Effect of race on the safety and efficacy outcomes of gemcitabine plus paclitaxel treated patients with metastatic breast cancer (MBC): Analyses from a phase III trial

1070 Background: Population-based studies often attribute racial disparities in breast cancer outcomes to differences in access to treatment, quality of care, or other socioeconomic factors. In a controlled clinical trial setting, these systemic differences between races should be minimal. To evaluate the potential impact of race on outcomes in a controlled clinical setting, we retrospectively analyzed data from a phase III trial (B9E-MC-JHQG; NCT00006459 ) of patients (pts) with MBC. Methods: Analyses were performed on the JHQG trial database after 440 total pt deaths for both study arms. Demographics, safety, and efficacy were analyzed using safety population data from 3 racial groups: Caucasian (CA), Asian (AS), and Hispanic (HP). CA was the reference for all pair-wise comparisons. The logistic model was used to calculate odds ratios for tumor response and the Cox model was used to calculate hazard ratios for time-to-event parameters, adjusting for significant prognostic factors. Results: We report analyses of the gemcitabine (G) + paclitaxel (T) treatment arm. Demographics were balanced across the 3 groups with the exception that ER+/PR+ status was lower for AS compared to CA and HP; unknown ER/PR status was higher for AS. AS had significantly less neutropenia, fatigue, and nausea, but more anemia compared to CA and HP. Median number of treatment cycles completed was lower, but mean dose intensities for G and T were slightly higher, for AS. Response rate and progression-free survival were similar in the 3 groups. Overall survival (OS) and post-study chemotherapy (PSC) were significantly reduced for AS. Conclusions: Our analysis suggests that AS pts were better able to tolerate GT therapy compared to CA and HP pts. However, AS pts had the poorest OS outcome of the 3 racial groups, potentially due to reduced participation in PSC. [Table: see text] [Table: see text]