Trastuzumab Combination Therapy Research Articles

Impact of oxaliplatin and trastuzumab combination therapy on tumor markers and T lymphocyte subsets for advanced gastric cancer.

Advanced gastric cancer (AGC) remains a challenging malignancy with poor prognosis. The combination of oxaliplatin and trastuzumab has shown promising results in AGC treatment. This study aimed to investigate the effects of oxaliplatin and trastuzumab combination therapy on serum tumor markers and T lymphocyte subsets in patients with AGC and to explore their potential as predictive biomarkers for treatment response. To investigate the impact of oxaliplatin and trastuzumab combination therapy on serum markers and T cell subsets in patients with AGC. This prospective study enrolled 60 patients with AGC. All patients received oxaliplatin (130 mg/m2, every 3 weeks) and trastuzumab (8 mg/kg loading dose, followed by 6 mg/kg every 3 weeks) for six cycles. Serum carcinoembryonic antigen (CEA), cancer antigen 19-9 (CA19-9), and cancer antigen 72-4 (CA72-4) were measured before and after treatment. T-lymphocyte subsets, including CD3+, CD4+, CD8+, and CD4+ /CD8+ ratios, were also evaluated. The clinical response was assessed using the Response Evaluation Criteria in Solid Tumors version 1.1. After six cycles of treatment, the CEA, CA19-9, and CA72-4 serum levels significantly decreased compared to baseline levels (P < 0.001). The percentages of CD3+ and CD4+ T lymphocytes increased significantly (P < 0.05), whereas the percentage of CD8+ T lymphocytes decreased (P < 0.05). The CD4+/CD8+ ratio also significantly increased after treatment (P < 0.05). Patients with a higher decrease in serum tumor markers (≥ 50% reduction) and a higher increase in CD4+/CD8+ ratio (≥ 1.5-fold) showed better clinical response rates (P < 0.05). Oxaliplatin and trastuzumab combination therapy effectively reduced serum tumor marker levels and modulated T lymphocyte subsets in patients with AGC. Combination therapy not only has a direct antitumor effect, but also enhances the immune response in patients with AGC. Serum tumor markers and T lymphocyte subsets may serve as potential predictive biomarkers for treatment response in patients with AGC receiving combination therapy.

Targeting ITGβ3 to Overcome Trastuzumab Resistance through Epithelial-Mesenchymal Transition Regulation in HER2-Positive Breast Cancer.

HER2-positive breast cancer, representing 15-20% of all breast cancer cases, often develops resistance to the HER2-targeted therapy trastuzumab. Unfortunately, effective treatments for advanced HER2-positive breast cancer remain scarce. This study aims to investigate the roles of ITGβ3, and Hedgehog signaling in trastuzumab resistance and explore the potential of combining trastuzumab with cilengitide as a therapeutic strategy. Quantitative gene expression analysis was performed to assess the transcription of EMT (epithelial-mesenchymal transition) markers Slug, Snail, Twist2, and Zeb1 in trastuzumab-resistant HER2-positive breast cancer cells. The effects of ITGβ3 and Hedgehog signaling were investigated. Additionally, the combination therapy of trastuzumab and cilengitide was evaluated. Acquired trastuzumab resistance induced the transcription of Slug, Snail, Twist2, and Zeb1, indicating increased EMT. This increased EMT was mediated by ITGB3 and Hedgehog signaling. ITGβ3 regulated both the Hedgehog pathway and EMT, with the latter being independent of the Hedgehog pathway. The combination of trastuzumab and cilengitide showed a synergistic effect, reducing both EMT and Hedgehog pathway activity. Targeting ITGβ3 with cilengitide, combined with trastuzumab, effectively suppresses the Hedgehog pathway and EMT, offering a potential strategy to overcome trastuzumab resistance and improve outcomes for HER2-positive breast cancer patients.

Preclinical and early clinical data of ZN-1041, a best-in-class BBB penetrable HER2 inhibitor to treat breast cancer with CNS metastases.

