sTILs and PD-L1 expression on stromal immune cells (Kendall’s τ =0.80). Interestingly, a significant inverse correlation was observed between PD-L1 expression on pretreatment sTILs and the T cell co-receptor CD3 expressed on posttreatment sTILs (Pearson’s ρ = -0.70). This finding was particularly evident in the arm B group (ρ = -0.85). Conclusions: NT with either SC or IV trastuzumab in combination with pertuzumab and chemotherapy had a significant effect on sTIL expression at surgery. In particular, the SC trastuzumab-based arm exerted the most relevant enrichment of sTILS in posttreatment residual tumors. These findings suggest a role for the SC administration of trastuzumab in determining favorable variations of host immune response parameters among pts with HER2-positive early BC who had residual disease after NT. Citation Format: Antonino Musolino, Stefania Gori, Elisabetta Cretella, Alessandra Marabese, Luigi Cavanna, Antonio Frassoldati, Giancarlo Bisagni, Chiara Casarini, Emilio Bria, Luisa Carbognin, Elena Fiorio, Alba A Brandes, Claudio Zamagni, Lorenzo Gianni, Alberto Zambelli, Filippo Montemurro, Michele Tognetto, Renata Todeschini, Giuseppe Maglietta, Gabriele Missale, Enrico M Silini. Phase II, open label, randomized, biomarker study of immune-mediated mechanism of action of neoadjuvant subcutaneous trastuzumab in patients with operable, locally advanced, or inflammatory HER2-positive breast cancer. ImmunHER trial on behalf of the Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-18-19.

120P - Early on-treatment vs pre-treatment tumour transcriptomes as predictors of response to neoadjuvant therapy for HER2-positive inflammatory breast cancer

BackgroundInflammatory breast cancer (IBC) is an understudied form of breast cancer (BC). The incidence of HER2-positive disease in IBC is 2-fold greater than that in non-IBC. Several studies evaluating dual-HER2 blockade in HER2-positive BC have demonstrated an association of specific gene expression signatures with response. Those analyses were based on pretreatment tumor characteristics and did not focus specifically on IBC. We used RNA-Seq to elucidate the impact of short term neoadjuvant dual-HER2 blockade on IBC transcriptomic profile and to identify early predictors of response. MethodsWe analyzed fresh frozen tumor samples prospectively obtained from 23 patients (pts) with HER2-positive IBC, treated at a single institution in a phase 2 trial (NCT01796197) with neoadjuvant trastuzumab, pertuzumab (HP) and paclitaxel for 16 weeks (wk). Breast biopsies were performed at baseline (D1) and 1 wk later (D8) after a single dose of dual blockade with HP before adding paclitaxel. Primary endpoint was pathologic complete response (pCR) defined as no evidence of invasive disease in breast or lymph nodes. Tumors from D1 and D8 were used for RNA-Seq analysis and assessment of tumor-infiltrating lymphocytes (TILs) and CelTIL score. ResultsPaired breast tumor biopsies (D1, D8) were obtained in all pts; 2 pts did not have surgery. In the intent-to-treat analysis, 10/23 (43%) pts achieved a pCR. Across all metrics, D8 biopsies were significantly better predictors of response than D1 (p-value: 1.0X10-15). Upregulation of immune signatures by RNA-Seq was observed at D1 and D8. D8 biopsies showed a greater upregulation of anti-tumor immunity and changes in multiple signalling pathways. Neither TILs nor CelTIL were associated with pCR. ConclusionsWe identified an accurate predictor of response based on transcriptomic profiling by RNAseq, following a single dose of neoadjuvant dual-HER2 blockade in HER2-positive IBC. It outperforms a similar predictor constructed on a pretreatment profile in the same cohort. Assessing early-changes in gene expression level by RNA-seq following one dose of treatment may provide insights for the molecular mechanisms underlying response or resistance to anti-HER2 therapy. Clinical trial identificationNCT01796197. Legal entity responsible for the studyDana-Farber Cancer Institute. FundingGenentech, Inc and the Inflammatory Breast Cancer (IBC) Network. DisclosureS. Pernas: Travel / Accommodation / Expenses: Roche; Advisory / Consultancy: Polyphor. S. Goel: Advisory / Consultancy, Research grant / Funding (institution): Eli Lilly; Advisory / Consultancy, Research grant / Funding (institution): Novartis; Advisory / Consultancy: G1 Therapeutics; Research grant / Funding (institution): Merck. J.L. Guerriero: Advisory / Consultancy, Research grant / Funding (institution): Glaxo-Smith Kline; Research grant / Funding (self): Eli Lilly. E.A. Mittendorf: Advisory / Consultancy: Amgen; Advisory / Consultancy, Research grant / Funding (institution): AstraZeneca; Advisory / Consultancy, Research grant / Funding (institution): Genentech; Advisory / Consultancy: Genomic Health; Advisory / Consultancy: Merck; Advisory / Consultancy: Peregrine Pharmaceuticals; Advisory / Consultancy, Research grant / Funding (institution): Sellas Lifesciences; Advisory / Consultancy: Tapimmune. B. Overmoyer: Research grant / Funding (institution): Genentech; Research grant / Funding (institution): Incyte; Research grant / Funding (institution): Eisai. All other authors have declared no conflicts of interest.

