Cardio-oncology in targeting the HER receptor family: the puzzle of different cardiotoxicities of HER2 inhibitors

Advances in HER2-Targeted Therapies: From monoclonal antibodies to dual inhibitors developments in cancer treatment

HER2 receptors, overexpressed in certain human cancers, have drawn significant attention in cancer research due to their correlation with poor survival rates. Researchers have developed monoclonal antibodies like Trastuzumab and Pertuzumab against HER2 receptors, which have proven highly beneficial in cancer therapy. Bispecific antibodies like Zanidatamab and antibody-drug conjugates like T-DM1 have been developed to overcome the resistance associated with monotherapy. Small molecules such as Lapatinib, Neratinib, and Pyrotinib were initially developed for treating breast cancer. However, ongoing research is investigating their potential use in other types of cancer, often in combination with other medications. EGFR/HER2 dual-targeted drugs have overcome drug resistance associated with HER2-targeted monotherapy. This comprehensive review covers the structural characteristics of HER2, the HER family signaling pathway mechanism, recent findings regarding HER2 receptor involvement in various cancers, and diverse HER2-targeted therapies. This information provides a comprehensive understanding of HER2-targeted strategies in the evolving field of cancer treatment.

Novel insights into cardiovascular toxicity of cancer targeted and immune therapies: Beyond ischemia with non-obstructive coronary arteries (INOCA)

Novel immune and targeted therapies approved over the past 2 decades have resulted in dramatic improvements in cancer-specific outcomes for many cancer patients. However, many of these agents can induce cardiovascular toxicity in a subset of patients. The field of cardio-oncology was established based on observations that anti-neoplastic chemotherapies and mantle radiation can lead to premature cardiomyopathy in cancer survivors. While conventional chemotherapy, targeted therapy, and immune therapies can all result in cardiovascular adverse events, the mechanisms, timing, and incidence of these events are inherently different. Many of these effects converge upon the coronary microvasculature to involve, through endocardial endothelial cells, a more direct effect through close proximity to cardiomyocyte with cellular communication and signaling pathways. In this review, we will provide an overview of emerging paradigms in the field of Cardio-Oncology, particularly the role of the coronary microvasculature in mediating cardiovascular toxicity of important cancer targeted and immune therapies. As the number of cancer patients treated with novel immune and targeted therapies grows exponentially and subsequently the number of long-term cancer survivors dramatically increases, it is critical that cardiologists and cardiology researchers recognize the unique potential cardiovascular toxicities of these agents.

Structural dynamics of the active HER4 and HER2/HER4 complexes is finely tuned by different growth factors and glycosylation

Human Epidermal growth factor Receptor 4 (HER4 or ERBB4) carries out essential functions in the development and maintenance of the cardiovascular and nervous systems. HER4 activation is regulated by a diverse group of extracellular ligands including the neuregulin (NRG) family and betacellulin (BTC), which promote HER4 homodimerization or heterodimerization with other HER receptors. Important cardiovascular functions of HER4 are exerted via heterodimerization with its close homolog and orphan receptor, HER2. To date structural insights into ligand-mediated HER4 activation have been limited to crystallographic studies of HER4 ectodomain homodimers in complex with NRG1β. Here, we report cryo-EM structures of near full-length HER2/HER4 heterodimers and full-length HER4 homodimers bound to NRG1β and BTC. We show that the structures of the heterodimers bound to either ligand are nearly identical and that in both cases the HER2/HER4 heterodimer interface is less dynamic than those observed in structures of HER2/EGFR and HER2/HER3 heterodimers. In contrast, structures of full-length HER4 homodimers bound to NRG1β and BTC display more large-scale dynamics mirroring states previously reported for EGFR homodimers. Our structures also reveal the presence of multiple glycan modifications within HER4 ectodomains, modeled for the first time in HER receptors, that distinctively contribute to the stabilization of HER4 homodimer interfaces over those of HER2/HER4 heterodimers.

Structural dynamics of the active HER4 and HER2/HER4 complexes is finely tuned by different growth factors and glycosylation

Human Epidermal growth factor Receptor 4 (HER4 or ERBB4) carries out essential functions in the development and maintenance of the cardiovascular and nervous systems. HER4 activation is regulated by a diverse group of extracellular ligands including the neuregulin (NRG) family and betacellulin (BTC), which promote HER4 homodimerization or heterodimerization with other HER receptors. Important cardiovascular functions of HER4 are exerted via heterodimerization with its close homolog and orphan receptor, HER2. To date structural insights into ligand-mediated HER4 activation have been limited to crystallographic studies of HER4 ectodomain homodimers in complex with NRG1β. Here we report cryo-EM structures of near full-length HER2/HER4 heterodimers and full-length HER4 homodimers bound to NRG1β and BTC. We show that the structures of the heterodimers bound to either ligand are nearly identical and that in both cases the HER2/HER4 heterodimer interface is less dynamic than those observed in structures of HER2/EGFR and HER2/HER3 heterodimers. In contrast, structures of full-length HER4 homodimers bound to NRG1β and BTC display more large-scale dynamics mirroring states previously reported for EGFR homodimers. Our structures also reveal the presence of multiple glycan modifications within HER4 ectodomains, modeled for the first time in HER receptors, that distinctively contribute to the stabilization of HER4 homodimer interfaces over those of HER2/HER4 heterodimers.

