Exploring the use and impact of adjuvant trastuzumab for HER2-positive breast cancer patients in a large UK cancer network. Do the results of international clinical trials translate into a similar benefit for patients in South East Wales?

Simulating Costs of Intravenous Biosimilar Trastuzumab vs. Subcutaneous Reference Trastuzumab in Adjuvant HER2-Positive Breast Cancer: A Belgian Case Study

This study aimed to compare drug costs and healthcare costs of a 1 year adjuvant course with intravenous biosimilar trastuzumab vs. subcutaneous reference trastuzumab in HER2-positive breast cancer from the Belgian hospital perspective. Our simulation is based on the methodology used by Tjalma and colleagues, and considered costs of drugs, healthcare professional time and consumables. We calculated intravenous drug costs for different body weights, and computed drug costs and healthcare costs to treat 100 patients with either trastuzumab formulation, assuming a binomial body weight distribution in this sample. Scenarios were run to account for drug discounts and intravenous vial sharing. Drug costs amounted to €1,431,282 with intravenous biosimilar trastuzumab and €1,522,809 with subcutaneous reference trastuzumab for a sample of 100 patients in the base case analysis. When healthcare professional time and consumables were also considered, healthcare costs with intravenous biosimilar trastuzumab were similar to those with subcutaneous reference trastuzumab. Differences in healthcare costs between intravenous biosimilar trastuzumab and subcutaneous reference trastuzumab depended on the level of discounts on these formulations and on intravenous vial sharing. Our case study demonstrates that comparing costs of intravenous vs. subcutaneous formulations is complex and multifactorial, and entails more than a simple cost comparison of products.

The use of trastuzumab affected by health insurance policy in Jiangsu Province of China

BACKGROUND

Breast cancer recurrence and mortality have been shown to decrease after trastuzumab treatment in human epidermal growth factor 2 (HER2)-positive early-stage breast cancer (EBC) patients. In Jiangsu Province, trastuzumab has been subsidized for patients with HER2-positive EBC since 2013. Several studies showed that Jiangsu was one of the provinces with the highest rates of adjuvant trastuzumab therapy. To uncover the underlying reason, we designed the study to investigate trastuzumab use for HER2-positive breast cancer patients, and to examine the changes caused by medical insurance coverage for trastuzumab in Jiangsu province of China.

METHODS

This was a retrospective, multicenter clinical study with follow-up data. HER2-positive EBC patients diagnosed in 7 representative hospitals in 2010, 2011, and 2013 were enrolled. Demographic and clinical data, and details of diagnosis, treatments, and prognosis, were collected. Data analysis included univariate analysis, multivariate logistic regression, survival analysis, and subgroup analysis.

RESULTS

Of the 641 patients (mean age 51.01±10.79 years) included, 412 (64.27%) patients had medical insurance. Trastuzumab therapy was given to 214 (33.39%) patients. The multivariate logistic regression showed that medical insurance coverage, age, and radiotherapy were associated with trastuzumab use (P<0.05). The overall survival was significantly better in the trastuzumab group than in the non-trastuzumab group (HR: 1.607; 95% CI: 1.046-2.469; P=0.040). Subgroup analysis revealed that there was a trend towards more patients with medical insurance (P=0.073), and significantly more patients received trastuzumab therapy (P<0.001) in 2013 than in 2010-2011. Additionally, trastuzumab use in China was lower than in developed countries. Patients with medical insurance were more likely to use trastuzumab, and more patients could afford trastuzumab therapy with the development of China's health-care reform.

CONCLUSIONS

Our study suggested that the percentage of patients who received trastuzumab in China was lower than developed countries. Patients who had medical insurance were more likely to use trastuzumab than those without medical insurance. The health insurance policy in China has improved access for breast cancer patients who require trastuzumab therapy.