Phase II trial of nivolumab with chemotherapy as neoadjuvant treatment in inflammatory breast cancer.

TPS604 Background: Inflammatory breast cancer (IBC) is the most aggressive form of breast cancer with poor prognosis and is often resistant to neoadjuvant chemotherapy with risk of early recurrence and systemic spread of disease. PD-L1 expression in IBC is frequent (Bertucci et al. Oncotarget 2015), and blockade of the PD-1/PD-L1 axis with checkpoint inhibitors has emerged as a promising treatment to enhance anti-tumor immunity and clinical response. We hypothesize that PD-1 blockade with nivolumab in combination with neoadjuvant (primary) chemotherapy will increase the rate of pathologic complete response (pCR) and reduce risk of recurrence in patients with IBC. Methods: This is a single-arm open-label multicenter phase II study of nivolumab with neoadjuvant chemotherapy in patients with non-metastatic IBC (n = 52) (ClinicalTrials.gov: NCT03742986). All breast cancer subtypes (based on ER/PR/HER2) will be allowed. Patients will receive nivolumab 360 mg IV on day 1 (21-day cycle) for four cycles in addition to standard chemotherapy. Cohort 1 (patients with triple negative breast cancer or hormone receptor-positive (HR)/HER2-negative IBC) will receive nivolumab in combination with paclitaxel followed by doxorubicin and cyclophosphamide (AC). Cohort 2 (patients with HER2-positive IBC) will receive nivolumab in combination with a taxane (docetaxel or paclitaxel), trastuzumab, and pertuzumab followed by AC. All patients will then undergo mastectomy followed by radiation. The primary study objective is pCR rate (ypT0/Tis ypN0). Secondary objectives will be safety, tolerability and invasive recurrence-free interval. Association of correlative biomarkers with pCR and sensitivity or resistance to therapy with the combination of nivolumab and chemotherapy will be evaluated. Analyses will include mutational and neoantigen load, tumor-infiltrating lymphocytes (TILs) by histopathological assessment, T-cell receptor (TCR) by immunosequencing, and immune gene profiles in the tumor. PD-L1 expression in tumor tissue is not required for enrollment but will be assessed as a predictive marker. Clinical trial information: NCT03742986.

