Clinical Efficacy Of Trastuzumab Research Articles

Abstract 5290: BSI-001, a novel anti-HER2 antibody exhibiting potent synergistic efficacy with trastuzumab

Abstract Background: Trastuzumab and pertuzumab are anti-HER2 antibodies that bind to two different epitopes of HER2. Although pertuzumab itself did not exhibit substantial clinical benefit as monotherapy, it was approved to be used in combination with trastuzumab because of its ability to enhance the clinical efficacy of trastuzumab. Currently, the combination of trastuzumab and pertuzumab is being used as first-line treatment for HER2-positive metastatic breast cancer. However, while the combination of trastuzumab and pertuzumab has been effective, there is still opportunity for greater effectiveness by identifying anti-HER2 mAbs that will be better synergistic partners of trastuzumab, allowing for better efficacy and/or broader indications. Methods: A SynAb࣪ Platform was used to identify BSI-001, an anti-HER2 mAb, through trastuzumab-based synergistic functional screening. A competitive ELISA was used to perform epitope binning of the anti-HER2 antibodies. BSI-001 was further characterized in combination with trastuzumab for its bioactivity in vitro, including inhibition of cell proliferation and antigen-mediated internalization of HER2 positive cell lines. The synergistic effect of BSI-001 with trastuzumab was also evaluated in trastuzumab-resistant cell lines. Multiple animal models were then employed to investigate the synergistic antitumor activity of the combination in vivo. Results: BSI-001 is the best functional partner of trastuzumab identified through the SynAb࣪ platform. BSI-001 binds to a unique epitope, distinct from the binding epitopes of trastuzumab and pertuzumab. It exhibits superior bioactivity and efficacy in vitro and in vivo when combined with trastuzumab. The combination of BSI-001 and trastuzumab inhibits HER2-positive cancer cell growth more potently than that of trastuzumab and pertuzumab. The combination of BSI-001 with trastuzumab also shows inhibition of cell growth of the trastuzumab-resistant cell line BT-474 Clone 5, whereas the combination of pertuzumab and trastuzumab did not. In addition, BSI-001 is able to synergize with trastuzumab to promote antigen-antibody internalization. In animal models, BSI-001 demonstrates superior synergistic antitumor activity when combined with trastuzumab as compared to pertuzumab. Summary: The combination of BSI-001 and trastuzumab showed significantly better in vitro and in vivo activity than the combination of trastuzumab and pertuzumab. In addition, because of the activity of the BSI-001/trastuzumab combination in a trastuzumab-resistant cancer cell line, there is the potential for this combination to be used to treat patients with trastuzumab-resistant cancer or patients who experienced relapse following trastuzumab and pertuzumab treatment. Citation Format: Shukai Xia, Zeyu Peng, Xiaoyu Ding, Wanjian Gu, Yujie Zhong, Jinyu Liu, Hongyan Li, Xiaoyao Hao, Xiaodong F. Liu, Mark Z. Ma, Lan Luo, Chunni Zhang, Mingjiu Chen. BSI-001, a novel anti-HER2 antibody exhibiting potent synergistic efficacy with trastuzumab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5290.

Abstract 4959: The gut microbiota contributes to the effectiveness of HER2-targeted therapy

