LBA4 Sacituzumab govitecan (SG) vs treatment of physician’s choice (TPC) in Asian patients with hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/HER2–) metastatic breast cancer (mBC): Results from the phase III EVER-002 study

Based on results from the global TROPiCS-02 study that enrolled predominantly non-Asian pts, SG has been approved in the US and Europe for pts with pretreated HR+/HER2– mBC. We report first results from the open-label, randomized, multicenter phase 3 EVER-132-002 trial, a pivotal study that assessed SG in Asian pts with endocrine-resistant, chemotherapy (chemo)-treated HR+/HER2– mBC. Adults from China, Korea, and Taiwan with HR+/HER2– mBC and 2-4 prior lines of systemic chemo (LOT) were randomized 1:1 to SG (10 mg/kg IV on days 1 and 8; 21-day cycle) or TPC. Pts were stratified based on number of prior LOT, visceral metastasis, and prior treatment with CDK4/6 inhibitors. The primary end point was progression-free survival (PFS) per blinded independent central review (BICR; RECIST v1.1). Secondary end points included overall survival (OS), objective response rate (ORR), clinical benefit rate (CBR) per BICR, and safety. Pts were randomized to SG (n = 166) or TPC (n = 165); median age was 52 y, 56% and 44% received 2 and 3-4 prior LOT for metastatic disease, respectively. At median follow-up of 13.4 mo, statistically significant improvement of PFS per BICR (33% reduction in the risk of progression or death) and clinically meaningful OS benefit (36% reduction in the risk of death) with SG vs TPC was observed (Table). Additional end points and a summary of treatment-emergent adverse events (TEAEs) are shown in the table. The most common grade ≥ 3 TEAE was neutropenia (69% for SG vs 62% for TPC).Table: LBA4Efficacy, ITTSG (n = 166)TPCa (n = 165)PFS per BICR, HR 0.67 (95% CI, 0.52-0.87) P-value .00286-mo rate, % (95% CI)41 (33-49)24 (17-32)PFS per investigator, HR 0.61 (95% CI, 0.48-0.79) P-value .00016-mo rate, % (95% CI)50 (42-58)26 (19-34)OS, HR 0.64 (95% CI, 0.47-0.88) P-value .006112-mo rate, % (95% CI)76 (68-82)62 (54-69)ORR per BICR, % (95% CI)21 (15-27)15 (10-22)CBR per BICR, % (95% CI)38 (31-46)22 (16-30)Safety, all treatedn =165n=164Any grade TEAEs, n (%)165 (100)164 (100)Grade ≥ 3135 (82)114 (70)Leading to dose reduction42 (25)53 (32)Leading to discontinuation5 (3)6 (4)aEribulin, capecitabine, gemcitabine, or vinorelbine. Open table in a new tab aEribulin, capecitabine, gemcitabine, or vinorelbine. EVER-132-002 confirmed efficacy benefit of SG in Asian pts. The safety profile of SG was generally consistent with prior global studies. The results from this pivotal study support the use of SG as a new treatment option for Asian pts with endocrine-resistant, chemo-treated HR+/HER2– mBC.