111Indium-trastuzumab visualises myocardial human epidermal growth factor receptor 2 expression shortly after anthracycline treatment but not during heart failure: a clue to uncover the mechanisms of trastuzumab-related cardiotoxicity

Role of hypertension on new onset congestive heart failure in patients receiving trastuzumab therapy for breast cancer

BACKGROUND

Adjuvant trastuzumab therapy improves survival of Human Epidermal growth factor receptor 2 (HER2)-positive women with early breast cancer (EBC). Trastuzumab-induced cardiotoxicity is not uncommon. In the setting of community patients, the incidence, timing and phenotype of new onset congestive heart failure (CHF) is unknown.

METHODS

Forty hundred and ninety nine consecutive HER2-positive women (mean age 55 ± 11) with EBC treated with trastuzumab between January 2008 and June 2009 at 10 Italian institutions were followed-up for 1 year. We evaluated incidence, time of occurrence, clinical features associated with CHF. Left ventricular ejection fraction (LVEF) was evaluated by echocardiography at baseline and 3, 6, 9and 12 months during trastuzumab therapy.

RESULTS

CHF occurred in 16 patients (3.2%), who were older, more hypertensive and with a higher degree of hypertension in comparison with patients who did not have CHF. All CHF patients had a significant reduction in LVEF with a mean peak of -12 points % detected at 3-month follow-up. CHF occurred in seven patients (44%) within 3-month follow-up, in four patients (25%) between 3-6 months, in three patients (19%) between 6-9 months and in two patients (12%) between 9 and 12 months. Trastuzumab was discontinued in 10 of 16 patients and re-started in five after LVEF recovery and clinical improvement. New onset CHF was predicted by the presence of hypertension [OR 2.9 (CI 1.1-7.9]).

CONCLUSION

New onset CHF occurs seldom in HER2-positive women with EBC, prevalently in the first 6 months of therapy. CHF is associated with a significant reduction in LVEF and is predicted by a history of hypertension.

Noninvasive imaging of cardiovascular injury related to the treatment of cancer

The introduction of multiple treatments for cancer, including chemotherapeutic agents and radiation therapy, has significantly reduced cancer-related morbidity and mortality. However, these therapies can promote a variety of toxicities, among the most severe being the ones involving the cardiovascular system. Currently, for many surviving cancer patients, cardiovascular (CV) events represent the primary cause of morbidity and mortality. Recent data suggest that CV injury occurs early during cancer treatment, creating a substrate for subsequent cardiovascular events. Researchers have investigated the utility of noninvasive imaging strategies to detect the presence of CV injury during and after completion of cancer treatment because it starts early during cancer therapy, often preceding the development of chemotherapy or cancer therapeutics related cardiac dysfunction. In this State-of-the-Art Paper, we review the utility of current clinical and investigative CV noninvasive modalities for the identification and characterization of cancer treatment-related CV toxicity.

Imaging EGFR and HER2 by PET and SPECT: a review

In an effort to discover a noninvasive method for predicting which cancer patients will benefit from therapy targeting the EGFR and HER2 proteins, a large body of the research has been conducted toward the development of PET and SPECT imaging agents, which selectively target these receptors. We provide a general overview of the advances made toward imaging EGFR and HER2, detailing the investigation of PET and SPECT imaging agents ranging in size from small molecules to monoclonal antibodies.

Traditional and novel methods to assess and prevent chemotherapy-related cardiac dysfunction noninvasively

The field of cardio-oncology is challenged to address an ever greater spectrum of cardiotoxicity associated with combination chemotherapy, greater dose intensity, extremes of age, and enhanced patient survival which exposes more protracted risk of developing congestive heart failure (CHF). Recent reports of chemotherapy-induced hypertension as a common adverse effect of angiogenesis inhibitors and immunosuppressants clarify the need for routine blood pressure (BP) monitoring and guideline-based management of hypertension as an integral strategy to preserve LV function. Serial monitoring of radionuclide left ventricular ejection fraction (LVEF) in adults and echocardiography in children continues to provide outcome based, cost-effective prevention of CHF in high risk patients receiving chemotherapy. To optimize treatment and monitoring strategies to eliminate late-onset LV dysfunction and CHF, traditional and novel candidate methods for assessment of chemotherapy-induced LV dysfunction are reviewed. These include serial assessment of LV volume indices by gated SPECT ERNA and gated SPECT MPI, 3D echocardiography and contrast 2D echocardiography; longitudinal strain imaging, diastolic functional parameters, (123)I-MIBG, (111)In-Antimyosin antibody imaging, and (99m)Tc-Annexin V apoptosis imaging, biomarkers including troponins and BNP; genetic markers, and both functional and tissue characterization techniques with T1 weighted and T2 weighted images with cardiac magnetic resonance imaging (CMR). In our quest to optimize strategies for long-term cancer survival and prevention of CHF for patients receiving chemotherapy, rigorous modality and guideline-specific clinical outcome trials are required. A new multi-modality monitoring approach is proposed, which integrates evidence-based strengths of CMR, echocardiography, ERNA, biomarkers, and BP management for surveillance and validation of cardiotoxicity and prevention of clinical heart failure in patients receiving a broad spectrum of cancer therapies.