Abstract P6-15-11: Weekly paclitaxel, pertuzumab and trastuzumab (TPH) neoadjuvant therapy for HER2 positive inflammatory breast cancer

Abstract Background: Inflammatory breast cancer (IBC) is inoperable at presentation, thus neoadjuvant systemic therapy (NAS) is the primary treatment for this aggressive disease. Due to its rarity, patients (pts) with IBC are incorporated into NAS clinical trials for locally advanced breast cancer, making it difficult to extrapolate efficacy specifically for pts with IBC. A commonly used regimen for the treatment of HER2+ IBC includes docetaxel, carboplatin, pertuzumab (P) and trastuzumab (H), yet only 6% of pts enrolled in the clinical trial for this regimen had IBC. We sought to examine the efficacy of maximizing anti-HER2 therapy combined with minimal chemotherapy using the THP regimen specifically for pts with HER2+ IBC. Methods: Pts with newly diagnosed HER2+ IBC received NAS with 16 weeks (wks) of paclitaxel (T) 80mg/m2/wk, H (2mg/kg/wk) and P(420mg/kg/3wk) followed by modified radical mastectomy (MRM) on a phase II prospective study. All pts had 2 research breast biopsies (rbx) for correlative assays prior to and 1 wk after the P (840mg/kg) and H (4 mg/kg) loading dose. Pts who achieved a pCR (pathologic complete response) could opt out of adjuvant doxorubicin (A) 60 mg/m2 + cyclophosphamide (C) 600mg/m2 x 4; pts with residual disease received AC. All pts received post-mastectomy radiation and maintenance P (420mg) + H (6mg/kg) every 3 wks x 12. Adjuvant endocrine therapy was given per standard of care. Primary objective was pCR rate in the breast and axillary lymph nodes. Residual Cancer Burden (RCB) was assessed. Based upon a Simon two-stage design, this regimen would be declared worthy of further study if >7/27 pCR were observed (15% vs 40%; target α=0.039 power=0.90). The study was closed after 23/27 pts were enrolled due to slow accrual. Results: 20 pts were enrolled as of 12/2016, 18 completed NAS and MRM. All but 1 had stage III disease at presentation. 1 pt was lost to follow-up; 1 developed CNS metastasis during NAS and did not undergo MRM. The mean age was 49 years, 10 pts had ER/PR negative disease. 15 pts completed 16 wks of T, 4 had 15 wks and 1 had 13 wks. During NAS, there was no grade (gd) 4 toxicity; 6 episodes of gd 3 toxicity (2 related to treatment-diarrhea); and no gd 3 cardiac events. In the intent to treat analysis, 10/20 pts achieved pCR (50%; 90% CI 30-70%) and 6 had RCB-1 (30%). 5 pts with RCB-1 response had <5 mm residual disease; 1 had lymph node involvement. Of those proceeding to MRM, pCR rate was 56% (10/18). 6/10 opted out of AC. Treatment and follow-up for clinical outcomes continue. Biologic correlatives investigating genomic profiling and patterns of HER2 resistance are being performed on rbx, residual disease and cfDNA. Conclusion: THP x 16wks is tolerable and effective NAS for HER2+ IBC, resulting in a high pCR rate with minimal toxicity. This study of NAS explored the benefit of maximizing HER2-directed therapy and minimizing chemotherapy and its associated toxicity. It has achieved its primary endpoint and will be used as the backbone NAS for HER2+ IBC, with future studies building upon this regimen. The result of this trial supports the benefit of clinical trials designed specifically for pts with IBC. Clinical trial information: NCT01796197. Citation Format: Overmoyer B, Regan M, Hu J, Nakhlis F, Dominici L, Lin NU, Freedman R, Morganstern DE, Partridge AH, Schlosnagle EJ, Hirshfield-Bartek J, Bellon J, Morikawa A, Harrison BT, Winer E. Weekly paclitaxel, pertuzumab and trastuzumab (TPH) neoadjuvant therapy for HER2 positive inflammatory breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-15-11.

