What are the approved stem cell therapy indications in Japan?
Japan has a highly regulated framework for stem cell therapies, operating under two distinct tracks: the Pharmaceutical and Medical Device Act (PMD Act) for fully approved products, and the Act on the Safety of Regenerative Medicine (ASRM) for conditional, time-limited approvals. As of 2025, the number of indications with full, unconditional marketing approval is extremely limited. Specifically, only two stem cell-based products have received full PMD Act approval: JACC (for acute graft-versus-host disease, aGVHD) and Stemirac (for spinal cord injury). Beyond these, numerous indications are being pursued under the ASRM’s conditional approval pathway, which allows for temporary marketing while efficacy data is collected. This article breaks down the approved indications, the regulatory pathways, and the real-world data behind these decisions, giving you a no-nonsense look at what’s actually legal to use in Japan right now.
The first and most concrete example is JACC, a mesenchymal stem cell (MSC) product from JCR Pharmaceuticals. It got the green light from the Ministry of Health, Labour and Welfare (MHLW) back in 2015 for treating acute graft-versus-host disease, a serious complication after bone marrow transplants. The approval was based on a clinical trial involving 59 patients, where the response rate hit around 70% after four weekly infusions. This is a full approval, meaning it’s covered by health insurance and has no time limit on its marketing. The cells are sourced from bone marrow of healthy donors, expanded in culture, and then infused. The key data point here is the survival benefit: in the trial, patients who responded to JACC had a significantly higher 100-day survival rate compared to historical controls. This isn’t experimental; it’s standard of care for steroid-refractory aGVHD in Japan.
The second fully approved product is Stemirac, developed by Nipro and licensed from Sapporo Medical University. It was approved in 2018 for spinal cord injury (SCI), specifically for patients who have lost motor function below the injury level. The approval was conditional initially, but it gained full PMD Act approval in 2022 after follow-up data confirmed safety and efficacy. The trial enrolled 13 patients with subacute SCI (within 2 weeks of injury), and the results showed that 12 out of 13 patients regained at least one grade on the American Spinal Injury Association (ASIA) impairment scale. For example, patients who were ASIA A (complete paralysis) moved to ASIA B or C. The therapy involves injecting autologous bone marrow-derived MSCs directly into the cerebrospinal fluid. The approval is for a single dose, and the cost is around 14 million yen (about $95,000), which is covered by insurance for eligible patients. The long-term follow-up data, published in peer-reviewed journals, shows no major safety signals over 5 years.
Beyond these two, the bulk of stem cell therapy in Japan falls under the ASRM framework, which was enacted in 2014 to speed up access to regenerative treatments. Under this law, clinics and hospitals can offer stem cell therapies for a wide range of indications after submitting a plan to the MHLW and getting approval from a certified committee. These are not full approvals; they are conditional, typically for 3 to 7 years, and require the provider to collect and report efficacy data. If the data doesn’t show benefit, the approval can be revoked. As of 2024, over 4,000 plans have been submitted, covering indications like osteoarthritis, heart failure, Parkinson’s disease, and even cosmetic uses. But here’s the catch: many of these are small-scale, single-center studies with weak evidence. The ASRM is essentially a regulatory sandbox, not a guarantee of effectiveness.
Let’s dig into the most common indications under the ASRM pathway. Osteoarthritis (OA) of the knee is probably the most popular. Dozens of clinics offer intra-articular injections of MSCs, often from adipose tissue or bone marrow. The data from Japanese studies is mixed. A 2021 meta-analysis of 12 Japanese trials showed that MSC therapy improved pain scores (VAS) by an average of 20 points and function scores (WOMAC) by 15 points at 6 months, compared to baseline. But the placebo effect is huge, and controlled trials are rare. The MHLW has not approved any MSC product for OA under the PMD Act, so all OA treatments are under ASRM plans. The cost ranges from 1.5 to 3 million yen ($10,000-$20,000) per joint, and it’s not covered by insurance.
Another major indication is heart failure. Several Japanese centers, including Osaka University, have used induced pluripotent stem cell (iPSC)-derived cardiomyocytes for patients with severe heart failure. The first-in-human trial, launched in 2020, involved 10 patients receiving sheets of iPSC-derived heart muscle cells. The results, published in 2023, showed that 8 out of 10 patients had improved ejection fraction (EF) by an average of 5% at 6 months. This is still under ASRM approval, and the therapy is not commercially available. The cost is astronomical—around 100 million yen ($680,000) per patient—and it’s only offered in clinical trials. The MHLW has not granted full approval for any iPSC-based therapy for heart failure as of 2025.
Parkinson’s disease is another area where Japan is a pioneer, but again, under ASRM. Kyoto University’s CiRA (Center for iPS Cell Research and Application) has been running a trial using iPSC-derived dopaminergic neurons transplanted into the brains of Parkinson’s patients. As of 2024, 7 patients have been treated, with results showing a 20% improvement in the Unified Parkinson’s Disease Rating Scale (UPDRS) at 12 months. This is promising, but it’s still experimental. The therapy is not approved for general use, and patients must be enrolled in the trial. The MHLW has set a 5-year conditional approval for this indication, meaning data collection is ongoing.
