According to a recent early on-line publication in the Journal of Clinical Oncology, results from a large phase III trial have confirmed that Abraxane® (albumin-bound paclitaxel) is superior to Taxol® (paclitaxel) in the treatment of metastatic breast cancer.
Breast cancer is one of the most common cancers diagnosed in women. It is estimated that approximately 250,000 women are diagnosed annually in the US, and 40,000 deaths are attributed to the disease each year.
Metastatic breast cancer refers to cancer that has spread to distant sites in the body, often invading vital organs. Standard treatment for metastatic breast cancer typically includes chemotherapy. Researchers continue to evaluate novel agents or therapeutic approaches for the treatment of metastatic breast cancer in order to improve long-term outcomes and quality of life for these patients.
Paclitaxel is a chemotherapy agent commonly used in the treatment of breast cancer. Patients with cancer that has recurred following previous therapy and/or has spread to distant sites in the body are often treated with paclitaxel. The drug is formulated with agents that allow for its proper storage and administration. These agents, however, are also responsible for of many side effects associated with paclitaxel.
Abraxane is a new form of paclitaxel that is bound with albumin, a type of protein normally found in the human body. This form of paclitaxel delivers high concentrations of the active ingredient into the cancer cells and, compared to the original form of the drug, reduces the incidence of side effects. Results from previous trials have demonstrated that Abraxane improves anticancer responses, delays cancer progression, and extends overall survival more effectively than Taxol in advanced breast cancer. In addition, Abraxane tends to be better tolerated than Taxol, administration times are shorter, and there are no premedication requirements (as with Taxol). The FDA recently approved Abraxane for the treatment of patients with breast cancer who have stopped responding to prior therapies including anthracyclines, a class of commonly used chemotherapy agents.
Abraxane continues to be studied in the treatment of breast cancer. A multi-institutional clinical trial was recently conducted to directly compare Abraxane to Taxol in the treatment of metastatic breast cancer. This trial was conducted to confirm evidence produced by earlier-stage clinical trials. It included approximately 450 patients; half of whom received Abraxane and half of whom received Taxol.
Abraxane provided superior results to that of Taxol with fewer side effects:
- Anticancer response rates were achieved in 33% of patients treated with Abraxane, compared with 19% treated with Taxol.
- Time to cancer progression was 23 weeks for those treated with Abraxane, compared with 17 weeks for those treated with Taxol.
- Low immune cell levels associated with fever (febrile neutropenia) occurred in only 9% of patients treated with Abraxane, compared with 22% of those treated with Taxol.
- No premedication was required for patients treated with Abraxane; those treated with Taxol required premedication to reduce risk of complications.
The researchers concluded that these results confirm those of previous studies evaluating Abraxane and provide further evidence that Abraxane is superior to Taxol in terms of anticancer response and cancer progression. Furthermore, Abraxane is better tolerated than Taxol and does not require intravenous premedication. Patients with breast cancer may wish to speak with their physician regarding the use of Abraxane in their treatment regimen.
Reference: Gradishar W, Tjulandin S, Davidson N, et al. Superior Efficacy of Albumin-Bound Paclitaxel, ABI-007, compared with Polyethylated Castor-oil Based Paclitaxel in Women with Metastatic Breast Cancer: Results of a Phase III Trial. Journal of Clinical Oncology. 2005; published online ahead of print Sep 19 2005. DOI: 10.1200/JCO.2005.04.937