Posted: Thursday, January 19, 2023
Patients with pretreated, endocrine-resistant, hormone receptor–positive, HER2-negative metastatic breast cancer appeared to derive a progression-free survival benefit from treatment with sacituzumab govitecan-hziy versus chemotherapy, regardless of Trop-2 expression, according to Hope S. Rugo, MD, FASCO, of the University of California, San Francisco, and colleagues. The post hoc analysis of the phase III TROPiCS-02 trial, which was presented during the 2022 San Antonio Breast Cancer Symposium (SABCS; Abstract GS5-11), reinforces that Trop-2 testing is not required to receive this antibody-drug conjugate.
In this trial, patients who experienced disease progression with endocrine-based therapies and at least two chemotherapies were randomly assigned to receive sacituzumab govitecan (n = 272; Trop-2–evaluable: n = 238) or physician’s choice of chemotherapy with eribulin, gemcitabine, capecitabine, or vinorelbine (n = 271; Trop-2–evaluable: n = 224). Membrane Trop-2 expression was assessed by immunohistochemistry and expressed as a histochemical score (H-score).
The median durations of progression-free survival with sacituzumab govitecan and chemotherapy were 5.3 and 4.0 months in patients with an H-score of less than 100 (hazard ratio [HR] = 0.77) and 6.4 and 4.1 months in those with an H-score of at least 100 (HR = 0.60); the median durations of overall survival were 14.6 versus 11.3 months (HR = 0.75) and 14.4 versus 11.2 months (HR = 0.83), respectively. Disease response was observed in the 34 patients with an H-score of up to 10 who were treated with sacituzumab govitecan. Those who received sacituzumab govitecan and had H-scores of up to 10, between 10 and 100, and at least 100 had overall response rates of 24%, 18%, and 23%, respectively. The safety profile of sacituzumab govitecan by Trop-2 H-score appeared to be congruent with previous reports.
Disclosure: For full disclosures of the study authors, visit sabcs.org.