First-line treatment patterns and real-world survival outcomes in PD-L1-negative locally recurrent inoperable or metastatic triple-negative breast cancer in the United States.

purposeContemporary real-world data on treatment patterns and clinical outcomes in patients with programmed death ligand 1 (PD-L1)-negative locally recurrent inoperable or metastatic triple-negative breast cancer (lr/mTNBC) are sparse. We describe first-line (1L) systemic therapies and real-world survival outcomes in this population in the United States (US).

methodsAdults with PD-L1-negative lr/mTNBC initiating 1L systemic treatment in the US were identified using the Komodo Research Data (KRD+; 1/1/2016-12/31/2023). Treatment patterns, including treatment durations and sequences from 1L through three lines of therapy, real-world overall survival (rwOS) and progression-free survival (rwPFS) from 1L, were analyzed. rwOS and rwPFS were summarized using Kaplan-Meier methods in subgroups of patients with ≥ 18 months and ≥ 6 months of potential follow-up, respectively.

resultsOverall, 929 patients were included (median age 59.0 years, 60.1% White, 26.4% Black or African American, 64.9% commercially insured). Most common 1L treatments included cyclophosphamide + doxorubicin-based regimens (28.1%), capecitabine (12.7%), and paclitaxel (10.4%); 44.5% were observed to receive a second-line treatment, and 16.0% a third-line treatment. Treatment sequences were heterogeneous, with 329 unique sequences captured. Median rwOS and rwPFS (95% confidence interval) were 12.2 (10.7, 14.4) months and 4.7 (4.5, 5.2) months, respectively.

conclusionIn this large real-world US cohort of patients with PD-L1-negative lr/mTNBC, 1L treatment regimens were highly heterogeneous and often diverged from guideline recommendations. Despite treatment, survival outcomes remain poor within this patient population. These findings highlight the need for more effective therapeutic options for this population.