Abstract OT1-1-01: Optimizing neoadjuvant systemic treatment in HER2 positive breast cancer - The TRAIN-2 study

Abstract Background Anthracycline-based regimens are still commonly used in HER2 positive (HER2+) breast cancer (BC), despite added toxicity compared to non-anthracycline containing regimens. The benefit of antracyclines in the era of trastuzumab containing regimens is controversial. Moreover, the value of anthracyclines in combination with dual-HER2 blockade is uncertain. We recently showed high pathologic complete response (pCR) rates with a weekly neoadjuvant paclitaxel-trastuzumab-carboplatin (PTC) regimen. We now aim to evaluate the effect of replacing 3 PTC cycles in this regimen with 3 FE90C-trastuzumab cycles, while adding pertuzumab to all cycles in both arms. Secondly, combined blockade of the estrogen-receptor (ER) pathway and the HER2-pathway in the presence of chemotherapy has not previously been investigated in HER2+/ER+ tumors. Trial design This is a randomized comparative trial evaluating pCR rate (ypT0/is ypN0) at surgery as primary endpoint after neoadjuvant systemic therapy with 9 cycles PTC plus pertuzumab q3w (paclitaxel 80mg/m2 day 1, 8 – trastuzumab 6mg/kg (loading dose 8mg/kg) day 1 – carboplatin AUC = 6 day 1 – pertuzumab 420mg (loading dose 840mg) day 1) versus 3 cycles FE90C-T plus pertuzumab q3w followed by 6 cycles PTC plus pertuzumab q3w. An optional second randomization (2×2 factorial design) will compare concurrent endocrine treatment with an aromatase inhibitor (and ovarian function suppression in premenopausal women and men) during neoadjuvant chemotherapy in combination with dual HER2-blockade, in patients with HER2+/ER+ tumors. Eligibility criteria Patients aged ≥18 year with histologically confirmed invasive HER2+ BC, stage II or III. Eligible patients have a performance status of 0 to 1 and adequate cardiac and organ function. Specific aims The primary objective is to compare the efficacy of 6 cycles neoadjuvant PTC plus pertuzumab preceded by either 3 cycles FE90C-T plus pertuzumab or 3 cycles PTC plus pertuzumab in stage II and III HER2+ BC. Secondary objectives are to describe the efficacy of combined HER2 and ER pathway blockade in HER2+/ER+ BC, to describe the safety of the various regimens and to identify prognostic and predictive biomarkers for pCR. Statistical methods The sample size of the study will be based on the primary objective. To detect an increase in pCR rate from 44% in the PTC arm to 58% in the FE90C-T arm at the 5% (2-sided) level of significance with an 80% power 437 patients need to be randomized (assuming ∼10% of patients will be not evaluable). Target accrual Recruitment will start in the summer of 2013 across ∼30 sites in the Netherlands. Unrestricted research support and pertuzumab are kindly provided by Roche Netherlands. The trial is sponsored by the Dutch Breast Cancer Trialists’ Group (BOOG). Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT1-1-01.