Cardiac side effects of trastuzumab in breast cancer patients - single centere experiences

AIM OF THE STUDY

The aim of this study was to present our own experiences concerning risk factors for cardiac side effects in the study group.

MATERIAL AND METHODS

The study was performed in 120 patients with HER2-overexpressing breast cancer who received immunotherapy in the Clinical and Experimental Oncology Department, between 2006 and 2011.

RESULTS

LVEF reduction > 10% of the baseline fraction was observed in 10 (8%) patients. Symptomatic heart failure occurred in two individuals. Due to persistent cardiotoxicity five patients (4%) had to discontinue therapy prematurely. Risk factors for cardiac toxicity in the analyzed group included: previous radiotherapy to the left side of the chest (p = 0.05), higher BMI (p = 0.05), negative steroid receptor status (p = 0.045) and low baseline LVEF (p < 0.001). Patients receiving radiotherapy were more likely to develop cardiotoxicity if presenting older age (p = 0.0003).

CONCLUSIONS

Previous radiotherapy to the left side of the chest, negative steroid receptor status, high BMI and low baseline LVEF were associated with increased risk of cardiac dysfunction. There was no difference between patients receiving adjuvant therapy and those treated due to metastatic disease.

Chemotherapy-related cardiotoxicity

Cardiovascular toxicity caused by cancer therapy is a challenging area which needs thorough evaluation and research. Numerous studies, meta-analyses and reviews have been published in the past discussing cardiotoxicity caused by chemotherapeutic agents. A brief review of the on-target and off-target cardiotoxicities caused by chemotherapeutic agents is presented here. Cardiotoxicities are broadly outlined in terms of left ventricular dysfunction, hypertension and thromboembolic events. The mechanisms leading to the cardiotoxicity profiles of various chemotherapeutic agents are discussed. The management of various cardiotoxicities of chemotherapeutic agents is also discussed.

Cardiac side effects of anticancer treatments: new mechanistic insights

Damage to heart cells leading to heart failure is a known complication of well-established cancer therapies including anthracycline antibiotics and radiation therapy, and the cardiovascular complications of these therapies has been controlled in large part through dose limitations and modifications of delivery methods. Recent research into the cellular and molecular mechanisms for the cardiovascular effects of these therapies may lead to other cardioprotective strategies that improve effectiveness of cancer treatments. Newer cancer therapies that have been developed based upon specifically targeting oncogene signaling also have been associated with heart failure. Rapid development of a detailed understanding of how these agents cause cardiac dysfunction promises to improve outcomes in cancer patients, as well as stimulate concepts of cardiovascular homeostasis that will likely accelerate development of cardiovascular therapies.

Detection and prevention of cardiac complications of cancer chemotherapy

Despite continuous improvements in management of patients with cancer, cardiac side-effects still account for a substantial limitation of chemotherapy. Evaluation of cardiac toxicity in patients includes consideration of biomarkers such as cardiac troponins and B-type natriuretic peptides, together with non-invasive imaging in the form of 2D-, 3D-, or strain-echocardiography, multiple gated radionuclide angiography, quantitative gated blood-pool SPECT, (123)I-metaiodobenzylguanidine scintigraphy, or cardiac magnetic resonance imaging. These approaches differ from each other with regards to availability, accuracy, sensitivity to detect early stages of cardiac injury, individual reliability, ease of use in a longitudinal follow-up perspective, and to related cost-effectiveness. Improving prevention of these cardiac side-effects depends on several, currently unresolved issues. Early detection and quantification of cardiac damage is required to adapt chemotherapy in progress for optimal management of patients. Whether increased availability of myocardial strain imaging and repeat blood biomarkers determinations will reliably and consistently achieve these goals remain to be confirmed. Also, protective approaches to reduce cardiac toxicity of anticancer drugs should be reconsidered according to the recently restricted approval for use of dexrazoxane. Anthracycline-based regimens, encapsulated anthracyclines and non-anthracycline regimens should be revisited with regards to antitumour efficacy and cardiac toxicity. Cardiovascular drugs that proved effective in prevention of anthracycline-induced cardiac toxicity in experimental models should be investigated in clinical trials. Finally, the efficacy of cardiovascular drugs that have already been tested in clinical settings should be confirmed and compared with each other in patients in increased numbers.

Administration of angiotensin-converting enzyme inhibitors and β-blockers during adjuvant trastuzumab chemotherapy for nonmetastatic breast cancer: marker of risk or cardioprotection in the real world?

BACKGROUND

Adjuvant trastuzumab therapy improves the outcome of patients with early breast cancer (EBC) and overexpression of human epidermal growth factor receptor 2 (HER2). However, it is potentially cardiotoxic. This study aims to evaluate the relationship between the use of angiotensin-converting enzyme inhibitors/receptor blockers (ACEi/ARBs) and/or β-blockers and development of heart failure (HF) and/or left ventricular dysfunction during 1 year of adjuvant trastuzumab therapy.

