Biologic Drug Nearly Doubles Overall Survival in Metastatic Triple-Negative Breast Cancer

By Reuters Staff

April 22, 2021

NEW YORK (Reuters Health) - Immunomedics' antibody-drug conjugate sacituzumab govitecan can cut the risk of disease progression or death by 59% and nearly double median overall survival among women with metastatic triple-negative breast cancer, according to results from a phase-3 study.

In the ASCENT trial of 468 patients, median progression-free survival was 5.6 months with the drug versus 1.7 months among women given conventional chemotherapy.

Median overall survival rates were 12.1 months and 6.7 months respectively (P<0.001 for both comparisons), researchers report in the New England Journal of Medicine.

"The benefit with sacituzumab govitecan was seen in all clinical and prespecified subgroups, including patients who received previous treatment with PD-1 or PD-L1 inhibitors," said the research team, led by Dr. Aditya Bardia of the Massachusetts General Hospital Cancer Center in Boston.

The treatment, which received accelerated approval from the U.S. Food and Drug Administration in April 2020, was given for a median of 4.4 months.

But the drug did not benefit everyone. About a third - 35% - of the women had an objective response to the drug, compared to 5% among those on chemotherapy.

Sacituzumab govitecan recipients were also more prone to side effects of grade 3 or higher. The rates for serious neutropenia were 51% with the drug versus 33% with chemotherapy.

Leukopenia ranking grade 3 or higher surfaced in 10% of sacituzumab govitecan patients and was half as prevalent with the conventional treatment. The rates of febrile neutropenia were 6% and 2% respectively. Serious diarrhea was seen in 10% in the experimental group and in fewer than 1% of control patients.

Only 5% of the women discontinued treatment because of adverse events.

Immunomedics, which sells the drug under the brand name Trodelvy, paid for the study.

The ASCENT findings were originally disclosed September 19 at the virtual congress of the European Society for Medical Oncology.

SOURCE: The New England Journal of Medicine, online April 21, 2021.