Trastuzumab emtansine for HER2-positive advanced breast cancer

IgE-based Immunotherapy of Cancer -A Comparative Oncology Approach

Antibody-based immunotherapies are important therapy options in human oncology. Although human humoral specific immunity is constituted of five different immunoglobulin classes, currently only IgG-based immunotherapies have proceeded to clinical application.

This review, however, discusses the benefits and difficulties of IgE-based immunotherapy of cancer, with special emphasis on how to translate promising preclinical results into clinical studies. Pursuing the “Comparative Oncology” approach, novel drug candidates are investigated in clinical trials with veterinary cancer patients, most often dogs. By this strategy drug development could be speeded up, animal experiments could be reduced and novel therapy options could be introduced benefitting humans as well as man’s best friend.

Phase II study of lapatinib in combination with vinorelbine, as first or second-line therapy in women with HER2 overexpressing metastatic breast cancer

Background

Lapatinib in combination with capecitabine is approved for the treatment of patients with advanced or metastatic breast cancer whose tumors overexpress the human epidermal growth factor receptor 2 (HER2) and who have received prior therapy including an anthracycline, a taxane, and trastuzumab. Based on our phase I trial, we conducted a single arm, multicenter phase II study of lapatinib in combination with vinorelbine.

Patient and methods

Women with HER2-positive advanced breast cancer, who had received up to one prior regimen for metastatic disease, were eligible. Prior trastuzumab was allowed. Patients received daily lapatinib 1500 mg orally and vinorelbine 20 mg/m² intravenously on days 1, 8 and 15 of a 28-day cycle. The primary endpoint was overall response rate (ORR).

Results

Forty-four patients received the combination treatment, including 48% as second-line therapy. The ORR was 41% (95% confidence interval [CI] 26–55%), including 9% with a complete response. Median progression-free survival was 24.1 weeks (95% CI 17–37 weeks) and median duration of response was 32 weeks (95% CI 18–42 weeks). Nearly 80% of patients did not require a dose reduction in lapatinib, although most patients required one dose reduction of vinorelbine secondary to neutropenia. The most common toxicities were grade 1 and 2 diarrhea, nausea, fatigue and rash, and grade 3 and 4 neutropenia. One case of grade 3 asymptomatic decreased left ventricular ejection fraction event was reported.

Conclusion

The combination of lapatinib and vinorelbine was active, feasible and well tolerated in patients with HER2-positive advanced breast cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/2193-1801-3-108) contains supplementary material, which is available to authorized users.

An antibody-drug conjugate that targets tissue factor exhibits potent therapeutic activity against a broad range of solid tumors

Tissue factor (TF) is aberrantly expressed in solid cancers and is thought to contribute to disease progression through its procoagulant activity and its capacity to induce intracellular signaling in complex with factor VIIa (FVIIa). To explore the possibility of using tissue factor as a target for an antibody-drug conjugate (ADC), a panel of human tissue factor-specific antibodies (TF HuMab) was generated. Three tissue factor HuMab, that induced efficient inhibition of TF:FVIIa-dependent intracellular signaling, antibody-dependent cell-mediated cytotoxicity, and rapid target internalization, but had minimal impact on tissue factor procoagulant activity in vitro, were conjugated with the cytotoxic agents monomethyl auristatin E (MMAE) or monomethyl auristatin F (MMAF). Tissue factor-specific ADCs showed potent cytotoxicity in vitro and in vivo, which was dependent on tissue factor expression. TF-011-MMAE (HuMax-TF-ADC) was the most potent ADC, and the dominant mechanism of action in vivo was auristatin-mediated tumor cell killing. Importantly, TF-011-MMAE showed excellent antitumor activity in patient-derived xenograft (PDX) models with variable levels of tissue factor expression, derived from seven different solid cancers. Complete tumor regression was observed in all PDX models, including models that showed tissue factor expression in only 25% to 50% of the tumor cells. In conclusion, TF-011-MMAE is a promising novel antitumor agent with potent activity in xenograft models that represent the heterogeneity of human tumors, including heterogeneous target expression.

Overview of diagnostic/targeted treatment combinations in personalized medicine for breast cancer patients

Breast cancer includes a body of molecularly distinct subgroups, characterized by different presentation, prognosis, and sensitivity to treatments. Significant advances in our understanding of the complex architecture of this pathology have been achieved in the last few decades, thanks to new biotechnologies that have recently come into the research field and the clinical practice, giving oncologists new instruments that are based on biomarkers and allowing them to set up a personalized approach for each individual patient. Here we review the main treatments available or in preclinical development, the biomolecular diagnostic and prognostic approaches that changed our perspective about breast cancer, giving an overview of targeted therapies that represent the current standard of care for these patients. Finally, we report some examples of how new technologies in clinical practice can set in motion the development of new drugs.

