On August 10, 2006, Shinya Yamanaka and colleagues at Kyoto University published a paper in Cell. Introduce four genes (Oct3/4, Sox2, Klf4, c-Myc) into a mouse skin cell and you get an induced pluripotent stem cell, capable of becoming any cell type. The biological rule that a differentiated cell cannot go back was overturned in a single report.

Human iPS cells followed in 2007, and in 2012 Yamanaka received the Nobel Prize in Physiology or Medicine, six years after the original paper.

In 2026, the twentieth year, the first regenerative medicine products derived from iPS cells anywhere in the world were approved, both of them Japanese.

March 2026: The First Approvals in the World

On March 6, 2026, Japan's Ministry of Health, Labour and Welfare granted conditional, time-limited approval to two iPS-derived regenerative medicine products. No iPS-derived product had been approved anywhere before, and neither had any product derived from pluripotent stem cells generally, including embryonic stem cells.

Parkinson's Disease: Sumitomo Pharma's Amchepry

Sumitomo Pharma filed for approval in August 2025 for iPS-derived dopaminergic progenitor cells, generic name raguneprocel. The treatment targets advanced Parkinson's disease that responds poorly to existing drug therapy. Cells are delivered by stereotactic surgery through small openings in the skull into the putamen on both sides of the brain.

In Parkinson's disease, the neurons that produce dopamine die off, producing tremor and slowed movement. As it advances, medication loses its grip and quality of life falls sharply.

The evidence came from an investigator-initiated trial at Kyoto University. Seven patients in their fifties and sixties received transplants; over 24 months of follow-up there were no serious adverse events, and among the six evaluated for efficacy, four showed improvement in motor symptoms. The results appeared in Nature in April 2025.

Severe Heart Failure: Cuorips' RiHEART

Cuorips, a venture out of Osaka University, filed in April 2025 for a cardiomyocyte sheet. It is indicated for severe heart failure from ischemic cardiomyopathy that standard treatment cannot control, and is applied directly to the surface of the heart through a left thoracotomy.

The sheet measures four to five centimeters across and about 0.1 millimeters thick. It secretes factors that encourage blood vessel regeneration, which in turn is thought to improve cardiac function. Yoshiki Sawa and colleagues at Osaka University began trials in 2020, transplanting sheets into eight patients with severe ischemic heart disease. Safety was confirmed in all of them, and more than half showed gains in exercise capacity or cardiac function. Improvement was greater at 52 weeks than at 26, and some patients returned to work.

Which Fields Are Furthest Along?

1. Ophthalmology (Retina and Cornea)

The first field to reach the clinic. In 2014, Masayo Takahashi of RIKEN, now chief executive of Vision Care, transplanted a sheet of iPS-derived retinal pigment epithelium into a patient with age-related macular degeneration, the world's first clinical surgery using iPS cells.

Work has since spread to retinitis pigmentosa and limbal stem cell deficiency, conditions with no effective treatment. Koji Nishida and colleagues at Osaka University completed the first clinical study anywhere of transplanted iPS-derived corneal epithelial sheets, confirming safety in all four cases, with one patient's corrected vision improving from 0.15 to 0.7. Sumitomo Pharma has also begun a trial in the United States for retinitis pigmentosa.

2. Neurological Disease (Parkinson's and Spinal Cord Injury)

Parkinson's has now reached approval, as described above. For spinal cord injury, Hideyuki Okano and colleagues at Keio University are running a clinical study transplanting iPS-derived neural progenitor cells into patients with complete subacute injuries. The first human transplant took place in December 2021, and a degree of safety has been established.

3. Cardiac Disease (Heart Failure)

Alongside the Cuorips sheet, Heartseed, a Keio University spinoff, is trialing an approach that injects spheroids of iPS-derived cardiomyocytes into the heart muscle.

Competition Is Getting Sharper

iPS cells are a Japanese invention, but the international field keeps tightening.

Cell Stem Cell counted 115 clinical trials worldwide using iPS or ES cells between 2010 and January 2025. The United States accounted for 38%, China for 15% and Japan for 12%.

Use of iPS cells has climbed steeply since 2020. ES cells carry an ethical debate because they come from fertilized eggs; iPS cells sidestep it, and development has accelerated everywhere. Private money has poured into American startups launching one trial after another, and China has invested at the national level, reporting results in iPS-based cardiac regeneration in 2023.

Okano has called this a make-or-break moment for Japanese regenerative medicine. The question is whether the regulatory framework Japan built first can be turned into speed to market.

What Comes After Approval

The Conditional, Time-Limited Approval System

Japan has its own framework for regenerative medicine products: if a small trial shows adequate safety and some efficacy, a provisional approval is granted, and the company gathers real-world data afterward while working toward full approval. Amchepry and RiHEART both went through it.

The clock runs seven years, to March 5, 2033. In that window Sumitomo Pharma must treat roughly 35 patients across about seven institutions, and Cuorips 75, then refile. Sumitomo president Toru Kimura put it plainly: it only becomes a real approval once seven sites produce the same result. The first patient is expected to be treated around the end of 2026.

The Argument Over Price and Reimbursement

[Update, July 2026] Amchepry was added to the national price list on May 20, 2026 and is now covered by public insurance, at 55,306,737 yen for a set of 18 vials. Use is restricted: the approval conditions require a physician trained and experienced in stereotactic surgery, working at an institution equipped to treat Parkinson's disease, so the number of sites will stay small for a while.

Not everyone accepts the price. On April 6, 2026, the Medwatcher Japan citizens' group filed an opinion with the health minister arguing against reimbursement, citing the small size of the trials and the subjectivity of the outcome measures. The underlying question, how much evidence of efficacy should be required, is aimed at the conditional approval system itself.

The Market and What It Will Cost

Manufacturing costs remain high. Cell culture demands advanced technique and equipment, and scaling up production is the pressing problem. The Kyoto University CiRA Foundation is automating clinical-grade iPS cell manufacturing with that in mind.

Japan's regenerative medicine market is projected to reach 1 trillion yen by 2030 and 1.6 trillion by 2040. Yamanaka has long said the work is only real when it helps patients in the clinic. Approval is the starting line; the next seven years of data will answer him.

Japan has led the world in this field. What is the conversation about regenerative and advanced medicine where you live? Expectations, worries, cost, ethics, any angle. We would like to hear it.

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