Bioequivalence Studies of A Generic Formulation (SW651K) to the Brand Drug S-1 in Tumor-Bearing Rat Models

The generic anticancer drugs are developed in the field of anticancer therapy and are commercially available. Generally, the safety and efficacy of a brand anticancer drug are determined by phase 1, 2 and 3 clinical trials. In contrast, clinical trials are not necessarily required by guidelines for the development of generic drugs and are usually not performed. Pharmacokinetic equivalence is considered particularly important for cytotoxic anticancer drugs because of the narrow therapeutic window. Differences in the content and purity of active and inactive pharmaceutical ingredients might have an important impact on pharmacokinetics of the generic cytotoxic anticancer drug and cause the difference in the pharmacodynamics. However the bioequivalent studies of PK/PD using the tumor-bearing rat models had been hardly reported before.