METHODS

A total of 499 women receiving adjuvant trastuzumab therapy for EBC entered in a multicenter registry and were divided into four subgroups according to treatment with ACEi/ARBs and/or β-blockers. Occurrence of HF and decrease of left ventricular ejection fraction (LVEF; minimum 10 percentage points) were recorded.

RESULTS

HF occurred in 2% of patients who did not take either ACEi/ARBs or β-blockers, 8% of patients receiving ACEi/ARBs alone, 8% receiving β-blockers alone (p = .03), and 19% receiving both medications (p < .01). The prevalence of patients with LVEF that decreased by at least 10 percentage points was similar in all groups. Combined ACEi/ARBs and β-blocker therapy was independently associated with hypertension and a significant reduction of LVEF from baseline to 3-month evaluation. The use of ACEi/ARBs alone or β-blockers alone was predicted only by hypertension. Combined therapy of ACEi/ARBs plus β-blockers predicted LVEF recovery from the 3-month to 12-month evaluation.

CONCLUSIONS

In clinical practice, the degree of hypertension and decrease in LVEF during the first 3 months of adjuvant trastuzumab therapy for EBC are associated with the use of ACEi/ARBs and β-blockers. The combined use of these two medications is associated with a recovery of LVEF during months 3-12 of adjuvant trastuzumab therapy.

Efficacy of primed in situ labelling in determination of HER-2 gene amplification and CEN-17 status in breast cancer tissue

Considerable attention has been given to the accuracy of HER-2 testing and the correlation between the results of different testing methods. This interest reflects the growing importance of HER-2 status in the management of patients with breast cancer. In this study the detection of HER-2 gene and centromere 17 status was evaluated using dual-colour primed in situ labelling (PRINS) in comparison with fluorescence in situ hybridization (FISH). These two methods were evaluated on a series of 27 formalin fixed paraffin embedded breast carcinoma tumours, previously tested for protein overexpression by HercepTest (grouped into Hercep 1+/0, 2+ and 3+). HER-2 gene amplification (ratio ≥ 2.2) by PRINS was found in 3:3, 6:21 and 0:3 in IHC 3+, 2+ and 1+/0 cases, respectively. Comparing FISH and IHC (immunohistochemistry), showed the same results as for PRINS and IHC. Chromosome 17 aneusomy was found in 10 of 21 IHC 2+ cases (47.6%), of which 1 (10%) showed hypodisomy (chromosome 17 copy number per cell ≤ 1.75), 7 (70%) showed low polysomy (chromosome 17 copy number per cell=2.26 - 3.75) and 2 (20%) showed high polysomy (chromosome 17 copy number per cell ≥ 3.76). The overall concordance of detection of HER-2 gene amplification by FISH and PRINS was 100% (27:27). Furthermore, both the level of HER-2 amplification and copy number of CEN17 analysis results correlated well between the two methods. In conclusion, PRINS is a reliable, reproducible technique and in our opinion can be used as an additional test to determine HER-2 status in breast tumours.

Non-invasive imaging and monitoring cardiotoxicity of cancer therapeutic drugs

Cardiotoxicity due to administration of cancer therapeutic agents such as anthracyclines and herceptin are well described. Established guidelines to screen for chemotherapy-related cardiotoxicity (CRC) are primarily based on serial assessment of left ventricular (LV) ejection fraction (EF). However, other parameters such as LV volume, diastolic function, and strain may also be useful in screening for cardiotoxicity. More recent advances in molecular imaging of apoptosis and tissue characterization by cardiac MRI are techniques which might allow early detection of patients at high risk for developing cardiotoxicity prior to a drop in EF. This comprehensive multi-modality review will discuss both the current established imaging techniques as well as the emerging technologies which may revolutionize the future of screening and evaluation for CRC.

Detection, monitoring, and management of trastuzumab-induced left ventricular dysfunction: an actual challenge

The antibody trastuzumab, targeted to inhibit the signalling of ErbB2, a tyrosine kinase receptor overexpressed in 20-30% of breast cancers, improves the prognosis in women affected by this tumour, but produces cardiotoxicity, since ErbB2 is also involved in myocardial homeostasis. In this review, we discuss the pathophysiology of trastuzumab cardiomyopathy and the complex interplay between ErbB2 inhibition and anthracyclines, and we focus on the actual challenges of detecting, monitoring, and managing trastuzumab cardiotoxicity: the research of new, sensitive markers of early trastuzumab toxicity, before the ejection fraction is reduced, is an active field of research.

