The overall response rate (ORR) across all dose levels was 14% (7 of 50 patients), with all responses occurring in patients with STS. The 6-month progression-free survival (PFS) was 26%, and the median overall survival (OS) for all treated patients was 11 months. There was no correlation between BRCA expression or BRCAness and response. However, patients with high PARP1 expression had improved outcomes compared to patients with low PARP1 expression, suggesting a potential role for PARP1 expression as a biomarker. The 6-month PFS in patients with high PARP1 expression was 59%, compared to 8% in patients with low PARP1 expression (HR 0.37, P = .01).
Based on these results, the investigators concluded that the combination of trabectedin and olaparib is active in advanced STS .