Trastuzumab Treatment in Multiple Lines: Current Data and Future Directions

Successful Application of CuAAC Click Reaction in Constructing 64Cu-Labeled Antibody Conjugates for Immuno-PET Imaging

Immuno-positron emission tomography (immuno-PET) is a rapidly growing imaging technique in which antibodies are radiolabeled to monitor their in vivo behavior in real time. However, effecting the controlled conjugation of a chelate-bearing radioactive atom to a bulky antibody without affecting its immunoreactivity at a specific site is always challenging. The in vivo stability of the radiolabeled chelate is also a key issue for successful tumor imaging. To address these points, a facile ultra-stable radiolabeling platform is developed by using the propylene cross-bridged chelator (PCB-TE2A-alkyne), which can be instantly functionalized with various groups via the click reaction, thus enabling specific conjugation with antibodies as per choice. The PCB-TE2A-tetrazine derivative is selected to demonstrate the proposed strategy. The antibody trastuzumab is functionalized with the trans-cyclooctene (TCO) moiety in the presence or absence of the PEG linker. The complementary ⁶⁴Cu-PCB-TE2A-tetrazine is synthesized via the click reaction and radiolabeled with ⁶⁴Cu ions, which then reacts with the aforementioned TCO-modified antibody via a rapid biorthogonal ligation. The ⁶⁴Cu-PCB-TE2A-trastuzumab conjugate is shown to exhibit excellent in vivo stability and to maintain a higher binding affinity toward HER2-positive cells. The tumor targeting feasibility of the radiolabeled antibody is evaluated in tumor models. Both ⁶⁴Cu-PCB-TE2A-trastuzumab conjugates show high tumor uptakes in biodistribution studies and enable unambiguous tumor visualization with minimum background noise in PET imaging. Interestingly, the ⁶⁴Cu-PCB-TE2A-PEG₄-trastuzumab containing an additional PEG linker displays a much faster body clearance compared to its counterpart with less PEG linker, thus affording vivid tumor imaging with an unprecedentedly high tumor-to-background ratio.

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.

Final results of the TANIA randomised phase III trial of bevacizumab after progression on first-line bevacizumab therapy for HER2-negative locally recurrent/metastatic breast cancer

BACKGROUND

The randomised phase III TANIA trial demonstrated that continuing bevacizumab with second-line chemotherapy for locally recurrent/metastatic breast cancer (LR/mBC) after progression on first-line bevacizumab-containing therapy significantly improved progression-free survival (PFS) compared with chemotherapy alone [hazard ratio (HR) = 0.75, 95% confidence interval (CI) 0.61-0.93]. We report final results from the TANIA trial, including overall survival (OS) and health-related quality of life (HRQoL).

PATIENTS AND METHODS

Patients with HER2-negative LR/mBC that had progressed on or after first-line bevacizumab plus chemotherapy were randomised to receive standard second-line chemotherapy either alone or with bevacizumab. At second progression, patients initially randomised to bevacizumab continued bevacizumab with their third-line chemotherapy, but those randomised to chemotherapy alone were not allowed to cross over to receive third-line bevacizumab. The primary end point was second-line PFS; secondary end points included third-line PFS, combined second- and third-line PFS, OS, HRQoL and safety.

RESULTS

Of the 494 patients randomised, 483 received second-line therapy; 234 patients (47% of the randomised population) continued to third-line study treatment. The median duration of follow-up at the final analysis was 32.1 months in the chemotherapy-alone arm and 30.9 months in the bevacizumab plus chemotherapy arm. There was no statistically significant difference between treatment arms in third-line PFS (HR = 0.79, 95% CI 0.59-1.06), combined second- and third-line PFS (HR = 0.85, 95% CI 0.68-1.05) or OS (HR = 0.96, 95% CI 0.76-1.21). Third-line safety results showed increased incidences of proteinuria and hypertension with bevacizumab, consistent with safety results for the second-line treatment phase. No differences in HRQoL were detected.