A liposome-based cancer vaccine for a rapid and high-titre anti-ErbB-2 antibody response

Vaccines are arguably the most important medical technology developed to date. However, effective treatment of diseases such as breast cancer have so far evaded standard vaccination strategies. One popular target for cancer treatment is the cell surface membrane protein, ErbB-2, also known as Her-2 or neu. It is localised to the cell surface and has raised expression in 15-30% of all breast cancers, as well as in ovarian, colon and lung cancer. Here, a liposomal system comprised of spatially separated ErbB-2 peptide, to activate B cells, and ovalbumin peptide OVA323-339, to provide non-cognate T cell support, was used to generate antibodies against the epitope of the ErbB-2 protein targeted by Pertuzumab, a monoclonal antibody licensed for the treatment of ErbB-2 expressing cancers. After just 7 days a raised (7.3-fold, p<0.01), isotype-switched, humoral immune response specific for the ErbB-2 peptide was achieved in mice with pre-existing immunity to OVA which were exposed to liposomes with external ErbB-2 and internal OVA323-339. The absence of pre-existing OVA immunity in the mice or OVA323-339 peptide in the liposomes removed the effect. The effect of this anti-ErbB-2 antibody response was characterised against an ErbB-2 overexpressing tumour cell line both in vitro and in vivo. Notably, antibody responses were demonstrated to induce cell death in vitro, resulting in 96% reduction in viable cells. This study, therefore, demonstrates the feasibility of this approach to generate a rapid, high-titre, isotype-switched, antibody response that specifically targets ErbB-2 overexpression on tumour cells and is capable of inducing cell death in vitro in the absence of complement or immune cells.

Adherence to human epidermal growth factor receptor-2 testing and adjuvant trastuzumab treatment guidelines in Ontario

OBJECTIVES

We evaluated adherence of human epidermal growth factor receptor-2 testing using immunohistochemistry and fluorescence in situ hybridization, as well as adjuvant trastuzumab treatment according to Canadian guidelines, and predictors of trastuzumab use in early-stage breast cancer in Ontario.

METHODS

Retrospective cohort of early-stage breast cancer patients identified in the Ontario Cancer Registry. Human epidermal growth factor receptor-2 test type, sequence, result(s), tumor grade, and hormone receptor status were abstracted from Ontario Cancer Registry pathology reports. Trastuzumab treatment was determined from provincial cancer agency records. Other variables were determined from administrative data sources. Logistic regression models were used to estimate adjusted odds ratios for factors associated with guideline adherence.

RESULTS

The first human epidermal growth factor receptor-2 test result was the strongest predictor of confirmatory testing (p < 0.05). Human epidermal growth factor receptor-2 testing by immunohistochemistry accounted for the majority of documented first tests (94%; n = 8249). Overall, 27% (n = 2360) of tested patients received a second test by fluorescence in situ hybridization (46%) or immunohistochemistry (49%) assay. Most human epidermal growth factor receptor-2 equivocal patients (89%; n = 784) received a confirmatory test. Among human epidermal growth factor receptor-2-positive patients, only 57% (n = 385) received trastuzumab treatment within the study period. Human epidermal growth factor receptor-2 status was the strongest predictor of trastuzumab use. Younger patients (<70 years at diagnosis) and negative hormone receptor status had higher odds of trastuzumab treatment (p < 0.05) compared to older and positive hormone receptor status patients.

CONCLUSIONS

Immunohistochemistry use as a first test was largely consistent with Canadian guidelines; however, immunohistochemistry was frequently used as a confirmatory test, which is not guideline-concordant. Monitoring these testing and treating patterns is necessary to optimize health outcomes associated with trastuzumab.

