Treatment patterns and survival in metastatic breast cancer patients by tumor characteristics

Abstract

Objectives:

Study objectives were to compare the treatment patterns and clinical outcomes among metastatic breast cancer (mBC) patients by receipt of HER2-targeted agents and among subgroups of HER2-targeted agent users.

Research design and methods:

Adult women newly diagnosed with mBC (index date) during 2008–2012 were selected from the Truven MarketScan databases and followed until end of enrollment or inpatient death. Patients with <12 months of data, pre-index primary cancers other than breast cancer, pregnancy, or HIV/AIDS were excluded. Study cohorts were users and nonusers of HER2-targeted agents and women with no treatment; and HER2-targeted agent subgroups by receipt of hormonal therapy (HT), de novo vs. recurrent status, and age group. Pre- and post-index breast cancer treatments were compared across cohorts. Relative risk of progression and death were evaluated among the subset of patients with mortality data.

Results:

Of 18,059 eligible women selected, 14.6% were users of HER2-targeted agents, 71.1% were nonusers, and 14.3% untreated. HER2-targeted agent users received more aggressive cancer treatments compared to nonusers. HER2-targeted agent users were 33% more likely to progress and had a similar risk of death compared to nonusers. Among HER2-targeted agent subgroups, the risk of progression was 30% lower among HT+ patients vs. HT-, 32% lower for de novo vs. recurrent, and similar across age groups. The risk of death was 52% lower for HT+ vs. HT−, 35% lower for de novo vs. recurrent, and increased with age.

Limitations:

Identification of distant metastasis, tumor receptor expression and disease progression were based on claims data rather than on clinical assessment.

Conclusions:

Receipt of HER2-targeted agents (vs. non-HER2-targeted agents) was significantly associated with receipt of pre- and post-index breast cancer treatments. HER2-targeted agent users were more likely to progress but had a similar risk of death during follow-up. Among HER2-targeted agent subgroups, HT+ and de novo status were associated with a reduced risk of progression and death.

Key words::

• De novo
• HER2-targeted agents
• Hormonal therapy
• Metastatic breast cancer
• Progression
• Survival
• Treatment patterns

Transparency

Declaration of funding

This research was conducted by Truven Health Analytics and funded by Novartis Pharmaceuticals Corporation.

Declaration of financial/other relationships

Y.H. and J.W.R. have disclosed that they are employees and stock shareholders of Novartis Pharmaceutical Corporation which is the sponsor of this study. N.M., X.S., N.S., W.J. and P.J. have disclosed that they are employees of Truven Health Analytics which was provided funding to develop and implement the study design and interpret the study results. D.A.Y. has disclosed that she is an employee of the Sarah Cannon Research Institute and Tennessee Oncology PLLC and that she does not receive any direct or indirect compensation for consulting services.

CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

Study results have previously been presented as the following posters and abstracts. Meyer N, Hao Y, Song X, et al. Comorbidity, metastases, and survival in women with metastatic breast cancer (mBC) receiving HER2-targeted agents (H2Ts). J Clin Oncol 2014;32(Suppl):abstr e11574. Johnson WM, Meyer N, Hao Y, et al. Disease and treatment (tx) characteristics in women with metastatic breast cancer (mBC) receiving HER2-targeted agents (H2Ts). J Clin Oncol 2014;32(Suppl):abstr e11594. Song X, Hao Y, Meyer N, et al. Health care utilization and costs in women with metastatic breast cancer (mBC) receiving HER2-targeted agents (H2Ts). J Clin Oncol 2014;32(Suppl):abstr e11573. Hao Y, Meyer N, Hao Y, et al. Disease characteristics and treatment outcomes of a large insured population with stage IV metastatic breast cancer by receipt of HER2-targeted agents. Poster presentation at the Academy of Managed Care Pharmacy Annual Meeting & Expo, 1–4 April 2014, Tampa, FL, USA. Hao Y, Meyer N, Hao Y, et al. Clinical histories and treatment patterns of a large insured population with stage IV metastatic breast cancer by receipt of HER2-targeted agents. Poster presentation at the Academy of Managed Care Pharmacy Annual Meeting & Expo, 1–4 April 2014, Tampa, FL, USA.