Abstract OT1-02-01: Phase III postneoadjuvant study evaluating sacituzumab govitecan (SG), an antibody drug conjugate in primary HER2-negative breast cancer patients with high relapse risk after standard neoadjuvant treatment - SASCIA

Abstract

Abstract Background: Women with triple-negative breast cancer (TNBC) with residual disease after neoadjuvant chemotherapy (NACT) or hormone-receptor (HR)-positive/HER2-negative breast cancer (BC) with a CPS (clinical and post treatment pathological stage) +EG (estrogen receptor status and grade) score ≥3 or score 2 and nodal involvement after NACT (ypN+) are at high risk of recurrence. SG is approved by the Food and Drug Administration for the treatment of patients with metastatic TNBC who received at least two prior therapies for metastatic disease and has shown activity in heavily pretreated patients with metastatic HR-positive/HER2-negative BC. SG may represent a new option against residual disease after NACT. Trial Design: SASCIA is a phase III, prospective, international, multicenter, randomized, open label, parallel group study (NCT04595565) of the GBG in collaboration with the AGO-B. Eligible patients must have received taxane-based NACT for 16 weeks, including 6 weeks of a taxane. Patients should have centrally confirmed HER2-negative BC (IHC score 0-1 or FISH negative) and either HR-negative (<1%), with any residual invasive disease > ypT1mi or HR-positive (≥1%), with a CPS+EG score ≥3 or CPS+EG score 2 and ypN+ using local ER and grade assessed on core biopsies taken before NACT. Radiotherapy should be delivered before study treatment start. Patients are randomized 1:1 to receive either SG 10 mg/kg body weight (days 1, 8 q3w for eight cycles) or treatment of physician´s choice (capecitabine 2000 mg/m² day 1-14 q21 or platinum-based chemotherapy i.e. carboplatin AUC 5 q3w or AUC 1.5 weekly for eight 3 weekly cycles or observation). Randomization is stratified by HR status (positive, negative) and nodal involvement after NACT (ypN+, ypN0). Endocrine-based therapy will be administered according to local guidelines in patients with HR-positive BC. The primary endpoint is invasive disease-free survival (iDFS). Secondary endpoints include comparison of overall survival (OS, key secondary endpoint), distant disease-free survival, locoregional recurrences-free interval, safety, compliance, iDFS and OS according to stratified and - predefined subgroups, patient reported outcome, and quality of life between treatment arms. As of 21st June 2021, 57/1200 patients have been randomized in Germany. Citation Format: Frederik Marmé, Marcus Schmidt, Jenny Furlanetto, Carsten Denkert, Anthony Goncalves, Elmar Stickeler, Mattea Reinisch, Silvia Antolín, Toralf Reimer, Wolfgang Janni, Philippe Aftimos, Michael Untch, Laura Michel, Marija Balic, Bruno Sinn, Volker Möbus, Patrick Morris, Laura Schöllhorn, Sabine Schmatloch, Julia Rey, Sibylle Loibl. Phase III postneoadjuvant study evaluating sacituzumab govitecan (SG), an antibody drug conjugate in primary HER2-negative breast cancer patients with high relapse risk after standard neoadjuvant treatment - SASCIA [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT1-02-01.