Smart Nanoscale Drug Delivery Platforms from Stimuli-Responsive Polymers and Liposomes

Since the 1960's, stimuli-responsive polymers have been utilized as functional soft materials for biological applications such as the triggered-release delivery of biologically active cargos. Over the same period, liposomes have been explored as an alternative drug delivery system with potentials to decrease the toxic side effects often associated with conventional small-molecule drugs. However, the lack of drug-release triggers and the instability of bare liposomes often limit their practical applications, causing short circulation time and low therapeutic efficacy. This perspective article highlights recent work in integrating these two materials together to achieve a targetable, triggerable nanoscale platform that fulfills all the characteristics of a near-ideal drug delivery system. Through a drop-in, post-synthesis modification strategy, a network of stimuli-responsive polymers can be integrated onto the surface of liposomes to form polymer-caged nanobins, a multifunctional nanoscale delivery platform that allows for multi-drug loading, targeted delivery, triggered drug-release, and theranostic capabilities.

Antibody-based therapy in colorectal cancer

Treatment in patients with nonresectable and resectable colorectal cancer at the advanced stage is challenging, therefore intensive strategies such as chemotherapy, signaling inhibitors and monoclonal antibodies (mAbs) to control the disease are required. mAbs are particularly promising tools owing to their target specificities and strong antitumor activities through multiple mechanisms, as shown by rituximab in B-cell non-Hodgkin's lymphoma and trastuzumab in breast cancer. Three mAbs (cetuximab, bevacizumab and panitumumab) have been approved for the treatment of colorectal cancer in the USA and many other mAbs are being tested in clinical trials. The potential of antibody therapy is associated with several mechanisms including interference of vital signaling pathways targeted by the antibody and immune cytotoxicity selectively directed against tumor cells by tumor-bound antibody through the Fc portion of the antibody, such as antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. Moreover, recent experimental findings have shown that immune complexes formed by therapeutic mAbs with tumor-released antigens could augment the induction of tumor-specific cytotoxic CD8(+) T cells through activation of APCs. In addition, antibodies targeting immune checkpoints on hematopoietic cells have recently opened a new avenue for the treatment of cancer. In this review, we focus on mAb treatment in colorectal cancer and its immunological aspects.

Identification of quinones as HER2 inhibitors for the treatment of trastuzumab resistant breast cancer

HER2 overexpression is associated with aggressive breast cancer with high recurrence rate and poor patient prognosis. Treatment of HER2 overexpressing patients with the HER2 targeting therapy trastuzumab results in acquired resistance within a year. The HER2/EGFR dual kinase inhibitor lapatinib was shown to inhibit some trastuzumab resistant breast cancer cell lines and is currently in clinical trials. Our group has found two new quinone compounds that show excellent inhibition of breast tumor cells expressing HER2 or the trastuzumab resistant HER2 oncogenic isoform, HER2Δ16. Compound 4 ((1R,2S,3S)-1,2,3,5,8-pentahydroxy-1,2,3,4-tetrahydroanthracene-9,10-dione) and compound 5 (5,8-dihydroxy-2,3-bis(hydroxymethyl)naphthalene-1,4-dione) showed sub-micromolar inhibition potency against these cell lines. These compounds also inhibit auto-phosphorylation of the Y1248 and Y1068 residues of HER2 and EGFR, respectively.

Endocytosis and cancer

Endocytosis entails selective packaging of cell-surface proteins, such as receptors for cytokines and adhesion components, in cytoplasmic vesicles (endosomes). The series of sorting events that determines the fate of internalized proteins, either degradation in lysosomes or recycling back to the plasma membrane, relies on intrinsic sequence motifs, posttranslational modifications (e.g., phosphorylation and ubiquitination), and transient assemblies of both Rab GTPases and phosphoinositide-binding proteins. This multicomponent process is enhanced and skewed in cancer cells; we review mechanisms enabling both major drivers of cancer, p53 and Ras, to bias recycling of integrins and receptor tyrosine kinases (RTKs). Likewise, cadherins and other junctional proteins of cancer cells are constantly removed from the cell surface, thereby disrupting tissue polarity and instigating motile phenotypes. Mutant forms of RTKs able to evade Cbl-mediated ubiquitination, along with overexpression of the wild-type forms and a variety of defective feedback regulatory loops, are frequently detected in tumors. Finally, we describe pharmacological attempts to harness the peculiar endocytic system of cancer, in favor of effective patient treatment.

Targeted cancer therapy--are the days of systemic chemotherapy numbered?

Targeted therapy or molecular targeted therapy has been defined as a type of treatment that blocks the growth of cancer cells by interfering with specific cell molecules required for carcinogenesis and tumor growth, rather than by simply interfering with all rapidly dividing cells as with traditional chemotherapy. There is a growing number of FDA approved monoclonal antibodies and small molecules targeting specific types of cancer suggestive of the growing relevance of this therapeutic approach. Targeted cancer therapies, also referred to as "Personalized Medicine", are being studied for use alone, in combination with other targeted therapies, and in combination with chemotherapy. The objective of personalized medicine is the identification of patients that would benefit from a specific treatment based on the expression of molecular markers. Examples of this approach include bevacizumab and olaparib, which have been designated as promising targeted therapies for ovarian cancer. Combinations of trastuzumab with pertuzumab, or T-DM1 and mTOR inhibitors added to an aromatase inhibitor are new therapeutic strategies for breast cancer. Although this approach has been seen as a major step in the expansion of personalized medicine, it has substantial limitations including its high cost and the presence of serious adverse effects. The Cancer Genome Atlas is a useful resource to identify novel and more effective targets, which may help to overcome the present limitations. In this review we will discuss the clinical outcome of some of these new therapies with a focus on ovarian and breast cancer. We will also discuss novel concepts in targeted therapy, the target of cancer stem cells.

