Sacituzumab Govitecan-hziy in Heavily Pretreated, Metastatic Triple-Negative Breast Cancer
In a phase I/II trial reported in The New England Journal of Medicine, Bardia et al found durable responses with the antibody-drug conjugate sacituzumab govitecan-hziy in patients with heavily pretreated, metastatic triple-negative breast cancer. The monoclonal antibody sacituzumab targets the human trophoblast cell-surface antigen 2 (Trop-2).
In the multicenter study, 108 patients who had received at least 2 prior therapies for metastatic disease received sacituzumab govitecan-hziy given intravenously at 10 mg/kg on days 1 and 8 of 21-day cycles until disease progression or unacceptable toxicity. Patients had received a median of 3 prior therapies (range = 2–10).
Treatment Response
On investigator assessment, the objective response rate was 33.3% (3 complete and 33 partial responses) and median duration of response was 7.7 months. The clinical benefit rate was 45.4%.
On post hoc independent central review, the response rate was 34.3% and median duration of response was 9.1 months. Median progression-free survival was 5.5 months, and median overall survival was 13.0 months.
Adverse Events
Grade 3 or 4 adverse events occurred in 85% of patients, with the most common being neutropenia (42%), anemia (11%), and decreased white blood cell count (11%). Febrile neutropenia occurred in 9% of patients.
Serious adverse events occurred in 32%, with the most common being febrile neutropenia (7%) and vomiting (6%). Adverse events led to treatment discontinuation in 3%. Adverse events led to death in 4 patients.
The investigators concluded, “Sacituzumab govitecan-hziy was associated with durable objective responses in patients with heavily pretreated metastatic triple-negative breast cancer. Myelotoxic effects were the main adverse reactions.”
Disclosure: The study was funded by Immunomedics. The study authors' full disclosures can be found at nejm.org.
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