Pre-Clinical Assessment of Lu-Labeled Trastuzumab Targeting HER2 for Treatment and Management of Cancer Patients with Disseminated Intraperitoneal Disease

Studies from this laboratory have demonstrated the potential of targeting HER2 for therapeutic and imaging applications with medically relevant radionuclides. To expand the repertoire of trastuzumab as a radioimmunoconjugate (RIC) vector, use of (177)Lu was investigated. The combination of a 6.7 d half-life, lower energy β(-)-emissions (500 keV max; 130 keV ave), and an imagable γ-emission make (177)Lu an attractive candidate for radioimmunotherapy (RIT) regimens for treatment of larger tumor burdens not possible with α-zparticle radiation. Radiolabeling trastuzumab-CHX-A"-DTPA with (177)Lu was efficient with a specific binding of 60.8 ± 6.8% with HER2 positive SKOV-3 cells. Direct quantitation of tumor targeting and normal tissue uptake was performed with athymic mice bearing subcutaneous and intraperitoneal LS-174T xenografts; a peak tumor %ID/g of 24.70 ± 10.29 (96 h) and 31.70 ± 16.20 (72 h), respectively, was obtained. Normal tissue uptake of the RIC was minimal. Tumor targeting was also demonstrated by γ-scintigraphy. A therapy study administering escalating doses of (177)Lu-trastuzumab to mice bearing three day LS-174T i.p. xenografts established the effective therapeutic dose of i.p. administered (177)Lu-trastuzumab at 375 μCi with a median survival of 124.5 d while a median survival of 10 d was noted for the control (untreated) group. In conclusion, trastuzumab radiolabeled with (177)Lu has potential for treatment of disseminated, HER2 positive, peritoneal disease.

Treatment of HER2-positive breast cancer: current status and future perspectives

The advent of HER2-directed therapies has significantly improved the outlook for patients with HER2-positive early stage breast cancer. However, a significant proportion of these patients still relapse and die of breast cancer. Trials to define, refine and optimize the use of the two approved HER2-targeted agents (trastuzumab and lapatinib) in patients with HER2-positive early stage breast cancer are ongoing. In addition, promising new approaches are being developed including monoclonal antibodies and small-molecule tyrosine kinase inhibitors targeting HER2 or other HER family members, antibodies linked to cytotoxic moieties or modified to improve their immunological function, immunostimulatory peptides, and targeting the PI3K and IGF-1R pathways. Improved understanding of the HER2 signaling pathway, its relationship with other signaling pathways and mechanisms of resistance has also led to the development of rational combination therapies and to a greater insight into treatment response in patients with HER2-positive breast cancer. Based on promising results with new agents in HER2-positive advanced-stage disease, a series of large trials in the adjuvant and neoadjuvant settings are planned or ongoing. This Review focuses on current treatment for patients with HER2-positive breast cancer and aims to update practicing clinicians on likely future developments in the treatment for this disease according to ongoing clinical trials and translational research.

The next generation of positron emission tomography radiopharmaceuticals in oncology

Although (18)F-fluorodeoxyglucose ((18)F-FDG) is still the most widely used positron emission tomography (PET) radiotracer, there are a few well-known limitations to its use. The last decade has seen the development of new PET probes for in vivo visualization of specific molecular targets, along with important technical advances in the production of positron-emitting radionuclides and their related labeling methods. As such, a broad range of new PET tracers are in preclinical development or have recently entered clinical trials. The topics covered in this review include labeling methods, biological targets, and the most recent preclinical or clinical data of some of the next generation of PET radiopharmaceuticals. This review, which is by no means exhaustive, has been separated into sections related to the PET radionuclide used for radiolabeling: fluorine-18, for the labeling of agents such as FACBC, FDHT, choline, and Galacto-RGD; carbon-11, for the labeling of choline; gallium-68, for the labeling of peptides such as DOTATOC and bombesin analogs; and the long-lived radionuclides iodine-124 and zirconium-89 for the labeling of monoclonal antibodies cG250, and J591 and trastuzumab, respectively.

Cardiotoxicity of anticancer treatments: what the cardiologist needs to know

Cardiotoxicity of anticancer treatments has become an increasingly important clinical problem faced by cardiologists. Left ventricular systolic dysfunction and heart failure generate the most concern, but clinical features and prognosis vary considerably depending on the causative agent. Anthracycline-related cardiomyopathy differs fundamentally from effects associated with newer targeted agents, such as trastuzumab. Other forms of cardiovascular disease that occur as a result of cancer treatment include hypertension, thromboembolic disease, pericardial disease, arrhythmia, and myocardial ischemia. The approach to cardiovascular disease in patients with cancer is often different from that in the general population, not only because of distinct underlying mechanisms and clinical features of their heart disease, but also because of the potential ongoing need for additional cancer treatment as well as the altered duration of anticipated survival. In an effort to maximize both quality of life and survival, cardiologists and oncologists should collaborate with the aim of balancing the risks of cardiotoxicity with the benefits of oncologic therapy.

A historical perspective of anthracycline cardiotoxicity

Anthracyclines remain important agents in the treatment of solid and hematological malignancy. Early experience with these drugs reported cardiac failure as an adverse event. Later, clinical recognition of cell injury at the time of administration was appreciated. This article explores the evolution of our understanding about anthracycline-associated cardiotoxicity, including the various strategies for the pretreatment assessment of patients for whom anthracyclines are contemplated, the frustrations associated with the lack of specific tests that could identify patients at risk of developing problems with their next 1 or 2 cycles, the concept of balancing oncologic benefit with cardiac risk in the treatment of cancer patients, and the newer strategies for reducing the potentially devastating complications of the treatment of malignant disease with anthracyclines.