1040 Background: HER2+ breast cancer brain metastases (BCBM) is an aggressive malignancy with high prevalence and limited treatment options. ZN-1041 is a best-in-class HER2 inhibitor designed to be delivered across the blood-brain barrier (BBB) with high selectivity and broader safety margin to treat HER2+ BCBM. Methods: Brain penetration of ZN-1041 and other approved HER2 tyrosine kinase inhibitors (TKI) were evaluated. Anti-tumor activity of ZN-1041 alone or in combination were evaluated in xenograft models. ZN-A-1041-101 (NCT04487236) is an on-going phase 1, multicenter, open-label study. The study comprises first-in-human dose escalation of ZN-1041 monotherapy (phase 1a) in HER2+ solid tumor patients (pts) with or without BM, dose escalation (phase 1b) and expansion (phase 1c) of ZN-1041 in combination with capecitabine and trastuzumab in pts with HER2+ BCBM (including active BM). The primary objective was safety and tolerability. The secondary objective includes pharmacokinetics and anti-tumor response including ORR per RECIST 1.1 and intracranial ORR (iORR) per RANO-BM. Results: Unlike currently approved HER2 TKIs which are strong human efflux transporter P-gp and BCRP substrates, ZN-1041 is not a substrate of either and has high BBB permeability, therefore predicted to have good BBB penetration. ZN-1041 alone demonstrated dose-dependent and significant anti-tumor activity when compared to tucatinib in BM model. ZN-1041 could synergize with capecitabine and trastuzumab to demonstrate significantly improved intracranial efficacy in BM models, while maintaining good tolerability. In total, 21 HER2+ mBC pts were enrolled to complete phase 1a and 1b. No dose-limiting toxicities or treatment-related SAE were observed across all dose levels. PK exposure was increased with dose escalation and Kpuu,CSF of ZN-1041 was 4.9. In ZN-1041 monotherapy, the overall ORR and iORR were 50% in TKI naïve, unequivocal HER2+ pts. The longest treatment duration was 15 months. As of data cutoff (Dec 02, 2022), totally 35 TKI naïve, HER2+ BCBM pts with median 2L treatments were enrolled for phase 1c and all pts were well tolerated to date. Adverse reactions of grade 3 or higher (≥5%) were hepatic function impairment (8.7%), headache (8.7%), hyperbilirubinemia (5.7%), ALT increased (5.7%), AST increased (5.7%), GGT increased (5.7%) and WBC decreased (5.7%). Among 19 BCBM pts with at least twice tumor assessment, the overall ORR was 78.9% (95% CI: 54.4–93.9) and iORR was 73.7% (95% CI: 48.8–90.9), DCR was 100%. In addition, 6 pts completed first tumor assessment and 5 achieved PR and 1 had SD per RECISIT 1.1. Conclusions: Encouraging efficacy and tolerability was observed for ZN-1041 monotherapy or combined with capecitabine and trastuzumab in TKI naïve, HER2+ BCBM patients. A Phase 2 pivotal trial for HER2+ BCBM with ZN-1041, capecitabine and trastuzumab combination therapy is planned. Clinical trial information: NCT04487236 .

Quantification of the growth suppression of HER2+ breast cancer colonies under the effect of trastuzumab and PD-1/PD-L1 inhibitor.

Immune checkpoint blockade (ICB)-based therapy is revolutionizing cancer treatment by fostering successful immune surveillance and effector cell responses against various types of cancers. However, patients with HER2+ cancers are yet to benefit from this therapeutic strategy. Precisely, several questions regarding the right combination of drugs, drug modality, and effective dose recommendations pertaining to the use of ICB-based therapy for HER2+ patients remain unanswered. In this study, we use a mathematical modeling-based approach to quantify the growth inhibition of HER2+ breast cancer (BC) cell colonies (ZR75) when treated with anti-HER2; trastuzumab (TZ) and anti-PD-1/PD-L1 (BMS-202) agents. Our data show that a combination therapy of TZ and BMS-202 can significantly reduce the viability of ZR75 cells and trigger several morphological changes. The combination decreased the cell's invasiveness along with altering several key pathways, such as Akt/mTor and ErbB2 compared to monotherapy. In addition, BMS-202 causes dose-dependent growth inhibition of HER2+ BC cell colonies alone, while this effect is significantly improved when used in combination with TZ. Based on the in-vitro monoculture experiments conducted, we argue that BMS-202 can cause tumor growth suppression not only by mediating immune response but also by interfering with the growth signaling pathways of HER2+BC. Nevertheless, further studies are imperative to substantiate this argument and to uncover the potential crosstalk between PD-1/PD-L1 inhibitors and HER2 growth signaling pathways in breast cancer.

A case study of a patient-centered reverse translational systems-based approach to understand adverse event profiles in drug development.

