- Japan has granted world-first approval for two stem cell–based regenerative therapies, one for Parkinson’s disease and one for severe heart failure.
- The Parkinson’s treatment uses induced pluripotent stem cells (iPSCs) that are converted into dopamine-producing neurons and transplanted into the brain to replace cells lost during the disease.
- The heart failure therapy involves placing sheets of stem cell–derived heart muscle cells onto the heart, which may help restore cardiac function by promoting tissue repair and new blood vessel growth.
- Both therapies received conditional approval, meaning they can be used clinically while researchers continue to collect additional safety and effectiveness data from patients.
Stem cells are a special type of cell that can develop into many different cell types. Stem cell therapy, or regenerative medicine, uses these cells to repair, replace, or regenerate diseased or injured tissue.
Currently, only a few stem cell products have
While these treatments hold immense promise for therapeutic interventions, stem cell-based therapies for all other conditions are still experimental.
However, Japan has approved two stem cell–based therapies for Parkinson’s disease and severe heart failure. The treatments, which rely on laboratory-grown cells to repair damaged tissues, could become the first commercially available therapies using induced pluripotent stem cells (iPSCs).
The first therapy, AMCHEPRY, was developed by the Japanese pharmaceutical company Sumitomo Pharma. The therapy aims to treat Parkinson’s disease by transplanting stem-cell–derived neurons into the brain. These cells may be able to replace dopamine-producing neurons that gradually die in people with the condition.
The second therapy, RiHEART, was developed by the biotech startup Cuorips. This therapy targets severe heart failure and involves placing sheets of stem-cell–derived heart muscle cells onto the heart to help stimulate the formation of new blood vessels and improve cardiac function.
Both treatments were approved by Japan’s health authorities under a conditional approval system designed to accelerate access to regenerative therapies.
While the approval of these products is promising, Hiroshi Kawaguchi, MD, PhD, an orthopaedic surgeon at Nadogaya Hospital in Chiba, Japan, cautions that further research is still necessary:
“The current evidence supporting these approvals remains very limited. The clinical studies involved only seven to eight patients and follow-up periods of one to two years, without randomized control groups.”
“While accelerated approval pathways may allow efficacy to be estimated from early-phase studies, safety risks are a separate and critical issue for pluripotent stem cell–derived therapies. Given the small sample sizes and short observation periods, the available data are insufficient to adequately evaluate long-term safety.”
— Hiroshi Kawaguchi, MD, PhD
Both therapies rely on iPSCs, which are adult cells that have been reprogrammed to behave like embryonic stem cells.
As such, these cells can develop into many different cell types in the body, including neurons and heart muscle cells.
The technology builds on work by Japanese scientist Shinya Yamanaka, who received the 2012 Nobel Prize in Physiology or Medicine for demonstrating that mature cells can be reprogrammed into pluripotent stem cells.
However, given the nature of iPSCs, Kawaguchi told Medical News Today that it is essential to monitor their long-term safety and effectiveness.
“These therapies are derived from induced pluripotent stem cells, which have biological properties that differ from most conventional regenerative medicine products. iPSCs are generated by introducing reprogramming factors into somatic cells, and this process carries potential risks such as genomic instability and tumor formation,” he explained.
“In addition, the current products rely on HLA-homozygous iPSC banks. While this approach may partially reduce immune incompatibility, it does not eliminate immune responses, including those mediated by minor histocompatibility antigens,” he added.
“Long-term monitoring will therefore be essential to detect potential issues such as tumorigenicity, chronic immune reactions, or gradual loss of graft function.”
— Hiroshi Kawaguchi, MD, PhD
The products gained approval under Japan’s Conditional and Time-Limited Approval pathway for regenerative medical products. This regulatory framework aims to accelerate patient access to promising therapies while additional clinical data are collected.
Amchepry gained approval based on the data from a
The trial involved 7 participants ages between 50 and 69 years. During the study, patients received between 5 and 10 million stem-cell–derived precursor cells, which were implanted on both sides of the brain. The cells were derived from donor iPSCs and programmed to develop into dopamine-producing neurons.
Participants were monitored for 2 years, during which researchers reported no major safety concerns. During this period, 4 of the participants experienced improvements in symptoms. Although the study was small, the findings supported the approach’s safety and potential effectiveness, paving the way for regulatory approval.
Similarly, RiHeart gained approval based on results from a trial led by Osaka University researchers, suggesting it may help with severe ischemic cardiomyopathy.
The trial involved 8 participants with advanced heart failure. Each received a single coin-shaped patch transplant and was monitored for heart function, exercise capacity, and safety outcomes.
While improvements in heart function were modest and not statistically significant, patients showed significant improvement in exercise tolerance after 52 weeks. All patients survived the 2- to 5-year follow-up period, and no tumors or serious arrhythmias were detected.
Although this was also a small study, the results support the therapy’s feasibility, helping it gain regulatory approval.
Scientists have long viewed stem cell therapies as a potential way to replace damaged or lost tissues in diseases that currently have no cure.
Parkinson’s disease affects millions of people worldwide and currently has no treatment that halts or reverses disease progression. Similarly, severe heart failure remains a leading cause of death globally.
Researchers suggest the approval of these therapies could represent a turning point for regenerative medicine, moving stem cell treatments from experimental studies into real-world clinical practice.
However, while the accelerated program seeks to boost innovation, health experts caution that it risks endorsing costly, unclear treatments under national health care. Although the data looks encouraging, it is still too early to talk about the commercialization of these products, and larger trials are still necessary.
How drug approval works in Japan
“Japan’s conditional approval system allows therapies to enter clinical practice while confirmatory evidence is still being generated. Importantly, once approved, these treatments may also become reimbursed under the national health insurance system,” Kawaguchi said.
“As a result, both biological uncertainties and financial costs may effectively be transferred to patients and taxpayers during the evidence-generation phase,” he stressed.
“In effect, this system allows early commercialization while the real clinical evidence is still being generated within the national healthcare system. These approvals, therefore, effectively shift part of the evidence-generation process from controlled clinical trials to routine clinical practice.”
— Hiroshi Kawaguchi, MD, PhD
“More broadly, these approvals should be viewed as a major regulatory experiment in the clinical translation of pluripotent stem cell therapies. Ensuring rigorous post-approval evaluation and transparent reporting of outcomes will be essential to maintain public trust in regenerative medicine,” Kawaguchi added.
