HMN-176

HMN-176 is an active metabolite of the synthetic antitumor compound HMN-214. HMN-176 shows potent cytotoxicity toward various human tumor cell lines, and in mitotic cells, it causes cell cycle arrest at M phase through the destruction of spindle polar bodies, followed by the induction of DNA fragmentation. However, no direct interactions of HMN-176 with tubulin are observed. Moreover, in animal models, it was observed that oral administration of the prodrug HMN-214 caused no significant nerve toxicity, a severe side effect often associated with microtubule binding agents such as Taxol and VCR.3 In Phase I clinical trials, HMN-214 has caused sensory neuropathy and ileus in some patients. However, the grade and frequency of these adverse effects were much lower than those of typical microtubule binding agents. As expected from the mechanism of action of HMN-214 (induction of G2-M arrest in dividing cells), the main adverse effect was neutropenia.