Abstract Recently, the composition of the gut microbiota, due to its influence on host immune system, has been linked to the effectiveness of chemotherapy and immunotherapy. Since trastuzumab, besides inhibiting the HER2 signaling, recruits innate and adaptive immune cells that mediate its cytotoxic activity in the tumor, we hypothesized that commensal bacteria can be a source of heterogeneity for the response to therapy in patients with HER2-positive breast cancer (HER2+BC). The impact of the gut microbiota on anti-HER2 therapy was studied in mice with the intestinal flora alterated by the treatment with vancomycin or streptomycin-two broad spectrum antibiotics poorly absorbed in the intestine. The association between commensal bacteria composition and clinical efficacy of trastuzumab was investigated in a cohort of HER2+BC patients treated with neoadjuvant trastuzumab. Administration of antibiotics impaired the efficacy of anti-HER2 monoclonal antibodies both in FVB and BALB/c mice bearing syngeneic mammary carcinomas expressing HER2. 16S rRNA gene profiling of FVB mouse feces showed that both antibiotics decreased bacterial α-diversity in the gut as evaluated by Chao1, Simpson and Shannon indices, lowering the abundance of Clostridiales bacteria. Mice transplanted with feces from antibiotic treated mice did not benefit from the anti-HER2 treatment supporting a direct relation between intestinal bacteria and therapeutic efficacy. Analysis by flow cytometry and immunohistochemistry of tumors grown in mice showed that alteration of gut microbiota compromised the recruitment of CD4+ T cells and Natural Killer (CD49b+, GZMB+) cells upon anti-HER2 administration. Fecal 16S rRNA gene sequencing demonstrated a significantly higher microbial α-diversity in patients who achieved a pathological complete response compared to non-responders using several indices. Moreover, a clustering effect by patient’s response was observed visualizing the β-diversity. OTUs belonging to the Clostridiales and Bacteroidales orders were reduced and enriched, respectively, in non-responders. Our data support that the composition of the gut microbiota, especially as regards the abundance of Clostridiales bacteria, has a role in the therapeutic efficacy of trastuzumab both in mice and patients. Therefore, the manipulation of intestinal bacteria may represent a new strategy to improve the cure of HER2+BC patients. (Supported by Associazione Italiana per la Ricerca sul Cancro). Citation Format: Martina Di Modica, Viola Regondi, Giorgio Gargari, Arianna Bonizzi, Stefania Arioli, Beatrice Belmonte, Claudio Tripodo, Simone Guglielmetti, Fabio Corsi, Tiziana Triulzi, Elda Tagliabue. The gut microbiota contributes to the effectiveness of HER2-targeted therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4959.

Aptamer-conjugated and doxorubicin-loaded grapefruit-derived nanovectors for targeted therapy against HER2+ breast cancer

Increased human epidermal growth factor receptor 2 (HER2) expression is a hallmark of HER2+ breast cancer. HER2 promotes the growth of cancer cells and makes them particularly aggressive. Currently, trastuzumab is the only HER2-targeted therapeutic agent approved by the FDA for HER2-overexpressing breast cancer treatment. However, clinical efficacy of trastuzumab is limited greatly by the occurrence of drug resistance. In this study, an aptamer (HA1) specific for HER2-overexpressing breast cancer cells was selected using Cell-SELEX. This allowed the development of grapefruit-derived nanovectors (GNVs) conjugated with HA1 that targeted specifically HER2+ breast cancer cells. In vitro experiments demonstrated that HA1 effectively promoted the internalisation of GNVs into cancer cells and tumour spheroids. In vivo data showed that drug delivery to tumour tissues and antitumor activities were dramatically enhanced by conjugating HA1 with drug-loaded GNVs. This study indicates that aptamers mediating targeted drug delivery by GNVs represent a promising strategy for HER2+ breast cancer therapy.

Abstract 25: Whole genome sequencing and quantitative proteomics reveal HPV integration and HER2 overexpression in a patient with cervical cancer: Comprehensive omics analysis driving clinical treatment decisions

Abstract Introduction: Selection of drugs to treat patients with cancer is typically based on the anatomical site in which the tumor is located. Here we report a treatment decision for a patient with relapsed, advanced cervical cancer that was based on a comprehensive omics analysis using whole genome sequencing (WGS) combined with quantitative proteomics. Methods: The patient was a 44-year-old female whose disease had progressed following surgery and more than 4 lines of chemotherapy. WGS was performed on the patient's formalin-fixed, paraffin-embedded (FFPE) metastatic tumor sample and a matched-normal reference sample. Quantitative proteomics was performed on the FFPE tumor sample by Selected Reaction Monitoring Mass Spectrometry and was quantitated at the atomolar level. Results: WGS found somatic mutations and rearrangements and reads mapping to human papillomavirus type 18 (HPV 18). Mutations more commonly found in breast cancer (ERBB2, CDH1, and CLTCL1) were noted. The HPV 18 genome was integrated into chromosome 17 in close proximity to a 7-fold amplification of the ERBB2 gene. Proteomic analysis of the FFPE tumor validated and quantitated overexpression of HER2 protein resulting from ERBB2 gene amplification, with 11,322 amol/μg of tissue protein. Clinically observed ranges for breast or gastric cancer are 150-500 amol/μg, with levels above 750 amol/μg correlating with FISH-positive amplification and clinical efficacy of trastuzumab (unpublished observation). Based on these comprehensive omic findings, trastuzumab, a therapy approved for breast and gastric cancer, was administered. The patient experienced a reduction in the size of her tumor (by CT/PET) and stabilization of her disease for 5 months. Conclusion: WGS and proteomic profiling of this patient's disease identified, confirmed, and quantitated an appropriate target for pharmaceutical intervention. The patient presented with cervical cancer; however, the WGS analysis pointed towards a potentially causative integration of the HPV 18 genome resulting in ERBB2 amplification along with genomic mutations more commonly found in breast cancer. Proteomic analysis further validated and quantitated the HER2 expression resulting from ERBB2 gene amplification, leading to the patient's treatment with trastuzumab. Our findings argue for the use of comprehensive omics analysis to guide decision support for personalized management of cancer care with therapies determined based on a quantitative proteomic signature, independent of anatomical tumor type. Citation Format: Stephen Benz, J Zackary Sanborn, Nicole S. Hensley, Todd Hembrough, Charles J. Vaske, Jon Burrows, Shahrooz Rabizadeh, Ivor Royston, Patrick Soon-Shiong. Whole genome sequencing and quantitative proteomics reveal HPV integration and HER2 overexpression in a patient with cervical cancer: Comprehensive omics analysis driving clinical treatment decisions. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Integrating Clinical Genomics and Cancer Therapy; Jun 13-16, 2015; Salt Lake City, UT. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(1_Suppl):Abstract nr 25.