MMP2 and MMP9 serum levels are associated with favorable outcome in patients with inflammatory breast cancer treated with bevacizumab-based neoadjuvant chemotherapy in the BEVERLY-2 study

PurposeAddition of bevacizumab to trastuzumab-based neoadjuvant chemotherapy in HER2-positive inflammatory breast cancer (IBC) was associated with favorable outcome in the BEVERLY-2 phase II trial. Circulating levels of matrix metalloproteinases (MMP) 2 and 9 were correlated to high response rate and prolonged survival in high-grade glioma treated with bevacizumab. We examined the prognostic impact of MMP2 and MMP9 serum levels in BEVERLY-2 patients.Experimental designMMP2 and MMP9 serum levels were assessed using ELISA at baseline and before surgery in 45/52 available samples. Correlations were tested with pathological complete response (pCR), disease-free survival (DFS) and overall survival (OS).ResultsBaseline (b) MMP2 and MMP9 serum levels were independent from patient characteristics and circulating tumor or endothelial cells, and were not correlated to pCR. High bMMP2 was correlated to better DFS (p=0.001) and OS (p=0.032), while low bMMP9 was correlated to better OS (p=0.022) and tended to be associated with longer DFS (p=0.071). In multivariate analyses, bMMP2 (p=0.003, Hazard Ratio [HR]: 0.115) and bMMP9 (p=0.041, HR: 3.511) remained correlated to DFS. As continuous variables, bMMP2 was associated with relapse (p=0.002) and death (p=0.049), while bMMP9 was associated with death (p=0.035). During treatment, significant increase in MMP2 and decrease in MMP9 levels (p<0.001 for both) were observed in 100% and 87% of patients respectively.ConclusionsHigh bMMP2 and low bMMP9 serum levels were associated with better survival in HER2-positive IBC patients treated with bevacizumab- and trastuzumab-based neoadjuvant chemotherapy. Their predictive value of bevacizumab benefit should be evaluated in a randomized trial.

Abstract P2-11-05: Overall survival in inflammatory breast cancer patients receiving Her-2 Neu directed tumor vaccine therapy: Matched comparison with SEER registry patients

Abstract Background Patients with inflammatory breast cancer (IBC) have a poor prognosis, primarily due to distant dissemination. Additionally, IBC patients have an increased rate of HER2 overexpression when compared to patients with non-inflammatory breast cancer. The forms the rationale for HER2 directed tumor vaccine therapy in these patients. The purpose of this study was to examine overall survival in IBC patients receiving HER2 directed tumor vaccine therapy when compared with matched control patients from the SEER Registry. Methods Patients with diagnosis of Stage III or IV HER2 positive IBC having completed standard initial therapy and without evidence of disease received HER2 vaccinations after being enrolled on 5 prospective clinical trials. Overall survival data were pooled and analyzed. A control group of matched IBC patients were identified by querying the SEER database from 1997-2011. The control group was identified as any individual in the database with a code for IBC. A secondary analysis comparing survival in HER2 positive IBC vs HER2 negative IBC patients was performed by querying the SEER database from 2010 onwards, the time point when the HER2 status was coded in the database. Propensity score adjustment were made to the control group to account for any imbalances between groups in measured covariates such as stage, race, age, sex, and era of enrollment and the time interval from diagnosis to enrollment on vaccine trial (median ∼2 years). Results A total of 37 IBC patients received HER2 directed vaccine therapy and 676 patients were identified for the SEER control group; Stage at enrollment: stage IIIB: 30 patients in the vaccine group and 639 patients in the control group; stage IIIC: 1 patient in the vaccine group and 15 patients in the control group; stage IV 6 patients in the vaccine group and 22 in the control group. The median survival of the overall population was 112 months for the vaccine group and 47 months for the control group (p=0.04). After using propensity scores to adjust the control for imbalances in measured covariates, the median survival for the overall population was 112 months for the vaccine group and 37 months for the control group (p=0.03). There was no difference in survival between HER2 positive and HER2 negative IBC patients in the control group (p=0.6). Conclusion These results demonstrate promising overall survival in HER2 positive IBC patients receiving HER2 directed vaccine therapy after initial therapy. Propensity matching was performed to adjust for imbalances in measured covariates and resulted in a modest decrease in survival of the control group after adjustment, suggesting that the vaccine trial group had relatively unfavorable pre-treatment characteristics. Despite these unfavorable characteristics, patients receiving vaccine had a median survival of 112 months. These results must be further confirmed in a prospective randomized trial. Citation Format: Rengan R, Baker K, Salazar L, Childs J, Higgins D, Redman M, Reichow J, Disis ML. Overall survival in inflammatory breast cancer patients receiving Her-2 Neu directed tumor vaccine therapy: Matched comparison with SEER registry patients. [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 P2-11-05.