Optimal tolerability and high efficacy of a modified schedule of lapatinib-capecitabine in advanced breast cancer patients

PURPOSE

Diarrhea in relation to the lapatinib-capecitabine regimen is a common and debilitating side effect which may interfere with optimal treatment delivery. We performed a post hoc analysis in human epidermal growth factor receptor 2-positive advanced breast cancer patients treated with a modified schedule in its administration, aimed primarily to evaluate grade (G) ≥ 2 diarrhea incidence and, secondarily, treatment efficacy.

PATIENTS AND METHODS

Treatment schedule consisted of lapatinib 1,250 mg daily for the first 10 days, then in combination with capecitabine, 2,000 mg/m(2), starting day 11 for the first cycle, and thereafter from day 8, for 14 days of a 21-day cycle, in 3 daily administrations. Lapatinib was dissolved in water, and cholestyramine was continuously given twice a day.

RESULTS

Among 38 patients treated and analyzed, the incidence of G ≥ 2 diarrhea was 13.2 %. In 28 patients diarrhea was not observed, while G1-2 diarrhea was reported in 9 (23.7 %) patients; a single episode of G3 diarrhea was observed in 1 (2.6 %) patient. Overall response rate was 34.2 %, clinical benefit 55.3 %, and median progression-free survival 10 months.

CONCLUSION

The results of the present post hoc analysis are very encouraging, both in terms of tolerability and treatment efficacy, and all data compare favorably with previous reports of "conventional" administration of the lapatinib-capecitabine regimen.

Surrogate endpoints in metastatic breast cancer treated with targeted therapies: an analysis of the first-line phase III trials

Progression-free survival (PFS) has not yet been established as a surrogate endpoint for overall survival (OS) in metastatic breast cancer (MBC). In particular, surrogacy has not been investigated with modern molecular agents. Randomized phase III trials for MBC were identified using a PubMed and EMBASE search. Correlations between PFS/time to progression (TTP), post-progression survival (PPS), response rate (RR) and OS were evaluated through a linear regression analysis. We also evaluated the potential of PFS to serve as a surrogate for OS in first-line trials exploring new drugs. Twenty trials with a total of 32 treatment arms and 10,138 patients were included. Spearman rank correlation coefficients (r s) between median PFS/TTP, RR and PPS with OS were 0.81 (95 % CI 0.58-0.92), 0.61 (95 % CI 0.59-0.63) and 0.73 (95 % CI 0.71-0.74). The correlation coefficient between hazard ratios in PFS/TTP and OS (HRPFS/TTP/HROS) was 0.73 (95 % CI 0.719-0.738; p < 0.00001); the slope of the regression line was 0.56 ± 0.0034, indicating that an agent producing a 10 % risk reduction for PFS will provide a 5.6 ± 0.34 % risk reduction for OS. In particular, the HRPFS/TTP/HROS correlation is stronger in an HER2-positive setting versus HER2-negative (r s = 0.91 vs. 0.67; p for difference <0.0001). These results suggest that improvements in PFS/TTP in MBC strongly correlate with improvements in OS with molecular agents, especially anti-HER2 therapeutics. Further analyses at patient-level data are required to confirm the surrogacy of PFS for OS with new agents.

The ErbB/HER family of protein-tyrosine kinases and cancer

The human epidermal growth factor receptor (EGFR) family consists of four members that belong to the ErbB lineage of proteins (ErbB1-4). These receptors consist of a glycosylated extracellular domain, a single hydrophobic transmembrane segment, and an intracellular portion with a juxtamembrane segment, a protein kinase domain, and a carboxyterminal tail. Seven ligands bind to EGFR including epidermal growth factor and transforming growth factor α, none bind to ErbB2, two bind to ErbB3, and seven ligands bind to ErbB4. The ErbB proteins function as homo and heterodimers. The heterodimer consisting of ErbB2, which lacks a ligand, and ErbB3, which is kinase impaired, is surprisingly the most robust signaling complex of the ErbB family. Growth factor binding to EGFR induces a large conformational change in the extracellular domain, which leads to the exposure of a dimerization arm in domain II of the extracellular segment. Two ligand-EGFR complexes unite to form a back-to-back dimer in which the ligands are on opposite sides of the aggregate. Following ligand binding, EGFR intracellular kinase domains form an asymmetric homodimer that resembles the heterodimer formed by cyclin and cyclin-dependent kinase. The carboxyterminal lobe of the activator kinase of the dimer interacts with the amino-terminal lobe of the receiver kinase thereby leading to its allosteric stimulation. Downstream ErbB signaling modules include the phosphatidylinositol 3-kinase/Akt (PKB) pathway, the Ras/Raf/MEK/ERK1/2 pathway, and the phospholipase C (PLCγ) pathway. Several malignancies are associated with the mutation or increased expression of members of the ErbB family including lung, breast, stomach, colorectal, head and neck, and pancreatic carcinomas and glioblastoma (a brain tumor). Gefitinib, erlotinib, and afatinib are orally effective protein-kinase targeted quinazoline derivatives that are used in the treatment of ERBB1-mutant lung cancer. Lapatinib is an orally effective quinazoline derivative used in the treatment of ErbB2-overexpressing breast cancer. Trastuzumab, pertuzumab, and ado-trastuzumab emtansine, which are given intravenously, are monoclonal antibodies that target the extracellular domain and are used for the treatment of ErbB2-positive breast cancer; ado-trastuzumab emtansine is an antibody-drug conjugate that delivers a cytotoxic drug to cells overexpressing ErbB2. Cetuximab and panitumumab are monoclonal antibodies that target ErbB1 and are used in the treatment of colorectal cancer. Cancers treated with these targeted drugs eventually become resistant to them. The role of combinations of targeted drugs or targeted drugs with cytotoxic therapies is being explored in an effort to prevent or delay drug resistance in the treatment of these malignancies.