Adverse drug reactions (ADRs) of targeted therapy drugs (TTDs) are frequently unexpected and long‐term toxicities detract from exceptional efficacy of new TTDs. In this proof‐of‐concept study, we explored how molecular causation involved in trastuzumab‐induced cardiotoxicity changes when trastuzumab was given in combination with doxorubicin, tamoxifen, paroxetine, or lapatinib. The data analytical platform Molecular Health Effect was utilized to map population ADR data from the US Food and Drug Administration (FDA) Adverse Event Reporting System to chemical and biological databases (such as UniProt and Reactome), for hypothesis generation regarding the underlying molecular mechanisms causing cardiotoxicity. Disproportionality analysis was used to assess the statistical relevance between adverse events of interest and molecular causation. Literature search was performed to compare the established hypotheses to published experimental findings. We found that the combination therapy of trastuzumab and doxorubicin may affect mitochondrial dysfunction in cardiomyocytes through different molecular pathways such as BCL‐X and PGC‐1α proteins, leading to a synergistic effect of cardiotoxicity. We found, on the other hand, that trastuzumab‐induced cardiotoxicity would be diminished by concomitant use of tamoxifen, paroxetine, and/or lapatinib. Tamoxifen and paroxetine may cause less cardiotoxicity through an increase in antioxidant activities, such as glutathione conjugation. Lapatinib may decrease the apoptotic effects in cardiomyocytes by altering the effects of trastuzumab on BCL‐X proteins. This patient‐centered systems‐based approach provides, based on the trastuzumab‐induced ADR cardiotoxicity, an example of how to apply reverse translation to investigate ADRs at the molecular pathway and target level to understand the causality and prevalence during drug development of novel therapeutics.

Sortilin-related receptor is a druggable therapeutic target in breast cancer.

In breast cancer, the currently approved anti‐receptor tyrosine‐protein kinase erbB‐2 (HER2) therapies do not fully meet the expected clinical goals due to therapy resistance. Identifying alternative HER2‐related therapeutic targets could offer a means to overcome these resistance mechanisms. We have previously demonstrated that an endosomal sorting protein, sortilin‐related receptor (SorLA), regulates the traffic and signaling of HER2 and HER3, thus promoting resistance to HER2‐targeted therapy in breast cancer. This study aims to assess the feasibility of targeting SorLA using a monoclonal antibody. Our results demonstrate that anti‐SorLA antibody (SorLA ab) alters the resistance of breast cancer cells to HER2 monoclonal antibody trastuzumab in vitro and in ovo. We found that SorLA ab and trastuzumab combination therapy also inhibits tumor cell proliferation and tumor cell density in a mouse xenograft model of HER2‐positive breast cancer. In addition, SorLA ab inhibits the proliferation of breast cancer patient‐derived explant three‐dimensional cultures. These results provide, for the first time, proof of principle that SorLA is a druggable target in breast cancer.

Efficacy of the eribulin, pertuzumab, and trastuzumab combination therapy for human epidermal growth factor receptor 2\u2013positive advanced or metastatic breast cancer: a multicenter, single arm, phase II study (JBCRG-M03 study)

SummaryPurpose To date, it is not clear which anticancer agent is useful in combination with trastuzumab and pertuzumab As the first and second selective regimens for advanced or metastatic breast cancer (AMBC), this multicenter, open-label, phase II trial (JBCRG-M03: UMIN000012232) presents a prespecified analysis of eribulin in combination with pertuzumab and trastuzumab. Methods We enrolled 50 patients with no or single prior chemotherapy for HER2-positive AMBC during November 2013–April 2016. All patients received adjuvant or first-line chemotherapy with trastuzumab and a taxane. The treatment comprised eribulin on days 1 and 8 of a 21-day cycle and trastuzumabplus pertuzumab once every 3 weeks, all administered intravenously. While the primary endpoint was the progression-free survival (PFS), secondary endpoints were the response rate and safety. Results Of 50 patients, 49 were eligible for safety analysis, and the full analysis set (FAS) included 46 patients. We treated 8 (16%) and 41 (84%) patients in first- and second-line settings, respectively. While 11 patients (23.9%) had advanced disease, 35 (76.1%) had metastatic disease. The median PFS was 9.2 months for all patients [95% confidence interval (CI): 7.0–11.4]. In the FAS, 44 patients had the measurable lesions and the complete response rate (CR) was 17.4%, and partial response rate (PR) was 43.5%. The grade 3/4 adverse events were neutropenia (5 patients, 10.2%), including febrile neutropenia (2 patients, 4.1%), hypertension (3 patients, 6.1%), and other (1 patient). The average of the left ventricular ejection fraction did not decline markedly. No symptomatic left ventricular systolic dysfunction was observed. Conclusions In patients with HER2-positive AMBC, eribulin, pertuzumab, and trastuzumab combination therapy exhibited substantial antitumor activity with an acceptable safety profile. Hence, we have started a randomized phase III study comparing eribulin and a taxane in combination with pertuzumab and trastuzumab for the treatment of HER2-positive AMBC. Trial registration ID: UMIN-CTR: UMIN000012232.

A phase I dose-escalation trial of alpha-tocopheryloxyacetic acid and concurrent trastuzumab in patients with treatment refractory HER2+ metastatic breast cancer.

