Novel agents and approaches for breast cancer

Cytotoxic chemotherapy remains an important part of the treatment paradigm for breast cancer. Anthracyclines and taxanes are the most active agents; however, limitations with their use include a maximum lifetime dose and tumor resistance with anthracycline, hypersensitivity reactions and cumulative toxicity with taxanes.

• Therefore, to meet these challenges, the development of new cytotoxics and novel taxane formulations is an important area of active research. Several recent advances have been made. Epothilones represent a novel group of cytotoxic agents, with proven activity in breast cancer.
• Nanoparticle drug delivery systems have led to the development of ABI-007, which has demonstrated superior response rates than 3-weekly paclitaxel, with a lower risk of hypersensitivity reactions.
• To circumvent the problem of taxane resistance, larotaxel, a semisynthetic taxoid, and vinflunine, a synthetic vinca alkaloid, have been developed with encouraging clinical results to date.
• Eribulin, a synthetic derivative of halichondrin has recently entered Phase III trials based on encouraging activity in heavily pretreated patients.
• A further novel approach is the conjugation of cytotoxic agents to targeted agents, such as with trastuzumab-MCC-DM1.