Trastuzumab emtansine (T-DM1) in patients With HER2-positive metastatic breast cancer previously treated with chemotherapy and 2 or more HER2-targeted agents: Results from the T-PAS expanded access study

Denise A. Yardley, Ian E. Krop, Patricia M. LoRusso, Musa Mayer, Brian Barnett, Bongin Yoo, Edith A. Perez

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Purpose: The antibody-drug conjugate trastuzumab emtansine (T-DM1) has improved outcomes in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC), as demonstrated in phase III studies. Few data approximating its use in routine clinical practice are available. Methods: The T-DM1 Patient Access Study was an expanded-access, multicenter study of T-DM1 in US patients with pretreated HER2-positive locally advanced breast cancer or MBC. The primary endpoint was safety. The secondary endpoint was investigator-assessed objective response rate among patients with measurable disease at baseline. Data are presented for the first 215 enrolled patients. Results: The median number of prior systemic MBC agents was 8 (range, 3-23). At baseline, median left ventricular ejection fraction was 60%, and 52.6% of patients had nonclinically significant cardiovascular disease. Median T-DM1 treatment duration was 5.0 months (range, 0-29 months; median follow-up, 5.9 months), with 18.6% having received more than 18 cycles. The most common any-grade adverse events were fatigue (50.7%) and nausea (38.1%). Adverse events of grade 3 or greater were reported in 46.5%, most commonly thrombocytopenia and platelet count decrease (10.2%). Bleeding of grade 3 or greater was reported in 4 patients (1.9%). Cardiac dysfunction (primarily asymptomatic left ventricular ejection fraction decreases) was reported in 14 patients (6.5%). Among those with measurable disease at baseline (n = 172), objective response rate was 25.6% (95% confidence interval, 19.2%-32.8%). Discussion: The safety profile of T-DM1 in this real-world setting of heterogeneous, HER2-positive, pretreated, locally advanced breast cancer or MBC was comparable with that reported in phases II and III studies of similar patient populations. T-DM1 was efficacious with no new safety signals.

Original languageEnglish (US)
Pages (from-to)357-364
Number of pages8
JournalCancer Journal (United States)
Volume21
Issue number5
StatePublished - Sep 1 2015

Keywords

  • Ado-trastuzumab emtansine
  • Breast cancer
  • Expanded access trials
  • Human epidermal growth factor receptor 2
  • Metastases
  • T-DM1

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

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