TROPiCS-02 is a statistically positive trial, with the primary endpoint met and also now with an overall survival gain of 3.2 months,” said the study’s invited discussant Meritxell Bellet Ezquerra, MD, PhD, a senior researcher at the Vall d’Hebron Institute of Oncology, Barcelona. “TROPiCS-02 is the largest late-line trial specifically conducted in the hormone receptor–positive HER2-negative metastatic breast cancer population and addresses a real unmet medical need. Altogether, in my opinion, the results are clinically meaningful and should lead to regulatory approval.”
Dr. Ezquerra emphasized the challenging nature of the population: 95% had visceral involvement, 86% had received at least 6 months of endocrine therapy for metastatic disease, a median of three prior lines of chemotherapy, and the time from metastatic diagnosis was 47 months. A survival benefit was seen in most subgroups, she noted, including the subset of 26 patients with nonvisceral disease. “This is an intriguing result,” she commented.
In addition, Dr. Ezquerra also pointed out the high rate (30%) of screening failures, which could indicate the results “may not apply to at least one-third of our patients with metastatic disease in this advanced setting.” The drug is also associated with off-target toxicities, including neutropenia, fatigue, and diarrhea, although quality of life in the study was similar to or better than treatment by physician’s choice, she added.
Furthermore, with fam-trastuzumab deruxtecan-nxki (T-DXd) having emerged as an effective later-line treatment for patients with hormone receptor–positive, HER2-low disease, the question of optimal sequencing arises, and the activity of sacituzumab govitecan after T-DXd is unknown. There will also be other antibody-drug conjugates emerging, with TROP2 and other targets, based on their activity in the hormone receptor–positive HER2-negative population, she predicted.
DISCLOSURE: Dr. Ezquerra has reported financial relationships with Pfizer, Novartis, and Lilly and is a member of the SOLTI Executive Board and Scientific Committee.
