Unmet need for patients with metastatic triple-negative breast cancer initiating first-line treatment: data from the prospective German tumor registry OPAL

Background: The treatment landscape for metastatic triple-negative breast cancer (mTNBC) has evolved. However, data on implementation of novel treatment approaches in clinical routine and current real-world outcomes are limited. Patients and methods: Patients with mTNBC who initiated first-line (1L) treatment between January 2018 and August 2023 were prospectively observed within the OPAL registry. Treatment patterns, median real-world overall survival (rwOS), and progression-free survival (rwPFS) were analyzed by programmed death-ligand 1 (PD-L1) status. Results: metastatic disease. Of patients with PD-L1-positive tumors, 81.2% received 1L PD-(L)1 inhibitors ± chemotherapy. Mono-chemotherapy was the most common treatment strategy for patients with PD-L1-negative and unknown status. At database cut, 25.8% of patients died before start of second line (2L). In the total cohort, rwOS was 17.6 months [95% confidence interval (CI) 15.6-19.7 months] and rwPFS was 6.8 months (95% CI 5.9-7.6 months). For patients with PD-L1-positive tumors treated with PD-(L)1 inhibitors, rwOS was 23.2 months (95% CI 17.5-28.2 months) and rwPFS was 7.2 months (95% CI 6.5-9.1 months). In patients with PD-L1-negative tumors receiving chemotherapy, rwOS was 16.0 months (95% CI 13.9-20.7 months) and rwPFS was 6.3 months (95% CI 4.9-7.6 months). Conclusions: Although new treatment options have been rapidly integrated into clinical routine, chemotherapy remains standard for most patients in 1L. Survival remains poor, with at least one-quarter dying without reaching 2L. This highlights the need for novel therapies to improve mTNBC outcomes.