Taxane-based mono- or combination therapy for managing metastatic breast cancer (MBC) in routine practice: a multinational prospective observational study

Palliative systemic therapy and overall survival of 1,395 patients with advanced breast cancer - Results from the prospective German TMK cohort study

Data on treatment and outcome of advanced breast cancer in routine practice are rare, especially concerning recurrent disease, but important to complement the results from clinical trials and to improve the standard of care. We present data on choice of systemic first-line treatment, number of treatment lines, and survival of patients treated by medical oncologists in Germany. 1395 patients recruited by 124 sites at start of first-line therapy into the ongoing, prospective German clinical cohort study TMK (Tumour Registry Breast Cancer) between February 2007 and October 2015 were analysed. The median OS was 33.8 months (95% CI 30.2-40.2) for HR-positive/HER2-negative, 38.2 months (95% CI 31.3-43.0) for HER2-positive and 16.8 months (95% CI 11.5-22.0) for triple negative breast cancer. Patients with triple negative tumours more often died before start of a third-line therapy than patients with HR-positive or HER2-positive tumours (44% vs. 25%). Use of taxane-based chemotherapies has increased since 2007, with 65% of all first-line chemotherapy-treatments containing taxanes in 2013-15 (60% HR-positive/HER2-negative, 75% HER2-positive, 56% triple negative). 52% of the patients with HR-positive/HER2-negative tumours received first-line endocrine therapy in 2013-15; when restricted to patients with only non-visceral metastases this percentage increased to 63%. To our knowledge, this is the first cohort study showing systemic first-line therapy for all subtypes of advanced breast cancer. Overall survival in the TMK is comparable to that reported by clinical trials despite the inclusion of older and comorbid patients.

Real-World Evidence: A Comparison of the Australian Herceptin Program and Clinical Trials of Trastuzumab for HER2-Positive Metastatic Breast Cancer

INTRODUCTION

Estimating the real-world cost-effectiveness of a new drug relies on understanding the differences between clinical trial data (pre-reimbursement) and clinical practice (post-reimbursement). This is important for decision makers when reviewing reimbursement decisions, prices, and considering other drugs for the same condition. Differences can arise from differences in patient characteristics, but also from the availability of new evidence and evolving treatment practices. This paper examines these issues using a case study.

METHODS

In 2001, the Australian Government funded trastuzumab for the treatment of HER2+ metastatic breast cancer through the Herceptin Program. The administrative arrangements of the Program resulted in rich observational data that captured information about patients treated with trastuzumab between 2001 and 2010 (n = 3830). The dataset included patient characteristics, dispensed medicines, medical service use and date of death.

RESULTS

Compared to participants in the clinical trials, patients were older, received more prior chemotherapies and a broader range of co-administered chemotherapies. Treatment practices differed from the clinical trials, but also changed over time. For example, in situ hybridization testing, rather than immunohistochemistry testing, and a three weekly administration schedule, rather than one weekly, were increasingly used. Compared to the clinical trials, patients administered trastuzumab with a concomitant chemotherapy generally experienced longer overall survival (151.3 weeks, 95 % CI: 142.6, 163.4), while those who received trastuzumab as a monotherapy experienced shorter overall survival (94.4 weeks, 95%CI: 86.4, 102.9). These findings may be due to a differing relative treatment effect in clinical practice, but may also be due to a range of other factors.

CONCLUSION

This analysis demonstrates the challenges for decision makers that arise because new evidence and evolving treatment practices create a gap between clinical trial data and real-world clinical practice and outcomes.