RARE DISEASE
Mitochondrial myopathy
Mitochondrial myopathy
Mitochondrial myopathy
Drug discovery
4
drugs
With orphan designations
Overview
Mitochondrial myopathies are genetic disorders resulting from impaired mitochondrial oxidative phosphorylation, leading to cellular energy deficits. Primarily affecting skeletal muscle, they manifest with progressive weakness, exercise intolerance, and multiorgan involvement (e.g., CNS, cardiac, endocrine). Diagnosis relies on genetic testing, muscle biopsy (ragged-red fibers, COX-negative fibers), and elevated lactate [1][6][12][19].
Burden
High morbidity: 69% develop CNS involvement; 21% have cardiac disease (median survival post-diagnosis: 10.9 years) [2][4].
Healthcare costs average $24,023/year pre-hospitalization, rising to $33,545/year post-hospitalization [4].
Mortality correlates with multisystem progression (e.g., median age at death: 55 years) [2].
Therapies
Supportive care: Coenzyme Q10, riboflavin, and L-carnitine to enhance energy metabolism [3][17].
Emerging therapies: Nicotinamide riboside (induces mitochondrial biogenesis) [13], gene therapy (e.g., mtDNA heteroplasmy shifting) [8], and hypoxia adaptation [3].
Symptomatic management: Anticonvulsants, cardiac interventions (e.g., ICDs for arrhythmias), and physical therapy [5][12].
Categories: rare genetic diseases, rare neurological diseases
Research Papers
1,202 drug discovery papers related to Mitochondrial myopathy, with 4 first-in-class and 9 next-in-class early-stage therapies forecasted to outperform the average preclinical success rate. Recent publications:
1,202 drug discovery papers related to Mitochondrial myopathy, with 4 first-in-class and 9 next-in-class early-stage therapies forecasted to outperform the average preclinical success rate. Recent publications:
2026-06-19 | Efficacy and safety of pyrimidine nucleos(t)ide therapy in thymidine kinase 2 deficiency.
Thymidine kinase 2 deficiency (TK2d) (MIM 609560) is an ultra-rare, autosomal recessive mitochondrial myopathy caused by TK2 variants, leading to mitochondrial DNA depletion and/or multiple deletions. People with thymidine kinase 2 deficiency experience progressive myopathy, bulbar weakness and respiratory insufficiency, often losing the ability to walk, eat and breathe independently. Doxecitine and doxribtimine represents the first approved treatment for patients with thymidine kinase 2 deficiency with age of symptom onset ≤12 years by the US Food and Drug Administration and the European Medicines Agency; previously, disease management was limited to supportive care. We investigated the efficacy and safety of pyrimidine nucleos(t)ide therapy in thymidine kinase 2 deficiency. Patients treated with pyrimidine nucleos(t)ides were pooled from retrospective (NCT03701568, NCT05017818) and prospective (NCT03845712) studies and company-supported Expanded Access Programs. Untreated patients were pooled from literature reviews and a retrospective chart review study (NCT05017818). Patient subgroups were stratified by age of thymidine kinase 2 deficiency symptom onset (≤12 years and >12 years). The primary outcome was survival in 50th-percentile matched pairs of treated and untreated patients. Other outcomes included status of developmental motor milestones, ventilatory and feeding tube support, and safety. In total, 218 patients were included (treated: 104; untreated: 114). Baseline demographics and characteristics were comparable between subgroups. Most patients had an age of symptom onset ≤12 years [treated: 82/104 (78.8%); untreated: 93/114 (81.6%)]. In the age-of-symptom-onset-≤12-years subgroup, restricted mean survival time (95% confidence interval) was 29.2 (28.2, 30.3) years over the 30 years after symptom onset for treated patients and 14.4 (11.1, 17.6) years for untreated patients. Loss of ≥1 acquired motor milestone was more frequent before treatment start than after. Substantially more patients regained ≥1 lost motor milestone after treatment start than before. Ventilatory and feeding support were used across all age-of-symptom-onset subgroups, but some patients reduced or discontinued support after starting treatment and fewer patients initiated support after treatment start than before. Most treatment-emergent adverse events (TEAEs) did not lead to discontinuation. The most frequent TEAE was diarrhoea [43/50 patients (86.0%)], which was generally mild or moderate and resolved with dose reduction. Serious TEAEs occurred in 28/50 patients (56.0%); few were considered to be drug related [4/50 (8.0%)]. In total, 3/67 patients (4.5%) experienced a fatal serious TEAE, which were not considered to be drug related. These findings indicate that pyrimidine nucleos(t)ide therapy improves survival and functional outcomes in people with thymidine kinase 2 deficiency, especially those with age of symptom onset ≤12 years, and has an acceptable safety profile.
