Guidance on Drug Interaction Studies: From the Aspect of Drug Development

Abstract

The mechanisms of drug interactions are divided into pharmacokinetic interactions and other interactions (pharmacodynamics etc). The Japanese Guidance on Drug Interaction Studies (draft), which was presented in April 2000 mainly refers to pharmacokinetic interactions and extensively covers all stages of drug development, including non-clinical, clinical, and post-marketing studies. On the other hand, drug interaction guidances have already been introduced in other regions in the world, and there are significant differences between Japan and other regions. Therefore, there is a need for worldwide harmonization (such as having it adopted as a topic of the ICH). Taking the above background into account, the Pre-Clinical Evaluation Subcommittee of the Drug Evaluation Committee of the JPMA (Japan Pharmaceutical Manufacturers Association) established a working group in the fourth division (responsible for ADME) to coordinate opinions of the pharmaceutical companies in cooperation with Clinical Evaluation Subcommittee. At the same time, we compared the Japanese draft guidance with the guidances of other regions and have already submitted the results to the regulatory authorities through the Japan Federation of Pharmaceutical Organizations (NICHIYAKUREN). This article discusses the issues that may be encountered in the actual process of interaction evaluation and differences from other regions impacting international harmonization.