Abstract 248P
Background
Refractory or relapsing metastatic triple-negative breast cancer (mTNBC) has a poor prognosis. Sacituzumab govitecan (SG) is a novel antibody-drug conjugate, targeting human trophoblast cell-surface antigen 2. This is the first time to report the efficacy and safety of SG in Chinese mTNBC patients.
Methods
EVER-132-001 (NCT04454437) was a multicenter, single-arm, phase IIb study in Chinese patients with mTNBC who failed ≥2 prior chemotherapy regimens. Eligible patients received 10 mg/kg SG on Days 1 and 8 of each 21-day treatment cycle, until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) measured by the Independent Review Committee (IRC) per RECIST v1.1. Secondary endpoints included: duration of response, clinical benefit rate (CBR; stable disease of duration ≥6 months + partial response + complete response), progression free survival (PFS), overall survival and safety. Treatment-emergent adverse events (TEAEs) were evaluated according to CTCAE v5.0.
Results
80 female Chinese patients with mTNBC were treated with SG. Patients were 47.6 years old (median; range 24–69.9), had received 4 (median; range 2–8) prior systemic cancer treatments. The most common metastatic sites at baseline were lymph node (61.3%), lung (52.5%), bone (33.8%), and liver (30.0%). ORR was 38.8% (95% confidence interval [CI] 28.06‒50.30). CBR was 43.8% (95% CI 32.68–55.30) and the median PFS was 5.55 months (95% CI 4.14 - NA). SG-related Grade ≥3 TEAEs were reported in 71.3% (57 patients), and the most common ones (preferred term) were neutrophil count decreased (62.5%), white blood cell count decreased (48.8%), and anemia (21.3%), with 6.3% discontinued SG because of TEAEs.
Conclusions
SG demonstrated significant clinical activity in heavily pretreated Chinese patients with mTNBC. The observed safety profile was generally manageable.
Clinical trial identification
NCT04454437 First Posted: July 1, 2020.
Editorial acknowledgement
Legal entity responsible for the study
Everest Medicines.
Funding
Everest Medicines.
Disclosure
X.J. Cong, J. Chen: Financial Interests, Personal, Other, employee: Everest Medicines. All other authors have declared no conflicts of interest.