Treatment of early-stage human epidermal growth factor 2-positive cancers among medicare enrollees: age and race strongly associated with non-use of trastuzumab

Guideline-concordant breast cancer care by patient race and ethnicity accounting for individual-, facility- and area-level characteristics: a SEER-Medicare study

PURPOSE

To examine racial-ethnic variation in adherence to established quality metrics (NCCN guidelines and ASCO quality metrics) for breast cancer, accounting for individual-, facility-, and area-level factors.

METHODS

Data from women diagnosed with invasive breast cancer at 66+ years of age from 2000 to 2017 were examined using SEER-Medicare. Associations between race and ethnicity and guideline-concordant diagnostics, locoregional treatment, systemic therapy, documented stage, and oncologist encounters were estimated using multilevel logistic regression models to account for clustering within facilities or counties.

RESULTS

Black and American Indian/Alaska Native (AIAN) women had consistently lower odds of guideline-recommended care than non-Hispanic White (NHW) women (Diagnostic workup: ORBlack 0.83 (0.79-0.88), ORAIAN 0.66 (0.54-0.81); known stage: ORBlack 0.87 (0.80-0.94), ORAIAN 0.63 (0.47-0.85); seeing an oncologist: ORBlack 0.75 (0.71-0.79), ORAIAN 0.60 (0.47-0.72); locoregional treatment: ORBlack 0.80 (0.76-0.84), ORAIAN 0.84 (0.68-1.02); systemic therapies: ORBlack 0.90 (0.83-0.98), ORAIAN 0.66 (0.48-0.91)). Commission on Cancer accreditation and facility volume were significantly associated with higher odds of guideline-concordant diagnostics, stage, oncologist visits, and systemic therapy. Black residential segregation was associated with significantly lower odds of guideline-concordant locoregional treatment and systemic therapy. Rurality and area SES were associated with significantly lower odds of guideline-concordant diagnostics and oncologist visits.

CONCLUSIONS

This is the first study to examine guideline-concordance across the continuum of breast cancer care from diagnosis to treatment initiation. Disparities were present from the diagnostic phase and persisted throughout the clinical course. Facility and area characteristics may facilitate or pose barriers to guideline-adherent treatment and warrant future investigation as mediators of racial-ethnic disparities in breast cancer care.

Population-level impact of adjuvant trastuzumab emtansine on the incidence of metastatic breast cancer: an epidemiological prediction model of women with HER2-positive early breast cancer and residual disease following neoadjuvant therapy

PURPOSE

Treating early-stage breast cancer (eBC) may delay or prevent subsequent metastatic breast cancer (mBC). In the phase 3 KATHERINE study, women with human epidermal growth factor receptor 2 (HER2)-positive eBC with residual disease following neoadjuvant therapy containing trastuzumab and a taxane experienced 50% reductions in disease recurrence or death when treated with adjuvant trastuzumab emtansine (T-DM1) vs adjuvant trastuzumab. We predicted the population-level impact of adjuvant T-DM1 on mBC occurrence in five European countries (EU5) and Canada from 2021-2030.

METHODS

An epidemiological prediction model using data from national cancer registries, observational studies, and clinical trials was developed. Assuming 80% population-level uptake of adjuvant treatment, KATHERINE data were extrapolated prospectively to model projections. Robustness was evaluated in alternative scenarios.

RESULTS

We projected an eligible population of 116,335 women in Canada and the EU5 who may be diagnosed with HER2-positive eBC and have residual disease following neoadjuvant therapy from 2021-2030. In EU5, the cumulative number of women projected to experience relapsed mBC over the 10-year study period was 36,009 vs 27,143 under adjuvant trastuzumab vs T-DM1, a difference of 8,866 women, equivalent to 25% fewer cases with the use of adjuvant T-DM1 in EU5 countries from 2021-2030. Findings were similar for Canada.

CONCLUSION

Our models predicted greater reductions in the occurrence of relapsed mBC with adjuvant T-DM1 vs trastuzumab in the indicated populations in EU5 and Canada. Introduction of T-DM1 has the potential to reduce population-level disease burden of HER2-positive mBC in the geographies studied.

