The CHO/HPRT assay: evaluation of 19 drug candidates.

The CHO/HPRT assay is used as part of basic mutagenicity screening batteries at the Upjohn Company. The results of this and other assays provides a way of identifying compounds likely to cause mutations in mammalian systems and for which additional testing may be required. This report provides results of testing 19 drugs and drug candidates for mutational properties in the CHO/HPRT assay. The results of these studies were uniformly negative. The diversity of structures and the fact that these compounds have potent (non-mutational) biological activity suggests that separation of mutagenic properties from other beneficial properties is feasible. These compounds have also been evaluated in several other assays (Aaron et al., 1989a-d) and were negative for genotoxicity. Thus, the results of this study and other available data fails to suggest any genotoxic hazard from these materials.