Antibody-drug conjugates: current status and future directions

Antibody-drug conjugates (ADCs) aim to take advantage of the specificity of monoclonal antibodies (mAbs) to deliver potent cytotoxic drugs selectively to antigen-expressing tumor cells. Despite the simple concept, various parameters must be considered when designing optimal ADCs, such as selection of the appropriate antigen target and conjugation method. Each component of the ADC (the antibody, linker and drug) must also be optimized to fully realize the goal of a targeted therapy with improved efficacy and tolerability. Advancements over the past several decades have led to a new generation of ADCs comprising non-immunogenic mAbs, linkers with balanced stability and highly potent cytotoxic agents. Although challenges remain, recent clinical success has generated intense interest in this therapeutic class.

Trends in cancer-targeted antibody-drug conjugates

Better knowledge of engineered antibodies and tumour biology has led to the development of novel targeted therapies, such as antibody-drug conjugates (ADCs). ADCs combine a monoclonal antibody, directed toward specific antigen highly expressed on the cancer cell, to potent cytotoxic drug through a stable linker. ADCs are designed to bind selectively to cancer cells and to deliver cytotoxic drugs into the cancer cell, which may preserve normal cells. ADCs should be stable and non-toxic in circulation. Upon binding to antigen, ADCs are internalized by different processes, followed by the intracellular release of an active form of the cytotoxic drug, which in turn kills the cancer cell. This technology has the potential to further improve the anticancer activity while limiting toxicity. First results from ongoing clinical trials are encouraging. Favourable pharmacokinetic profile was observed showing good stability in circulation. Clinical studies demonstrated that ADCs provide clinical efficacy with an acceptable safety profile. Objective responses and clinical benefits were demonstrated with the investigated ADCs. Major toxicities frequently associated to chemotherapy were barely or not reported with ADCs. Taken together, ADCs may become the new wave of anticancer drugs in the future.

Patient-reported outcomes from EMILIA, a randomized phase 3 study of trastuzumab emtansine (T-DM1) versus capecitabine and lapatinib in human epidermal growth factor receptor 2-positive locally advanced or metastatic breast cancer

BACKGROUND

This report describes the results of an analysis of patient-reported outcomes from EMILIA (TDM4370g/BO21977), a randomized phase 3 study of the antibody-drug conjugate trastuzumab emtansine (T-DM1) versus capecitabine and lapatinib in human epidermal growth factor receptor 2 (HER2)-positive locally advanced or metastatic breast cancer.

METHODS

A secondary endpoint of the EMILIA study was time to symptom worsening (time from randomization to the first documentation of a ≥ 5-point decrease from baseline) as measured by the Trial Outcome Index Physical/Functional/Breast (TOI-PFB) subset of the Functional Assessment of Cancer Therapy-Breast questionnaire. Predefined exploratory patient-reported outcome endpoints included proportion of patients with a clinically significant improvement in symptoms (per TOI-PFB) and proportion of patients with diarrhea symptoms (per Diarrhea Assessment Scale).

RESULTS

In the T-DM1 arm, 450 of 495 patients had a baseline and ≥ 1 postbaseline TOI-PFB score versus 445 of 496 patients in the capecitabine-plus-lapatinib arm. Time to symptom worsening was delayed in the T-DM1 arm versus the capecitabine-plus-lapatinib arm (7.1 months versus 4.6 months, respectively; hazard ratio = 0.796; P = .0121). In the T-DM1 arm, 55.3% of patients developed clinically significant improvement in symptoms from baseline versus 49.4% in the capecitabine-plus-lapatinib arm (P = .0842). Although similar at baseline, the number of patients reporting diarrhea symptoms increased 1.5- to 2-fold during treatment with capecitabine and lapatinib but remained near baseline levels in the T-DM1 arm.

CONCLUSIONS

Together with the EMILIA primary data, these results support the concept that T-DM1 has greater efficacy and tolerability than capecitabine plus lapatinib, which may translate into improvements in health-related quality of life.

