We conducted an investigator-initiated multicenter clinical trial targeting patients suffering from Familial Mediterranean Fever (FMF). Due to the rarity of the disease, the absolute number of candidates in Japan was considerably small (500 at most). We proceeded with subject recruitment and implemented methods to achieve the target study sample. Our operations team promoted patient recruitment by employing multiple strategies throughout the patient recruitment period. We achieved 95％ of the target study sample of 23 patients. Fifty patients gave informed consent to participate in the trial. We found that the flexibility according to the situation is an important and necessary element for successful recruitment.

Timely reporting and appropriate response to safety information related to ongoing clinical trials is crucial for conducting trials appropriately and safely. However, it is difficult to understand exactly what, when, and to whom information should be reported because there are different types of clinical trials in Japan, governed by different laws and regulations. For example, principal investigators need to report serious, unrelated adverse events in “Chiken” clinical trials, but not in clinical trials specified under the Clinical Trials Act 2017. This paper clarifies the principal investigator's responsibility for reporting under the three laws related to clinical trials: the Pharmaceuticals and Medical Devices Act, the Clinical Trials Act, and the Act on the Safety of Regenerative Medicine. Report items were explained and summarized in a table. The paper also separately covers trials under other frameworks, such as the Ethical Guidelines for Medical and Health Research Involving Human Subjects. The paper will therefore help principal investigators to better understand their responsibilities and manage safety information in clinical trials under various frameworks in Japan. The paper also discusses some current issues that still need resolving.