Trastuzumab uptake in HER2-positive breast cancer patients: a systematic review and meta-analysis of observational studies

Overexpression of the HER2 gene is predictive of treatment benefit with trastuzumab therapy for breast cancer (BC) patients. The study objective was to investigate whether all eligible patients with HER2-positive BC initiated trastuzumab therapy. A systematic search was conducted through PubMed, Web of Science PsycINFO, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Cochrane Library. From 2651 studies identified, 107 observational studies were included for full text review, of which 26 met the inclusion criteria and an additional 7 studies were identified through citation searching. Two independent reviewers extracted data for accuracy and completeness. From 33 observational studies, 14,644 patients were exposed to trastuzumab therapy. Age range varied across studies; the youngest cohort had a median age of 50 and the oldest had a median age of 84. Sample sizes ranged from 11 to 1928 and included patients from 10 countries. Studies were heterogenous and few studies accounted for confounders. We identified large variability in uptake of trastuzumab in HER2-positive early BC patients (9.1-100%) and metastatic BC patients (50.8-84.0%). The pooled uptake was 71.3% (95% CI 64.6-77.9%), with high heterogeneity (I² = 99.05%). The most conservative predictors of higher uptake included younger age (OR 2.09; 95% CI 1.36-3.20) and lower Charlson Comorbidity Index of patients (OR 1.62; 95% CI 1.32-1.99). In addition, tumour characteristics including higher tumour grade (OR 1.73; 95% CI 1.23-2.45), larger tumour size (OR 1.80; 95% CI 1.54-2.10), advanced tumour stage (OR 2.07; 95% CI 1.44-2.96) and hormone receptor negative tumor (OR 1.54; 95% CI 1.35-1.77) were associated with higher uptake. The uptake of trastuzumab therapy varied widely between studies and across subgroups suggesting that there may be some inequalities in the use of this agent. However, our findings should be interpreted with caution due to study heterogeneity and potential confounding, and thus additional studies of individual level data which control for confounders are needed to understand more about inequalities in uptake.

Trastuzumab without chemotherapy in the adjuvant treatment of breast cancer: subgroup results from a large observational study

Background

The topic of trastuzumab therapy without chemotherapy in early breast cancer (EBC) has been repeatedly discussed at international consensus meetings, but is compromised by the lack of solid evidence from clinical studies.

Methods

An observational study database of patients with EBC receiving trastuzumab-containing (neo)adjuvant therapy was screened to identify those patients who did not receive cytostatic agents.

Results

Of 3935 patients, 232 (6%) were identified who received no chemotherapy, being characterized by older age, worse performance status, and/or less aggressive histology. Relapse-free survival in this cohort was 84% (95% confidence interval [CI] 78–89%) at 3 years and 80% (95% CI 74–87%) at 5 years. However, these rates were significantly worse than those in the group of patients who received chemotherapy (hazard ratio 1.49; 95% CI 1.06–2.09; P = 0.022). A similar pattern was observed for overall survival, with marginally non-significant inferiority in the group receiving no chemotherapy (hazard ratio 1.56; 95% CI 1.00–2.44; P = 0.052). Survival rates in patients receiving no chemotherapy were 93% (95% CI 88–97%) and 87% (95% CI 81–93%) at 3 and 5 years, respectively. These findings were confirmed by a propensity score analysis accounting for selection bias.

Conclusions

Trastuzumab plus chemotherapy should remain the preferred option in all patients with HER2-positive EBC with an indication for adjuvant treatment. However, a limited proportion of patients will need an alternative treatment approach, either because of contraindications or the patient’s preference. In these selected patients, trastuzumab monotherapy, eventually combined with endocrine agents, might be a reasonable option offering favorable long-term outcomes by addressing the high-risk profile associated with HER2-positive disease.

Evolving landscape of human epidermal growth factor receptor 2-positive breast cancer treatment and the future of biosimilars