2026-06-18 | Mechanistic interactions between curcumin and statins: pharmacological convergence and therapeutic implications.
Cardiovascular and neurodegenerative disorders remain major contributors to global morbidity and mortality, underpinned by overlapping pathogenic processes including chronic inflammation, oxidative stress, endothelial dysfunction, and mitochondrial impairment. Therapeutic strategies capable of simultaneously modulating these interconnected pathways are increasingly recognized as essential for improving clinical outcomes. Curcumin (CUR), a pleiotropic polyphenolic compound derived from Curcuma longa, and statins, widely prescribed lipid-lowering agents, exhibit a broad spectrum of anti-inflammatory, antioxidant, and cytoprotective effects that extend beyond their canonical pharmacological actions. This review critically examines the molecular and pharmacological synergy between CUR and statins, with particular emphasis on their coordinated regulation of key signaling cascades, including NF-κB, iNOS, MAPK, and Nrf2-mediated antioxidant responses. Evidence from in vitro, in vivo, and emerging clinical studies indicates that CUR-statin co-administration may elicit additive or synergistic protective effects across diverse pathological contexts, such as atherosclerosis, myocardial ischemia-reperfusion injury, Alzheimer's disease, Parkinson's disease, and spinal cord injury, Myopathy, wound healing, and anti-cancer effects. Unfortunately, the majority of available experiments are preclinical and fewer clinical studies have been performed until now. At the cellular and tissue levels, this combinatorial approach appears to restore vascular homeostasis, preserve mitochondrial function, enhance neuronal survival, and suppress sustained inflammatory signaling. Collectively, the available data underscore a compelling pharmacological rationale for CUR-statin combination therapy as a multitarget intervention for complex cardiometabolic, neurodegenerative diseases, and a wide variety of disorders. Future investigations should focus on optimizing dosing regimens, improving CUR bioavailability, elucidating pharmacokinetic-pharmacodynamic interactions, and validating therapeutic efficacy through well-designed clinical trials.
2026-06-12 | Lipid mediated ER-stress contributes to the pathogenesis of mitochondrial myopathies
ABSTRACT Mitochondrial diseases are a heterogeneous group of genetic disorders caused by impaired oxidative phosphorylation (OxPhos). When skeletal muscle is predominantly affected, they are defined as primary mitochondrial myopathies. Although the genetic causes of mitochondrial myopathies and the resulting bioenergetic impairments are well established, the metabolic drivers behind progressive muscle dysfunction remain poorly defined. This gap in knowledge may contribute to the lack of effective treatments for these disorders. OxPhos defective muscle initiates a metabolic response coordinated by systemic signals which invokes the mobilization of fatty acids from white adipose tissue despite muscle inability to fully oxidize fatty acids due to OxPhos impairment. Here, we show that in human patients with mitochondrial disease and mice with OxPhos defective muscle, increased fatty acid mobilization from white adipose tissue leads to ectopic lipid accumulation and lipotoxicity in skeletal muscle. We find an increase in very long chain ceramides which are mechanistically linked to chronic ER stress, phosphorylation of eIF2α, and activation of ATF4 signaling. We propose that Ph-eIF2α-mediated attenuation of global protein synthesis and ATF4-initiated atrophy pathways contribute to muscle wasting and weakness. Importantly, inhibition of de novo synthesis of ceramides with myriocin reduces ER stress and improves muscle proteostasis, body weight, and motor functions in a conditional COX10 KO mouse model of mitochondrial myopathy. Together, these findings highlight altered lipid metabolism as a contributor of mitochondrial myopathy pathogenesis and identify lipid-mediated stress pathways that can be targeted therapeutically.