CONCLUSIONS

In this trial, continuing bevacizumab beyond first and second progression of LR/mBC improved second-line PFS, but no improvement in longer term efficacy was observed. The second-line PFS benefit appears to be achieved without detrimentally affecting quality of life.

CLINICALTRIALSGOV

NCT01250379.

National consensus in China on diagnosis and treatment of patients with advanced breast cancer

The recently available guidelines on the management of advanced breast cancer (ABC) organized by Chinese Anti-Cancer Association, Committee of Breast Cancer Society (CACA-CBCS) do not elucidate ABC in details. To instruct clinicians in treatment of ABC, a Chinese expert consensus meeting on diagnosis and treatment of ABC was held in June 2014 and a consensus is developed. The following consensus provides the level of evidence and supporting documents for each recommendation, and introduces research topics to be urgently addressed. Notably, the consensus on diagnosis and treatment of ABC in China is developed to be applied nationwide. In different areas, multidisciplinary treatment (MDT) tailored to the each patient and the disease itself should be applied based on the basic principles of modern oncology.

HER2-positive metastatic breast cancer: a changing scenario

Adjuvant trastuzumab (AT) dramatically improved HER2-positive breast cancer prognosis. Relapsed disease after AT has different patterns and information is available from observational studies. In this Review Chemotherapy regimens combined to anti-HER2 blockade are discussed, focusing in particular the role of anthracyclines, taxanes and capecitabine. The use of trastuzumab beyond progression and the role of other anti-HER2 agents like lapatinib, pertuzumab and T-DM1 are explored, as also dual blockade and in trastuzumab resistant Patients. Metastatic "de novo" HER2 Luminal (co-expression of HER2 and hormone receptors) Patients are eligible for anastrozole and trastuzumab but if pretreated with trastuzumab they are also eligible for lapatinib and letrozole. In any case endocrine treatment plays a complementary role to chemotherapy which remains pivotal. The last topic explored is treatment options for patients with brain metastases where both trastuzumab given concurrent with radiotherapy or lapatinib and capecitabine appear as potentially active.

Efficacy of TCH/TEC neoadjuvant chemotherapy for the treatment of HER-2-overexpressing breast cancer

The aim of the present study was to observe the efficacy of neoadjuvant trastuzumab combined with docetaxel and carboplatin (TCH), and docetaxel, epirubicin and cyclophosphamide (TEC) chemotherapy in human epidermal growth factor receptor-2 (HER-2)-overexpressing breast cancer. The total cohort of 64 cases of HER-2-overexpressing breast cancer patients was divided into two groups according to their treatment preferences: The TCH group, consisting of 39 patients, and the TEC group, consisting of 25 patients. The neoadjuvant chemotherapy was continued for six cycles prior to comparison of the treatment efficacy. The TCG and TEC groups exhibited an overall response rate of 94.9 and 72.0% (37/39 and 18/25 cases; P<0.05), respectively, and a pathological complete response (pCR; defined as the presence of no invasive or in situ residual tumors in the breast) rate of 69.2 and 32.0% (27/39 and 8/25 cases; P<0.05), respectively. Furthermore, no significant differences were identified between the two groups of patients in terms of adverse reactions, such as cardiac dysfunction, bone marrow suppression and liver function impairment. In the present study, the treatment of HER-2-overexpressing breast cancer patients with TCH neoadjuvant chemotherapy demonstrated more favorable efficacy and a higher pCR rate when compared with the TEC-treated group.