Patterns of Evidence-Based Care for the Diagnosis, Staging, and First-line Treatment of Breast Cancer by Race-Ethnicity: A SEER-Medicare Study

BACKGROUND

Racial and ethnic disparities in guideline-recommended breast cancer treatment are well documented, however studies including diagnostic and staging procedures necessary to determine treatment indications are lacking. The purpose of this study was to characterize patterns in delivery of evidence-based services for the diagnosis, clinical workup, and first-line treatment of breast cancer by race-ethnicity.

METHODS

SEER-Medicare data were used to identify women diagnosed with invasive breast cancer between 2000 and 2017 at age 66 or older (n = 2,15,605). Evidence-based services included diagnostic procedures (diagnostic mammography and breast biopsy), clinical workup (stage and grade determination, lymph node biopsy, and HR and HER2 status determination), and treatment initiation (surgery, radiation, chemotherapy, hormone therapy, and HER2-targeted therapy). Poisson regression was used to estimate rate ratios (RR) and 95% confidence intervals (CI) for each service.

RESULTS

Black and American Indian/Alaska Native (AIAN) women had significantly lower rates of evidence-based care across the continuum from diagnostics through first-line treatment compared to non-Hispanic White (NHW) women. AIAN women had the lowest rates of HER2-targeted therapy and hormone therapy initiation. While Black women also had lower initiation of HER2-targeted therapy than NHW, differences in hormone therapy were not observed.

CONCLUSIONS

Our findings suggest patterns along the continuum of care from diagnostic procedures to treatment initiation may differ across race-ethnicity groups.

IMPACT

Efforts to improve delivery of guideline-concordant treatment and mitigate racial-ethnic disparities in healthcare and survival should include procedures performed as part of the diagnosis, clinical workup, and staging processes.

Impact of Pertuzumab and Ado-Trastuzumab Emtansine on Cumulative Avoidance of Recurrence Among Women Treated for Locally Advanced, Inflammatory, or Early-Stage Nonmetastatic HER2-Positive Breast Cancer in the United States

INTRODUCTION

We assessed the impact of HER2-positive early breast cancer (EBC) treatment landscape changes following the introduction of pertuzumab and ado-trastuzumab emtansine (T-DM1) on cumulative population-level recurrences avoided since 2013 (first pertuzumab approval for EBC in the United States; US).

METHODS

We constructed a multi-year epidemiologic population treatment-impact model to estimate annual recurrences between 2013 and 2031. Parameters were: BC incidence; stage I-III proportion; HER2-positive disease proportion; treatment proportions for neoadjuvant-only, adjuvant-only, and neoadjuvant-adjuvant continuation; and therapeutic agent proportions within each of those settings (chemotherapy only, trastuzumab ± chemotherapy, pertuzumab with trastuzumab ± chemotherapy, or T-DM1). The primary endpoint was cumulative recurrences, estimated by incorporating extrapolated clinical trial data for each regimen of interest into the model under four scenarios.

RESULTS

Approximately 889,057 women were predicted to be diagnosed with stage I-III HER2-positive BC from 2006 to 2031 in the US and potentially indicated for HER2-targeted treatment. In steady-state equilibrium, the model estimated that real-world utilization of pertuzumab and T-DM1 will reduce the population-level number of recurrences by approximately 32%, with 7226 recurrences predicted in 2031 based on current utilization rates. In different modeled scenarios, use of neoadjuvant pertuzumab, continuation of pertuzumab in the adjuvant setting, and T-DM1 in the adjuvant setting in women with residual disease after neoadjuvant treatment were all predicted to reduce the number of recurrences.

CONCLUSION

Given the improvement of HER2-targeted treatments, alongside increases in BC disease burden, we expect that the population-level impact of HER2-targeted treatments will accelerate over the next decade. Our results suggest that utilization of HER2-targeted treatments in the US has the potential to change the epidemiology of HER2-positive EBC by preventing a substantial number of women from experiencing disease recurrence. These improvements may help to inform our understanding of the future disease and economic burden of HER2-positive BC in the US.