A new perspective in the prevention and treatment of antitumor therapy-related cardiotoxicity: Intestinal microecology

The continuous development of antitumor therapy has significantly reduced the mortality of patients with malignancies. However, the antitumor-related cardiotoxicity has become the leading cause of long-term mortality in patients with malignancies. Besides, the pathogenesis of antitumor-related cardiotoxicity is still unclear, and practical means of prevention and treatment are lacking in clinical practice. Therefore, the major challenge is how to combat the cardiotoxicity of antitumor therapy effectively. More and more studies have shown that antitumor therapy kills tumor cells while causing damage to sensitive tissues such as the intestinal mucosa, leading to the increased permeability of the intestine and the dysbiosis of intestinal microecology. In addition, the dysbiosis of intestinal microecology contributes to the development and progression of cardiovascular diseases through multiple pathways. Thus, the dysbiosis of intestinal microecology may be a potential mechanism and target for antitumor-related cardiotoxicity. We summarized the characteristics of intestinal microecology disorders induced by antitumor therapy and the association between intestinal microecological dysbiosis and CVD. And on this basis, we hypothesized the potential mechanisms of intestinal microecology mediating the occurrence of antitumor-related cardiotoxicity. Then we reviewed the previous studies targeting intestinal microecology against antitumor-associated cardiotoxicity, aiming to provide a reference for future studies on the occurrence and prevention of antitumor-related cardiotoxicity by intestinal microecology.

Cardiotoxicity from neoadjuvant targeted treatment for breast cancer prior to surgery

Cancer treatment has been gradually shifting from non-specific cytotoxic agents to molecularly targeted drugs. Breast cancer (BC), a malignant tumor with one of the highest incidence worldwide, has seen a rapid development in terms of targeted therapies, leading to a radical change in the treatment paradigm. However, the use of targeted drugs is accompanied by an increasing rate of deaths due to non-tumor-related causes in BC patients, with cardiovascular complications as the most common cause. Cardiovascular toxicity during antitumor therapy has become a high-risk factor for survival in BC patients. Targeted drug-induced cardiotoxicity exerts a wide range of effects on cardiac structure and function, including conduction disturbances, QT interval prolongation, impaired myocardial contractility, myocardial fibrosis, and hypertrophy, resulting in various clinical manifestations, e.g., arrhythmias, cardiomyopathy, heart failure, and even sudden death. In adult patients, the incidence of antitumor targeted drug-induced cardiotoxicity can reach 50%, and current preclinical evaluation tools are often insufficiently effective in predicting clinical cardiotoxicity. Herein, we reviewed the current status of the occurrence, causative mechanisms, monitoring methods, and progress in the prevention and treatment of cardiotoxicity associated with preoperative neoadjuvant targeted therapy for BC. It supplements the absence of relevant review on the latest research progress of preoperative neoadjuvant targeted therapy for cardiotoxicity, with a view to providing more reference for clinical treatment of BC patients.

Osimertinib and anti-HER3 combination therapy engages immune dependent tumor toxicity via STING activation in trans

Over the past decade, immunotherapy delivered novel treatments for many cancer types. However, lung cancer still leads cancer mortality, and non-small-cell lung carcinoma patients with mutant EGFR cannot benefit from checkpoint inhibitors due to toxicity, relying only on palliative chemotherapy and the third-generation tyrosine kinase inhibitor (TKI) osimertinib. This new drug extends lifespan by 9-months vs. second-generation TKIs, but unfortunately, cancers relapse due to resistance mechanisms and the lack of antitumor immune responses. Here we explored the combination of osimertinib with anti-HER3 monoclonal antibodies and observed that the immune system contributed to eliminate tumor cells in mice and co-culture experiments using bone marrow-derived macrophages and human PBMCs. Osimertinib led to apoptosis of tumors but simultaneously, it triggered inositol-requiring-enzyme (IRE1α)-dependent HER3 upregulation, increased macrophage infiltration, and activated cGAS in cancer cells to produce cGAMP (detected by a lentivirally transduced STING activity biosensor), transactivating STING in macrophages. We sought to target osimertinib-induced HER3 upregulation with monoclonal antibodies, which engaged Fc receptor-dependent tumor elimination by macrophages, and STING agonists enhanced macrophage-mediated tumor elimination further. Thus, by engaging a tumor non-autonomous mechanism involving cGAS-STING and innate immunity, the combination of osimertinib and anti-HER3 antibodies could improve the limited therapeutic and stratification options for advanced stage lung cancer patients with mutant EGFR.