New bifunctional chelator for 64Cu-immuno-positron emission tomography

A new tetraazamacrocyclic bifunctional chelator, TE2A-Bn-NCS, was synthesized in high overall yield from cyclam. An extra functional group (NCS) was introduced to the N-atom of TE2A for specific conjugation with antibody. The Cu complex of TE2A-Bn-NCS showed high kinetic stability in acidic decomplexation and cyclic voltammetry studies. X-ray structure determination of the Cu-TE2A-Bn-NH2 complex confirmed octahedral geometry, in which copper atom is strongly coordinated by four macrocyclic nitrogens in equatorial positions and two carboxylate oxygen atoms occupy the elongated axial positions. Trastuzumab was conjugated with TE2A-Bn-NCS and then radiolabeled with 64Cu quantitatively at room temperature within 10 min. Biodistribution studies showed that the 64Cu-labeled TE2A-Bn-NCS-trastuzumab conjugates maintain high stability in physiological conditions, and NIH3T6.7 tumors were clearly visualized up to 3 days by 64Cu-immuno-positron emission tomography imaging in animal models.

White matter changes in breast cancer brain metastases patients who undergo radiosurgery alone compared to whole brain radiation therapy plus radiosurgery

Delayed toxicity after whole brain radiation therapy (WBRT) is of increasing concern in patients who survive more than one year with brain metastases from breast cancer. Radiation-related white matter toxicity is detected by magnetic resonance imaging (MRI) and has been correlated with neurocognitive dysfunction. This study assessed the risk of developing white matter changes (WMC) in breast cancer patients who underwent either WBRT plus stereotactic radiosurgery (SRS) or SRS alone. We retrospectively compared 35 patients with breast cancer brain metastases who received WBRT and SRS to 30 patients who only received SRS. All patients had evaluable imaging at a median of one year after their initial management. The development of white matter T2 prolongation as detected by T2 or FLAIR imaging was graded: grade 1 = little or no white matter T2 hyperintensity; grade 2 = limited periventricular hyperintensity; and grade 3 = diffuse white matter hyperintensity. After WBRT plus SRS, patients demonstrated a significantly higher incidence of WMC (p < 0.0001). After one year, 71.5 % of patients whose treatment included WBRT demonstrated WMC (42.9 % grade 2; 28.6 % grade 3). Only one patient receiving only SRS developed WMC. In long-term survivors of breast cancer, the risk of WMC was significantly reduced when SRS alone was used for management. Further prospective studies are necessary to determine how these findings correlate with neurocognitive toxicity. WBRT usage as initial management of limited brain disease should be replaced by SRS alone to reduce the risk of delayed white matter toxicity.

Impact of trastuzumab treatment beyond disease progression for advanced/metastatic breast cancer on survival - results from a prospective, observational study in Germany

OBJECTIVES

Evidence suggests that continued trastuzumab therapy beyond progression (TBP) may provide additional survival benefit. Within the framework of an observational prospective study of patients with advanced/metastatic breast cancer receiving trastuzumab in routine clinical practice, we had the opportunity to examine the effect of TBP in a large population.

PATIENTS AND METHODS

Among a total of 1843 trastuzumab-treated patients, a sub-cohort of 418 fulfilled the selection criteria for the TBP analysis: 261 continued trastuzumab and 157 discontinued. Logrank tests and Cox models were used to compare survival and identify prognostic factors.

RESULTS

Survival from progression was significantly longer in those patients continuing trastuzumab treatment beyond disease progression (TBP: median 22.1 months; no TBP: median 14.9 months; HR = 0.64; P = 0.00021). In addition to TBP, a positive endocrine receptor status, a longer relapse-free interval, no visceral metastasis, no concomitant chemotherapy during first-line treatment, and first-line response were independently significant prognostic variables for longer survival on multivariate analysis.

CONCLUSION

The hitherto limited evidence for TBP benefit from randomized studies was confirmed. While a number of strong disease-related predictors for survival after first progression could be identified, the positive effect of trastuzumab continuation retained statistical significance in a multivariate model.