Polymeric nanoparticle system to target activated microglia/macrophages in spinal cord injury

The possibility to control the fate of the cells responsible for secondary mechanisms following spinal cord injury (SCI) is one of the most relevant challenges to reduce the post traumatic degeneration of the spinal cord. In particular, microglia/macrophages associated inflammation appears to be a self-propelling mechanism which leads to progressive neurodegeneration and development of persisting pain state. In this study we analyzed the interactions between poly(methyl methacrylate) nanoparticles (PMMA-NPs) and microglia/macrophages in vitro and in vivo, characterizing the features that influence their internalization and ability to deliver drugs. The uptake mechanisms of PMMA-NPs were in-depth investigated, together with their possible toxic effects on microglia/macrophages. In addition, the possibility to deliver a mimetic drug within microglia/macrophages was characterized in vitro and in vivo. Drug-loaded polymeric NPs resulted to be a promising tool for the selective administration of pharmacological compounds in activated microglia/macrophages and thus potentially able to counteract relevant secondary inflammatory events in SCI.

HER story: the next chapter in HER-2-directed therapy for advanced breast cancer

Untreated human epidermal growth factor receptor-2 (HER-2)-positive advanced breast cancer (ABC) is an aggressive disease, associated with a poor prognosis and short overall survival. HER-2-directed therapy prolongs both time to disease progression and overall survival when combined with chemotherapy and has become the standard of care for those with HER-2-positive breast cancer in the early and advanced settings. Despite the remarkable therapeutic impact HER-2-directed therapy has had on disease outcomes, some patients with HER-2-positive disease will have primary resistant disease and others will respond initially but will eventually have progression, underscoring the need for other novel therapeutic options. This article reviews recent phase III trial data and discusses a practical approach to sequencing of HER-2-directed therapy in patients with HER-2-positive ABC. The significant cumulative survival gains seen in these trials are slowly reshaping the landscape of HER-2-positive ABC outcomes.

Which patients with metastatic breast cancer benefit from subsequent lines of treatment? An update for clinicians

The outcome of patients with metastatic breast cancer (MBC) has clearly improved over the past decades and the proportion of women living with their disease for several years is increasing. However, the usefulness of multiple lines of treatment is still debated and under evaluation. The available data from both randomized trials and large retrospective series are reviewed and discussed in order to analyze management practices, with emphasis on potential prognostic and predictive factors for clinical outcome. At present, evidence-based medicine provides some support for the use of second-line and to a lesser degree and in selected cases, third-line chemotherapy in human epidermal growth factor receptor 2 (HER2) negative MBC. Beyond third-line treatment, messages from recently reported retrospective studies also suggest a clear potential gain for women receiving further therapies after disease progression, since each line can contribute to a longer survival. In HER2-positive disease, the data from observational and retrospective studies support a clinical benefit from the use of trastuzumab beyond disease progression and emerging evidences from randomized controlled trials are leading to the introduction of newer HER2-targeted therapies in multiple lines. The question 'How many lines of treatment should we give patients?' clearly needs further research through prospective, high-quality clinical trials, aiming for a better definition of factors with prognostic and predictive role. In the meantime, the 'optimal' treatment strategy should probably be to use as many therapeutic options as possible, either in sequence or combination, to keep the best efficacy/toxicity balance, considering MBC as a chronic disease.

Strategies for advancing cancer nanomedicine

Cancer nanomedicines approved so far minimize toxicity, but their efficacy is often limited by physiological barriers posed by the tumour microenvironment. Here, we discuss how these barriers can be overcome through innovative nanomedicine design and through creative manipulation of the tumour microenvironment.

Recommendations for human epidermal growth factor receptor 2 testing in breast cancer: American Society of Clinical Oncology/College of American Pathologists clinical practice guideline update

PURPOSE

To update the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guideline recommendations for human epidermal growth factor receptor 2 (HER2) testing in breast cancer to improve the accuracy of HER2 testing and its utility as a predictive marker in invasive breast cancer.

METHODS

ASCO/CAP convened an Update Committee that included coauthors of the 2007 guideline to conduct a systematic literature review and update recommendations for optimal HER2 testing.

RESULTS

The Update Committee identified criteria and areas requiring clarification to improve the accuracy of HER2 testing by immunohistochemistry (IHC) or in situ hybridization (ISH). The guideline was reviewed and approved by both organizations.

RECOMMENDATIONS

The Update Committee recommends that HER2 status (HER2 negative or positive) be determined in all patients with invasive (early stage or recurrence) breast cancer on the basis of one or more HER2 test results (negative, equivocal, or positive). Testing criteria define HER2-positive status when (on observing within an area of tumor that amounts to > 10% of contiguous and homogeneous tumor cells) there is evidence of protein overexpression (IHC) or gene amplification (HER2 copy number or HER2/CEP17 ratio by ISH based on counting at least 20 cells within the area). If results are equivocal (revised criteria), reflex testing should be performed using an alternative assay (IHC or ISH). Repeat testing should be considered if results seem discordant with other histopathologic findings. Laboratories should demonstrate high concordance with a validated HER2 test on a sufficiently large and representative set of specimens. Testing must be performed in a laboratory accredited by CAP or another accrediting entity. The Update Committee urges providers and health systems to cooperate to ensure the highest quality testing. This guideline was developed through a collaboration between the American Society of Clinical Oncology and the College of American Pathologists and has been published jointly by invitation and consent in both Journal of Clinical Oncology and the Archives of Pathology & Laboratory Medicine.

