Dual Blockage With Afatinib and Trastuzumab as Neoadjuvant Treatment for Patients With Locally Advanced or Operable Breast Cancer Receiving Taxane-anthracycline Containing Chemotherapy

Anthracycline/taxane based combination chemotherapy of at least 18 weeks represents the standard of care in the neoadjuvant setting. In HER2 positive disease trastuzumab is given simultaneously. Neoadjuvant anthracycline-taxane-based chemotherapy given simul-taneously with trastuzumab achieves a pCR rate of approx. 40%. Recent data showed that a double blockade of the HER2 receptor (e.g. trastuzumab + lapatinib; trastuzumab + pertuzumab) given together with a few cycles of chemotherapy can increase the pCR rate by approximately 20%. So far, there is uncertainty, if afatinib (BIBW 2992), an irreversible HER family blocker can lead to an even more complete blockade of the HER2 pathway when given in combination with trastuzumab. The neoadjuvant setting provides the unique opportunity to assess precisely and at short term the effect of systemic treatment by assessing the pCR at surgery. It also allows treating patients with HER2 positive breast cancer before surgery without standard trastuzumab treatment, as, according to current guideline, trastuzumab can also be given sequentially after surgery. The aim of the study is to show that chemotherapy + trastuzumab + afatinib can achieve significant pCR rates.

Primary objectives: To compare the pathological complete response (pCR = ypT0/is ypN0) rates of neoadjuvant treatment of afatinib in combination with weekly paclitaxel + trastuzumab followed by epirubicin/ cyclophosphamide/ trastuzumab in patients with HER2-positive primary breast cancer. Secondary objectives: To determine the rates of ypT0 ypN0; ypT0; ypT0/is; ypN0; and regression grades according to Sinn. To determine the response rates of the breast tumor and axillary nodes by physical examination and imaging tests (sonography, mammography, or MRI) after 6 weeks of the 2 anti-HER2 agents alone and at surgery. To determine the breast and axilla conservation rate after treatment. To assess the toxicity and compliance. To correlate skin toxicity and diarrhoea with pCR. To examine and compare pre-specified molecular markers such as EGFR, HER2, HER3, HER4, TGFß, EGF, AREG, HBEGF, BTC, EPIGEN, EREG, NRG1, NRG2, neuroglycan, tomoregulin, NRG4 and NRG3K-RAS, MET, IGF1R, IRS1, PTEN, FGFR1, FGFR2, FGFR3, AXL, RET, and PDGFR; EGFR signature, Ki67, p95HER2, and PI3K mutation before start of afatinib+trastuzumab, before and after chemotherapy.