Trastuzumab (herceptin): a retrospective analysis of the effects of long-term application in a series of patients with breast cancer

INTRODUCTION

About 20 % of all mamma carcinomas are HER2 positive. The overexpression of HER2 is considered to be a negative prognostic factor. Trastuzumab is a monoclonal anti-HER2 antibody developed to target HER2 overexpressing tumor cells. So far, there is only little data available on long-term effects of trastuzumab. This is why we analyzed the medical records of our patient collective with respect to tolerability and oncological outcomes of long-term trastuzumab treatment.

MATERIALS AND METHODS

Our retrospective observational study included all patients of the Saarland University Hospital with breast cancer who received trastuzumab for more than 18 months between 2003 and 2012. We analyzed the medical records with respect to oncological outcome, tolerability and cardiac side effects.

RESULTS

A total of n = 15 patients had been treated with trastuzumab for over 18 months with a mean therapy duration of 57.2 months (range 18-119 months). The mean follow-up time was 113.5 months (range 50-240 months). Three of the patients had a treatment interruption for an average of 2.6 months (range 3-5), which was not due to side effects. The left ventricular ejection fraction (LVEF) was controlled at regular intervals in all of the patients. Upon the beginning of the trastuzumab treatment, the mean LVEF was 68 %. In one patient, the trastuzumab treatment was discontinued after 41 months because of a decrease of the LVEF below normal levels.

CONCLUSION

Trastuzumab is well tolerated even during long-term use. Patients with HER2 overexpression and metastases can be treated well with trastuzumab for up to 119 months.

Neurocognitive assessment following whole brain radiation therapy and radiosurgery for patients with cerebral metastases

The treatment of metastatic brain lesions remains a central challenge in oncology. Because most chemotherapeutic agents do not effectively cross the blood-brain barrier, it is widely accepted that radiation remains the primary modality of treatment. The mode by which radiation should be delivered has, however, become a source of intense controversy in recent years. The controversy involves whether patients with a limited number of brain metastases should undergo whole brain radiation therapy (WBRT) or stereotactic radiosurgery (SRS) delivered only to the radiographically visible tumours. Survival is comparable for patients treated with either modality. Instead, the controversy involves the neurocognitive function (NCF) of radiating cerebrum that appeared radiographically normal relative to effects of the growth from micro-metastatic foci. A fundamental question in this debate involves quantifying the effect of WBRT in patients with cerebral metastasis. To disentangle the effects of WBRT on neurocognition from the effects inherent to the underlying disease, we analysed the results from randomised controlled studies of prophylactic cranial irradiation in oncology patients as well as studies where patients with limited cerebral metastasis were randomised to SRS versus SRS+WBRT. In aggregate, these results suggest deleterious effects of WBRT in select neurocognitive domains. However, there are insufficient data to resolve the controversy of upfront WBRT versus SRS in the management of patients with limited cerebral metastases.

Protein engineering to target complement evasion in cancer

The complement system is composed of soluble factors in plasma that enhance or "complement" immune-mediated killing through innate and adaptive mechanisms. Activation of complement causes recruitment of immune cells; opsonization of coated cells; and direct killing of affected cells through a membrane attack complex (MAC). Tumor cells up-regulate complement inhibitory factors - one of several strategies to evade the immune system. In many cases as the tumor progresses, dramatic increases in complement inhibitory factors are found on these cells. This review focuses on the classic complement pathway and the role of major complement inhibitory factors in cancer immune evasion as well as on how current protein engineering efforts are being employed to increase complement fixing or to reverse complement resistance leading to better therapeutic outcomes in oncology. Strategies discussed include engineering of antibodies to enhance complement fixation, antibodies that neutralize complement inhibitory proteins as well as engineered constructs that specifically target inhibition of the complement system.

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.