Targeting receptor tyrosine kinases in HER2-negative breast cancer

PURPOSE OF REVIEW

The targeting of receptor tyrosine kinases (RTKs) has been a major area for breast cancer therapy, exemplified by the targeting of HER2-amplified breast cancer.

RECENT FINDINGS

We review the data on the activation of RTKs in HER2-negative breast cancer, and discuss the clinical translational challenge of identifying cancers that are reliant on a specific kinase for growth and survival. Substantial evidence suggests that subsets of breast cancer may be reliant on specific kinases, and that this could be exploited therapeutically. The heterogeneity of breast cancer, however, and the potential for adaptive switching between RTKs after inhibition of a single RTK, present challenges to targeting individual RTKs in the clinic

SUMMARY

Targeting of RTKs in HER2-negative breast cancer presents a major therapeutic opportunity in breast cancer, although robust selection strategies will be required to identify cancers with activation of specific RTKs if this potential is to be realized.

Exploiting endocytosis for nanomedicines

In this article, we briefly review the endocytic pathways used by cells, pointing out their defining characteristics and highlighting physical limitations that may direct the internalization of nanoparticles to a subset of these pathways. A more detailed description of these pathways is presented in the literature. We then focus on the endocytosis of nanomedicines and present how various nanomaterial parameters impact these endocytic processes. This topic is an area of active research, motivated by the recognition that an improved understanding of how nanomaterials interact at the molecular, cellular, and whole-organism level will lead to the design of better nanomedicines in the future. Next, we briefly review some of the important nanomedicines already on the market or in clinical development that serve to exemplify how endocytosis can be exploited for medical benefit. Finally, we present some key unanswered questions and remaining challenges to be addressed by the field.

Inferring primary tumor sites from mutation spectra: a meta-analysis of histology-specific aberrations in cancer-derived cell lines

Next-generation sequencing technologies have led to profound characterization of mutation spectra for several cancer types. Hence, we sought to systematically compare genomic aberrations between primary tumors and cancer lines. For this, we compiled publically available sequencing data of 1651 genes across 905 cell lines. We used them to characterize 23 distinct primary tumor sites by a novel approach that is based on Bayesian spam-filtering techniques. Thereby, we confirmed the strong overall similarity of alterations between patient samples and cell culture. However, we also identified several suspicious mutations, which had not been associated with their cancer types before. Based on these characterizations, we developed the inferring cancer origins from mutation spectra (ICOMS) tool. On our cell line collection, the algorithm reached a prediction specificity rate of 79%, which strongly variegated between primary cancer sites. On an independent validation cohort of 431 primary tumor samples, we observed a similar accuracy of 71%. Additionally, we found that ICOMS could be employed to deduce further attributes from mutation spectra, including sub-histology and compound sensitivity. Thus, thorough classification of site-specific mutation spectra for cell lines may decipher further genome-phenotype associations in cancer.

Linked-in: design and efficacy of antibody drug conjugates in oncology

The use of antibody drug conjugates (ADCs) as targeted chemotherapies has successfully entered clinical practice and holds great promise. ADCs consist of an antibody and toxin-drug combined together via a chemical linker. While the antibody and drug are of vital importance in the direct elimination of cancer cells, more advanced linker technology was instrumental in the delivery of more potent drugs with fewer side effects. Here, we discuss the preclinical experience as well as clinical trials, with a specific emphasis on the clinical outcomes and side effects, in addition to linker strategies for five different ADCs, in order to describe different approaches in the development of this new class of anticancer agents. Brentuximab vedotin is approved for use in Hodgkin&rsquo;s lymphoma and Trastuzumab emtansine is approved for breast cancer. Combotox, Inotuzumab Ozogamicin, and Moxetumomab Pasudotox are in various stages of clinical development and are showing significant efficacy in lymphoid malignancies. These ADCs illustrate the promise and future potential of targeted therapy for presently incurable malignancies.

Emerging paradigms in cardiomyopathies associated with cancer therapies

The cardiovascular care of cancer patients (cardio-oncology) has emerged as a new discipline in clinical medicine, given recent advances in cancer therapy, and is driven by the cardiovascular complications that occur as a direct result of cancer therapy. Traditional therapies such as anthracyclines and radiation have been recognized for years to have cardiovascular complications. Less expected were the cardiovascular effects of targeted cancer therapies, which were initially thought to be specific to cancer cells and would spare any adverse effects on the heart. Cancers are typically driven by mutations, translocations, or overexpression of protein kinases. The majority of these mutated kinases are tyrosine kinases, though serine/threonine kinases also play key roles in some malignancies. Several agents were developed to target these kinases, but many more are in development. Major successes have been largely restricted to agents targeting human epidermal growth factor receptor-2 (mutated or overexpressed in breast cancer), BCR-ABL (chronic myelogenous leukemia and some cases of acute lymphoblastic leukemia), and c-Kit (gastrointestinal stromal tumor). Other agents targeting more complex malignancies, such as advanced solid tumors, have had successes, but have not extended life to the degree seen with chronic myelogenous leukemia. Years before the first targeted therapy, Judah Folkman correctly proposed that to address solid tumors one had to target the inherent neoangiogenesis. Unfortunately, emerging evidence confirms that angiogenesis inhibitors cause cardiac complications, including hypertension, thrombosis, and heart failure. And therein lies the catch-22. Nevertheless, cardio-oncology has the potential to be transformative as the human cardiomyopathies that arise from targeted therapies can provide insights into the normal function of the heart.