Effect of high MMP2 and low MMP9 baseline serum levels on outcome in patients with HER2-positive inflammatory breast cancer (IBC) treated with bevacizumab (BEV)- and trastuzumab (TRA)-based neoadjuvant chemotherapy (NAC) in the BEVERLY 2 study.

600 Background: Addition of BEV to TRA-based NAC in HER2-positive IBC has been associated with high pathological complete response (pCR) rate and favorable outcome in the BEVERLY 2 phase II trial (...

Traitements systémiques des cancers du sein inflammatoires : un état des lieux

The poor prognosis of inflammatory breast cancer (IBC) is due to its strong metastatic potential. During the last three decades, the introduction of neoadjuvant chemotherapy (CT), and its improvement with successive additions of anthracyclines and then taxanes, allowed to double the survival. However, the 5-year survival still remains lower than 50%, with the pathological complete response (pCR) to neoadjuvant CT being a major prognostic factor. Since 1995, several innovative approaches have been evaluated. Initially, the trials of high-dose CT with hematopoietic stem cell transplantation have generated promising results, but ultimately failed to change standards of treatment, in particular because of its toxicity. More recently, a few targeted therapies, combined to conventional CT, have been assessed, due to the frequent overexpression of HER2 and EGFR and the important vascularization of IBC. Trastuzumab, a monoclonal antibody targeting HER2, has shown a clear advantage in terms of pCR and survival in studies dedicated to, HER2-positive locally advanced breast cancers, including IBC. Lapatinib, a dual tyrosine kinase inhibitor anti-HER2 and EGFR, has shown significant activity in two phase II studies dedicated to HER2-positive IBC. The interest of HER2-double blockade by the combination of trastuzumab-pertuzumab combined to docetaxel has been demonstrated in term of pCR in the NEOSPHERE study which also included HER2-positive IBC. Among the anti-angiogenic drugs tested in studies dedicated to IBC, bevacizumab has given the most interesting results in term of efficacy/toxicity ratio. In the Beverly 2 study HER2-positive IBC patients were treated by the combination chemotherapy, trastuzumab and bevacizumab: the rate of pCR was 64%, and the 3-year disease-free and overall survivals were 68% and 90%, respectively; the increase of endothelial cells circulating was inversely correlated to the probability of pCR. All those treatments have been extrapolated from standard breast cancers. Thus, a deep molecular knowledge of IBC appears to be critical in order to develop specific treatments effectively targeting its particular aggressiveness.

333P - Circulating Tumor Cell Count at Baseline is an Independent Prognostic Factor from Pathological Complete Response Among Patients Treated for Primary Inflammatory Her2-Positive Breast Cancer: Survival Results of the Beverly-2 Study