2026-06-19 | Efficacy and safety of pyrimidine nucleos(t)ide therapy in thymidine kinase 2 deficiency.
Thymidine kinase 2 deficiency (TK2d) (MIM 609560) is an ultra-rare, autosomal recessive mitochondrial myopathy caused by TK2 variants, leading to mitochondrial DNA depletion and/or multiple deletions. People with thymidine kinase 2 deficiency experience progressive myopathy, bulbar weakness and respiratory insufficiency, often losing the ability to walk, eat and breathe independently. Doxecitine and doxribtimine represents the first approved treatment for patients with thymidine kinase 2 deficiency with age of symptom onset ≤12 years by the US Food and Drug Administration and the European Medicines Agency; previously, disease management was limited to supportive care. We investigated the efficacy and safety of pyrimidine nucleos(t)ide therapy in thymidine kinase 2 deficiency. Patients treated with pyrimidine nucleos(t)ides were pooled from retrospective (NCT03701568, NCT05017818) and prospective (NCT03845712) studies and company-supported Expanded Access Programs. Untreated patients were pooled from literature reviews and a retrospective chart review study (NCT05017818). Patient subgroups were stratified by age of thymidine kinase 2 deficiency symptom onset (≤12 years and >12 years). The primary outcome was survival in 50th-percentile matched pairs of treated and untreated patients. Other outcomes included status of developmental motor milestones, ventilatory and feeding tube support, and safety. In total, 218 patients were included (treated: 104; untreated: 114). Baseline demographics and characteristics were comparable between subgroups. Most patients had an age of symptom onset ≤12 years [treated: 82/104 (78.8%); untreated: 93/114 (81.6%)]. In the age-of-symptom-onset-≤12-years subgroup, restricted mean survival time (95% confidence interval) was 29.2 (28.2, 30.3) years over the 30 years after symptom onset for treated patients and 14.4 (11.1, 17.6) years for untreated patients. Loss of ≥1 acquired motor milestone was more frequent before treatment start than after. Substantially more patients regained ≥1 lost motor milestone after treatment start than before. Ventilatory and feeding support were used across all age-of-symptom-onset subgroups, but some patients reduced or discontinued support after starting treatment and fewer patients initiated support after treatment start than before. Most treatment-emergent adverse events (TEAEs) did not lead to discontinuation. The most frequent TEAE was diarrhoea [43/50 patients (86.0%)], which was generally mild or moderate and resolved with dose reduction. Serious TEAEs occurred in 28/50 patients (56.0%); few were considered to be drug related [4/50 (8.0%)]. In total, 3/67 patients (4.5%) experienced a fatal serious TEAE, which were not considered to be drug related. These findings indicate that pyrimidine nucleos(t)ide therapy improves survival and functional outcomes in people with thymidine kinase 2 deficiency, especially those with age of symptom onset ≤12 years, and has an acceptable safety profile.
2026-06-18 | Mechanistic interactions between curcumin and statins: pharmacological convergence and therapeutic implications.