Human epidermal growth factor receptor 2-positive (HER2+) breast cancer comprises approximately 15%-20% of all breast cancers and is associated with a poor prognosis. The introduction of anti-HER2 therapy has significantly improved clinical outcomes for patients with HER2+ breast cancer, and multiple HER2-directed agents (ie, trastuzumab, pertuzumab, lapatinib, and ado-trastuzumab emtansine [T-DM1]) are approved for clinical use in various settings. The treatment landscape for patients with HER2+ breast cancer is continuing to evolve. While novel agents and therapeutic strategies are emerging, biologic therapies, particularly trastuzumab, are likely to remain a mainstay of treatment. However, access issues create barriers to the use of biologics, and there is evidence for underuse of trastuzumab worldwide. A biosimilar is a biologic product that is highly similar to a licensed biologic in terms of product safety and effectiveness. Biosimilars of trastuzumab are in development and may soon become available. The introduction of biosimilars may improve access to anti-HER2 therapies by providing additional treatment options and lower-cost alternatives. Because HER2-targeted drugs may be administered for extended periods of time and in combination with other systemic therapies, biosimilars have the potential to result in significant savings for healthcare systems. Herein we review current and emerging treatment options for, and discuss the possible role of biosimilars in, treating patients with HER2+ breast cancer.

Trastuzumab in Human Epidermal Growth Factor Receptor 2-Positive Early Breast Cancer: Results of a Prospective, Noninterventional Study on Routine Treatment Between 2006 and 2012 in Germany

PURPOSE

Trastuzumab is part of the standard treatment in patients with human epidermal growth factor receptor 2-positive early breast cancer in addition to (neo)adjuvant chemotherapy. This German prospective noninterventional study, which included major patient cohorts underrepresented in the pivotal randomized studies, examined the generalizability of the results of those studies.

PATIENTS AND METHODS

Between 2006 and 2012, 4,027 patients were enrolled and treated with trastuzumab; they were unselected regarding age or concomitant/sequential adjuvant chemotherapy. Long-term outcome data were obtained in yearly intervals. All analyses were descriptive in nature.

RESULTS

Among 3,940 evaluable patients, 26% were elderly (older than 65 years of age). More than half of the population had pN0 tumor stage. Ninety-four percent received chemotherapy: 78% as adjuvant treatment and 14% as neoadjuvant treatment, 2% both. Anthracyclines were administered in 87% and taxanes in 66%. Trastuzumab was stopped prematurely in 9% (because of cardiotoxicity in 3.5%). Recurrence-free survival was 90.0% (95% confidence interval [CI], 88.9%-91.1%) and 82.8% (95% CI, 81.2%-84.4%) after 3 and 5 years, respectively. The corresponding figures for overall survival were 96.8% (95% CI, 96.1%-97.6%) and 90.0% (95% CI, 88.6%-91.4%). Pathological primary tumor size, lymph node involvement, and hormone receptor status had the greatest independent effect on recurrence risk. Cardiac function toxicity of National Cancer Institute common toxicity criteria grade ≥2 and ≥3 was observed in 2.5% and less than 1% of patients, respectively.

CONCLUSION

The maturing follow-up data seem to confirm the beneficial results of trastuzumab treatment for early breast cancer from the randomized studies. Moreover, these findings support use of trastuzumab-based therapy in patients groups less commonly included in the phase III trials (e.g., elderly patients and those with stage I disease). The Oncologist 2017;22:131-138Implications for Practice: On the basis of the results of large pivotal phase III studies, the inclusion of trastuzumab in adjuvant treatment regimens for human epidermal growth factor receptor 2-positive breast cancer is standard of care. However, in these trials, elderly patients, those with comorbidities, and/or those with contraindications or refusal of cytotoxic chemotherapy are typically underrepresented. This study provides data on observed treatment options, outcomes, and risks in a wider, unselected patient population (including more than 1,000 patients with stage I disease), treated routinely in several institutions of varying size and location across Germany.

Benefit of adjuvant chemotherapy with or without trastuzumab in pT1ab node-negative human epidermal growth factor receptor 2-positive breast carcinomas: results of a national multi-institutional study

PURPOSE

Benefit of adjuvant trastuzumab-based chemotherapy for node-positive and/or >1 cm human epidermal growth factor receptor 2-positive (HER2+) breast carcinomas has been clearly demonstrated in randomized clinical trials. Yet, evidence that adjuvant chemotherapy with or without trastuzumab is effective in pT1abN0 HER2+ tumors is still limited. The primary objective of this study was to investigate the impact of adjuvant chemotherapy ± trastuzumab on outcome in this subpopulation.