TPS1103 Background: Metastatic HER2+ breast cancer, while initially responsive to trastuzumab, pertuzumab, and TDM-1, eventually progresses. The FDA recently approved trastuzumab deruxtecan, showing benefit in progression free survival but not in overall survival to date. Thus, additional therapies are needed for patients who progress on these HER2 directed agents. In metastatic HER2+ breast cancer, HER2-specific Th1 immune responses and higher CD4+ Th1 and CD8+ TIL levels are associated with a survival benefit. As this Type 1 immunity occurs in a minority of patients, additional immune modulation is needed. Alpha-tocopheryloxyacetic acid (α-TEA) has been reported to augment Type 1 immunity through increasing activated effector memory CD4+ and CD8+ T cells and decreasing immune suppressive CD4+CD25+ regulatory T cells in the tumor microenvironment. When given concurrently with an anti-HER2 antibody (7.16.4) in a pre-clinical tumor model, α-TEA synergized with 7.16.4 to induce tumor regression. We hypothesize that α-TEA and trastuzumab combination therapy in metastatic HER2+ breast cancer will be well tolerated, induce a clinical response, and augment anti-tumor Th1 immunity. Methods: Trial Design: Phase I dose escalation trial of α-TEA in combination with trastuzumab. Patients with metastatic HER2+ breast cancer will receive one of four doses sequentially of α-TEA: 0.6 mg/kg, 1.2 mg/kg, 2.4 mg/kg, and 4.8 mg/kg. Toxicity is assessed at baseline and through end of study. Blood and tumor tissue will be collected for immunologic monitoring and evaluation. Clinical response will be evaluated according to RECIST 1.1. Eligibility : Patients with progressive metastatic HER2+ breast cancer who have previously progressed on trastuzumab/pertuzumab and TDM-1. Specific Aims: Determine: (1) safety of four escalating doses of α-TEA with concurrent trastuzumab, (2) clinical response rate of α-TEA with concurrent trastuzumab (3) if concurrent α-TEA and trastuzumab increases activated effector memory CD4+ and CD8+ T cells, and (4) if concurrent α-TEA and trastuzumab increase the number of HER2-specific T cells. Statistical Methods: (1) The sample size of 24 and cohort size of 6 are determined by simulation experiments and practical consideration, (2) clinical response will be evaluated; overall PFS and OS will be calculated, (3) activated effector memory CD4+ and CD8+ T-cells will be analyzed (4) HER2-specific IFN-g/IL-10 ratios will be evaluated. Targeted Accrual : Twenty-four (24) patients. Clinical trial information: NCT04120246 .

Abstract P3-10-16: Predicting pathological complete response by the combination of microRNAs in patients with HER2-positive primary breast cancer who received neoadjuvant combination therapy of trastuzumab, lapatinib and paclitaxel: Results from JBCRG-16 (NeoLath) study

Abstract [Background] JBCRG-16 (NeoLath) study is a five-arm study to evaluate the efficacy and safety of lapatinib and trastuzumab (6 weeks) followed by lapatinib and trastuzumab plus weekly paclitaxel (12 weeks) with/without prolongation of anti-HER2 therapy prior to chemotherapy (18 vs. 6 weeks), and with/without endocrine therapy in patients with HER2+ and/or estrogen receptor (ER)+ disease. The primary endpoint was pathological complete response (pCR) rate and pCR rate was 47.9% (Masuda N, et al. Breast Cancer, 2018). It is recently reported that microRNAs (miRNAs) are stably present in serum and potentially useful in the diagnosis and evaluation of treatment of cancer. We performed exploratory analysis of detecting pCR by comprehensive analysis of serum miRNAs. [Materials and Methods] Serum samples were obtained from study participants who received neoadjuvant systemic therapy with trastuzumab, lapatinib and paclitaxel. Before profiling of miRNAs, the overall serum samples were randomly devided in two sets, namely the training set and the testing set with pCR or non-pCR. Pathological complete response (pCR) was defined as the absence of residual invasive cancer of the resected breast specimen and all sampled regional lymph nodes. Total RNA was extracted from a 300 ul serum sample using 3D-Gene® RNA extraction reagent from a liquid sample kit. A comprehensive quantitative expression analysis of miRNA was performed using the by DNA chip 3D-Gene®, which was designed to detect 2565 miRNA sequences registered in miRBase release 21 (http://www.mirbase.org/). The expression level of miRNAs were normalized by internal control (miR-2861, miR-149-3p and miR-4463). Clinicopathological data was retrieved from trial data. [Results] A total of 112 samples were obtained. Seventy were used in the training set and others were used in the testing set. Median age was 54 years (range 26-70). Sixty-five (58%) patients were pre-menopausal. ER was positive in 59 patients (52.7%). Fourteen (12.5%) were T1c, 78 (69.6%) were T2 and 20 (17.9%) were T3. Fifty-seven (50.9%) patients were node-positive. Fifty-nine (52.7%) patients achieved pCR. The formula with the combination of three miRNAs (miR-A, miR-B, miR-C) was found to be able to predict pCR. This set had a sensitivity of 62.5%, specificity of 86.7% and accuracy of 71.8% in the testing cohort. Area under curve of receiver operationg characteristic curve was 0.753. [Conclusion] The combination of three miRNAs has potential to predict pCR in patients who received neoadjuvant combination therapy of trastuzumab, lapatinib and paclitaxel in HER2-positive primary breast cancer. The further analysis of changing expression of miRNAs during neoadjuvant therapy is underway and further results will be presented in the symposium. Citation Format: Shimomura A, Masuda N, Kawauchi J, Takizawa S, Ichikawa M, Matasuzaki J, Kuroi K, Hara H, Yamamoto N, Inoue K, Suganuma N, Aogi K, Ohno S, Tamura K, Ochiya T, Toi M. Predicting pathological complete response by the combination of microRNAs in patients with HER2-positive primary breast cancer who received neoadjuvant combination therapy of trastuzumab, lapatinib and paclitaxel: Results from JBCRG-16 (NeoLath) study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-10-16.