Clinical efficacy of trastuzumab in the therapy of HERS2-positive gastric cancer: Review of clinical experience

Clinical efficacy of trastuzumab in the therapy of HERS2-positive gastric cancer: Review of clinical experience

Reply to V. Pitini et al

We appreciate the comments of Pitini et al regarding our recent report of 7-year follow-up of cardiac function in National Surgical Adjuvant Breast and Bowel Project protocol B-31, which is evaluating the benefits and risks of adding trastuzumab to standard chemotherapy for the adjuvant treatment of women with early stage human epidermal growth factor receptor 2–positive breast cancer. We agree that a dynamic evaluation of cardiac function, for example by echocardiogram, provides more detailed assessment of myocardial function than multigated acquisition (MUGA) scans, and clearly all imaging modalities carry a margin of error. It is worth pointing out that for the first 1,000 patients enrolled onto B-31, the primary end point of the protocol was not the clinical efficacy of trastuzumab but cardiac safety. As such, patients with any significant cardiac condition were excluded from participation, including those with any arrhythmia requiring medication. The cardiac risk score applies only to those patients who would have met the eligibility requirements of the protocol from which it was developed. As we mentioned in the Methods section, MUGA scans were chosen over echocardiograms in order to write rules for holding or stopping trastuzumab and to minimize observer variability across institutions. We also agree that the accuracy of the baseline left ventricular ejection fraction (LVEF) measurement is critical, not only for the cardiac risk score, but also because it serves as the comparison point for subsequent LVEF measurements in determining whether to hold or continue trastuzumab. For instance, if a patient is dehydrated when her baseline LVEF study is performed, the value obtained may be higher than a true reflection of her level of systolic function, and the difference between baseline and subsequent measurements then may be exaggerated, in some cases potentially affecting decisions about whether to hold or continue trastuzumab. Finally, we welcome the important work that is being done using biomarkers such as ultrasensitive troponin, and we cite two such studies in our discussion. In the end, however, any indicators of potential cardiac risk, whether by risk score, biomarkers, or genetics, must be integrated into clinical decision algorithms regarding optimal use of trastuzumab in the treatment of patients with breast cancer.

A different immunologic profile characterizes patients with HER-2-overexpressing and HER-2-negative locally advanced breast cancer: implications for immune-based therapies

IntroductionThe clinical efficacy of trastuzumab and taxanes is at least partly related to their ability to mediate or promote antitumor immune responses. On these grounds, a careful analysis of basal immune profile may be capital to dissect the heterogeneity of clinical responses to these drugs in patients with locally advanced breast cancer undergoing neoadjuvant chemotherapy.MethodsBlood samples were collected from 61 locally advanced breast cancers (36 HER2- and 25 HER2+) at diagnosis and from 23 healthy women. Immunophenotypic profiling of circulating and intratumor immune cells, including regulatory T (Treg) cells, was assessed by flow cytometry and immunohistochemistry, respectively. Serum levels of 10 different cytokines were assessed by multiplex immunoassays. CD8+ T cell responses to multiple tumor-associated antigens (TAA) were evaluated by IFN-γ-enzyme-linked immunosorbent spot (ELISPOT). The Student's t test for two tailed distributions and the Wilcoxon two-sample test were used for the statistical analysis of the data.ResultsThe proportion of circulating immune effectors was similar in HER2+ patients and healthy donors, whereas higher percentages of natural killer and Treg cells and a lower CD4+/CD8+ T cell ratio (with a prevalence of naïve and central memory CD8+ T cells) were observed in HER2- cases. Higher numbers of circulating CD8+ T cells specific for several HLA-A*0201-restricted TAA-derived peptides were observed in HER2+ cases, together with a higher prevalence of intratumor CD8+ T cells. Serum cytokine profile of HER2+ patients was similar to that of controls, whereas HER2- cases showed significantly lower cytokine amounts compared to healthy women (IL-2, IL-8, IL-6) and HER2+ cases (IL-2, IL-1β, IL-8, IL-6, IL-10).ConclusionsCompared to HER2- cases, patients with HER2-overexpressing locally advanced breast cancer show a more limited tumor-related immune suppression. This may account for the clinical benefit achieved in this subset of patients with the use of drugs acting through, but also promoting, immune-mediated effects.

