The investigative agent, Tecentriq (atezolizumb), in addition to the chemotherapy agent, Abraxane (nab-paclitaxel), provides high anti-cancer responses among patients with triple-negative breast cancer.
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 about 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.
Standard treatment for TNBC typically consists of surgery, chemotherapy and/or radiation therapy. However, optimal chemotherapy regimens for TNBC continue to be explored.
Researchers recently updated the results of a clinical trial to explore the effectiveness of a treatment combination consisting of the targeted immunotherapy drug Tecentriq combined with Abraxane.
Tecentriq belongs to an exciting new class of drugs that target PD-1, PD-L1 and CTL-4. Known as “checkpoint inhibitors” these drugs help the immune system recognize cancer cells as a threat, so that an immune attack is initiated against the cancer. These drugs are rapidly being incorporated into the overall treatment strategy of many cancer types.
In the recent trial that included women with advanced TNBC, anti-cancer responses with tecentriq were achieved in 46% of very heavily pretreated patients. Serious side effects were not increased with the addition of Tecentriq to Abraxane, when compared to prior results of patients treated with Abraxane alone.
Treatment combinations consisting of checkpoint inhibitors plus Abraxane and other known active drugs in TNBC like Gemzar (gemcitabine) and Carboplatin are ongoing to determine the optimal way to incorporate this new class of drugs into the overall management of TNBC.
Adams S, et al. Phase Ib trial of atezolizumab (anti-PD-L1) in combination with nab-paclitaxel in patients with triple-negative breast cancer. J Clin Oncol. 2016:34 (suppl: abst 1009)
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