Chemotherapy-associated cardiotoxicity: how often does it really occur and how can it be prevented?

Cardiotoxicity remains the limiting factor for many forms of cancer therapy and is the focus of growing research and clinical emphasis. This article outlines the current clinical evidence for left ventricular dysfunction and heart failure for the two most important classes of cardiotoxic chemotherapeutic agents, examines the potential pitfalls that have led to underestimated rates of left ventricular dysfunction from these agents, and reviews strategies for screening for and providing prophylaxis against chemotherapy-associated left ventricular dysfunction.

Cardiovascular side effects of cancer therapies: a position statement from the Heart Failure Association of the European Society of Cardiology

The reductions in mortality and morbidity being achieved among cancer patients with current therapies represent a major achievement. However, given their mechanisms of action, many anti-cancer agents may have significant potential for cardiovascular side effects, including the induction of heart failure. The magnitude of this problem remains unclear and is not readily apparent from current clinical trials of emerging targeted agents, which generally under-represent older patients and those with significant co-morbidities. The risk of adverse events may also increase when novel agents, which frequently modulate survival pathways, are used in combination with each other or with other conventional cytotoxic chemotherapeutics. The extent to which survival and growth pathways in the tumour cell (which we seek to inhibit) coincide with those in cardiovascular cells (which we seek to preserve) is an open question but one that will become ever more important with the development of new cancer therapies that target intracellular signalling pathways. It remains unclear whether potential cardiovascular problems can be predicted from analyses of such basic signalling mechanisms and what pre-clinical evaluation should be undertaken. The screening of patients, optimization of therapeutic schemes, monitoring of cardiovascular function during treatment, and the management of cardiovascular side effects are likely to become increasingly important in cancer patients. This paper summarizes the deliberations of a cross-disciplinary workshop organized by the Heart Failure Association of the European Society of Cardiology (held in Brussels in May 2009), which brought together clinicians working in cardiology and oncology and those involved in basic, translational, and pharmaceutical science.

Scintigraphic techniques for early detection of cancer treatment-induced cardiotoxicity

New antitumor agents have resulted in significant survival benefits for cancer patients. However, several agents may have serious cardiovascular side effects. Left ventricular ejection fraction measurement by (99m)Tc multigated radionuclide angiography is regarded as the gold standard to measure cardiotoxicity in adult patients. It identifies left ventricular dysfunction with high reproducibility and low interobserver variability. A decrease in left ventricular ejection fraction, however, is a relatively late manifestation of myocardial damage. Nuclear cardiologic techniques that visualize pathophysiologic processes at the tissue level could detect myocardial injury at an earlier stage. These techniques may give the opportunity for timely intervention to prevent further damage and could provide insights into the mechanisms and pathophysiology of cardiotoxicity caused by anticancer agents. This review provides an overview of past, current, and promising newly developed radiopharmaceuticals and describes the role and recent advances of scintigraphic techniques to measure cardiotoxicity. Both first-order functional imaging techniques (visualizing mechanical [pump] function), such as (99m)Tc multigated radionuclide angiography and (99m)Tc gated blood-pool SPECT, and third-order functional imaging techniques (visualizing pathophysiologic and neurophysiologic processes at the tissue level) are discussed. Third-order functional imaging techniques comprise (123)I-metaiodobenzylguanidine scintigraphy, which images the efferent sympathetic nervous innervations; sympathetic neuronal PET, with its wide range of tracers; (111)In-antimyosin, which is a specific marker for myocardial cell injury and necrosis; (99m)Tc-annexin V scintigraphy, which visualizes apoptosis and cell death; fatty-acid-use scintigraphy, which visualizes the storage of free fatty acids in the lipid pool of the cytosol (which can be impaired by cardiotoxic agents); and (111)In-trastuzumab imaging, to study trastuzumab targeting to the myocardium. To define the prognostic importance and clinical value of each of these functional imaging techniques, prospective clinical trials are warranted.

Targeting HER2: a report on the in vitro and in vivo pre-clinical data supporting trastuzumab as a radioimmunoconjugate for clinical trials

The potential of the HER2-targeting antibody trastuzumab as a radioimmunoconjugate useful for both imaging and therapy was investigated. Conjugation of trastuzumab with the acyclic bifunctional chelator CHX-A"-DTPA yielded a chelate:protein ratio of 3.4 ± 0.3; the immunoreactivity of the antibody unaffected. Radiolabeling was efficient, routinely yielding a product with high specific activity. Tumor targeting was evaluated in mice bearing subcutaneous (s.c.) xenografts of colorectal, pancreatic, ovarian, and prostate carcinomas. High uptake of the radioimmunoconjugate, injected intravenously (i.v.), was observed in each of the models, and the highest tumor %ID/g (51.18 ± 13.58) was obtained with the ovarian (SKOV-3) tumor xenograft. Specificity was demonstrated by the absence of uptake of 111In-trastuzumab by melanoma (A375) s.c. xenografts and 111In-HuIgG by s.c. LS-174T xenografts. Minimal uptake of i.v. injected 111In-trastuzumab in normal organs was confirmed in non-tumor-bearing mice. The in vivo behavior of 111In-trastuzumab in mice bearing intraperitoneal (i.p.) LS-174T tumors resulted in a tumor %ID/g of 130.85 ± 273.34 at 24 h. Visualization of tumor, s.c. and i.p. xenografts, was achieved by γ-scintigraphy and PET imaging. Blood pool was evident as expected, but cleared over time. The blood pharmacokinetics of i.v. and i.p. injected 111In-trastuzumab was determined in mice with and without tumors. The data from these in vitro and in vivo studies supported advancement of radiolabeled trastuzumab into two clinical studies, a Phase 0 imaging study in the Molecular Imaging Program of the National Cancer Institute and a Phase 1 radioimmunotherapy study at the University of Alabama.

