Combining emerging agents in advanced breast cancer.

Newer treatments have improved survival for patients with metastatic breast cancer over the last two decades, and a battery of new cytotoxic and targeted therapies is continuing to enhance this trend. This review outlines recent data and ongoing research in this area, by highlighting new developments (regarding approved but relatively new classes of cytotoxic and targeted agents) and also new classes of targeted therapy that are undergoing clinical evaluation. Mechanisms for synergy between agents are discussed where data are available, as is information on the rationale behind the development of agents that inhibit angiogenesis, DNA repair, histone deacetylases, heat shock proteins, or various signaling pathways in tumor proliferation. The abundance of clinical research surrounding anticancer agents, together with ongoing cancer biology research, is expected to further increase the available pool of therapeutic options for metastatic breast cancer. Concomitantly, in the absence of an effective targeted monotherapy, a better understanding of the interplay between biologic and cytotoxic anticancer agents will improve our ability to rationally design combination regimens with better efficacy and tolerability.