A Review of Cancer Immunotherapy Toxicity II: Adoptive Cellular Therapies, Kinase Inhibitors, Monoclonal Antibodies, and Oncolytic Viruses

Immunotherapy for cancer has undergone a rapid expansion in classes, agents, and indications. By utilizing aspects of the body's innate immune system, immunotherapy has improved life expectancy and quality of life for patients with several types of cancer. Adoptive cellular therapies, including chimeric antigen receptor T (CAR T) cell therapy, involve the genetic engineering of patient T cells to allow for targeting of neoplastic cells. Monitoring of patients during the lymphodepletion prior to therapy and following CAR T cell infusion is necessary to detect toxicity of therapy. Specific toxicities include cytokine release syndrome and neurologic toxicity, both of which may be life-threatening. Tocilizumab and/or corticosteroids should be considered for moderate to severe toxicity. Kinase inhibitor toxicity can occur as "on target" effects or "off target" effects to multiple organ systems due to shared protein epitopes. Treatments are organ-specific. Infusion reactions are common during treatment with monoclonal antibodies and treatment is largely supportive. Clinical experience with oncolytic viruses is limited, but local reactions including cellulitis as well as systemic influenza-like syndromes have been seen but are typically mild. Although clinical experience with adverse effects due to newer immunotherapy agents is growing, an up-to-date understanding of their mechanisms and potential toxicities is critical.

Evaluation of dexrazoxane effect on preventing acute cardiac arrhythmia in patients with breast cancer treated with neoadjuvant/adjuvant anthracycline-based chemotherapy

INTRODUCTION

Adding dexrazoxane to the treatment during neoadjuvant/adjuvant anthracycline-based chemotherapy in patients with breast cancer prevents the development of heart failure. In this study, we investigated whether dexrazoxane has a protective effect on arrhythmia resulting from chemotherapy.

METHODS

Patients with breast cancer who received neoadjuvant/adjuvant anthracycline-based chemotherapy in the medical oncology polyclinic between 2017 and 2020 were included in the study. To investigate the effect of dexrazoxane on arrhythmia, this retrospective study included 70 patients, whose 12-lead surface electrocardiograms (ECGs) and echocardiography were obtained before receiving anthracycline-based treatment and after receiving four cycles of chemotherapy. Thirty-two patients received anthracycline only, and 38 patients received anthracycline and dexrazoxane. Arrhythmia parameters such as QT interval, QTc interval, Tp-e interval, Tp-e/QT, Tp-e/QTc and frontal QRS-T angle were calculated from 12-lead ECGs.

RESULTS

Arrhythmia parameters such as frontal QRS-T angle , QT , QTc and heart rate were significantly increased after chemotherapy in both the groups that received dexrazoxane and did not receive dexrazoxane (P < .05). Contrary to the ECG parameters, ejection fraction was decreased in the dexrazoxane group (60.5 ± 2.2 vs 60.1 ± 2.0; P = .038) and the other group (60.4 ± 1.3 vs 60.0 ± 2.6; P = .043) after the chemotherapy.

CONCLUSION

This study demonstrated that dexrazoxane may not have a protective effect on ECG parameters which are predictors of arrhythmia, at breast cancer patients who received anthracyclines.

Comparative Analysis of BTK Inhibitors and Mechanisms Underlying Adverse Effects

The cytoplasmic protein-tyrosine kinase BTK plays an essential role for differentiation and survival of B-lineage cells and, hence, represents a suitable drug target. The number of BTK inhibitors (BTKis) in the clinic has increased considerably and currently amounts to at least 22. First-in-class was ibrutinib, an irreversible binder forming a covalent bond to a cysteine in the catalytic region of the kinase, for which we have identified 228 active trials listed at ClinicalTrials.gov. Next-generation inhibitors, acalabrutinib and zanubrutinib, are approved both in the United States and in Europe, and zanubrutinib also in China, while tirabrutinib is currently only registered in Japan. In most cases, these compounds have been used for the treatment of B-lymphocyte tumors. However, an increasing number of trials instead addresses autoimmunity and inflammation in multiple sclerosis, rheumatoid arthritis, pemphigus and systemic lupus erythematosus with the use of either irreversibly binding inhibitors, e.g., evobrutinib and tolebrutinib, or reversibly binding inhibitors, like fenebrutinib. Adverse effects (AEs) have predominantly implicated inhibition of other kinases with a BTKi-binding cysteine in their catalytic domain. Analysis of the reported AEs suggests that ibrutinib-associated atrial fibrillation is caused by binding to ERBB2/HER2 and ERBB4/HER4. However, the binding pattern of BTKis to various additional kinases does not correlate with the common assumption that skin manifestations and diarrhoeas are off-target effects related to EGF receptor inhibition. Moreover, dermatological toxicities, diarrhoea, bleedings and invasive fungal infections often develop early after BTKi treatment initiation and subsequently subside. Conversely, cardiovascular AEs, like hypertension and various forms of heart disease, often persist.