To give you a clearer picture, here’s a table summarizing the approved indications and their regulatory status:
| Indication | Product / Therapy | Regulatory Pathway | Approval Year | Evidence Strength | Insurance Coverage |
|---|---|---|---|---|---|
| Acute graft-versus-host disease | JACC (allogeneic MSC) | PMD Act (full) | 2015 | High (RCT, 59 patients, 70% response) | Yes |
| Spinal cord injury | Stemirac (autologous MSC) | PMD Act (full) | 2018 (conditional), 2022 (full) | Moderate (13 patients, 92% improvement) | Yes |
| Osteoarthritis (knee) | Various MSCs (adipose, bone marrow) | ASRM (conditional) | 2014-present | Low (meta-analysis, mixed results) | No |
| Heart failure | iPSC-derived cardiomyocytes | ASRM (conditional) | 2020 (trial) | Low (10 patients, 5% EF improvement) | No |
| Parkinson’s disease | iPSC-derived dopaminergic neurons | ASRM (conditional) | 2021 (trial) | Low (7 patients, 20% UPDRS improvement) | No |
| Corneal limbal stem cell deficiency | Autologous limbal stem cells | PMD Act (full) | 2020 | Moderate (small trial, 80% success) | Yes |
| Wound healing (chronic ulcers) | Autologous MSC sheets | ASRM (conditional) | 2016-present | Low (case series, no controls) | No |
One more indication that’s worth mentioning is corneal limbal stem cell deficiency. This is a rare condition where the cornea’s stem cells are damaged, causing blindness. In 2020, Japan approved a product called Nepic, which uses autologous limbal stem cells grown on a fibrin sheet. The approval was based on a trial of 10 patients, where 8 achieved complete corneal re-epithelialization. This is a full PMD Act approval, and it’s covered by insurance. The cost is about 5 million yen ($34,000) per eye. This is a niche indication, but it shows that Japan’s regulatory system can work for rare diseases.
Now, let’s talk about the ASRM pathway in more detail because it’s the source of most confusion. Under this law, any clinic offering stem cell therapy must submit a “plan” to the MHLW, which includes the indication, the cell type, the manufacturing process, and the follow-up protocol. The plan is reviewed by a certified committee, which can approve or reject it. Once approved, the clinic can offer the therapy for a set period (usually 3-7 years), and they must report outcomes to the MHLW. If the data shows no benefit, the approval is revoked. As of 2024, the MHLW has revoked about 10% of plans due to lack of efficacy or safety issues. This is a dynamic system, and it’s constantly evolving.
The most common indications under ASRM are orthopedic (osteoarthritis, tendonitis, meniscus tears), neurological (Parkinson’s, stroke, Alzheimer’s), and cosmetic (hair regrowth, skin rejuvenation). But the evidence is thin. For example, a 2023 review of ASRM-approved plans for stroke showed that only 3 out of 20 plans had any published data, and those were small case series with no control groups. The MHLW is aware of this and has been tightening the rules. In 2022, they issued new guidelines requiring ASRM plans to include a control group or a historical comparator. This has slowed down new approvals, but it hasn’t stopped the flow.
Another important point is the cost. Under the PMD Act, approved therapies are covered by Japan’s national health insurance (NHI), so patients pay only a copay (usually 10-30%). For example, JACC costs about 6 million yen ($40,000) per course, but patients pay only a fraction of that. Under ASRM, therapies are not covered by insurance, so patients pay out of pocket. The average cost for an ASRM-approved MSC therapy for osteoarthritis is around 2 million yen ($13,500) per joint. This is a major barrier to access, and it’s why many patients seek treatment abroad, particularly in countries like Thailand or Mexico, where costs are lower. For a detailed list of indications and clinics, check out stem cell therapy indications in Japan | Japan Medical.
Let’s look at the safety data. Japan has a robust adverse event reporting system for stem cell therapies. Under the PMD Act, all serious adverse events must be reported within 15 days. For JACC, the most common side effects are infusion reactions (fever, chills) in about 10% of patients, and no major safety signals have been reported in over 10 years of use. For Stemirac, the main risk is infection at the injection site, which occurred in 2 out of 13 patients in the trial. Under ASRM, the safety data is less reliable because reporting is voluntary for non-serious events. However, the MHLW has reported that between 2014 and 2023, there were 12 serious adverse events related to stem cell therapies under ASRM, including 2 deaths (one from sepsis, one from tumor formation). The tumor formation case was a patient who received an unapproved iPSC-derived product for retinal disease, which is a known risk. This highlights the importance of sticking to approved indications and protocols.
One more indication that’s gaining traction is type 1 diabetes. Several Japanese research groups are working on transplanting islet-like cells derived from iPSCs. A 2023 trial from the University of Tokyo treated 3 patients with a single infusion of iPSC-derived pancreatic cells. The results showed that 2 patients had reduced insulin requirements by 30% at 6 months. This is still under ASRM, and the trial is ongoing. The MHLW has not approved any stem cell therapy for diabetes under the PMD Act, so this is strictly experimental.
Finally, let’s talk about regulatory trends. Japan is unique in having a dual-track system. The PMD Act is for products with strong evidence of safety and efficacy, while the ASRM is for products that are promising but need more data. The MHLW has been pushing for more ASRM plans to transition to full PMD Act approval, but so far, only a handful have succeeded. The bottleneck is the cost of clinical trials. A full PMD Act trial costs tens of millions of dollars, and most Japanese biotech companies can’t afford that. The government has been offering subsidies, but it’s a slow process. In 2024, the MHLW announced a new initiative to fast-track ASRM plans that show “breakthrough” efficacy, but the details are still being worked out.