ABSTRACT Aim: The BEVERLY-2 single-arm phase 2 trial assessed the efficacy and safety of combining neoadjuvant chemotherapy with bevacizumab and trastuzumab for the treatment of HER2-positive inflammatory breast cancer (Pierga JY et al, Lancet Oncol 2012). We report the results of the association between outcome, circulating biomarkers and pathological complete response (pCR) at three years of follow-up. Methods: Circulating tumor (CTC) and endothelial cell (CEC) counts were assessed at baseline, cycle 5, pre-operative, post-operative and at one year by the CellSearch technique. Results: 52 patients were included. 3-year DFS in patients with ≥1 CTC/7.5 mL at baseline was significantly lower (43% [95% CI: 20; 64]) than for patients with no CTC detected at baseline (81% [95% CI: 62; 91]; hazard ratio 3.69 [1.34; 10.21]; p = 0.012). Due to the low number of CTC-positive patients at all other time points, there was no significant association between CTC and DFS other than that observed at baseline. Detection of CTC at any point during the trial period was associated with a significant reduction in DFS; patients with at least one positive CTC sample had a DFS of 54% (95% CI: 32; 71), compared with a DFS of 83% (95% CI: 61; 93) in patients where no CTC were detected at any time (hazard ratio 3.62 [95% CI: 1.15; 11.39]; p = 0.018). In a multivariate analysis including factors that were associated with DFS in univariate analysis (pCR, SBR grade and baseline CTC status), only SBR grade and baseline CTC status were found to be independent prognostic factors. No impact of CEC count on DFS was observed at univariate analysis. Patients with baseline CTC Conclusions: Combination of pCR and CTC positivity defines specific patient subgroups at very low (no CTC detected at baseline and pCR) and high (CTC detected at baseline and no pCR) risk of early relapse. These parameters could be used to build specific clinical trial with new targeted treatments for patients with inflammatory breast cancer. Disclosure: J. Pierga: honoraria and research funds from Roche and Janssen diagnotics; M. Coudert: Roche employee; J. Hernandez: Roche employee; P. Viens: Roche research funding. All other authors have declared no conflicts of interest.

Abstract P6-12-06: Three-year follow up results of a phase II study of neoadjuvant bevacizumab, chemotherapy, and trastuzumab in HER2-positive inflammatory breast cancer: BEVERLY2 study

Abstract Background: Bevacizumab (Bev) and trastuzumab (H) are proven treatments of advanced or HER2-positive metastatic breast cancer; however, few data exist for these drugs in inflammatory breast cancer (IBC). The aim of our study was to assess efficacy and safety of neoadjuvant Bev combined with H and chemotherapy (CT) in patients (pts) with primary HER2 positive IBC. The primary endpoint of the study, pathological complete response (pCR) rate by central review according to Sataloff classification, has been previously reported (pCR = 63.5%) together with circulating tumor cells (CTC) and circulating endothelial cells (CEC) detection rates and changes during treatment (Pierga et al, Lancet Oncol 2012). In the present abstract we are reporting the 3 year follow up analysis results. Methods: In this phase 2, multicentre, open-label, single-arm, non-comparative trial, we enrolled women with histologically confirmed HER2-positive non-metastatic IBC. The primary endpoint was to determine the rate of pCR; secondary endpoints included disease-free survival (DFS), overall survival (OS), safety (CTCAE v3) and potential predictive markers. Pts received 4 cycles of FEC100 + BEV 15 mg/kg, d1 q21d, followed by 4 cycles of docetaxel 100 mg/m2 + BEV 15 mg/kg + H 8→6 mg/kg q21d. Pts underwent surgery 4–6 weeks after the last dose, followed by radiotherapy (RT). H was continued during surgery and RT and as adjuvant therapy. BEV was re-introduced as adjuvant therapy for 10 cycles, giving a total of 18 cycles each of BEV and H. CTC and CEC were detected by the CellSearch system. Results: We enrolled 52 pts in 21 centers; 42 (81%) of 52 pts received all eight cycles of neoadjuvant therapy, 49 pts (94%) underwent surgery; 48 pts (92%) received adjuvant treatment and 44 pts (85%) were followed during 3 years (there were 8 withdrawals from study treatment period). Grade ≥3 adverse events (AEs) in &amp;gt;5% of pts were: neutropenia (44% of pts); febrile neutropenia (29%); alopecia and leukopenia (10%), hand-foot syndrome and febrile bone marrow aplasia (8%), increased γ-glutamyltransferase (8%), anemia, hypertension and mucositis (each 6%). There were 9 pts with grade ≥3 AE of special interest for BEV: hypertension in 3 pt; proteinuria in 2 pts; postoperative wound complication, infected lymphocele, incision site abscess and impaired healing in 1 pt each and cardiac failure in 1 pt. Ten pts developed a cardiac failure (Grade ≥1), which was mostly Grade 2 and resolved in all cases. There was no treatment-related death. Median follow-up was 36 months. 3-year DFS rate was 67.8% [52.8- 79.0] and OS rate was 89.8% [77.2- 95.6]. pCR was significantly associated with DFS: 3 year DFS rate was 78% [95% CI:58- 89] in pts with pCR vs 53% [95% CI:29- 72] in pts without pCR (p = 0.0445). CTC positivity (≥1CTC/7.5ml) at baseline (35% of pts) was also strongly associated with lower DFS rate (3 year DFS: 43% [95% IC: 20- 64] vs 81% [95% IC: 62- 91], p&amp;lt;0.01). Conclusion: Neoadjuvant BEV, H, and CT is highly active in IBC (3-y DFS 67.8%) with an acceptable safety profile. CTC positivity (≥1CTC/7.5ml) at baseline and pCR at the end of neoadjuvant treatment are two prognostic factors for DFS in non-metastatic IBC. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-06.

