Mechanism of Action

IXEMPRA® (ixabepilone) is a non-taxane microtubule-targeting agent1

In preclinical studies, IXEMPRA, a semisynthetic analog of epothilone B, had low susceptibility to multiple mechanisms of resistance1-4,*

  • IXEMPRA binds directly to beta-tubulin subunits and suppresses their dynamic instability, blocking the mitotic phase of the cell division cycle and inducing cell death1
  • IXEMPRA has antitumor activity in vivo against multiple human tumor xenografts, including drug-resistant types that1:
    • Harbor tubulin mutations
    • Overexpress efflux transporters such as P-gp and MRP1
    • Overexpress beta-III tubulin isoforms
  • IXEMPRA is also active in xenografts resistant to multiple agents, including taxanes, anthracyclines, and vinca alkaloids1
  • IXEMPRA works synergistically with capecitabine and possesses anti-angiogenic activity1
* The clinical significance of this has not been determined.

IXEMPRA mechanism of action1,2

References: 1. IXEMPRA (ixabepilone) Prescribing Information; January 2016. 2. Vahdat L. Ixabepilone: a novel antineoplastic agent with low susceptibility to multiple tumor resistance mechanisms. Oncologist. 2008;13(3):214-221. 3. Shen H, Lee FY, Gan J. Ixabepilone, a novel microtubule-targeting agent for breast cancer, is a substrate for P-glycoprotein (P-gp/MDR1/ABCB1) but not breast cancer resistance protein (BCRP/ABCG2). J Pharmacol Exp Ther. 2011;337(2):423-432. 4. Dumontet C, Jordan MA, Lee FFY. Ixabepilone: targeting βIII-tubulin expression in taxane-resistant malignancies. Mol Cancer Ther. 2009;8(1):17-25.

Indications and Important Safety Informationexpand

Important Safety Information
WARNING: Toxicity in hepatic impairment


Peripheral neuropathy


Hypersensitivity reaction


Cardiac adverse reactions

Potential for cognitive impairment from excipients

Adverse reactions


Combination with capecitabine

Cremophor is a registered trademark of BASF AG.

AST = aspartate aminotransferase; ALT = alanine aminotransferase; ULN = upper limit of normal; CTC = common terminology criteria.


IXEMPRA® (ixabepilone) is indicated in combination with capecitabine for the treatment of patients with metastatic or locally advanced breast cancer resistant to treatment with an anthracycline and a taxane, or whose cancer is taxane resistant and for whom further anthracycline therapy is contraindicated.

  • Anthracycline resistance is defined as progression while on therapy or within 6 months in the adjuvant setting or 3 months in the metastatic setting
  • Taxane resistance is defined as progression while on therapy or within 12 months in the adjuvant setting or 4 months in the metastatic setting

IXEMPRA is indicated as monotherapy for the treatment of metastatic or locally advanced breast cancer in patients whose tumors are resistant or refractory to anthracyclines, taxanes, and capecitabine.

Please see US Full Prescribing Information, including boxed WARNING regarding hepatic impairment.

Medical information

For product information or to report an adverse reaction, please call 1-844-586-8953 or e-mail

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The R-Pharm US Access and Support logo is a trademark and IXEMPRA® is a registered trademark of R-Pharm US Operating LLC, a wholly owned subsidiary of R-Pharm US LLC.

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