Cardiovascular Toxicity of Novel HER2-Targeted Therapies in the Treatment of Breast Cancer

PURPOSE OF REVIEW

HER2-targeted therapies have led to improved clinical outcomes in early and advanced breast cancer (BC). We review the long-term cardiotoxicity of HER2-targeted therapy in early and advanced BC, our current knowledge of cardiotoxicity of novel HER2-targeted therapies, and propose a cardiac monitoring (CM) strategy for this population.

RECENT FINDINGS

Long-term data from studies with HER2-targeted therapy in the adjuvant setting have failed to demonstrate an increase in cardiotoxicity over time, and rates of cardiotoxicity seen with novel HER2 agents remain low. Despite over a decade of experience with HER2-targeted therapy, CM in clinical practice is inconsistent in patients with early BC and almost non-existent in advanced BC. Long-term follow-up of clinical trials with HER2-targeted agents in early and advanced BC has failed to demonstrate increased rates of cardiotoxicity over time, attesting to the long-term safety of this class of drugs for the majority of patients, although the long-term cardiac safety of newer HER2 agents in the non-clinical trial setting is largely unknown. We propose CM incorporating clinical history, cardiac imaging, and biomarkers.

Risk factors for chemotherapy-related cardiac toxicity

PURPOSE OF REVIEW

The purpose of this review is to discuss the clinical and treatment-related factors that increase the risk of cardiotoxicity with anthracyclines and human epidermal growth factor 2 receptor inhibitors.

RECENT FINDINGS

Age and preexisting left ventricular dysfunction have been identified most consistently as being associated with the development of clinical heart failure or a worsening of left ventricular function with chemotherapy. Other cardiovascular conditions, including hypertension, diabetes, and coronary artery disease, are also associated with the risk of cardiotoxicity. There is growing evidence that Blacks are at a higher risk of developing cardiotoxicity than Whites, even after adjusting for known confounders. Pharmacogenomics is also emerging as a potential tool to help identify patients who are at higher risk for cardiotoxicity. Treatment-related risk factors include the dose of anthracycline or its formulation, whether the patient is receiving additional chemotherapeutic agents or radiation.

SUMMARY

Several clinical and treatment-related risk factors are associated with cardiotoxicity. Further study is needed to determine whether optimization of modifiable risk factors prior to treatment can reduce the risk of cardiotoxicity.

Impacts of non-recovery of trastuzumab-induced cardiomyopathy on clinical outcomes in patients with breast cancer

OBJECTIVES

The impacts of non-recovery of trastuzumab-induced left ventricular dysfunction (LVD) on clinical outcomes in breast cancer have been poorly studied. We investigated the predictors of LV-functional non-recovery and its impacts on clinical outcomes in breast cancer patients with trastuzumab-induced LVD.

METHODS AND RESULTS

A total of 243 patients with trastuzumab-induced LVD were divided into the recovered LVD group (n = 195) and non-recovered LVD group (n = 48). Major adverse clinical events (MACEs) including death, symptomatic heart failure (HF), and HF hospitalization (HHF) were compared. Hemoglobin and albumin levels were significantly lower in non-recovered LVD than in recovered LVD group. Non-recovered LVD group showed significantly larger LV end-diastolic and systolic dimension, higher pulmonary artery systolic pressure, lower LV ejection fraction (EF), and decreased global longitudinal strain than in recovered LVD group. Decreased LVEF, enlarged LV size, pulmonary hypertension, and anemia were independent predictors of LV-functional non-recovery. During 45.9 ± 23.5 months of follow-up, MACEs were developed in 32 patients: 15 deaths, 28 symptomatic HF, and 22 HHF. In Kaplan-Meier survival analysis, MACE free survival was significantly lower in non-recovered LVD group than in recovered LVD group (log rank p = 0.002).

CONCLUSION

LV-functional non-recovery was not uncommon in breast cancer patients with trastuzumab-induced cardiomyopathy, and non-recovered LVD was significantly associated with MACEs. Decreased LVEF, enlarged LV size, pulmonary hypertension, and anemia were independent predictors of LV-functional non-recovery. Careful monitoring for MACEs and intensive medical management should be considered in trastuzumab-induced cardiomyopathy with these characteristics.