Alterations in mRNA profiles of trastuzumab‑resistant Her‑2‑positive breast cancer.

Breast cancer is one of the most common malignancies in women. Neoadjuvant trastuzumab therapy improves the prognosis of certain Her-2-positive breast cancer patients, however around two-thirds of patients with Her-2-positive breast cancer do not benefit from Her-2-targeted therapy. To investigate the key mechanisms in trastuzumab resistance, potential biomarkers for neoadjuvant trastuzumab sensitivity were investigated using the gene expression omnibus (GEO) database for mRNA microarray data of Her-2-positive breast cancer patients who received neoadjuvant trastuzumab therapy. GEO profiles of 22 patients with a complete response and 48 patients with a partial response were identified in the GSE22358, GSE62327 and GSE66305 datasets. A total of 2,376, 1,000 and 1,152 differentially expressed genes in GSE22358, GSE62327 and GSE66305 datasets were demonstrated, respectively, utilizing GEO2R software. Furthermore, enriched gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways were analyzed using the Database for Annotation, Visualization and Integrated Discovery software. Subsequently, a protein-protein interaction network was established using STRING software. The results demonstrated that low sex-determining region Y-box 11 and high Bcl-2 expression may be employed as markers for neoadjuvant trastuzumab therapy for Her-2-positive breast cancer. More importantly, phosphoinositide 3-kinase/Akt and angiogenesis pathways, which are known to be the key targets of trastuzumab, were activated at a lower level in the partial response patients, while the Wnt and estrogen receptor signaling pathways were activated in these patients. Therefore, combination therapy of trastuzumab and anti-Wnt or hormone therapy may be a promising treatment modality and should be tested in further studies.

Efficacy and safety of short course adjuvant trastuzumab combination chemotherapy in breast cancer

Background:The adjuvant short course 9-week trastuzumab combination therapy for human epidermal receptor 2 positive breast cancer patients may often be considered as a cost-effective and safe option and has important implications for the Indian subcontinent as well as other developing countries. However, such regimens of shorter duration trastuzumab therapy like FinHer, offered in view of economic constraints, may not be able to achieve globally comparable cure rates in early breast cancer especially with high-risk women with more than 3 lymph node positive.Methods and Material:Outcome of 21 patients with HER2 positive breast cancer was treated with short course trastuzumab combination chemotherapy in the adjuvant setting was studied.Results:Out of 21 patients 15 are alive and disease free with a follow up of up to 73 months (median follow up 42 months).

Phase I study of nanoparticle albumin-bound paclitaxel, carboplatin and trastuzumab in women with human epidermal growth factor receptor 2-overexpressing breast cancer

