Methylglyoxal-bis(guanylhydrazone) (Methyl-GAG): current status and future prospects.

Initial clinical trials of methyl-GAG (MGBG) showed that repetitive daily administration produced severe, occasionally fatal, toxic reactions. After two decades of neglect, recent studies have shown that doses of 500-600 mg/sq m administered every 7-14 days are very well tolerated. Moreover, current results indicate that MGBG has useful antitumor activity in patients with advanced malignant lymphoma and carcinomas of the head and neck, esophagus, and lung (non-small cell). The drug's mechanism of cytotoxic action and its toxic effects are not shared by most other cancer chemotherapeutic drugs. Furthermore, Phase II and Phase III evaluation are required to determine the therapeutic potential of this unique agent.