Chemotherapeutic Drugs and Mitochondrial Dysfunction: Focus on Doxorubicin, Trastuzumab, and Sunitinib

Many cancer therapies produce toxic side effects whose molecular mechanisms await full elucidation. The most feared and studied side effect of chemotherapeutic drugs is cardiotoxicity. Also, skeletal muscle physiology impairment has been recorded after many chemotherapeutical treatments. However, only doxorubicin has been extensively studied for its side effects on skeletal muscle. Chemotherapeutic-induced adverse side effects are, in many cases, mediated by mitochondrial damage. In particular, trastuzumab and sunitinib toxicity is mainly associated with mitochondria impairment and is mostly reversible. Vice versa, doxorubicin-induced toxicity not only includes mitochondria damage but can also lead to a more robust and extensive cell injury which is often irreversible and lethal. Drugs interfering with mitochondrial functionality determine the depletion of ATP reservoirs and lead to subsequent reversible contractile dysfunction. Mitochondrial damage includes the impairment of the respiratory chain and the loss of mitochondrial membrane potential with subsequent disruption of cellular energetic. In a context of increased stress, AMPK has a key role in maintaining energy homeostasis, and inhibition of the AMPK pathway is one of the proposed mechanisms possibly mediating mitochondrial toxicity due to chemotherapeutics. Therapies targeting and protecting cell metabolism and energy management might be useful tools in protecting muscular tissues against the toxicity induced by chemotherapeutic drugs.

A novel way to manage trastuzumab cardiotoxicity

PURPOSE

Trastuzumab is the most widely prescribed anti-HER2 humanized monoclonal antibody. Cardiac toxicity is the only limiting toxicity of trastuzumab and it is of particular concern in patients with complete response, since the drug needs to be stopped, with a risk of disease relapse. To date, no pharmacological data on trastuzumab cardiotoxicity in patients have been made available. Here, we provide proof of concept, demonstrating that it was possible to prevent trastuzumab-induced cardiotoxicity by modifying the drug administration schedule.

METHODS

In this paper, we report the case of a patient with metastatic breast cancer responding to trastuzumab, who developed severe cardiac toxicity twice using a 3-weekly regimen. Considering preclinical pharmacological data on trastuzumab cardiotoxicity, we hypothesized that a weekly schedule of trastuzumab with lower peaks of serum concentration could be safe while remaining efficient. With the patient's consent, we started a weekly combination of carboplatin (AUC2) and trastuzumab (2 mg/kg) with close monitoring of trastuzumab concentrations.

RESULTS

We successfully controlled the disease for an additional 6 months with relevant trough concentrations of trastuzumab of around 50 mg/L. Another important aspect is that, with this weekly schedule, we observed no cardiac toxicity, and the left ventricular ejection fraction remained stabilized, at over 50%.

CONCLUSIONS

Trastuzumab is the most widely prescribed anti-HER2 monoclonal antibody for the treatment of HER2 metastatic breast cancer, and it is the only drug that has been approved for the treatment of localized HER2 breast cancer, 1-year treatment being required after surgery. In case of cardiac toxicity, particularly in women over 60 years of age, a weekly regimen with lower peaks of concentration could be an alternative to the standard 3-weekly regimen.

Cardioprotective Effect of Dexrazoxane in Patients with HER2-Positive Breast Cancer Who Receive Anthracycline Based Adjuvant Chemotherapy Followed by Trastuzumab

Purpose

We intended to determine whether dexrazoxane (DZR) is cardioprotective during administration of adjuvant anthracycline-based chemotherapy followed by a 1-year trastuzumab treatment.

Methods

The medical records of 228 patients who underwent surgical resection and received adjuvant chemotherapy with trastuzumab for human epidermal growth factor receptor type 2 (HER2)-positive breast cancer between January 2010 and December 2014 were reviewed. Approximately 25% of patients received DZR prior to each administration of doxorubicin during doxorubicin with cyclophosphamide (AC) chemotherapy. DZR was not administered during the 1-year trastuzumab maintenance period. Rates of cardiac events (reduction in left ventricular ejection fraction [LVEF] by 10% or more; reduction in absolute LVEF to <45%) and cardiac event-free duration (CFD) were examined. The trastuzumab interruption rate was also assessed.

Results

Twelve percent of patients experienced a cardiac event. Repeated-measures analysis of variance for ejection fraction revealed a significant main effect of time, and a significant group (DZR)×time interaction. The group treated with adjuvant chemotherapy and DZR experienced significantly lower frequencies of cardiac events than the adjuvant chemotherapy only group. In multivariate analysis, DZR administration was associated with significantly fewer cardiac events. Moreover, DZR administration was an independent good prognostic factor for CFD. Only one patient (2.3%) experienced early interruption of trastuzumab in the adjuvant chemotherapy with DZR group due to cardiac toxicity, whereas 10 patients (7.6%) experienced a trastuzumab stop event in the adjuvant chemotherapy only group.

