Treatment with sacituzumab govitecan vs physician’s choice of therapy yielded a significant benefit in PFS among patients with hormone receptor (HR)–positive, human epidermal growth factor receptor 2 (HER2)–negative unresectable locally advanced or metastatic breast cancer, according to results from the phase 3 TROPiCS-02 trial.

These findings were presented at the 2022 ASCO Annual Meeting by Hope Rugo, MD, University of California San Francisco, Helen Diller Family Comprehensive Cancer Center, lead author of the study.

The TROPiCS-02 trial enrolled adult patients with HR-positive, HER2-negative unresectable locally advanced or metastatic breast cancer. Patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 and received 2 to 4 prior chemotherapy regimens. Patients who received 1 prior therapy were allowed if their disease progressed within 12 months after neoadjuvant therapy. In addition, patients had to have received 1 prior taxane, CDK4/6 inhibitor, and endocrine therapy in any setting.

Patients were randomized in a 1:1 ratio to receive sacituzumab govitecan or physician’s choice of therapy until disease progression or unacceptable toxicity. Physician’s choice of therapy included capecitabine, eribulin, vinorelbine, or gemcitabine.

The primary end point of the trial was PFS by blinded independent central review. Overall survival (OS) was a secondary end point. The data cutoff for this analysis was January 3, 2022.

A total of 543 patients were enrolled in the trial and randomized to sacituzumab govitecan (n = 272) or physician’s choice of therapy (n = 271). Patient characteristics were similar between the 2 treatment arms.

Median PFS with sacituzumab govitecan was 5.5 months vs 4 months with physician’s choice of therapy (hazard ratio [HR], 0.66; 95% confidence interval [CI], 0.53 to 0.83; P = .0003). At 6 months, the PFS rates were 46% vs 30%, respectively. The 12-month PFS rates were 21% vs 7%, respectively.

Median OS was 13.9 months with sacituzumab govitecan vs 12.3 months, though this increase was not considered significant (HR, 0.84; P = .143). The overall response rate was 34% vs 22%, clinical benefit rate was 21% vs 14%, and median duration of response was 7.4 vs 5.6 months, respectively.

Grade ≥3 treatment-emergent adverse events (AEs) were reported in 74% of patients received sacituzumab govitecan vs 60% of patients receiving physician’s choice of therapy. The most common grade ≥3 AEs were neutropenia (51% vs 39%) and diarrhea (10% vs 1%). AEs leading to treatment discontinuation occurred in 6% of patients received sacituzumab govitecan vs 4% receiving physician’s choice of therapy. One treatment-related death occurred in the sacituzumab govitecan arm.

“[Socituzumab govitecan] had a statistically significant, clinically meaningful PFS benefit over single-agent chemotherapy and a manageable safety profile in patients with heavily pretreated [HR–positive/HER2–negative] endocrine–resistant, unresectable locally advanced or [metastatic breast cancer], who have limited treatment options,” concluded Dr Rugo and colleagues.

Source:

Rugo HS, Bardia A, Marmé F, et al. Primary results from TROPiCS-02: A randomized phase 3 study of sacituzumab govitecan (SG) versus treatment of physician’s choice (TPC) in patients (Pts) with hormone receptor–positive/HER2-negative (HR+/HER2-) advanced breast cancer. Presented at: ASCO Annual Meeting; June 3-7, 2022. Chicago, IL, and virtual. Abstract LBA1001.