Anticancer therapy induced cardiotoxicity: review of the literature

Innovative anticancer strategies have contributed to an improved survival of patients suffering from malignancies, and in some cases, have turned cancer into a chronic disease. Therefore, the early and particularly late onsets of adverse cardiovascular effects of systemic anticancer treatments are of increasing interest. Among a rapidly increasing variety of anticancer drugs, the anthracyclines and the monoclonal antibody, trastuzumab, are the agents with a well-known cardiotoxicity. The diagnostic work-up, the cardiotoxic risk of anthracyclines and trastuzumab, and additionally, cardiotoxicity as a risk factor of a multimodal therapeutic approach in breast cancer patients is discussed in this study.

[Toxic effects and use of therapeutic monoclonal antibodies]

The extensive use of therapeutic monoclonal antibodies in clinic has shown that toxic effects may occur in patients. Examples such as muromonab (anti-CD3) and recently TGN1412 (anti-CD28) clearly establish that prediction of toxic effects for these targeted therapies is still complex. These undesirable effects can be classified in four categories: cytokine release syndrome, auto-immune diseases, organ toxicity and opportunistic infections. Immunogenicity, which is highly variable depending on the degree of humanization, could also potentially lead to adverse effects due to immune-complexes formation. The recent accident observed with the anti-CD28 TGN1412 has led to the conclusion that the relative confidence in the safety of monoclonal antibodies should be revised. In addition, the prediction of non-clinical models is rather limited and extrapolation of animal results to the human situation should be performed with caution. A better knowledge of the cellular target of the antibodies and of their mechanisms of action and the identification of risk factors (immune cell activation, wide expression of the target...) should improve the clinical safety of these products. .

Molecular imaging of solid tumors: exploiting the potential

Targeted treatment has substantially changed the field of oncology. Compared with cytotoxic chemotherapy, many novel targeted therapies are administered over long periods of time, and result in disease stabilization rather than tumor shrinkage. The activity of these novel agents might, therefore, be better reflected by changes in molecular features of the tumor rather than reduction in size or volume. Thus, noninvasive procedures to measure such features are urgently needed. Factors that need to be predicted are early response (silencing of tumor signaling) or resistance to therapy, and whether therapy can be interrupted. Molecular imaging techniques, such as PET, may provide clinically relevant information; however, data are so far available mainly from small, observational, retrospective studies. Findings need to be further assessed in clinical trials to assess whether molecular imaging can be exploited and widely introduced to aid daily practice in oncology.

Improving the therapeutic index of anthracycline chemotherapy: focus on liposomal doxorubicin (Myocet)

Anthracyclines are valuable cytotoxic agents in cancer treatment. However, their usefulness is limited by cumulative dose-dependent cardiotoxicity that may manifest as life-threatening congestive heart failure. To avoid cardiotoxicity, the use of doxorubicin is typically capped at a safe cumulative dose. Liposomal formulations may reduce cardiac risks whilst maintaining anti-cancer efficacy. Efficacy and safety studies of non-pegylated liposomal doxorubicin (NPLD) in metastatic breast cancer (MBC) are reviewed, along with studies that examine efficacy and cardiac tolerability in combination with newer agents such as paclitaxel and trastuzumab. These show that cardiac safety of liposomal doxorubicin is similar to that of epirubicin in cumulative dose, but that the formulation, unlike epirubicin, has similar anti-cancer efficacy to doxorubicin at equimolar doses. Liposomal doxorubicin may have a better therapeutic index than non-liposomal anthracyclines. This justifies further studies in patients where cumulative cardiotoxicity is a concern, as does study of its use with other potentially cardiotoxic agents.

Use of myocardial deformation imaging to detect preclinical myocardial dysfunction before conventional measures in patients undergoing breast cancer treatment with trastuzumab

BACKGROUND

Trastuzumab prolongs survival in patients with human epidermal growth factor receptor type 2-positive breast cancer. Sequential left ventricular (LV) ejection fraction (EF) assessment has been mandated to detect myocardial dysfunction because of the risk of heart failure with this treatment. Myocardial deformation imaging is a sensitive means of detecting LV dysfunction, but this technique has not been evaluated in patients treated with trastuzumab. The aim of this study was to investigate whether changes in tissue deformation, assessed by myocardial strain and strain rate (SR), are able to identify LV dysfunction earlier than conventional echocardiographic measures in patients treated with trastuzumab.