Although the concurrent use of anthracycline-containing chemotherapy and taxane with trastuzumab are considered the treatment of choice for the primary systemic therapy of human epidermal growth factor receptor 2 (HER2)-overexpressing early breast cancer, non-anthracycline regimens, such as concurrent administration of docetaxel and carboplatin with trastuzumab, exhibited similar efficacies in a previous study. In addition, tri-weekly treatment with nanoparticle albumin-bound paclitaxel (nab-paclitaxel) resulted in significantly higher response rates and a favorable safety profile compared with standard paclitaxel for metastatic breast cancer patients in another phase III study. Based on these results, a phase I study of combination therapy with nab-paclitaxel, carboplatin and trastuzumab was planned, in order to estimate its efficacy and safety for HER2-overexpressing locally advanced breast cancer. The present study was designed to determine the dose-limiting toxicity (DLT), maximum tolerated dose and recommended dose of this combination treatment in women with HER2-overexpressing locally advanced breast cancer. The starting dose of nab-paclitaxel was 220 mg/m2 (level 1), and the dose was escalated to 260 mg/m2 (level 2). Nab-paclitaxel was administered with carboplatin (area under the curve, 6 mg/ml/min) and trastuzumab tri-weekly. A total of 6 patients were enrolled. Although no DLT was observed during the first cycle, 4 patients developed grade 4 thrombocytopenia, 2 had grade 4 neutropenia and 3 exhibited a grade 4 decrease in hemoglobin levels. In the present phase I study, although no patients experienced DLTs, this regimen was associated with severe hematological toxicities and it was not well tolerated. However, considering the high efficacy and lower risk of cardiotoxicity and secondary carcinogenesis with taxane, platinum and trastuzumab combination therapy, further evaluation of another regimen including weekly administration or a more accurate dose setting should be conducted.

Abstract 3142: Derivation and analysis of preclinical models of human her-2 positive breast cancer

Abstract Although a number of Her-2 targeting drugs are now available for the treatment of Her-2 positive breast cancers, resistance to these therapies rapidly emerges. There is therefore a need to study how Her-2 targeting strategies work in vivo, and the mechanisms by which tumors eventually become resistant to anti-Her-2 therapies. We report the in vivo selection of variants of the human Her-2 positive breast cancer cell lines BT474 and MDA-MB361. Both cell lines were initially implanted orthotopically into Severely Compromised Immunodeficient mice, and the resulting tumors were serially passaged into new hosts over a 4 year period. This selection process produced the BT474V3 and MDA361V3 variants, which grow rapidly in vivo and which retain their Her-2 over-expression, and which respond (p&amp;lt;0.05, relative to controls) to trastuzumab (20mg/kg i.p. every 3 days). Tumor variants were also derived from selected tumors that relapsed after 3 months of continuous trastuzumab monotherapy. MDA361V3 tumors showed a significant (p&amp;lt;0.05) response to the combination therapy of trastuzumab plus metronomic cyclophosphamide (20mg/kg/day, p.o.). Tumors eventually progressed under this combination therapy, and cell lines were derived from the drug resistant tumors. Non-invasive monitoring of the Her-2 positive models in vivo was achieved by luciferase transfection of the tumor variants, or by transfection of chorionic gonadotropin (hCG) cDNA which allows for relative tumor growth to be evaluated via the resulting hCG levels in the mouse urine. Luciferase transfected BT474V3 were implanted intracranially (coordinates for implantation from Bregma were AP, +1.1; LM, -2.0; and DV, -3), and bioluminescence was detectable 20 days later. The implanted tumors in the brain eventually showed a doubling of bioluminescence every 2 weeks, which provides ample time for therapeutic intervention in this model of Her-2 positive breast cancer brain metastasis. To further model the response of Her-2 positive metastatic breast cancer, we employed our met2.hCG model, derived from the human MDA-MB-231 human breast cancer cell line. Thus, MDA-MB-231 were transduced to overexpress Her-2, then tagged with hCG, and then selected for high spontaneous metastatic capacity. Orthotopically implanted met2.hCG tumors responded to trastuzumab as a monotherapy, and when given in combination with metronomic cyclophosphamide. Following surgical removal of the orthotopically implanted met2.hCG tumors, urine hCG levels indicated that the metastases also responded (p&amp;lt;0.05, compared to saline treated controls) to the combination of metronomic cyclophosphamide plus trastuzumab, but they did not respond to the trastuzumab monotherapy. Collectively, our data shows that we have derived models of Her-2 positive breast cancer that can be used to evaluate anti-Her-2 therapeutic strategies, and to study the emergence of resistance to anti-Her-2 based therapies. Citation Format: Paloma A. Valenzuela, Sarah N. Jallad, Karla Parra, Natzidielly Lerma, Irving Miramontes, Alejandra Gallegos, Ping Xu, William Cruz-Munoz, Shan Man, Robert S. Kerbel, Giulio Francia. Derivation and analysis of preclinical models of human her-2 positive breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3142. doi:10.1158/1538-7445.AM2014-3142

760: Enhanced antitumor effects of oncolytic reovirus and trastuzumab combination therapy in human HER2-positive gastric cancer

760: Enhanced antitumor effects of oncolytic reovirus and trastuzumab combination therapy in human HER2-positive gastric cancer

The ErbB2-targeting antibody trastuzumab and the small-molecule SRC inhibitor saracatinib synergistically inhibit ErbB2-overexpressing gastric cancer