Immune-Based Cancer Treatment: Addressing Disparities in Access and Outcomes

Avoidable differences in the care and outcomes of patients with cancer (i.e., cancer care disparities) emerge or worsen with discoveries of new, more effective approaches to cancer diagnosis and treatment. The rapidly expanding use of immunotherapy for many different cancers across the spectrum from late to early stages has, predictably, been followed by emerging evidence of disparities in access to these highly effective but expensive treatments. The danger that these new treatments will further widen preexisting cancer care and outcome disparities requires urgent corrective intervention. Using a multilevel etiologic framework that categorizes the targets of intervention at the individual, provider, health care system, and social policy levels, we discuss options for a comprehensive approach to prevent and, where necessary, eliminate disparities in access to the clinical trials that are defining the optimal use of immunotherapy for cancer, as well as its safe use in routine care among appropriately diverse populations. We make the case that, contrary to the traditional focus on the individual level in descriptive reports of health care disparities, there is sequentially greater leverage at the provider, health care system, and social policy levels to overcome the challenge of cancer care and outcomes disparities, including access to immunotherapy. We also cite examples of effective government-sponsored and policy-level interventions, such as the National Cancer Institute Minority-Underserved Community Oncology Research Program and the Affordable Care Act, that have expanded clinical trial access and access to high-quality cancer care in general.

Are there socio-economic inequalities in utilization of predictive biomarker tests and biological and precision therapies for cancer? A systematic review and meta-analysis

BACKGROUND

Novel biological and precision therapies and their associated predictive biomarker tests offer opportunities for increased tumor response, reduced adverse effects, and improved survival. This systematic review determined if there are socio-economic inequalities in utilization of predictive biomarker tests and/or biological and precision cancer therapies.

METHODS

MEDLINE, Embase, Scopus, CINAHL, Web of Science, PubMed, and PsycINFO were searched for peer-reviewed studies, published in English between January 1998 and December 2019. Observational studies reporting utilization data for predictive biomarker tests and/or cancer biological and precision therapies by a measure of socio-economic status (SES) were eligible. Data was extracted from eligible studies. A modified ISPOR checklist for retrospective database studies was used to assess study quality. Meta-analyses were undertaken using a random-effects model, with sub-group analyses by cancer site and drug class. Unadjusted odds ratios (ORs) and 95% confidence intervals (CIs) were computed for each study. Pooled utilization ORs for low versus high socio-economic groups were calculated for test and therapy receipt.

RESULTS

Among 10,722 citations screened, 62 papers (58 studies; 8 test utilization studies, 37 therapy utilization studies, 3 studies on testing and therapy, 10 studies without denominator populations or which only reported mean socio-economic status) met the inclusion criteria. Studies reported on 7 cancers, 5 predictive biomarkers tests, and 11 biological and precision therapies. Thirty-eight studies (including 1,036,125 patients) were eligible for inclusion in meta-analyses. Low socio-economic status was associated with modestly lower predictive biomarker test utilization (OR 0.86, 95% CI 0.71-1.05; 10 studies) and significantly lower biological and precision therapy utilization (OR 0.83, 95% CI 0.75-0.91; 30 studies). Associations with therapy utilization were stronger in lung cancer (OR 0.71, 95% CI 0.51-1.00; 6 studies), than breast cancer (OR 0.93, 95% CI 0.78-1.10; 8 studies). The mean study quality score was 6.9/10.

CONCLUSIONS

These novel results indicate that there are socio-economic inequalities in predictive biomarker tests and biological and precision therapy utilization. This requires further investigation to prevent differences in outcomes due to inequalities in treatment with biological and precision therapies.

Factors Influencing Adjuvant Chemotherapy and Trastuzumab Choice in Older Human Epidermal Growth Factor Receptor 2-positive Breast Cancer Patients

Objectives: This study aims to evaluate influence factors for adjuvant chemotherapy regimen choice on the basis of trastuzumab in older human epidermal growth factor receptor 2 (HER2)-positive breast cancer under multi-disciplinary team (MDT) modality.

Materials and Methods: HER2-positive breast cancer patients aged ≥ 60 years who received breast cancer surgery between April 2013 and December 2017 in Shanghai Ruijin Hospital were retrospectively enrolled. Clinical and pathological features, MDT recommendations, administration of adjuvant treatment, cardiotoxicity, and disease outcome information were reviewed and analyzed.

