[How to plan and execute multinational clinical studies properly-management of ethnic differences, private...

The need for multinational clinical studies in the oncology field has grown stronger not only for the purpose of registration but also the creation of scientific evidence for proper use of anti-cancer agents. Now almost all clinical study has been planned and executed under international collaboration, including Japan. Multinational study has several advantages to enhance faster accrual from more sites for patients with common malignancies and even with rare tumors, to provide scientific data for the approvals of participating countries, and to deliver meaningful information to medical sites in a broader range at reasonable cost. On the other hand, because of the close relationship between genetic variance and cancer occurrence, each region, US, EU, and Asia/Japan, has been showing differences in the prevalence of cancer, its management, and consequently the drug responses, both in terms of efficacy and safety. This phenomenon has been more commonly observed in clinical studies of recent molecular targeting agents. From the study management viewpoint, the regulations in each region may differ to some extent, although efforts of harmonization has been initiated. Therefore, at the study planning stage, the ethnic or regional differences and those in regulations should be taken into consideration in the preparation of study protocol, and several measures should be prepared and implemented for the smooth conduction of the study. It is also recommended that Japan be involved in the development activity at an earlier phase, so that appropriate alternatives, including Asian collaborative studies, could be considered when needed.