METHODS

Sequential echocardiograms (n = 152) were performed in 35 female patients (51 +/- 8 years) undergoing trastuzumab therapy for human epidermal growth factor receptor type 2-positive breast cancer. Left ventricular EF was measured by 2- and 3-dimensional (2D and 3D) echocardiography, and myocardial deformation was assessed using tissue Doppler imaging and 2D-based (speckle-tracking) strain and SR. Change over time was compared every 3 months between baseline and 12 months.

RESULTS

There was no overall change in 3D-EF, 2D-EF, myocardial E-velocity, or strain. However, there were significant reductions seen in tissue Doppler imaging SR (P < .05), 2D-SR (P < .001), and 2D radial SR (P < .001). A drop > or =1 SD in 2D longitudinal SR was seen in 18 (51%) patients; 13 (37%) had a similar drop in radial SR. Of the 18 patients with reduced longitudinal SR, 3 had a concurrent reduction in EF > or =10%, and another 2 showed a reduction over 20 months follow-up.

CONCLUSIONS

Myocardial deformation identifies preclinical myocardial dysfunction earlier than conventional measures in women undergoing treatment with trastuzumab for breast cancer.

Cardiovascular toxicity caused by cancer treatment: strategies for early detection

Cardiovascular toxicity is one of the most devastating complications of cancer treatment and can arise during or shortly after treatment, or even several years later. Identification of the left ventricular ejection fraction (LVEF) is the most common method to screen for toxic effects on the heart; however, this approach underestimates cardiac damage and additional strategies for the monitoring of treatment-induced cardiotoxicity are being explored. Guidelines for monitoring have been formulated for several cancer treatments; however, appropriate underlying evidence is still largely absent. In this Review, we summarise conventional and contemporary methods for early detection of cardiotoxicity and designate a level of evidence for the basis of each method.

Molecular imaging as a tool for translating breast cancer science

The ability to measure biochemical and molecular processes underlies progress in breast cancer biology and treatment. These assays have traditionally been performed by analysis of cell culture or tissue samples. More recently, functional and molecular imaging has allowed the in vivo assay of biochemistry and molecular biology, which is highly complementary to tissue-based assays. This review briefly describes different imaging modalities used in molecular imaging and then reviews applications of molecular imaging to breast cancer, with a focus on translational work. It includes sections describing work in functional and physiological tumor imaging, imaging gene product expression, imaging the tumor microenvironment, reporter gene imaging, and cell labeling. Work in both animal models and human is discussed with an eye towards studies that have relevance to breast cancer treatment in patients.

Ventricular ErbB2/ErbB4 activation and downstream signaling in pacing-induced heart failure

The neuregulin-1 (NRG-1)/ErbB system has emerged as a cardioprotective system that becomes activated during myocardial stress, most convincingly shown in response to cardiotoxic chemotherapy. Direct evidence of increased ventricular ErbB receptor activity in heart failure unrelated to cardiotoxic drugs is, however, limited. We investigated changes in NRG-1 expression, ErbB receptor phosphorylation and downstream activation of intracellular ErbB targets during rapid pacing and progressive ventricular dysfunction in the dog. Heart failure was induced in dogs by 7 weeks of rapid pacing. Ventricular function was assessed by echocardiography. Messenger RNA expression was investigated in ventricular biopsies using quantitative PCR. Activation of NRG-1/ErbB signaling and of downstream targets was investigated using immunoprecipitation and/or Western blotting. Over the course of 7 weeks of pacing and ventricular dilatation, ventricular levels of NRG-1, but not of other ErbB4 ligands, and of ADAM19, a protease promoting NRG-1 release, progressively increased. In parallel, levels of activated ErbB2 and ErbB4, phosphorylated at tyrosine residues 877/1248 and 1284 respectively, became progressively higher. Similarly, levels of total and phosphorylated PI-3 kinase increased. Surprisingly, however, and in contrast with activation of downstream targets of ErbB receptors in normal hearts, Akt and ERK1/2, remained inactivated. This study shows that ventricular ErbB2 and ErbB4 receptors become activated during the development of pacing-induced heart failure, but that downstream signaling is, at least partly, abrogated. Abrogation of cardioprotective signaling after ErbB activation is an unanticipated phenomenon in the progression of heart failure with possibly major pathophysiological significance. The underlying mechanisms should be further elucidated.

Development of automated brightfield double in situ hybridization (BDISH) application for HER2 gene and chromosome 17 centromere (CEN 17) for breast carcinomas and an assay performance comparison to manual dual color HER2 fluorescence in situ hybridization (FISH)

Background

Human epidermal growth factor receptor 2 (HER2) fluorescence in situ hybridization (FISH) is a quantitative assay for selecting breast cancer patients for trastuzumab therapy. However, current HER2 FISH procedures are labor intensive, manual methods that require skilled technologists and specialized fluorescence microscopy. Furthermore, FISH slides cannot be archived for long term storage and review. Our objective was to develop an automated brightfield double in situ hybridization (BDISH) application for HER2 gene and chromosome 17 centromere (CEN 17) and test the assay performance with dual color HER2 FISH evaluated breast carcinomas.

