1086 Background: The approved capecitabine (X) regimen in MBC is 1,250 mg/m2 bid, d1-14 q21d (Xint). However, dose modifications are often required primarily for hand-foot syndrome and diarrhea. Therefore we designed an alternative regimen aimed to reduce the severity of these side effects while maintaining the total cumulative dose and efficacy of X.
METHODS
The primary objective was to show non-inferiority of X 800 mg/m2 bid, d1-21 q21d (Xcont) to Xint in terms of 1-year PFS rate. Secondary endpoints included response rate (RECIST), PFS, duration of response, OS, and safety (NCI CTCAE v2.0). Assuming median PFS of 5 months and 2-sided α=0.05, 176 evaluable patients (pts) will be needed to give 80% power. Pts are ineligible if they have received >2 chemotherapy regimens for MBC or prior X, or if they have HER2-positive MBC or symptomatic CNS metastases. Treatment is continued until progression, unacceptable toxicity, or refusal. Dose interruption/reduction is implemented if pts experience grade 2-4 clinically relevant adverse events.
RESULTS
The current interim analysis includes the first 60 pts, with median age 55 years (range 33-79) in the Xcont arm and 67 years (range 34-88) in the Xint arm. 26% and 14%, respectively, were hormone receptor negative. Prior chemotherapy included a taxane in 48% vs 52% and an anthracycline in 65% vs 76%, respectively. X was given as first-line chemotherapy in 48% and 38% of pts, respectively. Median duration of treatment was 7 cycles for Xcont vs 6 cycles for Xint. Dose reduction was required in 10% of cycles in each arm. Toxicity led to treatment discontinuation in 1 vs 8 pts, respectively. Activity and safety results at interim analysis are summarized below (Table).
CONCLUSIONS
Xcont and Xint seem similarly active in MBC in this interim analysis. Xcont appeared slightly better tolerated. The study will continue recruiting additional pts. [Table: see text] No significant financial relationships to disclose.