Results: A total of 222 older HER2-positive breast cancer patients were included and recommended to receive adjuvant chemotherapy plus trastuzumab therapy. Paclitaxel plus trastuzumab (PH, 41/222, 18.5%), docetaxel plus carboplatin and trastuzumab (TCH, 62/222, 27.9%), and antharcyclines plus cyclophosphamide followed by taxanes and trastuzumab (AC-TH, 119/222, 53.6%) were the three main regimens. Patients with T1a-b (P<0.001), grade 1-2 (P=0.008), node-negative (P<0.001), stage I (P<0.001), low Ki-67 level (P<0.001) disease, with cardiovascular comorbidities (P=0.011), and aged ≥ 70 years (P<0.001) were more likely to be recommended to PH regimen. Among the 178 patients who finally received adjuvant chemotherapy plus one-year trastuzumab treatment, only four patients (4/117, 3.4%) were recorded to have asymptomatic LVEF declining ≥ 10% but remaining ≥ 50% within one-year trastuzumab treatment.

Conclusions: Clinical factors, including age, tumor size, node status, and cardiovascular comorbidity influenced the recommendation of trastuzumab with chemotherapy for older HER2-positive breast cancer patients. Low risk older HER2-positive breast cancer patients treated with PH had favorable outcome and good cardiac safety, which needed further clinical validation.

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.

Breast cancer-specific survival by age: Worse outcomes for the oldest patients

BACKGROUND

Although breast cancer often is perceived to be indolent in older women, breast cancer outcomes in the oldest patients are variable. In the current study, the authors examined breast cancer-specific death by age, stage, and disease subtype in a large, population-based cohort.

METHODS

Using Surveillance, Epidemiology, and End Results data, a total of 486,118 women diagnosed with American Joint Committee on Cancer stage I to IV breast cancer between 2000 and 2012 were identified. Using a series of Fine and Gray regression models to account for competing risk, the authors examined the risk of breast cancer-specific death by age and stage (I-IV) for subcohorts with hormone receptor (HR)-positive, HR-negative, human epidermal growth factor receptor 2-positive, and triple-negative disease, adjusting for demographic and clinical variables.

RESULTS

Overall, 18% of women were aged 65 to 74 years, 13% were aged 75 to 84 years, and 4% were aged ≥85 years. Regardless of stage of disease within the HR-positive and HR-negative cohorts, patients aged ≥75 years (vs those aged 55-64 years) experienced a higher adjusted hazard of breast cancer-specific death, which was particularly evident for those with early-stage, HR-positive disease (hazard ratio for those aged 75-84 years, 1.88 [95% confidence interval, 1.68-2.09] and hazard ratio for those aged ≥85 years, 3.59 [95% confidence interval, 3.12-4.13] [both for stage I disease]). In the cohorts with human epidermal growth factor receptor 2-positive and triple-negative disease, women aged ≥70 years had a consistently higher risk of breast cancer-specific death across disease stages (vs those aged 51-60 years), with the exception of stage IV triple-negative disease.

CONCLUSIONS

Older patients experience worse breast cancer outcomes, regardless of disease subtype and stage. With an increasing number of older patients anticipated to develop breast cancer in the future, addressing disparities for older patients must emerge as a clinical and research priority. Cancer 2018;124:2184-91. © 2018 American Cancer Society.

Emerging Data and Current Challenges for Young, Old, Obese, or Male Patients with Breast Cancer