PATIENTS AND METHODS

A total of 356 cases of pT1abN0M0 HER2 + breast cancers were retrospectively identified from a large cohort of 22,334 patients, including 1248 HER2+ patients who underwent primary surgery at 17 French centers, between December 1994 and January 2014. The primary end point was disease-free survival (DFS). A multivariate Cox model was built, including adjuvant chemotherapy, tumor size, hormone receptor status, and Scarff Bloom Richardson (SBR) grade.

RESULTS

A total of 138 cases (39%) were treated with trastuzumab-based chemotherapy, 29 (8%) with chemotherapy alone, and 189 (53%) received neither trastuzumab nor chemotherapy. Adjuvant chemotherapy ± trastuzumab was associated with a significant DFS benefit (3-year 99 vs. 90%, and 5-year 96 vs. 84%, Hazard ratio, HR 0.26 [0.10-0.67]; p = 0.003, logrank test) which was maintained in multivariate analysis (HR 0.19 [0.07-0.52]; p = 0.001). Metastasis-free survival was also increased (HR 0.25 [0.07-0.86]; p = 0.018, logrank test) at 3-year (99 vs. 95%) and 5-year (98 vs. 89%) censoring. Exploratory subgroup analysis found DFS benefit to be significant in hormone receptor-negative, hormone receptor-positive, and pT1b tumors, but not in pT1a tumors.

CONCLUSIONS

Adjuvant chemotherapy ± trastuzumab is associated with a significantly reduced risk of recurrence in subcentimeter node-negative HER2+ breast cancers. Most of the benefit may be driven by pT1b tumors.

The antineoplastic drug, trastuzumab, dysregulates metabolism in iPSC-derived cardiomyocytes

Background

The targeted ERBB2 therapy, trastuzumab, has had a tremendous impact on management of patients with HER2+ breast cancer, leading to development and increased use of further HER2 targeted therapies. The major clinical side effect is cardiotoxicity but the mechanism is largely unknown. On the basis that gene expression is known to be altered in multiple models of heart failure, we examined differential gene expression of iPSC-derived cardiomyocytes treated at day 11 with the ERBB2 targeted monoclonal antibody, trastuzumab for 48 h and the small molecule tyrosine kinase inhibitor of EGFR and ERBB2.

Results

Transcriptome sequencing was performed on four replicates from each group (48 h untreated, 48 h trastuzumab and 48 h lapatinib) and differential gene expression analyses were performed on each treatment group relative to untreated cardiomyocytes. 517 and 1358 genes were differentially expressed, p < 0.05, respectively in cardiomyocytes treated with trastuzumab and lapatinib. Gene ontology analyses revealed in cardiomyocytes treated with trastuzumab, significant down-regulation of genes involved in small molecule metabolism (p = 3.22 × 10⁻⁹) and cholesterol (p = 0.01) and sterol (p = 0.03) processing. We next measured glucose uptake and lactate production in iPSC-derived cardiomyocytes 13 days post-plating, treated with trastuzumab up to 96 h. We observed significantly decreased glucose uptake from the media of iPSC-derived cardiomyocytes treated with trastuzumab as early as 24 h (p = 0.001) and consistently up to 96 h (p = 0.03).

Conclusions

Our study suggests dysregulation of cardiac gene expression and metabolism as key elements of ERBB2 signaling that could potentially be early biomarkers of cardiotoxicity.

Electronic supplementary material

The online version of this article (doi:10.1186/s40169-016-0133-2) contains supplementary material, which is available to authorized users.

