Ixabepilone plus capecitabine for breast cancer patients with an early metastatic relapse after adjuvant chemotherapy: two clinical trials

BackgroundDespite recent advances in treating patients with metastatic breast cancer (MBC), outcomes remain poor. Ixabepilone is a semisynthetic analogue of epothilone B with low susceptibility to multiple mechanisms of tumor-cell resistance. This review examined the results of 2 phase III clinical trials of ixabepilone in patients with drug-resistant or heavily pretreated, locally advanced breast cancer or MBC.Patients and MethodsIn both studies, women with locally advanced breast cancer or MBC pretreated with, or resistant to, taxanes or anthracyclines were randomly assigned to ixabepilone plus capecitabine, or capecitabine alone, until disease progression or unacceptable toxicity occurred.ResultsIxabepilone plus capecitabine significantly prolonged progression-free survival (PFS) compared with capecitabine alone. The median PFS was prolonged by 1.5 months and 1.8 months in the 2 studies (hazard ratio, < 0.8 in both studies; P ≥ .001). These observations remained valid within several patient subsets: those receiving ixabepilone as first-line therapy, those with taxane-resistant disease, and those with particularly poor prognostic features. Ixabepilone plus capecitabine significantly improved overall survival (OS) compared with capecitabine in patients with symptomatic disease (12.3 vs. 9.5 months, respectively; P = .015). Peripheral neuropathy with ixabepilone was generally reversible and was effectively managed by dosage reduction in most patients. Ixabepilone did not exacerbate capecitabine-induced hand-foot syndrome or diarrhea.ConclusionThe results of these 2 large phase III trials suggest that ixabepilone plus capecitabine may improve treatment outcomes for patients with locally advanced breast cancer or MBC resistant to, or heavily pretreated with, taxanes or anthracyclines, even in those with poor prognostic features.