Conclusion

DZR is cardioprotective in HER2-positive breast cancer patients who received adjuvant chemotherapy with trastuzumab. A large cohort randomized trial is needed to determine if DZR has an effect on trastuzumab interruption and completion of 12-month trastuzumab. Because cardiac toxicity has a significant negative effect on trastuzumab maintenance and quality of life, DZR administration could be considered concomitantly with anthracycline-based adjuvant chemotherapy with trastuzumab.

The cardiotoxicity of cetuximab as single therapy in Chinese chemotherapy-refractory metastatic colorectal cancer patients

The cardiac safety of cetuximab, particularly as single approach, has not been investigated extensively. This trial was designed to evaluate the cardiac safety of cetuximab as salvage monotherapy in Chinese chemotherapy-refractory metastatic colorectal cancer (mCRC) patients.Cetuximab was administrated at an initial dose of 400 mg/mon day 1 (week 1), followed by a maintenance dose of 250 mg/m on day 1 of each 7-day cycle. Electrocardiograph (ECG), routine laboratory tests, and troponin I (TNI) Ultra were performed at baseline, during, and after the cetuximab therapy. The incidence of abnormal ECGs, elevated TNI Ultra, cardiac events, and noncardiac events were recorded and analyzed.TNI Ultra+ was found in 20 patients (32.3%) during the cetuximab therapy.TNI Ultra+ occurred more frequently in patients with more than 3 organs affected and accepted fourth or above lines of chemotherapy. The most frequent abnormal ECG was ST depression in 24 (38.7%) patients. The elevated TNI Ultra and abnormal ECGs could recover after the cetuximab therapy. The most of cardiac adverse events were mild and transient and the noncardiac adverse events were also consistent with the known safety profile for cetuximab.Cetuximab showed its cardiac safety as a single agent for chemotherapy-refractory mCRC patients. And TNI Ultra and ECG could be sensitive and convenient approaches for the surveillance of adverse events.

Anticancer therapy-induced vascular toxicity: VEGF inhibition and beyond

Cardiotoxicity induced by chemotherapeutic agents and radiotherapy is a growing problem. In recent years, an increasing number of new drugs with targeted action have been designed. These molecules, such as monoclonal antibodies and tyrosine kinase inhibitors, can cause different type of toxicities compared to traditional chemotherapy. However, they can also cause cardiac complications such as heart failure, arterial hypertension, QT interval prolongation and arrhythmias. Currently, a field of intense research is the vascular toxicity induced by new biologic drugs, particularly those which inhibit vascular endothelial growth factor (VEGF) and its receptor (VEGF-R) and other tyrosine kinases. In this review, we aim at focusing on the problem of vascular toxicity induced by new targeted therapies, chemotherapy and radiotherapy, and describe the main mechanisms and emphasizing the importance of early diagnosis of vascular damage, in order to prevent clinical complications.

Trastuzumab and target-therapy side effects: Is still valid to differentiate anthracycline Type I from Type II cardiomyopathies?

The improvement in cancer therapy and the increasing number of long term survivors unearth the issue of cardiovascular side effects of anticancer treatments. As a paradox in cancer survivors, delayed cardiotoxicity has emerged as a significant problem. Two categories of cardiotoxic side effects of antineoplastic drugs have been previously proposed: Type I cardiotoxicity, defined as permanent cardiotoxicity, is usually caused by anthracyclines; Type II cardiotoxicity, considered as reversible cardiotoxicity, has been mainly related to monoclonal antibodies. The cardiotoxicity of antibodies has been associated to trastuzumab, a humanized anti-ErbB2 monoclonal antibody currently in clinical use for the therapy of breast carcinomas, which induces cardiac dysfunction when used in monotherapy, or in combination with anthracyclines. Furthermore, recent retrospective studies have shown an increased incidence of heart failure and/or cardiomyopathy in patients treated with trastuzumab, that can persist many years after the conclusion of the therapy, thus suggesting that the side toxic effects are not always reversible as it was initially proposed. On the other hand, early detection and prompt therapy of anthracycline associated cardiotoxicity can lead to substantial recovery of cardiac function. On the basis of these observations, we propose to find a new different classification for cardiotoxic side effects of drugs used in cancer therapy.

Risk of severe cardiotoxicity following treatment with trastuzumab: a meta-analysis of randomized and cohort studies of 29,000 women with breast cancer

