Myelosuppression with capecitabine

Ixabepilone, a microtubule stabilizing agent, is indicated as monotherapy or in combination with capecitabine in MBC patients who have previously received an anthracycline and a taxane. Response rates and time to progression were increased with combination therapy as compared with capecitabine alone. Adverse effects include myelosuppression, peripheral neuropathy, and myalgias/arthralgias. 

Although not a taxane, ixabepilone is a novel microtubule inhibitor that was recently approved for metastatic breast cancer in combination with the oral fluoropyrimidine capecitabine or as monotherapy. It is a semisynthetic analog of epothilone B, and is active in the M phase of the cell cycle. This agent binds directly to 6-tubulin subunits on microtubules, leading to inhibition of normal microtubule dynamics. Of note, this agent continues to have activity in drug-resistant tumors that overexpress P-glycoprotein or tubulin mutations. The main adverse effects include myelosuppression, hypersensitivity reactions, and neurotoxicity in the form of peripheral sensory neuropathy. 

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