The anti-ErbB2 antibody trastuzumab has shown significant clinical benefits in ErbB2-overexpressing breast and gastric cancer, but resistance to the drug is common. Here, we investigated the antitumor activity of the combination of trastuzumab and the SRC inhibitor saracatinib in ErbB2-overexpressing trastuzumab-resistant gastric cancer. The ErbB2-overexpressing human gastric cancer cell line NCI-N87 was treated with trastuzumab to obtain the trastuzumab-resistant cell line NCI-N87R. The NCI-N87R cell line showed a marked increase in SRC activity and ErbB signaling compared with the NCI-N87 cell line. Our data demonstrated that trastuzumab plus saracatinib was much more potent than either agent alone in reducing the phosphorylation of ErbB3 and AKT in both NCI-N87 and NCI-N87R gastric cancer cell lines. Trastuzumab and saracatinib synergistically inhibited the in vitro growth of NCI-N87 and NCI-N87R cell lines. Further data showed that combination therapy of trastuzumab with saracatinib resulted in a significant benefit over either agent alone in both NCI-N87 and NCI-N87R xenograft models, suggesting its potential use for treating ErbB2-overexpressing gastric cancer.

Development of preclinical models of human BT474 and MDA-MB-361 breast cancer that endogenously overexpress HER2 and that respond to trastuzumab.

e11061 Background: The anti-Her-2 antibody trastuzumab can be effectively combined with chemotherapy to treat Her-2 positive metastatic breast cancers. However, Her-2 positive breast cancers readily develop resistance to trastuzumab based therapies, and new models are needed to study such resistance, and to find new therapeutic options. Methods: We began the in vivo selection of human Her-2 positive breast cancer cell lines, BT474 and MDA-MB-361, in Severely Compromised Immunodeficient (SCID) mice. Tumor cells were implanted orthotopically into the mammary fat pad of SCID mice, and resulting tumors were serially passaged into new hosts over a 3 year period. Results: The resulting variants grow rapidly in SCID mice. Variants of both BT474 and MDA-MB-361 respond in vivo to trastuzumab monotherapy (20mg/kg twice weekly, i.p.) compared to controls (p&lt;0.05). After 2-6 months of trastuzumab monotherapy, all variants developed resistance to trastuzumab; such resistant variants were adapted to tissue culture. BT474 variants produced a spontaneous lymph node metastasis in SCID mice, 10 months after the surgical resection of the orthotopically implanted primary tumor; this metastatic variant was also adapted to tissue culture. BT474 variants were tagged with luciferase and then implanted intracranially into SCID mice; the progressive growth of the tumors cells in the mouse brain was thereafter monitored for 3 months by bioluminescence imaging, which provides ample opportunity to test new treatments for brain metastases. MDA-MB-361 variants growing orthotopically responded (i.e. p&lt;0.05 vs. controls) to the combination therapy of trastuzumab (20mg/kg twice weekly, i.p.) plus chemotherapy; chemotherapy consisted of a bolus of cyclophosphamide (CTX, 100mg/kg, i.p) followed by a maintenance metronomic CTX (20mg/kg/day, p.o.) regimen. Conclusions: We developed two preclinical models of human Her-2 positive breast cancer which may be used to study trastuzumab based therapies, Her-positive metastatic breast cancer, the growth of Her-2 positive breast cancer at a secondary site (i.e. the brain), as well as the evolution of tumor resistance to trastuzumab based therapies.

Phase II trial of preoperative paclitaxel, gemcitabine, and trastuzumab combination therapy in HER2 positive stage II/III breast cancer: The Korean Cancer Study Group BR 07-01

An addition of trastuzumab preoperatively to chemotherapy for human epidermal growth factor receptor 2 (HER2) positive breast cancer improved relapse-free survival (RFS). This study was designed to evaluate the efficacy and safety of preoperative paclitaxel, gemcitabine, and trastuzumab (PGH) combination for HER2-positive breast caner. Pathologically, proven node positive stage II/III breast cancer patients with adequate organ function and no history of anti-cancer therapy were eligible. Patients received weekly trastuzumab with paclitaxel 80 mg/m(2) and gemcitabine 1,200 mg/m(2) on days 1 and 8, every 3 weeks for 6 cycles. Postoperatively, patients completed trastuzumab for 1 year and hormone therapy for 5 years if indicated. All patients received postoperative radiation therapy. Of 53 enrolled patients with a median tumor of 5.3 (range, 2.0 to >12) cm; 43.4%, T3/T4; 75.4%, N2/N3; and 45.3%, positive hormone receptors. The pathologic complete response (pCR) rate was 58.5% in both tumor and lymph nodes. Grade 3/4 adverse events were neutropenia (32%), febrile neutropenia (0.6%), and transient elevation of AST/ALT (1.6%) during a total of 318 cycles. All patients maintained normal cardiac function. With a median follow-up of 40 months, 3-year RFS rate was 84% with 91.7% distant metastasis-free survival rates. Remarkable pCR rate was obtained with non-anthracycline-based PGH therapy for HER2-positive stage II/III breast cancer. Adverse events were mild with few incidences of febrile neutropenia.

