First, iPSCs are prepared by collecting cells from the patient’s blood and skin and introducing reprogramming genes. Since large numbers of cells are required for cell transplantation and drug discovery, once iPSCs are generated, they are expanded (to increase the number of cells). By transforming a large number of iPSCs to target cells such as neurons, cardiomyocytes, blood cells, bone, etc., it is possible to obtain enough cells for cell transplantation treatment and drug discovery. The resulting cells can be roughly divided into two uses. One is regenerative medicine that improves the functions of the body by transplanting cells such as the differentiated cardiomyocytes and neurons into the human body. Since Professor Shinya Yamanaka announced the successful generation of human iPSCs in 2007, various studies have been conducted for clinical applications in Japan and overseas. Examples of diseases for which clinical research has already begun include age-related macular degeneration, Parkinson’s disease, severe ischemic cardiomyopathy, and spinal cord injury. In addition, research is being conducted on application to diabetes, corneal disease, cerebral infarction, and liver and kidney diseases, among many others.

Also, CAR-T cell therapy research is attracting attention as one example of cancer treatment using iPSCs. This is an immunotherapy in which a patient’s blood-derived iPSCs are genetically modified to produce T cells that can recognize and attack specific cancer cells when returned to the patient’s body. The second application is to reproduce disease in a culture dish using iPSCs and use it to study disease mechanisms and develop new drugs. Utilizing iPSCs for drug discovery has two significant benefits. One is that it can be performed using human cells, as opposed to animals. Second, iPSCs can grow indefinitely, so researchers can get as many cells as needed. By successfully combining cells made from patient-derived iPS cells with animal experiments, we can efficiently develop new drugs in a short period of time and evaluate drug efficacy more accurately. In addition, the effects and side effects of individual drugs may differ due to differences in genetic background and environmental factors. With iPSC technology, optimal drug for each individual can be tested on patient-derived iPSC-based assays so personalized medicine is no longer a dream. In particular, iPSCs can greatly reduce the cost of orphan drug research and development.