There are distinct subgroups of patients who have historically been underrepresented in most prospective clinical trials in breast cancer, including the youngest and oldest patients, male patients, and those struggling with obesity. Herein, we review current and future directions in research for each of these special populations with breast cancer, highlighting significant knowledge gaps and priorities in tumor biology and heterogeneity, therapeutic decision making promotion of adherence, supportive care, and psychosocial and functional well-being. In younger women, future study should focus on the biological underpinnings of aggressive disease and optimizing adherence and treatment decision making while addressing their unique survivorship needs. The latter includes generating a scientific basis for interruption of therapy for pregnancy. Among older patients, interventions should focus on increasing clinical trial accrual, predicting and mitigating toxicity so that functional status can be optimized, tailoring needs for dose modification, and anticipating life expectancy in the context of competing causes of death. For men with breast cancer, we need worldwide collaboration to answer even basic questions on optimal treatment, supportive care, and survivorship strategies. Finally, for those struggling with obesity, we need to better understand the biological associations with cancer incidence, prognosis and outcome, and how we can best intervene to assure weight loss at the "right time." It is only through highly collaborative, far-reaching, prospective, multidisciplinary, patient-centered, and patient-engaged efforts that we can optimize the physical and psychologic outcomes for all patients with breast cancer. Clin Cancer Res; 23(11); 2647-54. ©2017 AACRSee all articles in this CCR Focus section, "Breast Cancer Research: From Base Pairs to Populations."

Comparative Toxicity and Effectiveness of Trastuzumab-Based Chemotherapy Regimens in Older Women With Early-Stage Breast Cancer

Purpose The combination of chemotherapy and trastuzumab is the standard of care for adjuvant treatment of human epidermal growth factor receptor 2-positive breast cancer. Two regimens have been widely adopted in the United States: doxorubicin, cyclophosphamide, paclitaxel, and trastuzumab (ACTH) and docetaxel, carboplatin, and trastuzumab (TCH). No head-to-head comparison of these regimens has been conducted in a clinical trial, and existing trial data have limited generalizability to older patients. Methods We used SEER-Medicare data from 2005 to 2013 to compare outcomes of ACTH versus TCH among patients age older than 65 years. Propensity score matching was used to balance cohort characteristics between treatment arms. Outcomes included toxicity-related hospitalization, survival, and trastuzumab completion. Data from 1,077 patients receiving ACTH or TCH were analyzed, and the propensity-matched subsample included 416 women. Results There was a significant shift toward TCH over time, with 88% of patients receiving ACTH in 2005 compared with 15% by 2011. Among propensity score-matched patients, we found no difference between regimens in health care use overall or for chemotherapy-related adverse events (ACTH, 34% v TCH, 36.5%; P = .46). Patients receiving TCH were significantly more likely to complete trastuzumab (89% v 77%; P = .001). There was no difference in 5-year breast cancer-specific survival (ACTH, 92% v TCH, 96%; hazard ratio, 2.08; 95% CI, 0.90 to 4.82) or overall survival. Conclusion Among a matched sample of older patients, ACTH compared with TCH was not associated with a higher rate of serious adverse events or hospitalizations, but it was associated with less completion of adjuvant trastuzumab. We did not detect a difference in 5-year survival outcomes for ACTH compared with TCH. In the context of limited evidence in older patients, selection between these two regimens on the basis of concerns about differential toxicity or efficacy may not be appropriate.

Changing Natural History of HER2-Positive Breast Cancer Metastatic to the Brain in the Era of New Targeted Therapies

BACKGROUND

Given the wide adoption of human epidermal growth factor receptor 2 (HER2)-targeted therapies for advanced HER2-positive breast cancer, we studied the natural history of patients with HER2-positive breast cancer brain metastases (BCBM) over time.

PATIENTS AND METHODS

Patients with HER2-positive BCBM identified from a prospectively maintained database at the University of North Carolina were divided into 3 cohorts by year of BCBM diagnosis. Cohorts were selected by year of HER2-targeted therapy US Food and Drug Administration approval. Overall survival (OS), time to first metastasis, time to BCBM, and BCBM survival were estimated by the Kaplan-Meier method. Associations between OS after BCBM and clinical variables were assessed by Cox proportional hazards regression models.