Delay in initiation of adjuvant trastuzumab therapy leads to decreased overall survival and relapse-free survival in patients with HER2-positive non-metastatic breast cancer

Trastuzumab reduces the risk of relapse in women with HER2-positive non-metastatic breast cancer, but little information exists on the timing of trastuzumab initiation. The study investigated the impact of delaying the initiation of adjuvant trastuzumab therapy for >6 months after the breast cancer diagnosis on time to relapse, overall survival (OS), and relapse-free survival (RFS) among patients with non-metastatic breast cancer. Adult women with non-metastatic breast cancer who initiated trastuzumab adjuvant therapy without receiving any neoadjuvant therapy were selected from the US Department of Defense health claims database from 01/2003 to 12/2012. Two study cohorts were defined based on the time from breast cancer diagnosis to trastuzumab initiation: >6 months and ≤6 months. The impact of delaying trastuzumab initiation on time to relapse, OS, and RFS was estimated using Cox regression models adjusted for potential confounders. Of 2749 women in the study sample, 79.9 % initiated adjuvant trastuzumab within ≤6 months of diagnosis and 20.1 % initiated adjuvant trastuzumab >6 months after diagnosis. After adjusting for confounders, patients who initiated trastuzumab >6 months after the breast cancer diagnosis had a higher risk of relapse, death, or relapse/death than those who initiated trastuzumab within ≤6 months of diagnosis (hazard ratios [95 % CIs]: 1.51 [1.22-1.87], 1.54 [1.12-2.12], and 1.43 [1.16-1.75]; respectively). The results of this population-based study suggest that delays of >6 months in the initiation of trastuzumab among HER2-positive non-metastatic breast cancer patients are associated with a higher risk of relapse and shorter OS and RFS.

Survival in patients with non-metastatic breast cancer treated with adjuvant trastuzumab in clinical practice

PURPOSE

The NSABP Trial B-31 and NCCTG Trial N9831 (B-31/N9831 trials, Romond et al. in N Engl J Med 353:1673-84, 2005. doi:10.1056/NEJMoa052122; Perez et al. in J Clin Oncol 32:3744-52, 2014. doi:10.1200/JCO.2014.55.5730) established the efficacy of adjuvant trastuzumab for patients with HER2-positive early stage breast cancer. We aimed to estimate the overall survival (OS) and relapse-free survival (RFS) of HER2-positive non-metastatic breast cancer patients treated with adjuvant trastuzumab in a clinical practice setting in the United States.

METHODS

Adult women initiating adjuvant trastuzumab within 1 year of breast cancer surgery were identified in the health claims database of the US Department of Defense (01/2003-12/2012). OS and RFS unadjusted rates at 4 and 6 years after the first trastuzumab treatment following the breast cancer diagnosis were estimated from Kaplan-Meier analyses.

RESULTS

The study sample included 3188 women followed for a median of 3.3 years after trastuzumab initiation and treated continuously with trastuzumab for a median of 12 months. The OS rates (95 % confidence intervals) at 4 and 6 years were 90.0 % (88.6-91.2) and 87.1 (85.3-88.6), respectively. The corresponding RFS rates were 75.8 % (74.0-77.5) and 72.7 (70.7-74.7), respectively. The OS and RFS rates at 6 years reported in the B-31/N9831 trials were 89.8 and 81.4 %, respectively.

CONCLUSIONS

OS rates estimated in this study were in range with those estimated in the B-31/N9831 trials, while RFS rates were lower. However, patients in the B-31/N9831 trials were younger and possibly had fewer comorbidities than patients in the current study; these differences were not adjusted for in the crude OS and RFS analyses.

Metformin effects on malignant cells and healthy PBMC; the influence of metformin on the phenotype of breast cancer cells

