According to results recently published in the Journal of Clinical Oncology, the chemotherapy agent Abraxane (paclitaxel protein-bound particles) is highly effective and well tolerated as initial therapy for metastatic breast cancer.1
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 United States, and 40,000 deaths are attributed to breast cancer 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, as well as quality of life, for these patients.
Paclitaxel is a chemotherapy agent that is 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 formulation of paclitaxel includes agents that allow for the proper storage and administration of the drug. 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 anti-cancer responses, delays cancer progression, and extends overall survival more effectively than Taxol® in advanced breast cancer.2,3 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 that included a class of commonly used chemotherapy agents referred to as anthracyclines. 4
A recent multi-institutional clinical trial was conducted to further evaluate Abraxane in the treatment of metastatic breast cancer. Participants included women who had never received prior therapy. Sixty-three women, 48 who had received prior therapy and 39 of who had not, participated in the trial.
Following treatment with Abraxane, nearly half (48%) of all patients achieved a complete or partial disappearance of their cancer. For the group of patients that were treated with Abraxane as initial therapy for their metastatic breast cancer, 64% achieved a complete or partial disappearance of their cancer. For the group of patients that had received prior therapy for metastatic disease, 21% achieved a complete or partial disappearance of their cancer. The average time to cancer progression was approximately 48 weeks in patients who achieved an anti-cancer response to Abraxane, and the overall average duration of survival was over one year (approximately 64 weeks) for the entire group of patients. The most common severe side effect was low levels of immune cells.
The researchers concluded that these results provide further evidence that Abraxane is highly effective in the treatment of metastatic breast cancer. Patients treated with Abraxane as initial therapy for metastatic disease achieved impressive results with low rates of serious side effects. Patients with advanced breast cancer may wish to speak with their physician regarding their individual risks and benefits of treatment with Abraxane, or the participation in a clinical trial further evaluating Abraxane. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (www.cancer.gov) and www.cancerconsultants.com.
1 Ibrahim N, Samuels B, Page R, et al. Multicenter Phase II Trial of ABI-007, an Albumin-Bound Paclitaxel, in Women With Metastatic Breast Cancer. Journal of Clinical Oncology 2005:23;6019–6026.
2 Desai N, et al. ABI-007 (ABRAXANE), a nanoparticle albumin-bound (NAB) paclitaxel demonstrates superior efficacy vs. Taxol in MBC: a phase III trial. Proceedings from the 2003 San Antonio Breast Cancer Symposium. San Antonio TX. 2003. Abstract #44.