AbstractPurpose
To assess the efficacy and safety of trabectedin for advanced breast cancer.
Patients and Methods
In an open-label, phase II, multicenter study, women with advanced breast cancer previously treated with ≤2 lines of chemotherapy for advanced disease, including both anthracyclines and taxanes, were randomized (1:1) to 3-hour infusions of trabectedin 1.3 mg/m2 once every 3 weeks (1/3 treatment arm) or 0.58 mg/m2 every week for 3 of 4 weeks (3/4 treatment arm). The primary end point was objective response. Secondary end points included time to progression (TTP), progression-free survival (PFS), and overall survival (OS).
Results
Fifty-two women (median age, 50 y; median chemotherapy agents, 4) were enrolled. Relative trabectedin dose intensities were 81% and 76% in the 1/3 and 3/4 treatment arms, respectively. Objective response rates were 12% (3/25) and 4% (1/27), respectively. Stable disease was observed in 14 (56%) and 11 (41%) patients in the 1/3 and 3/4 treatment arms, respectively, with median durations of 3.5 and 3.7 months. Median TTP and PFS were higher in the 1/3 treatment arm (3.1 mos each) than in the 3/4 treatment arm (2.0 mos each). At a median follow-up of 7 months in both treatment arms, median OS was not reached in the 1/3 treatment arm and was 9.4 months in the 3/4 treatment arm. The most frequent drug-related adverse events in the 1/3 and 3/4 treatment arms, respectively, were alanine aminotransferase (ALT) elevations (68% vs. 63%), nausea (56% vs. 59%), and asthenia (56% vs. 48%). Neutropenia and ALT elevations were the most frequent grade 3/4 events. Both types of events were usually transient and reversible.
Conclusion
In the population studied, trabectedin showed a manageable safety profile for both regimens analyzed. There were higher objective response rates and a longer PFS in the 1/3 treatment arm compared with the 3/4 treatment arm.