Trastuzumab Emtansine (T-DM1) in Patients With HER2-Positive Metastatic Breast Cancer Previously Treated With Chemotherapy and 2 or More HER2-Targeted Agents. Issue 5 (September 2015)

• Record Type: Journal Article
• Authors: Yardley, Denise A.; Krop, Ian E.; LoRusso, Patricia M.; Mayer, Musa; Barnett, Brian; Yoo, Bongin; Perez, Edith A.
• Is Part Of: Cancer journal. Volume 21:Issue 5(2015)
• Publication Date: 2015-09
• Subjects: Cancer -- Periodicals; 616.994005
• DOI: 10.1097/PPO.0000000000000144
• Languages: English
• ISSNs: 1528-9117

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title>Purpose</title> <p>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.</p> </sec> <sec> <title>Methods</title> <p>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.</p> </sec> <sec> <title>Results</title> <p>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%).</p> </sec> <sec> <title>Discussion</title> <p>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.</p> </sec> </abstract>