Abstract P4-14-11: Efficacy and cardiac safety in neoadjuvant treatment of Her2 positive breast cancer with concomitant nonpegylated liposomal doxorubicin, docetaxel and dual blockade with trastuzumab and pertuzumab: A retrospective analysis

Abstract

Background: Approval to pertuzumab as part of a complete treatment regimen for patients with early stage breast cancer (EBC) before surgery (neoadjuvant setting) was granted by the FDA in September 2013. Since then, the relevance of neoadjuvant treatment in Her2 overexpressing breast cancer has increased considerably. This for instance has been emphasized by the results of the Neosphere Study, in which dual blockade of Her2 was combined with docetaxel as chemotherapy backbone and resulted in favorable pCR rates. But it is likely, that anthracyclines could play an important role in enhancing the effectiveness of the above mentioned treatment. However, there is only little data about the cardiac safety of this combination. The use of liposomal doxorubicin might be a valuable alternative with low cardiotoxicity, as it has been shown in comparable publications without the use of pertuzumab. Therefore we report pCR-rate and cardiac safety of a single arm, retrospective, multicenter analysis of neoadjuvant treatment for Her2 positive EBC with liposomal doxorubicin, docetaxel, trastuzumab and pertuzumab. Methods: In this study 42 women with Her2 positive EBC were investigated in 4 oncological departments in Austria. 41 patients were treated with liposomal doxorubicin (50 mg/m2), docetaxel (75 mg/m2) concurrent with trastuzumab and pertuzumab in standard dosage for 6 cycles as neoadjuvant therapy. One patient refused to receive a chemotherapy but agreed to be treated with combined antibody therapy alone. All patients were free of cardiovascular disease and had a left ventricular ejection fraction (LVEF) of ≥ 50%. Cardiac function was measured by LVEF and was examined at regular intervals (cycles 0-3, cycle 6, FU). Clinical response was evaluated by diagnostic breast imaging after cycles 3 and 6. All patients underwent surgery after neoadjuvant chemotherapy. The absence of any residual invasive cancer in the breast and axilla was defined as pathological complete response (pCR). Median follow up was 1.3 years. Results: Median age of the patients was 49 years. After 6 cycles of treatment the pCR rate was 76.2%. In this cohort a negative estrogen-and/or progesteron receptor was predictive for pCR (p<0.001). These patients achieved pCR in 95.2%. The antibody only treatment in one case also resulted in a pCR. No patient progressed during treatment. Only one of the patients (2,4%) suffered symptomatic heart failure after surgery. The patient initially presented with an LVEF of 16%. Conclusions: In this multicenter analysis we observed a considerably high rate of pCR in HER2-positive EBC treated with liposomal doxorubicin, docetaxel, trastuzumab and pertuzumab. Especially the group of hormone receptor negative patients showed a remarkable response rate. The addition of liposomal doxorubicin entails a very favorable cardiotoxicity profile. This regimen is a safe treatment option in patients with HER-2 positive breast cancer. Citation Format: Egle D, Hubalek M, Hager C, Poyßl C, Lang A, Jäger T, Volgger B, Abdel-Azim S, Tiechl J, Angerer J, Marth C. Efficacy and cardiac safety in neoadjuvant treatment of Her2 positive breast cancer with concomitant nonpegylated liposomal doxorubicin, docetaxel and dual blockade with trastuzumab and pertuzumab: A retrospective analysis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-11.