Abstract OT1-1-07: Phase II trial of paclitaxel combined with trastuzumab and pertuzumab as preoperative therapy for HER2 positive inflammatory breast cancer

Abstract Background: Inflammatory breast cancer (IBC) is a rare and virulent disease, accounting for 2-5% of breast cancer (BC) in the United States. The molecular analysis of IBC reveals a propensity to segregate into more proliferative intrinsic subtypes, such as HER2 positive (+) (Van Laere, et al, Br Ca Res Treat 2006). Studies demonstrate a 40-50% incidence of HER2+ disease among IBC, which is &amp;gt;2x the incidence in non-IBC (Turpin E, et al, Br Ca Res Treat 2002). The prevalence of HER2+ IBC and the availability of agents targeting the HER2 domain support investigation into the optimal preoperative regimen incorporating HER2 targeting agents. This preoperative trial evaluates combination pertuzumab (P) paclitaxel (T) and trastuzumab (H) in patients (pts) with newly diagnosed HER2+ IBC. Methods: Pts with HER2+ Stage III (cT4d, any N, M0) IBC (male or female) are eligible if they have not received prior therapy for BC, have adequate organ function, ECOG PS ≤ 1, cardiac ejection fraction ≥ 50%, and willing to undergo 2 research biopsies (bx) of the affected breast for correlative assays. Staging studies, research bx and whole blood sample are obtained at baseline. Pts receive a loading dose of P 840mg and H 4mg/kg IV (day (d) 1, week (wk) 1). On d8, wk2, a 2nd breast bx and whole blood sample are obtained and wkly H 2mg/kg with T 80mg/m2 IV are administered for a total of 16 wks. P 420mg is given concurrently every 21d for 5 doses beginning on d21, wk3. Following adequate tumor response, pts proceed to modified radical mastectomy followed by doxorubicin (A) 60mg/m2 with cyclophosphamide(C) 600mg/m2 every 21d for 4 cycles. Following AC, the chest wall and regional lymph nodes are treated with radiation concurrently with a loading dose of P 840mg and H 8mg/kg followed by P 420mg and H 6mg/kg every 21d for 12 doses. Adjuvant endocrine therapy is given with P and H if estrogen and/or progesterone receptor positive. Correlatives: To investigate whether the pre-treatment status of the tumor predicts HER2-resistance, next-generation sequencing technology will be employed to explore gene expression patterns including PAM50-based intrinsic subtyping. Both de novo and acquired mechanisms of resistance to HER2 therapy will be explored including analysis of residual disease obtained at mastectomy. Exploration of early adaptive molecular changes seen in d8, wk2 tumor samples will provide information useful in developing improved therapeutic strategies. Statistics: The primary endpoint is pathologic complete response (pCR) following therapy with PTH. A Simon minimax two-stage design is being used. If the proportion of pts having pCR is ≤ 0.15 then PTH is considered minimally effective, versus alternative hypothesis that PTH is worthy of further study if proportion pCR ≥ 0.40. In the 1st stage, if ≤ 2/16 pts have pCR, the study is stopped; if ≥ 3 pts have pCR, the study proceeds. In the 2nd stage, PTH is rejected if ≤ 7 of 27 pts have a pCR (α = 0.039; β = 0.05). Up to 30 pts will be enrolled. Secondary objectives are disease-free survival, time to tumor failure and overall survival. Time-to-event distributions are summarized using Kaplan-Meier and 2-sided 90% CI for the medians. Clinical trial information: NCT01796197. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT1-1-07.