Trastuzumab prolongs survival in women with HER2-positive breast cancer, but may increase the risk of heart disease. The occurrence of severe cardiotoxicity, however, is not defined in real-life settings. We performed a meta-analysis of clinical trials and cohort studies to estimate the frequency of cardiotoxicities following trastuzumab treatment. We searched MEDLINE, EMBASE, and the Cochrane Library (1996-January 2014). The primary outcome was the frequency of severe cardiotoxicities up to 3-years after trastuzumab initiation. Among 58 studies (29,598 patients), severe cardiotoxicity occurred in 3.00% (95% CI 2.41-3.64), 2.62% (95% CI 1.97-3.35), and 3.14% (95% CI 2.12-4.37) of overall, early (EBC) and metastatic (MBC) breast cancer patients, respectively. In EBC, the proportion increased from 2.40% at the first year to a plateau of approximately 3% after the second year. In MBC, the proportion increased from 3.00 to 3.68% when trastuzumab was used as first line or further lines of therapy, respectively. In EBC, cardiotoxicity occurred in 2.90% of patients treated with taxanes and anthracyclines compared to 0.92% in patients treated with taxanes without anthracyclines. The occurrence of cardiotoxicity varied according to age, increasing from 2.31% in individuals <50 years, to 3.46% in those 50-59 years, to 4.91% in those >60 years of age. Cardiotoxicity was higher in smokers (5.3%), dyslipidemic patients (3.9%), BMI ≥25 (6.5%), diabetes (6.2%), hypertension (5.5%), or positive history of cardiac disease (19.1%). RCTs consistently report lower cardiac toxicity rates than observational studies (EBC: 1.7 versus 3.2; MBC: 2.8 versus 4.4). Following trastuzumab initiation, approximately three in 100 patients develop severe cardiotoxicity after 2 years. Patients enrolled in cohort studies, who more closely reflect women treated for breast cancer in real-life settings compared to RCTs, are at higher risk of developing cardiac events.

Targets for Ibrutinib Beyond B Cell Malignancies

Ibrutinib (Imbruvica^™) is an irreversible, potent inhibitor of Bruton's tyrosine kinase (BTK). Over the last few years, ibrutinib has developed from a promising drug candidate to being approved by FDA for the treatment of three B cell malignancies, a truly remarkable feat. Few, if any medicines are monospecific and ibrutinib is no exception; already during ibrutinib's initial characterization, it was found that it could bind also to other kinases. In this review, we discuss the implications of such interactions, which go beyond the selective effect on BTK in B cell malignancies. In certain cases, the outcome of ibrutinib treatment likely results from the combined inhibition of BTK and other kinases, causing additive or synergistic, effects. Conversely, there are also examples when the clinical outcome seems unrelated to inhibition of BTK. Thus, more specifically, adverse effects such as enhanced bleeding or arrhythmias could potentially be explained by different interactions. We also predict that during long‐term treatment bone homoeostasis might be affected due to the inhibition of osteoclasts. Moreover, the binding of ibrutinib to molecular targets other than BTK or effects on cells other than B cell‐derived malignancies could be beneficial and result in new indications for clinical applications.

Effects of 5-fluorouracil on morphology, cell cycle, proliferation, apoptosis, autophagy and ROS production in endothelial cells and cardiomyocytes

Antimetabolites are a class of effective anticancer drugs interfering in essential biochemical processes. 5-Fluorouracil (5-FU) and its prodrug Capecitabine are widely used in the treatment of several solid tumors (gastro-intestinal, gynecological, head and neck, breast carcinomas). Therapy with fluoropyrimidines is associated with a wide range of adverse effects, including diarrhea, dehydration, abdominal pain, nausea, stomatitis, and hand-foot syndrome. Among the 5-FU side effects, increasing attention is given to cardiovascular toxicities induced at different levels and intensities. Since the mechanisms related to 5-FU-induced cardiotoxicity are still unclear, we examined the effects of 5-FU on primary cell cultures of human cardiomyocytes and endothelial cells, which represent two key components of the cardiovascular system. We analyzed at the cellular and molecular level 5-FU effects on cell proliferation, cell cycle, survival and induction of apoptosis, in an experimental cardioncology approach. We observed autophagic features at the ultrastructural and molecular levels, in particular in 5-FU exposed cardiomyocytes. Reactive oxygen species (ROS) elevation characterized the endothelial response. These responses were prevented by a ROS scavenger. We found induction of a senescent phenotype on both cell types treated with 5-FU. In vivo, in a xenograft model of colon cancer, we showed that 5-FU treatment induced ultrastructural changes in the endothelium of various organs. Taken together, our data suggest that 5-FU can affect, both at the cellular and molecular levels, two key cell types of the cardiovascular system, potentially explaining some manifestations of 5-FU-induced cardiovascular toxicity.

