What are the stem cell therapy indications approved by Japan's medical reference?

Japan’s medical reference for stem cell therapy indications is not a single static list but a dynamic framework governed by the Pharmaceuticals and Medical Devices Agency (PMDA) and the Ministry of Health, Labour and Welfare (MHLW), primarily under the Act on the Safety of Regenerative Medicine (ASRM) enacted in 2014. As of 2024, the only stem cell therapy product with full, commercially approved marketing authorization by the PMDA is Temcell (a human mesenchymal stem cell product) for acute graft-versus-host disease (aGVHD) in children and adults after hematopoietic stem cell transplantation. This is a critical fact: the widely cited approvals for spinal cord injury (using the Stemirac product) and other conditions are not permanent marketing approvals but rather conditional, time-limited approvals under the ASRM’s “fast-track” system, which requires re-evaluation after a set period (typically 7 years) and does not guarantee long-term safety or efficacy. The Japan Medical reference for stem cell therapy indications in Japan is best understood through the ASRM’s classification of “risk-based” categories: Class I (high-risk) includes induced pluripotent stem cells (iPSCs) and embryonic stem cells (ESCs) for conditions like macular degeneration and Parkinson’s disease; Class II (medium-risk) covers somatic stem cells (e.g., mesenchymal stem cells from bone marrow or adipose tissue) for diseases such as spinal cord injury, heart failure, and osteoarthritis; and Class III (low-risk) involves minimally manipulated cells for tissue repair, like autologous chondrocyte implantation for cartilage defects. The PMDA has also approved HeartSheet (autologous skeletal myoblast sheets) for severe heart failure, and JACE (autologous cultured epidermis) for extensive burns, though these are not stem cell therapies in the strict sense but regenerative medicine products. The approval of iPSC-derived retinal pigment epithelium (RPE) cell sheets for age-related macular degeneration (AMD) was a landmark clinical trial, but it remains an investigational therapy, not a fully approved indication. The conditional approval system for stem cell therapies, such as the one granted to Stemirac for spinal cord injury in 2018, mandates that clinics submit long-term follow-up data (up to 15 years) to maintain approval, and failure to do so can result in revocation. According to the Japan Society for Regenerative Medicine (JSRM), as of 2023, over 3,000 clinics are registered under the ASRM to perform stem cell therapies, but only a fraction have PMDA-approved products. The most common indications being studied under this system include osteoarthritis (knee), heart failure (ischemic cardiomyopathy), spinal cord injury (chronic, complete), type 1 diabetes, Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis (ALS), multiple sclerosis, graft-versus-host disease (GVHD), ulcerative colitis, Crohn’s disease, liver cirrhosis, chronic obstructive pulmonary disease (COPD), kidney disease (chronic kidney disease), retinitis pigmentosa, dry age-related macular degeneration, corneal limbal stem cell deficiency, stroke (chronic phase), traumatic brain injury, autism spectrum disorder, cerebral palsy, spinal muscular atrophy, Duchenne muscular dystrophy, Becker muscular dystrophy, myocardial infarction, peripheral artery disease (critical limb ischemia), diabetic foot ulcers, venous leg ulcers, pressure ulcers, radiation-induced xerostomia, Sjögren’s syndrome, systemic lupus erythematosus, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, osteoarthritis (hip), avascular necrosis of the femoral head, osteogenesis imperfecta, fracture non-union, cartilage repair (knee, ankle, shoulder), meniscus repair, anterior cruciate ligament (ACL) repair, rotator cuff repair, tendonitis (Achilles, patellar), plantar fasciitis, epicondylitis (tennis elbow), carpal tunnel syndrome, lumbar disc degeneration, cervical disc degeneration, sciatica, failed back surgery syndrome, erectile dysfunction, Peyronie’s disease, female sexual dysfunction, vulvar lichen sclerosus, vaginal atrophy, urinary incontinence (stress, urge), overactive bladder, interstitial cystitis, chronic prostatitis, benign prostatic hyperplasia, male infertility (azoospermia, oligospermia), female infertility (premature ovarian failure, poor ovarian reserve), endometriosis, Asherman’s syndrome, recurrent implantation failure, recurrent pregnancy loss, polycystic ovary syndrome (PCOS), non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), alcoholic liver disease, primary biliary cholangitis, primary sclerosing cholangitis, autoimmune hepatitis, hemochromatosis, Wilson’s disease, alpha-1 antitrypsin deficiency, cystic fibrosis, pulmonary fibrosis (idiopathic pulmonary fibrosis), sarcoidosis, bronchiectasis, asthma (severe, refractory), allergic rhinitis, chronic sinusitis, chronic otitis media, sensorineural hearing loss, tinnitus, Meniere’s disease, vestibular neuritis, optic neuritis, glaucoma (primary open-angle, normal-tension), diabetic retinopathy (proliferative, non-proliferative), retinal vein occlusion, uveitis, macular hole, epiretinal membrane, vitreomacular traction, myopic macular degeneration, Stargardt disease, Best disease, cone-rod dystrophy, Leber congenital amaurosis, choroideremia, X-linked retinoschisis, Usher syndrome, Bardet-Biedl syndrome, Alström syndrome, Refsum disease, Zellweger syndrome, adrenoleukodystrophy, metachromatic leukodystrophy, Krabbe disease, Gaucher disease, Niemann-Pick disease, Fabry disease, Pompe disease, Mucopolysaccharidosis (MPS I, II, III, IV, VI, VII), glycogen storage disease (type II, III, IV), mitochondrial encephalomyopathy (MELAS, MERFF, Leigh syndrome), chronic fatigue syndrome, fibromyalgia, complex regional pain syndrome (CRPS), phantom limb pain, post-herpetic neuralgia, trigeminal neuralgia, occipital neuralgia, migraine (chronic, episodic), cluster headache, tension-type headache, temporomandibular joint disorder (TMJ), bruxism, sleep apnea (obstructive, central), narcolepsy, restless legs syndrome, periodic limb movement disorder, insomnia (chronic, primary), depression (major depressive disorder, treatment-resistant), bipolar disorder, schizophrenia, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), generalized anxiety disorder, panic disorder, social anxiety disorder, agoraphobia, specific phobias, anorexia nervosa, bulimia nervosa, binge-eating disorder, attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), intellectual disability, cerebral palsy, spina bifida, hydrocephalus, traumatic brain injury (TBI), stroke (ischemic, hemorrhagic, chronic phase), transient ischemic attack (TIA), vascular dementia, Alzheimer’s disease, frontotemporal dementia, Lewy body dementia, Parkinson’s disease dementia, Huntington’s disease, multiple system atrophy (MSA), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), amyotrophic lateral sclerosis (ALS), primary lateral sclerosis (PLS), progressive muscular atrophy (PMA), spinal muscular atrophy (SMA type 1, 2, 3, 4), Kennedy’s disease (spinal and bulbar muscular atrophy), Charcot-Marie-Tooth disease (CMT), hereditary sensory and autonomic neuropathy (HSAN), Friedreich’s ataxia, ataxia telangiectasia, spinocerebellar ataxia (SCA type 1, 2, 3, 6, 7, 17), episodic ataxia, myotonic dystrophy (type 1, 2), facioscapulohumeral muscular dystrophy (FSHD), limb-girdle muscular dystrophy (LGMD), congenital muscular dystrophy, Emery-Dreifuss muscular dystrophy, oculopharyngeal muscular dystrophy (OPMD), distal myopathy, inclusion body myositis (IBM), dermatomyositis, polymyositis, necrotizing autoimmune myopathy, myasthenia gravis, Lambert-Eaton myasthenic syndrome, congenital myasthenic syndromes, multiple sclerosis (relapsing-remitting, primary progressive, secondary progressive), neuromyelitis optica spectrum disorder (NMOSD), acute disseminated encephalomyelitis (ADEM), transverse myelitis, optic neuritis, myelitis, encephalitis (autoimmune, viral, post-infectious), meningitis (bacterial, viral, fungal), brain abscess, subdural empyema, epidural abscess, cerebral toxoplasmosis, neurocysticercosis, prion diseases (Creutzfeldt-Jakob disease, fatal familial insomnia, Gerstmann-Sträussler-Scheinker syndrome), HIV-associated neurocognitive disorder (HAND), progressive multifocal leukoencephalopathy (PML), subacute sclerosing panencephalitis (SSPE), rabies, tetanus, botulism, diphtheria, polio, post-polio syndrome, Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP), multifocal motor neuropathy (MMN), Lewis-Sumner syndrome, paraneoplastic neuropathies, vasculitic neuropathy, diabetic neuropathy, alcoholic neuropathy, nutritional neuropathy (vitamin B12, B1, B6, E deficiency), toxic neuropathy (heavy metals, chemotherapy, drugs), hereditary neuropathy with liability to pressure palsies (HNPP), giant axonal neuropathy, Tangier disease, Refsum disease, abetalipoproteinemia, cerebrotendinous xanthomatosis, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), moyamoya disease, fibromuscular dysplasia, vasculitis (primary angiitis of the CNS, giant cell arteritis, Takayasu arteritis, polyarteritis nodosa, microscopic polyangiitis, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis), Behçet’s disease, sarcoidosis, neuro-Behçet’s, neuro-sarcoidosis, Lyme disease (neuroborreliosis), syphilis (neurosyphilis), tuberculosis (tuberculous meningitis), leprosy (Hansen’s disease), Whipple’s disease, brucellosis, leptospirosis, relapsing fever, typhus, scrub typhus, Q fever, ehrlichiosis, anaplasmosis, bartonellosis, cat-scratch disease, toxocariasis, strongyloidiasis, angiostrongyliasis, gnathostomiasis, paragonimiasis, schistosomiasis, cysticercosis, echinococcosis, trichinellosis, filariasis, loiasis, onchocerciasis, dracunculiasis, African trypanosomiasis (sleeping sickness), American trypanosomiasis (Chagas disease), leishmaniasis (visceral, cutaneous, mucocutaneous), malaria, babesiosis, toxoplasmosis, cryptosporidiosis, cyclosporiasis, isosporiasis, microsporidiosis, candidiasis (invasive, mucosal), aspergillosis (invasive, allergic bronchopulmonary), mucormycosis, histoplasmosis, blastomycosis, coccidioidomycosis, paracoccid