Abstract PL2-1: Drug Development — Targeting HER2 beyond Trastuzumab

Abstract The use of trastuzumab in the treatment of early and advanced stage HER2 overexpressing (HER2+) breast cancers represents a significant advance in the treatment of breast cancer. In the advanced stage setting, the development of therapeutic resistance, either primary or secondary/acquired, is a clinical problem limiting the clinical efficacy of trastuzumab. This discussion will include alternative approaches to the treatment of HER2+ breast cancers, and strategies to enhance the clinical efficacy of trastuzumab by overcoming the development of therapeutic resistance. Elucidating mechanisms of resistance provides an opportunity to develop combination strategies based on scientific rationale to overcome or prevent its development. For example, the IGF1/IGF-1R signaling axis, which is frequently co-expressed in HER2+ breast cancers promotes trastuzumab resistance in preclinical models. IGF-1R inhibitors overcomes trastuzumab resistance in preclinical models, providing a strong rationale for evaluating the combination in clinical trials. Similarly, the pro-survival PI3K-Akt signaling network is frequently deregulated in breast cancers as a consequence of PI3KCA gain-of-function mutations or loss of the tumor suppressor PTEN. In preclinical models, deregulated PI3K signaling mediates therapeutic resistance to trastuzumab, and small molecule PI3K inhibitors have been shown to overcome trastuzumab resistance. Other mechanisms of resistance to trastuzumab include the presence of heregulin (HRG), a soluble growth factor ligand to HER3 and HER4, which promotes the formation of HER2/HER3 heterodimers, a complex that potently activates PI3K signaling. Other HER2 antibodies e.g. pertuzumab, are more effective at blocking the effects of HRG on HER2/HER3 dimerization. Another mechanism of resistance is truncation of HER2, resulting in a receptor that lacks the extracellular domain that contains the trastuzumab binding site. Strategies to prevent HER2 truncation have been examined preclinically. HER2 signaling has also been targeted using small molecules that compete with ATP for binding at the catalytic kinase domain of HER2. Lapatinib, an oral, reversible inhibitor of HER2 and EGFR tyrosine kinases is approved in combination with capecitabine for treating advanced stage HER2+ breast cancers that progressed on prior trastuzumab-based therapies. The dilemma is that the majority of women treated with lapatinib develop therapeutic resistance within 12 months of initiating therapy. Mechanisms of therapeutic resistance to lapatinib have been identified including (i) de-repression of estrogen receptor (ER) signaling, and (ii) activation of the pro-survival mediator NF-kB; the role of PTEN loss and the presence of PI3K activating mutations in the development of lapatinib resistance remains controversial. This insight has led to rational combinations to overcome or perhaps even delay the development of lapatinib resistance e.g. approval of letrozole plus lapatinib in HER2+/ER+ breast cancers. And finally, other HER2 targeted approaches will be discussed, including hsp90 antagonists, HER2 antibody conjugates (e.g. T-DM1), HER2 vaccines, and combinations of antibody-based and HER2 kinase inhibitors. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PL2-1.

