rhizoxin

Rhizoxin is a macrocyclic lactone antimitotic agent originally isolated from the fungus *Rhizopus microsporus*, though it is produced by the endosymbiotic bacterium *Burkholderia rhizoxinica*. It functions by binding to the maytansine site on beta-tubulin, which inhibits microtubule assembly and leads to cell cycle arrest at the G2/M phase. Developed by Fujisawa Pharmaceutical (now Astellas) in collaboration with the National Cancer Institute (NCI), rhizoxin was evaluated in several Phase II clinical trials for various solid tumors, including breast, colon, and non-small cell lung cancers. Despite its potent in vitro activity, clinical development was discontinued in the late 1990s due to a lack of significant therapeutic efficacy and the occurrence of dose-limiting toxicities such as peripheral neuropathy and myelosuppression.

Other names

Rhizoxin A