Methods

The BDISH assay was developed with the nick translated dinitrophenyl (DNP)-labeled HER2 DNA probe and DNP-labeled CEN 17 oligoprobe on the Ventana BenchMark^® XT slide processing system. Detection of HER2 and CEN 17 signals was accomplished with the silver acetate, hydroquinone, and H₂O₂ reaction with horseradish peroxidase (HRP) and the fast red and naphthol phosphate reaction with alkaline phosphatise (AP), respectively. The BDISH specificity was optimized with formalin-fixed, paraffin-embedded xenograft tumors, MCF7 (non-amplified HER2 gene) and BT-474 (amplified HER2 gene). Then, the BDISH performance was evaluated with 94 routinely processed breast cancer tissues. Interpretation of HER2 and CEN 17 BDISH slides was conducted by 4 observers using a conventional brightfield microscope without oil immersion objectives.

Results

Sequential hybridization and signal detection for HER2 and CEN 17 ISH demonstrated both DNA targets in the same cells. HER2 signals were visualized as discrete black metallic silver dots while CEN 17 signals were detected as slightly larger red dots. Our study demonstrated a high consensus concordance between HER2 FISH and BDISH results of clinical breast carcinoma cases based on the historical scoring method (98.9%, Simple Kappa = 0.9736, 95% CI = 0.9222 – 1.0000) and the ASCO/CAP scoring method with the FISH equivocal cases (95.7%, Simple Kappa = 0.8993%, 95% CI = 0.8068 – 0.9919) and without the FISH equivocal cases (100%, Simple Kappa = 1.0000%, 95% CI = 1.0000 – 1.0000).

Conclusion

Automated BDISH applications for HER2 and CEN 17 targets were successfully developed and it might be able to replace manual two-color HER2 FISH methods. The application also has the potential to be used for other gene targets. The use of BDISH technology allows the simultaneous analyses of two DNA targets within the context of tissue morphological observation.

Antibodies for molecular imaging of cancer

Antibodies have attained a central role as targeted therapeutics, with several significant drugs on the market and many more in clinical development for oncological applications. Expansion of the role of antibodies in cancer imaging has been accelerated by a number of factors, including the recognition that antibodies can provide a powerful class of molecular imaging probes for interrogating cell surfaces in vivo. Identification of relevant cell surface biomarkers as imaging targets, coupled with advances in antibody technology, facilitate the generation of antibodies optimized for noninvasive imaging. Developments in imaging instrumentation and radionuclide availability have paved the way for broader evaluation and implementation of radioimmunoscintigraphy and immunoPET. Antibody imaging can provide a sensitive, noninvasive means for molecular characterization of cell surface phenotype in vivo, which can in turn guide diagnosis, prognosis, therapy selection, and monitoring of treatment in cancer.

Associations between the uptake of 111In-DTPA-trastuzumab, HER2 density and response to trastuzumab (Herceptin) in athymic mice bearing subcutaneous human tumour xenografts

PURPOSE

The purpose of the study was to investigate the associations between uptake of (111)In-DTPA-trastuzumab, tumour HER2 density and response to trastuzumab (Herceptin) of human breast cancer (BC) xenografts in athymic mice.

MATERIALS AND METHODS

The tumour uptake of (111)In-DTPA-trastuzumab in athymic mice bearing BC xenografts with increasing HER2 density (0 to 3+) was evaluated. Specific uptake ratios were established in biodistribution (SUR) and imaging studies (ROI-SUR) using (111)In-labeled mouse IgG ((111)In-DTPA-mIgG). Further corrections were made for circulating radioactivity using tumour-to-blood ratios defined as a localization index (LI) and region-of-interest localization index (ROI-LI), respectively. Mice were treated with trastuzumab (Herceptin). A tumour growth inhibition index (TGI) was calculated and relative TGIs calculated by dividing the TGI of control by that of trastuzumab-treated mice.

RESULTS

Strong, nonlinear associations with HER2 density were obtained if the uptake of (111)In-DTPA-trastuzumab was corrected for nonspecific IgG localization (i.e., SUR; r (2) = 0.99) and circulating radioactivity (i.e., LI; r (2) = 0.87), but without these corrections, the association between HER2 density and tumour uptake was poor (r (2) = 0.22). There was a strong association between ROI-SUR and ROI-LI values and HER2 expression (r (2) = 0.90 and r (2) = 0.95, respectively. All tumours were imaged. Relative TGI values were associated with increasing uncorrected tumour uptake of (111)In-DTPA-trastuzumab but not always with HER2 density (i.e., MCF-HER2-18 cells with trastuzumab-resistance).

CONCLUSION

HER2 expression (0 to 3+) can be differentiated using (111)In-DTPA-trastuzumab, but requires correction of tumour uptake for nonspecific IgG localization and circulating radioactivity. The uncorrected uptake of (111)In-DTPA-trastuzumab was associated with tumour response to trastuzumab.