Thymidine enhancement of carboplatin cytotoxicity: in vivo studies in normal B6D2 F1 mice.

Our laboratory has previously demonstrated that 4-24-h thymidine exposures (50-1000 micrograms/ml) will enhance carboplatin cytotoxicity 2-3.3-fold in vitro. In order to show that these results are clinically applicable, we performed 24-h thymidine infusions with and without carboplatin in B6D2 F1 mice. The mice were evaluated for myelosuppression, weight loss and development of diarrhea. Results obtained demonstrated that thymidine did not enhance systemic carboplatin toxicity. The clinical relevance of these results is discussed.