Seven-year (yr) follow-up of adjuvant paclitaxel (T) and trastuzumab (H) (APT trial) for node-negative, HER2-positive breast cancer (BC).

• DOI: 10.1200/jco.2017.35.15_suppl.511
• Publication Date: 2018-09-06T15:38:19Z
• Authors: Sara M. Tolaney; William Thomas Barry; Hao Guo; Deborah Dillon; Chau T. Dang; Denise A. Yardley; Beverly Moy; P. Kelly Marcom; Kathy S. Albain; Hope S. Rugo; Matthew James Ellis; Iuliana Shapira; Antonio C. Wolff; Lisa A. Carey; Beth Overmoyer; Ann H. Partridge; Clifford A. Hudis; Ian E. Krop; Harold J. Burstein; Eric P. Winer
• Keywords: Micrometastasis; Clinical endpoint

511 Background: Retrospective data suggest that patients (pts) with small HER2+ cancers have more than just minimal risk of disease recurrence. The APT trial was designed to address treatment for such pts. We previously reported 3-yr disease-free survival (DFS) and here we provide an updated analysis 7-yr DFS. Methods: is a single arm multicenter, phase II study TH. Pts BC (IHC 3+ and/or FISH ratio > 2.0) negative nodes (a axillary lymph node micrometastasis allowed) tumor size < 3 cm were eligible. received T (80 mg/m 2 ) H x 12 weekly (w), followed by (weekly or q3w) 39w. primary endpoint Recurrence Free Interval (RFI), Breast Cancer Specific Survival (BCSS), overall (OS) also analyzed. Intrinsic subtyping PAM50 performed on the nCounter Analysis system archival tissue. Results: 410 pts enrolled from September 2007 2010 406 began protocol therapy. 67% had hormone-receptor (HR)+ tumors. Distribution size: 2% T1mi; 17% T1a; 30% T1b; 42% T1c, 9% T2 ≤ cm. 6 nodal micrometastasis. With median follow-up 6.5 yrs, there 23 DFS events observed: 4 (1.0%) distant recurrences, 5 local/regional recurrences (1.2%), new contralateral (1.5%), 8 deaths without documented recurrence (2.0%). 93.3% (95% CI 90.4-96.2); HR+ 94.6% 91.8-97.5) HR- 90.7% 84.6-97.2). RFI 97.5% 95.9-99.1); 7-year BCSS 98.6% 97.0-100); OS 95.0% 92.4-97.7). Ongoing testing (n = 227 pts) identified 142 (63%) HER2-enriched; 22 (10%) luminal A, 26 (11%) B, 20 (9%) basal-like; 17 samples poor quality assay. Additional associations clinical outcomes will be presented at meeting. Conclusions: These TH as adjuvant therapy node-negative associated few only longer follow-up. Based these data, if chemotherapy/trastuzumab given pt stage I breast cancer, regimen should considered standard treatment. Clinical information: NCT00542451.