Abstract PD02-05: Low Immunogenicity of Breast Cancer Stem Cells Leads to Selective Survival When Challenged with Trastuzumab and Natural Killer Cells

Abstract Although trastuzumab (Herceptin) has substantially improved the overall survival of patients with mammary carcinomas, even initially well-responding tumors often become resistant. Considering that clinical efficacy of trastuzumab correlates with the infiltration of natural killer (NK) cells into the tumor site, we established a cell-culture-system to select for ovarian cancer and mammary carcinoma cells that survive a challenge by trastuzumab and NK cells. Under these conditions, NK cells can eliminate tumor cells either via antibody-dependent-cell-mediatedcytotoxicity (ADCC) or by direct recognition of tumor-associated ligands for NKG2D or DNAM-1. The most striking phenotypic alteration observed in immunoselected ovarian cancer cells was a down-regulation of HER2 expression, leading to an ADCC-resistant phenotype. All breast cancer cells tested (MCF7, SK-BR-3, MDA-MB231, BT474), however, failed to develop resistance in vitro. Instead, treatment with trastuzumab and polyclonal NK-cells resulted in the preferential survival of individual sphere-forming cells that displayed a CD44highCD24low ‘'cancer-stem-celllike” phenotype (CSC) and expressed significantly less HER2 compared with non-stem cells. Moreover, the molecular determinants for the direct recognition of transformed cells, most notably the NKG2D ligands MICA, MICB, ULBP1-4 and the DNAM-1 ligands CD112 and CD155, were virtually absent from CSC. When immunoseleced breast cancer cells were then re-expanded, they mostly lost the observed phenotype and regenerated a tumor cell culture that displayed initial HER2 surface expression and ADCC susceptibility, but was enriched in CD44highCD24low CSC. This translated into increased clonogenicity in vitro and tumorigenicity in vivo. We provide evidence that recruition of NK-cells and induction of ADCC by trastuzumab may spare actual tumor-initiating-cells, which could explain clinical relapse. Moreover, our observation that “relapsed” in vitro cultures show identical HER2 surface expression and susceptibility toward ADCC suggests that administration of trastuzumab beyond relapse might be considered, especially when combined with proteasome inhibition which increase the expression of NKG2D ligands. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD02-05.

Cross-Talk Between the ErbB/HER Family and the Type I Insulin-Like Growth Factor Receptor Signaling Pathway in Breast Cancer

Understanding the molecular mechanisms involved in tumorigenesis and their influence on clinical outcome is providing specific molecular markers for targeted therapy. Activation of tyrosine kinase receptors from the human epidermal growth factor receptor family (EGFR, HER2, HER3, HER4) and the insulin-like growth factor receptor I (IGF-IR) plays a key role in the initiation and progression of breast cancer. HER2 overexpression is a validated therapeutic target, as shown by the clinical efficacy of trastuzumab and lapatinib. However, only 25-30% of patients with HER2-overexpressing tumors respond to single-agent trastuzumab or lapatinib, and resistance develops even in responding patients. Therefore, to optimize therapeutic efficacy, it is urgent to elucidate the complex network of signaling pathways that develop in breast cancer cells. Signaling interactions have been reported between ErbB/HER family members and IGF-IR. As increased IGF-IR signaling has been implicated in trastuzumab resistance, agents targeting HER2, and IGF-IR could be potential therapeutic tools in breast cancers that develop resistance to HER2-directed therapy.

HER2 regulates the mammary stem/progenitor cell population driving tumorigenesis and invasion

The cancer stem cell hypothesis proposes that cancers arise in stem/progenitor cells through disregulation of self-renewal pathways generating tumors, which are driven by a component of 'tumor-initiating cells' retaining stem cell properties. The HER2 gene is amplified in 20-30% of human breast cancers and has been implicated in mammary tumorigenesis as well as in mediating aggressive tumor growth and metastasis. We demonstrate that HER2 overexpression drives mammary carcinogenesis, tumor growth and invasion through its effects on normal and malignant mammary stem cells. HER2 overexpression in normal mammary epithelial cells (NMEC) increases the proportion of stem/progenitor cells as demonstrated by in vitro mammosphere assays and the expression of stem cell marker aldehyde dehydrogenase (ALDH) as well as by generation of hyperplastic lesions in humanized fat pads of NOD (nucleotide-binding oligomerization domain)/SCID (severe combined immunodeficient) mice. Overexpression of HER2 in a series of breast carcinoma cell lines increases the ALDH-expressing 'cancer stem cell' population which displays increased expression of stem cell regulatory genes, increased invasion in vitro and increased tumorigenesis in NOD/SCID mice. The effects of HER2 overexpression on breast cancer stem cells are blocked by trastuzumab in sensitive, but not resistant, cell lines, an effect mediated by the PI3-kinase/Akt pathway. These studies provide support for the cancer stem cell hypothesis by suggesting that the effects of HER2 amplification on carcinogenesis, tumorigenesis and invasion may be due to its effects on normal and malignant mammary stem/progenitor cells. Furthermore, the clinical efficacy of trastuzumab may relate to its ability to target the cancer stem cell population in HER2-amplified tumors.