(ChemotherapyAdvisor) – Reducing the dose of ixabepilone does not improve the efficacy of combination regimens containing ixabepilone and capecitabine in patients with metastatic breast cancer, according to a team of researchers of the M.D. Anderson Cancer Center, Houston, TX. This conclusion is based on a study entitled “Maintenance of Clinical Efficacy after Dose Reduction of Ixabepilone Plus Capecitabine in Patients With Anthracycline- and Taxane-Resistant Metastatic Breast Cancer: A Retrospective Analysis of Pooled Data From 2 Phase III Randomized Clinical Trials,” which was published in the August issue of Clinical Breast Cancer

In this study, the investigators aimed to determine the impact of early dose reduction on the efficacy of ixabepilone plus capecitabine in women with metastatic breast cancer (MBC). To meet this aim, 2 phase 3 trials were retrospectively analyzed. In these trials, patients with pretreated MBC (N = 1973) had been randomized to receive a 3-week course of either a combination therapy containing ixabepilone (40mg/m2, day 1) plus capecitabine (1000mg/m2, 2X/day, days 1–14) or capecitabine monotherapy (1250mg/m2, 2X/day, days 1–14). These analyses were restricted to patients who received ≥ 4 courses of ixabepilone.

In 566 evaluable patients, early dose reduction led to similar objective response rates (ORRs) and progression-free survival (PFS) as no/late dose reduction. ORRs were 62.6% (95% confidence interval [CI], 55.8%–69.0%) and 55.3% (95% CI, 49.9%–60.6%), respectively; median PFS was 7.2 months (95% CI, 6.6–8.0) and 7.0 months (95% CI, 6.5–7.5), respectively (hazard ratio = 0.98; 95% CI, 0.83–1.17).

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Based on the results of this study, the investigators concluded that “early ixabepilone dose reduction did not affect the overall efficacy of ixabepilone plus capecitabine in patients with MBC who received ≥ 4 courses of treatment.”