The chemotherapy combination consisting of Abraxane® (nab-paclitaxel) plus carboplatinum (carbo) improves outcomes compared with Abraxane plus Gemzar (gemcitabine) for triple negative breast cancer. These results were presented at the 2015 annual San Antonio Breast Cancer Symposium (SABCS).
Approximately 10-20% of breast cancers are referred to as triple negative breast cancer (TNBC). These types of cancers are both hormone-negative, and HER2-negative.
Hormone-negative breast cancer refers to a type of breast cancer that is both estrogen- and progesterone-receptor negative. This means that this type of cancer is not stimulated to grow from exposure to the female hormones estrogen and/or progesterone. Only approximately one-third or fewer breast cancers are hormone-negative.
Approximately 25-30% of breast cancers are referred to as human epidermal growth factor receptor (HER) 2-positive, in which the cancer cells have a gene mutation that causes extra HER2 receptors to be present on the cell surface. Since the HER2 pathway is involved in cellular growth and replication, excessive HER2 receptors result in uncontrolled replication and spread of the HER2-positive cancer cells.
HER2-negative breast cancer refers to cancer that does not have a mutated HER2 pathway, and therefore, is not stimulated to replicate and spread through the activity of excessive HER2 receptors.
Many treatments are available specifically for hormone-positive breast cancers, as well as HER2-breast cancers. Since these treatments are ineffective in TNBC, research efforts are underway to find new treatment options or optimal combinations of agents for this type of breast cancer. Data has demonstrated that patients who achieved a pathologic complete response (pCR)—meaning a complete disappearance of detectable cancer through laboratory examination—from therapy have improved long-term outcomes compared to those who do not achieve pCR.
Standard treatment for TNBC typically consists of surgery, chemotherapy and/or radiation therapy. However, optimal chemotherapy regimens for TNBC has not been determined.
Researchers recently compared two different chemotherapy regimens for the treatment of TNBC for the ADAPT trial. The trial included 336 patients from 47 different medical centers with early TNBC. One group of patients was treated with nab-paclitaxel (nab-pac) plus carbo and the other group was treated with nab-pac plus gemcitabine prior to surgery. Patients were treated with the chemotherapy for 2 cycles consisting of 12 weeks.
- pCR was achieved in 46.8% among patients treated with nab-pac/carbo, compared with only 26.9% among patients treated with nab-pac/gemcitabine.
- Dose reductions due to side effects were required in 20.6% of patients treated with nab-pac/gemcitabine, compared with 11.9% of patients treated with nab-pac/carbo.
The researchers stated that “Our results suggest superior efficacy and excellent toxicity of Nab-Pac/Carbo vs. Gem.” Importantly, these treatment regimens did not include the chemotherapy agents referred to as anthracyclines, which are associated with significant side effects, and continue to identify optimal treatment regimens for TNBC.
Reference: Gluz O, Nitz U, Liedtke C, et al. Comparison of 12 weeks neoadjuvant Nab-paclitaxel combined with carboplatinum vs. gemcitabine in triple- negative breast cancer: WSG-ADAPT TN randomized phase II trial. Proceedings from the 2015 annual San Antonio Breast Cancer Symposium. Abstract S6-07.