Background

Induced pluripotent stem cell (iPSC) technology, which reprograms a patient's skin cells into a state similar to embryonic stem cells (ESCs), is celebrating its 20th anniversary. In 2006, Professor Shinya Yamanaka's team at Kyoto University, Japan, revolutionized the medical field by successfully reprogramming adult mouse cells into a pluripotent state by introducing four transcription factors. This contrasts with previous research that relied on ESCs, which involved the destruction of embryos and faced ethical barriers. Reprogramming a patient's own cells has emerged as an alternative that addresses ethical concerns. Over the past 20 years, the scientific community has been striving to overcome the dogma of unidirectional cell differentiation and establish a foundation for clinical application.

Early iPSC research remained at the level of basic science, but the successful replication of human cells opened the way for disease treatment. The technique of constructing disease models using patient-derived cells to screen new drug candidates has become widespread. Furthermore, organoids have been created to mimic organ function, leading to success in areas such as the discovery of treatments for amyotrophic lateral sclerosis (ALS).

Key Findings

iPSC technology is moving beyond the laboratory research stage and progressing towards actual clinical applications aimed at treating patients. In 2026, Japanese authorities granted conditional approval for two iPSC-derived cell therapies for Parkinson's disease (PD) and heart failure. This can be interpreted as regulatory authorities accepting early data demonstrating safety. Clinical trials for treatments for age-related macular degeneration and diabetes are currently underway, and major results are expected to be announced within the next five years.

The initial reprogramming process had an efficiency of only 1%, which hindered the acquisition of therapeutic materials. Dr. Deepak Srivastava's research team at the Gladstone Institutes in the United States has achieved a heart cell conversion efficiency of over 90% through extensive development efforts. This was followed by the achievement of synchronized beating of heart cells in culture. In addition, a control technology is being introduced to prevent undifferentiated cells from forming tumors in the patient's body.

Significance and Prospects

Current iPSC research is at a turning point that will determine whether it will be commercialized. There is a significant risk that the entire ecosystem will be frozen if even a single serious safety incident occurs during clinical trials. Rather than rushing to launch treatments, a responsible attitude that prioritizes ensuring safety through thorough verification is paramount. The industry as a whole needs to exercise caution to avoid repeating the failures of the past in the field of gene therapy.

It is also urgent to reduce manufacturing costs in order to provide treatment opportunities to more patients. Personalized therapies have been identified as a barrier to widespread adoption due to their high production costs and long manufacturing times. Accordingly, researchers appear to be accelerating research on allogeneic approaches, which involve mass-producing therapies using cells from healthy donors. Professor Yamanaka emphasizes that translational research is not a sprint but a marathon, and advises that we should move forward with the benefit of patients as our compass.