New agents in the treatment of primary brain tumors.

A review of single agent trials of cytotoxic agents in adults with high grade gliomas is presented. The rationale for testing these agents in patients with brain tumors was variable and is discussed. The criteria to evaluate responses were also variable ranging from subjective evaluation of clinical improvement with a stable radiographic assessment to the same objective response criteria utilized for solid tumors. Trials of agents specifically designed for brain tumors such as AZQ and spiromustine have been disappointing. There are encouraging results being seen in early trials of newer agents which await confirmation in larger trials but which hold promise for improving the disappointing results seen so far with chemotherapy in primary brain tumors.