Cytotoxic drugs for patients with breast cancer in the era of targeted treatment: back to the future?

Background: Despite current trend of targeted therapy development, cytotoxic agents are a mainstay of treatment of patients with breast cancer. We reviewed recent advances in cytotoxic therapy for patients with metastatic breast cancer (MBC). Materials and methods: Medline searches were conducted for English language studies using the term 'MBC' and 'cytotoxic drugs'. The data search was restricted to the period 2000-2011. Results: Several novel cytotoxic compounds, all microtubule inhibitors, have been approved for clinical use in MBC: (i) nab-paclitaxel, reported to improve tumour response and decrease hypersensitivity reactions in comparison with other taxanes; (ii) ixabepilone, shown to have clinical benefit in taxane-and anthracycline-resistant disease and (iii) eribulin, shown to improve overall survival in heavily pre-treated patients, when compared with best available standard treatment. Agents, such as larotaxel, vinflunine, trabectidin and formulations, including cationic liposomal paclitaxel or paclitaxel poliglumex, are currently under evaluation in phase II/III trials. Conclusion: Toxicity and chemotherapy resistance are still major limitations in the treatment of patients with MBC. Further research into new cytotoxic compounds is needed in order to maximise benefit, whilst minimising toxicity.