Abstract GS3-05: Survival analysis of the prospectively randomized phase III GeparSepto trial comparing neoadjuvant chemotherapy with weekly nab-paclitaxel with solvent-based paclitaxel followed by anthracycline/cyclophosphamide for patients with early breast cancer – GBG69

Introduction The GeparSepto study showed that the substitution of paclitaxel (P) with nab-paclitaxel (nP) followed by epirubicin/cyclophosphamide (EC) as neoadjuvant chemotherapy increased the rate of pathological complete response (pCR) from 29% to 38% (p Patients and Methods In the GeparSepto trial (NCT01583426) patients were randomized in a 1:1 ratio to receive either nP 125mg/m 2 or P 80 mg/m 2 q1w for 12 weeks followed by 4 cycles of conventionally dosed EC (E: 90mg/m 2 ; C: 600 mg/m 2 ) q3w (Furlanetto et al. Annals Oncol 2016). Patients with HER2+ tumors received trastuzumab 6(8)mg/kg q3w and pertuzumab 420(840)mg q3w concomitantly to all chemotherapy cycles (Loibl et al. Annals Oncol 2016). Patients with untreated, histologically confirmed uni- or bilateral, cT2- cT4d breast carcinoma, and no clinically relevant cardiovascular and other co-morbidities were included. Primary objective was pCR rate (ypT0 ypN0). Secondary objectives were invasive disease-free survival (IDFS), and overall survival (OS) overall and according to stratified subpopulations, amongst other time to event endpoints, quality of life focusing on peripheral sensory neuropathy (PNP), treatment of PNP, and cardiac toxicity, detection of circulating tumor (ct) DNA at the time of surgery and during follow up and correlation with pCR and early relapses. The IDFS analysis is planned after 248 events have occurred. The log-rank test will have 80% power to detect an improvement of the 5 year IDFS from 75% to 81.8% (HR=0.70) at a 2-sided significance level of α=0.05. Results In 69 German centers, 1229 patients were randomly assigned (07/2012 – 12/2013) to receive either nP (606) or P (600). nP was given for the majority of cycles at a dose of 150mg/m 2 to 179 patients and at a dose of 125mg/m 2 to 426 patients. Follow-up is still ongoing. The expected number of events will be awaited for October 2017. Conclusion Neoadjuvant GeparSepto study demonstrated a significantly higher pCR rate when patients received nP instead of P as part of an anthracycline/taxane based sequential chemotherapy. The expected long-term results will help to assess the overall benefit of nP in BC and the surrogate value of pCR for survival endpoints. Citation Format: Schneeweiss A, Jackisch C, Schmatloch S, Aktas B, Denkert C, Schem C, Wiebringhaus H, Kummel S, Rhiem K, Warm M, Fasching PA, Just M, Hanusch C, Hackmann J, Blohmer JU, Gerber B, Furlanetto J, von Minckwitz G, Nekljudova V, Loibl S, Untch M. Survival analysis of the prospectively randomized phase III GeparSepto trial comparing neoadjuvant chemotherapy with weekly nab-paclitaxel with solvent-based paclitaxel followed by anthracycline/cyclophosphamide for patients with early breast cancer – GBG69 [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr GS3-05.