Phase 3 TROPiCS-02 Trial Meets Primary End Point of PFS in HR+/HER2- Metastatic Breast Cancer

Treatment with sacituzumab govitecan-hziy in patients with hormone receptor–positive/HER2-negative metastatic breast cancer who previously received treatment with endocrine therapy, CDK4/6 inhibitors, and 2 to 4 lines of chemotherapy resulted in a statistically significant improvement in progression-free survival vs physician’s choice of chemotherapy.

The primary end point of progression-free survival (PFS) was met in the phase 3 TROPiCS-02 trial (NCT03901339) for patients treated with sacituzumab govitecan-hziy (Trodelvy) for hormone receptor (HR)–positive/HER2-negative metastatic breast cancer, and who were previously treated with endocrine therapy, CDK4/6 inhibitors, and 2 to 4 lines of chemotherapy, according to a press release from Gilead Sciences.1

Aside from the statistically significant improvement in PFS vs physician’s choice of chemotherapy, trial had a targeted reduction in risk of disease progression or death of 30%. The results were consistent with what was previously observed in the phase 1/2 IMMU-132-01 study (NCT01631552) in a subset of patients with HR-positive/HER2-negative metastatic breast cancer.2 Additionally, the TROPiCS-02 trial will continue to evaluate patients for overall survival, a key secondary end point. Additional results from the study will be presented at an upcoming meeting.

“[Sacituzumab govitecan] demonstrated consistent activity in this difficult-to-treat patient population. We are evaluating the data and will explore potential pathways with regulatory authorities to bring [sacituzumab govitecan] to this group of patients. As we work to expand the patient benefit of [sacituzumab govitecan] beyond its current indications for second-line metastatic triple-negative breast cancer and accelerated approval in second-line metastatic bladder cancer, we are pursuing studies across multiple tumor types and earlier lines of therapy,” Merdad Parsey, MD, PhD, chief medical officer at Gilead Sciences, said in the press release.

This trial was randomized 1:1 and enrolled 543 pre-treated patients. Patients were given 10 mg/kg of sacituzumab govitecan intravenously on days 1 and 8 of each 21-day cycle. The comparator arm had physician’s choice treatment of either eribulin at 1.4 mg/m2 in North America or 1.23 mg/m2 for Europe intravenously on days 1 and 8; capecitabine at 1000 to 1250 mg/m2 twice daily for 2 weeks then a rest week; gemcitabine at 800 to 1200 mg/m2 intravenously on days 1, 8, and 15; or vinorelbine at 25 mg/m2 intravenously on day 1.

Additional secondary end points included objective response rate, duration of response, clinical benefit rate, and time to deterioration.

Patients were eligible for treatment if they had documented evidence of disease, relapse after 2 but not more than 4 lines of chemotherapy, were eligible for 1 chemotherapy option in the physician’s choice arm, and had adequate bone marrow, renal, and hepatic function.

Exclusion criteria included previous treatment with topoisomerase 1 inhibitors, history of cardiovascular disease, individuals with Gilbert’s disease, and active serious infection in need of antibiotics.

Investigators noted that sacituzumab govitecan had a consistent safety profile as seen in prior studies, and no new concerns had emerged in the TROPiCS-02 population. The boxed warning highlights the possibility of severe or life-threatening neutropenia and severe diarrhea.

References

1. Phase 3 TROPiCS-02 study met the primary endpoint of progression-free survival in late-line HR+/HER2- metastatic breast cancer. News Release. March 7, 2022. Accessed March 8, 2022. https://bit.ly/3HToQKP

2. Kalinsky K, Diamond JR, Vahdat LT, et al. Sacituzumab govitecan in previously treated hormone receptor-positive/HER2-negative metastatic breast cancer: final results from a phase I/II, single-arm, basket trial. Ann Oncol. 2020;31(12):1709-1718. doi:10.1016/j.annonc.2020.09.004