A phase 3 clinical trial confirms the efficacy of the antibody-drug conjugate (ADC) sacituzumab govitecan in patients with relapsed or refractory metastatic triple-negative breast cancer (mTNBC): the latest data from the ASCENT study, published in The New England Journal of Medicine, confirm the superiority of the drug over single-agent chemotherapy in terms of both progression-free survival (PFS) and overall survival (OS).
Sacituzumab govitecan is an ADC composed of an irinotecan active metabolite (the topoisomerase I inhibitor SN-38) coupled to an antibody targeting the human trophoblast cell-surface antigen 2 (Trop-2), a surface glycoprotein expressed in more than 90% of TNBCs, a tumor without many treatment options beyond standard chemotherapy. The study involved 468 patients without brain metastases who had previously received taxanes, randomly assigned to receive either sacituzumab govitecan (235 patients) or single-agent chemotherapy (233 patients, treated with either eribulin, vinorelbine, capecitabine or gemcitabine). The median PFS was 5.6 months with sacituzumab govitecan vs 1.7 months with chemotherapy, OS was 12.1 months vs 6.7 months, respectively. The percentage of patients with an objective response was 35% with sacituzumab govitecan and 5% with chemotherapy; however, the incidence of adverse events was also higher with sacituzumab govitecan (51% versus 33%), including leukopenia, diarrhea, anemia and febrile neutropenia.
The ASCENT study was stopped early due to the superiority of the results with sacituzumab govitecan; these data are a more complete analysis of the elements collected over time and were published a few days after the approval of the drug by the US Food and Drug Administration (FDA). On April 7, FDA granted regular approval to sacituzumab govitecan for patients with unresectable locally advanced or metastatic triple-negative breast cancer who have received two or more prior systemic therapies, with at least one of them in the metastatic setting; the product is now under accelerated review by the European Medicines Agency (EMA).