The aim of research was to determine the effects of maximally therapeutically achievable concentrations of metformin on malignant cells and healthy peripheral blood mononuclear cells (PBMC). Eight patients with T2D or hyperglycemia and nine healthy volunteers were included in the study. For determination of the influence of metformin on the phenotype of breast carcinoma, 1,410 patients with surgically removed tumors were included. From this group 37 breast cancer patients had DM type 2 or hyperglycemia and were pretreated with metformin alone or sometimes in combination with other antidiabetic drugs. Our results proved that metformin at low concentrations induced mild decrease in survival of malignant cells and PBMC stimulated for proliferation, but it didn't affect survival of resting PBMC. The effects of plasma of hyperglycemic patients who were under metformin therapy on autologous PBMC-induced decrease in survival of MDA-MB-361 cells, was noticeable in some patients. Metformin pretreatment for 24 h of HER2+ MDA-MB-361 cells, which were subsequently treated for 48 h with Herceptin, induced additional decline in cell survival. The analysis of influence of metformin on phenotype of breast cancer cells revealed significantly lower number of diabetic cancer patients treated with metformin with overexpressed HER2+ tumors (p < 0.013), while the number of patients with ER+PR+ tumors was not significantly changed (p < 0.832). In conclusion, therapeutically used concentrations of metformin exhibit mild cytotoxic action on malignant and dividing normal cells pointing to its preferred role in malignant and autoimmune diseases. The use of metformin was associated with pronounced decrease in HER2 overexpressing tumors.

Cardiovascular events, early discontinuation of trastuzumab, and their impact on survival

To evaluate how often trastuzumab therapy is ended early (i.e., early discontinuation) and how cardiovascular events and early discontinuation affect survival among older women with breast cancer. A population-based cohort of female Medicare beneficiaries with stage I-III breast cancer in 2005-2009 who received trastuzumab was assembled and followed through 2011. Completed trastuzumab treatment was defined as ≥11 months of continuous trastuzumab treatments with no delay between trastuzumab treatments >45 days. We identified trastuzumab-associated cardiovascular events as those occurring within 45 days before or after the last trastuzumab treatment. Using Cox proportional hazard models, we examined the association between early discontinuation of trastuzumab and cardiovascular events on all-cause mortality. Our cohort consisted of 585 women (mean age: 71.6 years). Approximately 41 % of women discontinued trastuzumab therapy early. Patients with early discontinuation of trastuzumab were more likely to have heart failure /cardiomyopathy, atrial fibrillation, and other cardiovascular events than women who completed trastuzumab. Cardiovascular events were strongly associated with an increased risk of all-cause mortality [adjusted hazard ratio (AHR) 3.54; 95 % confidence interval (CI) 1.87 to 6.68]. Women with early discontinuation of trastuzumab had a non-significant increase in risk of all-cause mortality (AHR: 1.74; 95 % CI 0.94 to 3.23), compared to women who completed trastuzumab. Early trastuzumab discontinuation was common among older patients, and often associated with adverse cardiovascular events. Development of cardiovascular events was associated with a higher mortality risk than early trastuzumab discontinuation, implying that reducing cardiovascular complications from trastuzumab therapy could likely have a substantive impact on overall survival in this population.

Impact of HER2 copy number in IHC2+/FISH-amplified breast cancer on outcome of adjuvant trastuzumab treatment in a large UK cancer network

Background:

Adjuvant trastuzumab with chemotherapy is standard treatment for HER2-positive breast cancer, defined as either HER2 IHC3+ or IHC2+ and FISH amplified. The aim of this study was to investigate the degree to which HER2 amplification in terms of HER2 gene copy numbers in HER2+IHC2+ cancers affected the outcome in a community setting.

Methods:

Case records of 311 consecutive patients with early breast cancer presenting between 1st January 2005 and 31st December 2008 were reviewed. Progression-free survival and overall survival were calculated with the Kaplan–Meier method using STATA 13.

Results:

Among 3+ cases (n=230) 163 received T vs 67 no-T. Among 2+ cases (n=81) 59 received T vs 22 no-T. Among 59 IHC2+-treated cases n=28 had an average of >12, n=13 had >6 to <12, and n=18 had >2 to <6 HER2 gene copies, respectively. The time of progression and overall survival of high and low copy number patients was similar and better than the intermediate copy number and the untreated cohorts.

Conclusions:

High HER2 copy number (>12) appears to be associated with consistently better response compared with patients with intermediate HER2 copy numbers (6–12). In light of emerging data of patients showing insensivity to trastuzumab therapy, we propose that the HER2 gene copy number value should be included as an additional indicator for stratifying both the management and the follow-up of breast cancer patients.