Outcome of patients with HER2-positive breast cancer treated with or without adjuvant trastuzumab in the Finland Capecitabine Trial (FinXX)

Abstract

Background. Little information is available about survival outcomes of patients with HER2-positive early breast cancer treated with adjuvant capecitabine-containing chemotherapy with or without trastuzumab. Patients and methods. One thousand and five hundred patients with early breast cancer were entered to the Finland Capecitabine trial (FinXX) between January 2004 and May 2007, and were randomly assigned to receive either three cycles of adjuvant TX (docetaxel, capecitabine) followed by three cycles of CEX (cyclophosphamide, epirubicin, capecitabine; TX-CEX) or three cycles of docetaxel followed by three cycles of CEF (cyclophosphamide, epirubicin, fluorouracil; T-CEF). The primary endpoint was recurrence-free survival (RFS). The study protocol was amended in May 2005 while study accrual was ongoing to allow adjuvant trastuzumab for patients with HER2-positive cancer. Of the 284 patients with HER2-positive cancer accrued to FinXX, 176 (62.0%) received trastuzumab after amending the study protocol, 131 for 12 months and 45 for nine weeks. The median follow-up time was 6.7 years. Results. Patients with HER2-positive cancer who received trastuzumab had better RFS than those who did not (five-year RFS 89.2% vs. 75.9%; HR 0.41, 95% CI 0.23–0.72; p = 0.001). Patients treated with trastuzumab for 12 months or nine weeks had similar RFS. There was no significant interaction between trastuzumab administration and the type of chemotherapy. Four (2.3%) patients treated with trastuzumab had heart failure or left ventricular dysfunction, three of these received capecitabine. Conclusion. Adjuvant trastuzumab improves RFS of patients treated with TX-CEX or T-CEF. Few patients had cardiac failure.

Declaration of interest: The authors alone are responsible for the content and writing of the paper.

The FinXX study was sponsored by the Finnish Breast Cancer Group, and supported financially by Roche, Sanofi-Aventis, AstraZeneca, Cancer Society of Finland, Academy of Finland, Helsinki University Research Funds, Sigrid Juselius Foundation. We are indebted to the study monitor Ms. Raija Husa, and many medical, nursing, and clerical staff members for the support at the participating centers; and to all women participating in the FinXX trial for their contribution to this research. The clinical research institute of HJ has received research funding from Sanofi and Novartis; P-LK-L has received honoraria, research funding and other remuneration from Sanofi, Roche and Pfizer; MT honoraria or remuneration from AstraZeneca, GlaxoSmithKline, Roche, MSD and Novartis; LH a fee from Roche; GN honoraria from Roche, Sanofi and AstraZeneca; and VK honoraria from Roche and Sanofi. RH, AJ-V, RK, JA, PA, OS, KV, PN, ML, PB and HL declare no conflict of interest.