RESULTS

One hundred twenty-three patients were identified. Median age was 51 years, and 58% were white and 31% African American. OS from initial breast cancer diagnosis improved over time: 3.6 years (95% confidence interval [CI], 2.8-6.1) in the 1998-2007 cohort, 6.6 years (95% CI, 4.5-8.6) in the 2008-2012 cohort, and 7.6 years (95% CI, 4.4-9.6) in the 2013-2015 cohort (P = .05). While time from initial diagnosis to first metastasis did not differ (P = .12), time to BCBM increased over time (2.6 years [95% CI, 1.3-3.5] for 1998-2007; 2.6 years [95% CI, 2.1-4.3] for 2008-2012, and 3.3 years [95% CI, 2.2-6] for 2013-2015; P = .05). Although OS from BCBM did not significantly differ by cohort, patients who received HER2-targeted therapy after BCBM had a prolonged OS (2.1 years [95% CI, 1.6-2.6] vs. 0.65 years [95% CI, 0.4-1.3]; P = .001).

CONCLUSION

OS from initial breast cancer diagnosis significantly improved over time for patients with HER2-positive breast cancer who develop BCBM, now exceeding 7 years; survival from BCBM diagnosis may now exceed 2 years.

Initiation of Trastuzumab by Women Younger Than 64 Years for Adjuvant Treatment of Stage I-III Breast Cancer

Purpose: Studies have reported disparities by age and race in the initiation of adjuvant trastuzumab for the initial treatment of older women with early-stage breast cancer, but less is known about its initiation in younger patients. Therefore, we assessed temporal trends and clinical and demographic factors associated with trastuzumab initiation in a large, population-based cohort of patients aged <64 years in 5 states. Methods: Using a cancer registry and claims-linked data set of 13,398 women with incident invasive breast cancer from 2006 to 2011, we identified 934 patients aged <64 years with HER2-positive stage I-III breast cancer. We assessed trastuzumab initiation within the first 9 months after diagnosis and conducted logistic regression analyses to assess sociodemographic and clinical factors associated with trastuzumab initiation. Results: From 2006 to 2011, trastuzumab initiation steadily increased in patients with node-positive (from 65% to 91%) and node-negative (from 39% to 75%) breast cancers. Several tumor-related factors were associated with trastuzumab initiation, including high histologic grades (adjusted odds ratio [aOR], 6.43; 95% CI, 3.27-12.65; and aOR, 3.25; 95% CI, 1.66-6.36, for grades 3 and 2, respectively), node-positive status (aOR, 1.88; 95% CI, 1.28-2.78; P=.001), tumor size >2 cm (aOR, 1.50; 95% CI, 1.04-2.16; P=.03), and hormone receptor-negative status (aOR, 1.51; 95% CI, 1.01-2.26; P=.04). We found a null effect of race. Conclusions: Adjuvant trastuzumab therapy for early-stage breast cancer has been widely disseminated among women aged <64 years. The initiation of this targeted therapy was associated with higher-risk features, consistent with practice guidelines.

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.

Use and outcomes of targeted therapies in early and metastatic HER2-positive breast cancer in Australia: protocol detailing observations in a whole of population cohort

BACKGROUND

The management of human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) has changed dramatically with the introduction and widespread use of HER2-targeted therapies. However, there is relatively limited real-world information on patterns of use, effectiveness and safety in whole of population cohorts. The research programme detailed in this protocol will generate evidence on the prescribing patterns, safety monitoring and outcomes of patients with BC treated with HER2-targeted therapies in Australia.

METHODS/DESIGN

Our ongoing research programme will involve a series of retrospective cohort studies that include every patient accessing Commonwealth-funded HER2-targeted therapies for the treatment of early BC and advanced BC in Australia. At the time of writing, our cohorts consist of 11 406 patients with early BC and 5631 with advanced BC who accessed trastuzumab and lapatinib between 2001 and 2014. Pertuzumab and trastuzumab emtansine were publicly funded for metastatic BC in 2015, and future data updates will include patients accessing these medicines. We will use dispensing claims for cancer and other medicines, medical service claims and demographics data for each patient accessing HER2-targeted therapies to undertake this research.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the Population Health Service Research Ethics Committee and data access approval has been granted by the Australian Department of Human Services (DHS) External Review Evaluation Committee. Our findings will be reported in peer-reviewed publications, conference presentations and policy forums. By providing detailed information on the use and outcomes associated with HER2-targeted therapies in a national cohort treated in routine clinical care, our research programme will better inform clinicians and patients about the real-world use of these treatments and will assist third-party payers to better understand the use and economic costs of these treatments.