SEOM clinical guidelines for the management of metastatic breast cancer 2013

Patients with metastatic breast cancer should be offered comprehensive and personalized medical attention including, but not limited to, psychosocial, supportive and symptom-related interventions. A large number of treatment options are available and several prognostic and predictive factors are useful to identify the best therapeutic options individually.

Trastuzumab emtansine: a novel antibody-drug conjugate for HER2-positive breast cancer

Trastuzumab emtansine (T-DM1) is a novel HER2-directed antibody-drug conjugate. T-DM1 consists of the potent antimicrotubule agent DM1, linked via a noncleavable linker to the HER2-specific monoclonal antibody trastuzumab. Preclinical studies demonstrate that T-DM1 has dual mechanisms of action: selective delivery of DM1 to the HER2-positive (HER2(+)) tumor cell combined with trastuzumab's activation of antibody-dependent cell-mediated cytotoxicity and inhibition of HER2-mediated signal transduction. In phase II studies, T-DM1 was active in patients with trastuzumab- and lapatinib-refractory metastatic breast cancer and led to improved progression-free survival compared with the combination of trastuzumab and docetaxel in the first-line setting. In a recent phase III trial in patients with metastatic breast cancer who previously received trastuzumab and a taxane, T-DM1 resulted in improved progression-free and overall survival compared with capecitabine and lapatinib. T-DM1 is associated with a favorable toxicity profile; reversible thrombocytopenia and hepatic transaminase elevations are the only grade ≥3 adverse event present in 5% or more of patients. Alopecia, peripheral neuropathy, and neutropenia are distinctly uncommon. On the basis of its improved efficacy and toxicity compared with capecitabine/lapatinib, T-DM1 should be considered the standard for patients with HER2(+) metastatic breast cancer who have previously progressed on trastuzumab and a taxane. Results from additional randomized studies in metastatic breast cancer are pending, and trials in the (neo)adjuvant setting are being initiated.

Personalizing therapies for gastric cancer: molecular mechanisms and novel targeted therapies

Globally, gastric cancer is the 4(th) most frequently diagnosed cancer and the 2(nd) leading cause of death from cancer, with an estimated 990000 new cases and 738000 deaths registered in 2008. In the advanced setting, standard chemotherapies protocols acquired an important role since last decades in prolong survival. Moreover, recent advances in molecular therapies provided a new interesting weapon to treat advanced gastric cancer through anti-human epidermal growth factor receptor 2 (HER2) therapies. Trastuzumab, an anti-HER2 monoclonal antibody, was the first target drug in the metastatic setting that showed benefit in overall survival when in association with platinum-5-fluorouracil based chemotherapy. Further, HER2 overexpression analysis acquired a main role in predict response for trastuzumab in this field. Thus, we conducted a review that will discuss the main points concerning trastuzumab and HER2 in gastric cancer, providing a comprehensive overview of molecular mechanisms and novel trials involved.

An improved radiolabelled RNA aptamer molecule for HER2 imaging in cancers

Human epidermal growth factor receptor 2 (HER2) expression has been shown to be increased in several types of human tumours. In this study, for the imaging of HER2-related tumours, a modified RNA aptamer with HER2-specific targeting was labelled with (99m)Tc, by using hydrazino nicotinamide (HYNIC) as the chelator in the presence of tricine or ethylenediamine-N,N'-diacetic acid (EDDA) as the co-ligand. Stability testing of the radiolabelled aptamers in the serum was performed through SDS-PAGE. The aptamer-radionuclide conjugate was evaluated for its cellular HER2-specific binding in ovarian cancer cells (SKOV-3), and its biodistribution properties were assessed in normal and SKOV-3 tumour-bearing mice. In the presence of either tricine or EDDA, the HYNIC-RNA aptamers were labelled with (99m)Tc at a high yield and radiochemical purity. Cellular experiments confirmed the specific binding of the RNA aptamer to the HER2 receptor. In the animal biodistribution study, uptake of the EDDA-co-liganded (99m)Tc-HYNIC-RNA aptamer by the liver and spleen was remarkably lower than that of the aptamer with tricine. Tumours also showed a higher accumulation of radioactivity with the EDDA-co-liganded aptamer complex. This study demonstrated EDDA to be better than tricine for use as a co-ligand with the RNA aptamer, which can be a potential tool for the molecular imaging of HER2-overexpressing cancers.

Structural basis for eliciting a cytotoxic effect in HER2-overexpressing cancer cells via binding to the extracellular domain of HER2

Human epidermal growth factor receptor-2 (HER2) is a receptor tyrosine kinase directly linked to the growth of malignancies from various origins and a validated target for monoclonal antibodies and kinase inhibitors. Utilizing a new approach with designed ankyrin repeat proteins (DARPins) as alternative binders, we show that binding of two DARPins connected by a short linker, one targeting extracellular subdomain I and the other subdomain IV, causes much stronger cytotoxic effects on the HER2-addicted breast cancer cell line BT474, surpassing the therapeutic antibody trastuzumab. We determined crystal structures of these DARPins in complex with the respective subdomains. Detailed models of the full-length receptor, constrained by its rigid domain structures and its membrane anchoring, explain how the bispecific DARPins connect two membrane-bound HER2 molecules, distorting them such that they cannot form signaling-competent dimers with any EGFR family member, preventing any kinase dimerization, and thus leading to a complete loss of signaling.