Drug rechallenge and treatment beyond progression--implications for drug resistance

The established dogma in oncology for managing recurrent or refractory disease dictates that therapy is changed at disease progression, because the cancer is assumed to have become drug-resistant. Drug resistance, whether pre-existing or acquired, is largely thought to be a stable and heritable process; thus, reuse of therapeutic agents that have failed is generally contraindicated. Over the past few decades, clinical evidence has suggested a role for unstable, non-heritable mechanisms of acquired drug resistance pertaining to chemotherapy and targeted agents. There are many examples of circumstances where patients respond to reintroduction of the same therapy (drug rechallenge) after a drug holiday following disease relapse or progression during therapy. Additional, albeit limited, evidence suggests that, in certain circumstances, continuing a therapy beyond disease progression can also have antitumour activity. In this Review, we describe the anticancer agents used in these treatment strategies and discuss the potential mechanisms explaining the apparent tumour re-sensitization with reintroduced or continued therapy. The extensive number of malignancies and drugs that challenge the custom of permanently switching to different drugs at each line of therapy warrants a more in-depth examination of the definitions of disease progression and drug resistance and the resulting implications for patient care.

Kinesin spindle protein (KSP) inhibitors in combination with chemotherapeutic agents for cancer therapy

A diverse group of proteins, the activities of which are precisely orchestrated during mitosis, have emerged as targets for cancer therapeutics; these include the Aurora kinases (AKs), Polo-like kinases (PLKs), and the kinesin spindle protein (KSP). KSP is essential for the proper separation of spindle poles during mitosis. Agents that target KSP selectively act on cells undergoing cell division, which means that KSP inhibitors are mitosis-specific drugs, and have demonstrated remarkable activities in vitro. However, a significant obstacle to the success of KSP inhibitors is that these compounds, with tremendous efficacy in vitro, have demonstrated little or even no antitumor activity in vivo. Accumulated data suggest that a combination of KSP inhibitors with various cytostatic drugs will result in a more powerful tumor-killing effect than monotherapy. Combination therapies might predominate and represent the next frontier in the discovery research of KSP inhibitors as potential anticancer drugs. Few published studies have reviewed combination therapy using KSP inhibitors. Herein we provide a comprehensive review of the literature on KSP inhibitor monotherapy and therapeutic combinations. The current state and problems are also discussed.

Targeted anti-vascular therapies for ovarian cancer: current evidence

Ovarian cancer presents at advanced stage in around 75% of women, and despite improvements in treatments such as chemotherapy, the 5-year survival from the disease in women diagnosed between 1996 and 1999 in England and Wales was only 36%. Over 80% of patients with advanced ovarian cancer will relapse and despite a good chance of remission from further chemotherapy, they will usually die from their disease. Sequential treatment strategies are employed to maximise quality and length of life but patients eventually become resistant to cytotoxic agents. The expansion in understanding of the molecular biology that characterises cancer cells has led to the rapid development of new agents to target important pathways but the heterogeneity of ovarian cancer biology means that there is no predominant defect. This review attempts to discuss progress to date in tackling a more general target applicable to ovary cancer-angiogenesis.

Targeted treatments of HER2-positive metastatic breast cancer: trastuzumab and beyond

SUMMARY HER2 positivity defines a molecular subtype of breast cancer with aggressive biological behavior. HER2 has been clinically validated as a prominent therapeutic target in breast cancer, and an abundance of data from clinical trials proving the efficacy of trastuzumab, a humanized anti-HER2 monoclonal antibody, has changed the natural history of this disease. Despite positive results from many trials, resistance to anti-HER2 agents inevitably occurs in both the metastatic and adjuvant settings. This clinical reality has led to the development of various other targeted agents designed to block the HER2 receptor. Similarly, attempts to elucidate the molecular mechanisms of resistance to the already established anti-HER2 agents have opened new therapeutic avenues with numerous promising agents. This review presents a comprehensive overview of the data available on anti-HER2-targeted agents other than trastuzumab, and describes both challenges and directions for the future.

1st International consensus guidelines for advanced breast cancer (ABC 1)

The 1st international Consensus Conference for Advanced Breast Cancer (ABC 1) took place on November 2011, in Lisbon. Consensus guidelines for the management of this disease were developed. This manuscript summarizes these international consensus guidelines.