Ziopharm Oncology has announced the results of a preclinical study that show ZIO-101, an organic arsenic drug, kills myeloma cells. The data suggest ZIO-101 might be active in cancers where arsenic trioxide (ATO) is ineffective or too toxic.
In the study, activity of ZIO-101 was compared to ATO in four human myeloma cell lines. The extent of cell-kill was similar for both compounds; however, the effect on killing of ascorbic acid, a glutathione (GSH)-depleting agent, was different for the two arsenics as was response to adding extra-cellular GSH. These data indicate ZIO-101 and ATO kill myeloma cells, but sometimes operate through different mechanisms.