Hope S. Rugo, MD, FASCO, discusses data presented at the 2021 American Society of Clinical Oncology annual meeting from the phase 3 ASCENT study of patients with metastatic triple-negative breast cancer treated with sacituzumab govitecan.
Hope S. Rugo, MD, FASCO, discusses data from the following presentation:
Assessment of Sacituzumab Govitecan vs Treatment of Physician’s Choice Cohort by Agent in the Phase 3 ASCENT Study of Patients with Metastatic Triple-Negative Breast Cancer. (O’Shaughnessy, ASCO 2021, Abstract 1077)
The objective of this study is to report results in patients with metastatic triple-negative breast cancer (mTNBC) treated with sacituzumab govitecan or treatment of physician’s choice (TPC).
Sacituzumab govitecan (SG) is an antibody-drug conjugate comprised of an anti–Trop-2 antibody coupled to a cytotoxic SN-38 through a hydrolyzable linker.
529 patients with mTNBC who had received ≥ 2 prior chemotherapies were randomly assigned 1:1 to either SG 10 mg/kg intravenously on days 1 & 8, every 21-day cycle (n=267), or treatment of physician’s choice (capecitabine, eribulin, vinorelbine, or gemcitabine) (n=262).
Efficacy outcomes were assessed in the brain metastases-negative population for each agent:
Progression-free survival (PFS) assessed by blinded independent central review per RECIST 1.1.
Secondary end points were objective response rate (ORR) assessed by blinded independent central review per RECIST 1.1, duration of response, overall survival (OS), and safety.
Conclusions: efficacy
SG resulted in longer median PFS vs each TPC agent (eribulin, vinorelbine, capecitabine, gemcitabine): 5.6 vs 2.1, 1.6, 1.6, and 2.7 months, respectively.
SG treatment also resulted in longer median OS vs eribulin, vinorelbine, capecitabine, or gemcitabine (12.1 vs 6.9, 5.9, 5.2, and 8.4 months, respectively).
The ORR (35% vs 5%, 4%, 6%, and 3%) and clinical benefit rate (45% vs 8%, 6%, 10%, and 14%) were higher with SG vs eribulin, vinorelbine, capecitabine, or gemcitabine.
Median duration of response for SG was 6.3 months compared to eribulin, vinorelbine, capecitabine, or gemcitabine (3.6, 2.8, not evaluable, and 2.9 months, respectively).
Conclusions: safety
Grade ≥3 treatment-related adverse events (AEs) with SG vs eribulin vs the other 3 TPC agents combined included neutropenia (51% vs 31% vs 36%), leukopenia (10% vs 5% vs 6%), diarrhea (10% vs 0% vs 1%), anemia (8% vs 2% vs 8%), febrile neutropenia (6% vs 2% vs 2%), and fatigue (2% vs 5% vs 6%).
SG has a manageable safety profile and low rates of discontinuation due to AEs, and no treatment-related deaths were reported.
An efficacy benefit was seen with SG vs TPC and retained when evaluating each TPC chemotherapy agent individually.
These results support consideration of SG as a new standard of care in patients with pretreated mTNBC.