Pharmacokinetics, clinical indications, and resistance mechanisms in molecular targeted therapies in cancer

The strategy for discovery and development of new cancer drugs has shifted the field from cytotoxic agents to therapies that selectively target oncogenic drivers. In the last decade, a number of targeted cancer therapies have been discovered and proven effective in a variety of hematological and solid malignancies. In this article, we review clinical pharmacokinetic characteristics of the U.S. Food and Drug Administration-approved targeted therapies and provide an overview of key clinical trials that led to approval of these drugs. The major limiting factor of targeted treatment is the development of resistance. We describe general principles of resistance and specific, clinically confirmed mechanisms of resistance to several therapies in different malignancies.

HER2 expression beyond breast cancer: therapeutic implications for gynecologic malignancies

HER2 or ErbB2 is a member of the epidermal growth factor family and is overexpressed in subsets of breast, ovarian, gastric, colorectal, pancreatic, and endometrial cancers. HER2 regulates signaling through several pathways (Ras/Raf/mitogen-activated protein kinase and phosphatidylinositol-3 kinase/protein kinase B/mammalian target of rapamycin pathways) associated with cell survival and proliferation. HER2-overexpressed and/or gene-amplified tumors are generally regarded as biologically aggressive neoplasms. In breast, cervical, endometrial, and ovarian cancer, there have been several studies linking the amplification of the c-erbB2 gene with chemoresistance and overall poor survival. Tyrosine kinase inhibitors and immunotherapy with monoclonal antibodies targeting HER2 hold promise for patients harboring these aggressive neoplasms. Trastuzumab combined with cytotoxic chemotherapy agents or conjugated with radioactive isotopes is currently being investigated in clinical trials of several tumor types.

Paclitaxel and Trastuzumab as Maintenance Therapy in Patients with HER2-Positive Metastatic Breast Cancer Who Underwent High-Dose Chemotherapy and Autologous Hematopoietic Stem Cell Transplantation

We examined the feasibility and safety of using paclitaxel and trastuzumab as maintenance therapy after high-dose chemotherapy (HDC) with autologous hematopoietic stem cell transplantation (AHST) for patients with HER2-positive metastatic breast cancer. Ten patients (9 women and 1 man) were enrolled in the study. The median age was 46.5 years (range, 27-65 years). The median follow-up time was 1003 days (range, 216-2526 days). All patients had metastatic disease, but 2 had only bone metastasis. One patient had complete response, 6 had partial response and 3 had stable disease to the standard-dose chemotherapy prior to transplantation. The conditioning regimen consisted of cyclophosphamide, carmustine, and thiotepa. After AHST, patients received weekly paclitaxel for 12 doses and trastuzumab every 3 weeks for 1 year as maintenance therapy. All patients experienced successful engraftment. The only grade 4 toxic effects observed were leukopenia and thrombocytopenia. The most common grade 3 toxic effect was neutropenic fever. No treatment-related deaths were observed. The median progression-free survival time was 441 days, and the median overall survival time was 955 days. Two patients died in accidents while their disease remained in remission. Five patients died with disease progression. At the time of this report, 3 patients are alive with stable disease, 1 of whom has remained free of disease progression for 2526 days since transplantation. Our findings indicate that paclitaxel plus trastuzumab as maintenance therapy after HDC with AHST for patients with HER2-positive metastatic breast cancer not only is feasible and safe but also results in survival outcomes similar to historical results.

Why your preferred targeted drugs may become unaffordable

Trastuzumab, a monoclonal antibody directed at the HER2 receptor, is one of the most impressive targeted drugs developed in the last two decades. Indeed, when given in conjunction with chemotherapy, it improves the survival of women with HER2 positive breast cancer, both in advanced and in early disease. Its optimal duration, however, is poorly defined in both settings with a significant economic impact in the adjuvant setting where the drug is arbitrarily given for 1 year. This article reviews current attempts at shortening this treatment duration, emphasizing the likelihood of inconclusive results and, therefore, the need to investigate this important variable as part of the initial pivotal trials and with the support of public health systems. Failure to do so has major consequences on treatment affordability. Ongoing adjuvant trials of dual HER2 blockade, using trastuzumab in combination with a second anti-HER2 agent, and trials of the antibody-drug conjugate T-DM1 (trastuzumab-emtansine) have to all be designed with 12 months of targeted therapy.

Antibody therapeutics in cancer

In a relatively short period of time, monoclonal antibodies have entered the mainstream of cancer therapy. Their first use was as antagonists of oncogenic receptor tyrosine kinases, but today monoclonal antibodies have emerged as long-sought vehicles for the targeted delivery of potent chemotherapeutic agents and as powerful tools to manipulate anticancer immune responses. With ever more promising results from the clinic, the future will likely see continued growth in the discovery and development of therapeutic antibodies and their derivatives.