Alternative dosing schedules and administration updates for Ixabepilone

Abstract

Ixabepilone 40 mg/m 2 (every 3 weeks) is approved for use in metastatic breast cancer as monotherapy as early as third line and in combination with capecitabine as early as first line in tumors that are resistant or refractory to anthracyclines and taxanes. This article seeks to familiarize oncology pharmacists with the options at their disposal to aid in management of ixabepilone therapy. Toxicity with ixabepilone is reversible and responsive to dose reduction or delay, and the 40 mg/m2 dose may be reduced to 32 mg/m2 and subsequently to 25 mg/m2 should toxicities arise. However, available clinical data cannot support beginning ixabepilone therapy at a reduced dose to mitigate toxicity. Because ixabepilone’s mechanism of action and adverse event profile resemble those of the taxanes, it has been postulated that weekly administration of ixabepilone (15—20 mg/m2 weekly for 3 weeks with a 1 week break) may provide similar advantages to those seen with weekly metronomic paclitaxel administration. Within the last year, preliminary data has emerged that begins to answer questions regarding the use of weekly ixabepilone. The regimen appears to be effective and well-tolerated in metastatic breast cancer and other tumor types, although data from definitive head-to-head studies with the approved regimen are not yet available. Moreover, a recent label change now incorporates alternative infusion liquids to Lactated Ringer’s Solution into the approved dilution protocol for ixabepilone, and similarities and differences from taxane administration are discussed. It is hoped that the influx of new data regarding dosing, scheduling, and administration options for ixabepilone will continue to increase the pharmacist’s ability to optimize treatment outcomes for breast cancer patients.