Evaluation of Trastuzumab Without Chemotherapy as a Post-operative Adjuvant Therapy in HER2-positive Elderly Breast Cancer Patients: Randomized Controlled Trial [RESPECT (N-SAS BC07)

This trial is conducted to investigate the benefit of trastuzumab monotherapy compared with a combination therapy of trastuzumab and chemotherapy in women over 70 years with human epidermal growth factor receptor type-2-positive primary breast cancer. Inclusion criteria are the following: histologically diagnosed as invasive breast cancer and received curative operation for primary breast cancer; Stage I, IIA, IIB or IIIA/M0; and baseline left ventricular ejection fraction is ≥55%. Patients are randomized to receive either trastuzumab (8 mg/kg loading dose, 6 mg/kg every 3 weeks for 1 year) plus chemotherapy selected from regimens specified on the protocol or trastuzumab monotherapy. The primary endpoint is disease-free survival. Secondary endpoints are overall survival, relapse-free survival, safety, health-related quality of life, comprehensive geriatric assessment and cost effectiveness. Patients recruitment has been commenced in October 2009. Enrollment of 300 patients is planned during the 4-year recruitment period. We hereby report the study concept.

The use of protein array to identify targetable receptor tyrosine kinases for treatment of human colon cancer

Several studies have reported that activated receptor tyrosine kinases (RTKs) are highly expressed in colon cancer and may promote tumor growth and survival. However, there is little information available as to the function and signaling of RTKs in colon cancers. In the present study, we performed protein array technology to determine the expression status of various RTKs that are activated in colon cancer compared to normal colonic cells and tissues. Of the 42 different phospho-RTKs, 5 (ErbB2, FGFR1, FGFR2a, FGFR3 and MSPR) were activated in Caco-2, SW480, WiDr, Lovo colon cancer cell lines and cancerous tissues. In order to determine the effect of inhibition of RTKs, especially ErbB2, athymic nude mice bearing xenograft tumors were treated with the ErbB2-targeting drug trastuzumab alone, or in combination with 5-Fluorouracil (5-FU). Similar to the treatment of 5-FU alone, trastuzumab suppressed the growth of colon cancer. Combination therapy of trastuzumab and 5-FU inhibited tumor growth significantly compared to the treatment of 5-FU alone or trastuzumab alone. In addition, xenograft tumors were also analyzed by phospho-MAPK protein array. The activity of Akt3/PKBgamma was inhibited with 5-FU alone and trastuzumab, indicating that trastuzumab may inhibit colon cancer growth through ErbB2-Akt3/PKBgamma signaling. These data demonstrate that ErbB2 could be an important candidate for colon cancer therapy and the addition of trastuzumab to 5-FU therapy might augment the clinical response in colon cancer patients. Therefore, the analysis of phospho-RTK expression by protein array as a useful tool might identify novel therapies for individual patients with colon cancer.

A case of osteonecrosis of the jaw in a breast cancer patient with bone metastases receiving long-term treatment with bisphosphonates

Bisphosphonates (BPs) are often used for the treatment of several diseases such as osteoporosis, cancer-associated hypercalcemia, and osteolytic bone metastasis. Recently, there have been reports of osteonecrosis of the jaw (ONJ) in cancer patients whose treatment regimens include BPs. In this case report, we describe complications and treatment of ONJ in a breast cancer patient with bone metastases who received long-term treatment with BPs. A 70-year-old woman underwent modified radical mastectomy on her left breast cancer and received oral 5-fluorouracil derivatives for 2 years in another hospital. Eleven years after the surgery, she came to our hospital complaining of spinalgia and was diagnosed with recurrent breast cancer with multiple metastases to the stomach, liver, multiple lymph nodes, and spine. After surgery for spine metastases, she was given a combination therapy of trastuzumab (initial bolus: 170 mg/body, followed by two or more cycles of 85 mg/body) every week, docetaxel (100 mg/body) every 3 weeks, and BPs (90 mg/body) every 4 weeks. About 1 year and 4 months later, she complained of pain in her right maxilla; biopsy revealed ONJ. Medical oncologists need to recognize ONJ as a serious side effect of BP treatment; dentists and oral and maxillofacial surgeons need to thoroughly consult patients regarding the administration of BPs and have them make an informed consent.