Examining the protective role of ErbB2 modulation in human-induced pluripotent stem cell-derived cardiomyocytes

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are being used as an in vitro model system in cardiac biology and in drug discovery (e.g., cardiotoxicity testing). Qualification of these cells for use in mechanistic investigations will require detailed evaluations of cardiomyocyte signaling pathways and cellular responses. ErbB signaling and the ligand neuregulin play critical roles in survival and functional integrity of cardiac myocytes. As such, we sought to characterize the expression and activity of the ErbB family of receptors. Antibody microarray analysis performed on cell lysates derived from maturing hiPSC-CMs detected expression of ∼570 signaling proteins. EGFR/ErbB1, HER2/ErbB2, and ErbB4, but not ErbB3 receptors, of the epidermal growth factor receptor family were confirmed by Western blot. Activation of ErbB signaling by neuregulin-1β (NRG, a natural ligand for ErbB4) and its modulation by trastuzumab (a monoclonal anti-ErbB2 antibody) and lapatinib (a small molecule ErbB2 tyrosine kinase inhibitor) were evaluated through assessing phosphorylation of AKT and Erk1/2, two major downstream kinases of ErbB signaling, using nanofluidic proteomic immunoassay. Downregulation of ErbB2 expression by siRNA silencing attenuated NRG-induced AKT and Erk1/2 phosphorylation. Activation of ErbB signaling with NRG, or inhibition with trastuzumab, alleviated or aggravated doxorubicin-induced cardiomyocyte damage, respectively, as assessed by a real-time cellular impedance analysis and ATP measurement. Collectively, these results support the expanded use of hiPSC-CMs to examine mechanisms of cardiotoxicity and support the value of using these cells in early assessments of cardiotoxicity or efficacy.

Chemotherapy-Induced Cardiotoxicity: Pathophysiology and Prevention

Along with the remarkable progress registered in oncological treatment that led to increased survival of cancer patients, treatment-related comorbidities have also become an issue for these long-term survivors. Of particular interest is the development of cardiotoxic events, which, even when asymptomatic, not only have a negative impact on the patient`s cardiac prognosis, but also considerably restrict therapeutic opportunities. The pathophysiology of cytostatic-induced cardiotoxicity implies a series of complex and intricate mechanisms, whose understanding enables the development of preventive and therapeutic strategies. Securing cardiac function is an ongoing challenge for the pharmaceutical industry and the physicians who have to deal currently with these adverse reactions. This review focuses on the main mechanism of cardiac toxicity induced by anticancer drugs and especially on the current strategies applied for preventing and minimizing the cardiac side effects.

Are monoclonal antibodies a safe treatment for cancer during pregnancy?

Monoclonal antibodies (mAbs) are the cornerstone of the treatment of several types of tumors, but their use in pregnant women is not clearly defined. Here, we report and analyze all available data on mAb treatment in pregnant cancer patients. A literature search was performed from 2000 until January 2013 and all articles addressing safety of mAbs during pregnancy were reviewed. We found very few data on the use of bevacizumab in pregnant women. However, owing to its antiangiogenic effects and possible consequences on fetal development, it should be avoided during pregnancy. Trastuzumab administration has been associated with an elevated incidence of oligohydramnios and poor neonatal outcomes, particularly when prescribed after the first trimester for repeated infusions, and therefore it is not recommended. Rituximab does not seem to be teratogenic, but a transient prolonged neutropenia in the newborns was reported, without major infectious consequences in most cases. Few data are available about other mAbs, and hence their use during pregnancy remains discouraged.

Role of renal function on the development of cardiotoxicity associated with trastuzumab-based adjuvant chemotherapy for early breast cancer

Anthracyclines, taxanes and trastuzumab are used for therapy in early breast cancer (EBC) overexpressing Human Epidermal Growth Factor 2 (HER2+). These drugs, considered alone, do not present potential nephrotoxicity. However, renal dysfunction (RD) may increase the myocardial sensibility to the insult of these chemotherapies used in combination. The aim of the study is to assess the role of RD on the development of cardiotoxicity associated with trastuzumab-based adjuvant therapy (aTrastC) for EBC. Clinical and echocardiographic data of 499 women with ERB2+ EBC were analyzed. At 12-month evaluation, any symptoms of heart failure or decrease in left ventricular ejection fraction (LVEF) were recorded. Patients who had cardiotoxicity (n = 130, 26 %) were older (57 ± 11 vs. 55 ± 11 years; p = 0.03), had lower glomerular filtration rate (GFR) (76 ± 15 vs. 83 ± 19 ml/min/1.73 m(2); p = 0.003), higher LVEF (69 ± 6 vs. 63 ± 5 %; p < 0.001) and received more frequent doses of doxorubicin (18 vs. 9 %; p = 0.01) than those who did not. In patients with GFR 60-90 and <60 ml/min/1.73 m(2), the 1-year event rate of cardiotoxicity was 25 and 38 %, respectively. ROC analysis showed that the best cut-off point of GFR for predicting cardiotoxicity was 78 ml/min/1.73 m(2) (AUC = 0.66, [95 % CI 0.57-0.74]). Multiple logistic regression revealed that GRF <78 ml/min/1.73 m(2) was the strongest predictor of cardiotoxicity (OR 3.32 [CI = 1.30-8.65]), independent of doxorubicin treatment and left ventricular ejection fraction. A reduced renal function represents a condition of higher risk of developing cardiotoxicity at 12-month follow-up in patients with HER2 + EBC treated with aTrastC.