Abstract P6-12-08: Serum biomarkers identification using quantitative proteomics in patients with HER2-positive inflammatory breast cancer receiving trastuzumab plus bevacizumab-based chemotherapy (BEVERLY 2 trial)

Abstract Background Inflammatory breast cancer (IBC) is a rare but aggressive form of locally advanced breast cancer, the optimal systemic treatment of which is still discussed. Beverly 2 trial was a phase II study evaluating the efficacy and safety of a preoperative regimen associating bevacizumab, trastuzumab, and chemotherapy in 52 patients with non-metastatic HER2-positive IBC, reporting a promising rate of pathological complete response (pCR, 63.5%, 95% CI 49.4–77.5; Pierga et al, Lancet Oncol, 2012). During the study, serum samples were collected at baseline and subjected to proteomic-based approaches to identify circulating biomarkers predictive of treatment response. Methods Baseline serum samples from responsive (pCR, according to Sataloff classification, n = 12) and non-responsive (no pCR, n = 11) patients were subjected to isobaric Tag for Relative and Absolute Quantification (iTRAQ)-based proteomics. Samples were pooled according to pCR and hormone receptor (HR) status, to constitute 4 independent mixes (pCR/HR-positive, pCR/HR-negative, nopCR/HR-positive, nopCR/HR-negative). Each of them underwent immuno-depletion of highly abundant proteins, concentration, reduction, alkylation and tryptic digestion. Then, each mix was fractionated and subjected to iTRAQ identification and quantitation using nano-liquid chromatography (LC) and electrospray ionisation (ESI)-orbitrap tandem mass spectrometry (MS/MS) (LTQ-orbitrap, Thermofisher). Differentially expressed proteins were analysed using IPA (IngenuitySystems) to highlight biological functions and signalling pathways that were most significantly enriched. Results iTRAQ-based measurements identified and quantified a total of 302 serum proteins. Among them, 48 proteins displayed a significant (fold-change &amp;gt; 1.5 and p-value &amp;lt; 0.05) differential expression between pCR and noPCR pts (18 proteins down-regultated and 30 proteins up-regulated in pCR patients), some of them previously described to be involved in breast cancer biology and/or angiogenesis, including : Alpha-1-acid glycoprotein 1, von Willebrand factor, Galectin-3-binding protein, serum amyloid A-1, Apolipoprotein E, Pigment epithelium-derived factor, Corticosteroid-binding globulin (down-regulated proteins in pCR patients); serum amyloid P-component, angiotensinogen, plasma serine protease inhibitor, carbonic anhydrase 1, mannose-binding protein C, hyaluronan-binding protein 2, peroxiredoxin-2, properdin, ADAMTS13, tetranectin, biotinidase, lumican (up-regulated proteins in pCR patients). Proteins with differential expression during treatment were involved in various biological processes, including cell-to-cell signaling and interaction, lipid metabolism, small molecule biochemistry, molecular transport, cellular function and maintenance as well as various canonical pathways such as acute phase response signalling, LXR/RXR activation and coagulation system. Conclusion iTRAQ-based quantitative proteomics identify serum proteins that could predict the therapeutic response to pre-operative trastuzumab plus bevacizumab-based chemotherapy in HER2-positive IBC. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-08.