Comparative in Vitro Activity of 4′-Deoxy-4′-iododoxorubicin and Other Anthracyclines in the Human Tumor Clonogenic Assay

A new halogenated anthracycline analog 4'-deoxy-4'-iododoxorubicin (IODO) was compared with doxorubicin (DOX) and deoxydoxorubicin (DEOX) in the human tumor clonogenic assay (HTCA) using human tumor cell lines. For all cell lines tested, IODO had lower ID50 value and thus greater in vitro potency and cytotoxicity than DOX. DEOX had lower average ID50 values than either IODO or DOX in all cell lines except HEC1A, where DEOX was equal to IODO. Analysis of variance likewise confirmed significantly greater activity for IODO versus DOX in most cell lines tested. Previous in vivo studies demonstrate oral activity in a variety of tumors as well as less cardiotoxicity. Thus, the results of in vitro and in vivo studies suggest that IODO is an active compound of potential clinical interest.