Improving the delivery of therapeutic agents to CNS neoplasms: a clinical review

Even though nearly thirty-years of clinical research has attempted to improve the outcomes for patients with central nervous system neoplasms, the survival remains limited for a majority of these patients. Diverse intracellular signaling pathways involving apoptosis, invasion, angiogenesis and relevant mechanisms of resistance associated with CNS neoplasms are continuing to be elucidated. Phase I and II studies of systemically delivered chemotherapeutic agents and biological agents targeting these pathways have largely resulted in modest outcomes. Although the functional blood brain barrier was identified nearly eighty years ago only recently has the complexity and relevance of the blood brain-tumor barrier (BTB) been recognized as an important factor that limits the effective treatment of CNS neoplasms. Several groups have focused their efforts at improving the delivery of therapeutic agents across the blood brain-tumor barrier. The purpose of the article is to review novel methods that have attempted to improve the delivery of therapeutic agents into the CNS for the treatment of CNS neoplasm.