Cardiovascular and neurodegenerative disorders remain major contributors to global morbidity and mortality, underpinned by overlapping pathogenic processes including chronic inflammation, oxidative stress, endothelial dysfunction, and mitochondrial impairment. Therapeutic strategies capable of simultaneously modulating these interconnected pathways are increasingly recognized as essential for improving clinical outcomes. Curcumin (CUR), a pleiotropic polyphenolic compound derived from Curcuma longa, and statins, widely prescribed lipid-lowering agents, exhibit a broad spectrum of anti-inflammatory, antioxidant, and cytoprotective effects that extend beyond their canonical pharmacological actions. This review critically examines the molecular and pharmacological synergy between CUR and statins, with particular emphasis on their coordinated regulation of key signaling cascades, including NF-κB, iNOS, MAPK, and Nrf2-mediated antioxidant responses. Evidence from in vitro, in vivo, and emerging clinical studies indicates that CUR-statin co-administration may elicit additive or synergistic protective effects across diverse pathological contexts, such as atherosclerosis, myocardial ischemia-reperfusion injury, Alzheimer's disease, Parkinson's disease, and spinal cord injury, Myopathy, wound healing, and anti-cancer effects. Unfortunately, the majority of available experiments are preclinical and fewer clinical studies have been performed until now. At the cellular and tissue levels, this combinatorial approach appears to restore vascular homeostasis, preserve mitochondrial function, enhance neuronal survival, and suppress sustained inflammatory signaling. Collectively, the available data underscore a compelling pharmacological rationale for CUR-statin combination therapy as a multitarget intervention for complex cardiometabolic, neurodegenerative diseases, and a wide variety of disorders. Future investigations should focus on optimizing dosing regimens, improving CUR bioavailability, elucidating pharmacokinetic-pharmacodynamic interactions, and validating therapeutic efficacy through well-designed clinical trials.
2026-06-12 | Lipid mediated ER-stress contributes to the pathogenesis of mitochondrial myopathies
ABSTRACT Mitochondrial diseases are a heterogeneous group of genetic disorders caused by impaired oxidative phosphorylation (OxPhos). When skeletal muscle is predominantly affected, they are defined as primary mitochondrial myopathies. Although the genetic causes of mitochondrial myopathies and the resulting bioenergetic impairments are well established, the metabolic drivers behind progressive muscle dysfunction remain poorly defined. This gap in knowledge may contribute to the lack of effective treatments for these disorders. OxPhos defective muscle initiates a metabolic response coordinated by systemic signals which invokes the mobilization of fatty acids from white adipose tissue despite muscle inability to fully oxidize fatty acids due to OxPhos impairment. Here, we show that in human patients with mitochondrial disease and mice with OxPhos defective muscle, increased fatty acid mobilization from white adipose tissue leads to ectopic lipid accumulation and lipotoxicity in skeletal muscle. We find an increase in very long chain ceramides which are mechanistically linked to chronic ER stress, phosphorylation of eIF2α, and activation of ATF4 signaling. We propose that Ph-eIF2α-mediated attenuation of global protein synthesis and ATF4-initiated atrophy pathways contribute to muscle wasting and weakness. Importantly, inhibition of de novo synthesis of ceramides with myriocin reduces ER stress and improves muscle proteostasis, body weight, and motor functions in a conditional COX10 KO mouse model of mitochondrial myopathy. Together, these findings highlight altered lipid metabolism as a contributor of mitochondrial myopathy pathogenesis and identify lipid-mediated stress pathways that can be targeted therapeutically.
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Drug Discovery Landscape
4 orphan drug designations for Mitochondrial myopathy.
4 orphan drug designations for Mitochondrial myopathy.
Drug | Therapy type | Regulator | Orphan designation | Approval | Sponsor |
|---|---|---|---|---|---|
2-(1H-imidazol-1-yl)-N-(2-(2-methoxyethoxy) pyrimidin-5-yl)-6-(trifluoromethyl) pyrimidine-4-carboxamide | small molecules | FDA | 2024-08-26 | — | Immunophage Biotech (Shanghai) Co., Ltd. |
Sodium (4-{(E)-3-(4-fluorophenyl)-3-[4-(3-morpholin-4-yl-prop-1ynyl)phenyl]allyloxy}-2-methylphenoxy)acetate | small molecules | FDA | 2020-06-02 | — | Reneo Pharmaceuticals Inc. |
elamipretide | peptides | FDA | 2017-09-05 | — | Stealth BioTherapeutics |
Levocarnitine | small molecules | FDA | 1997-04-07 | — | Leadiant Biosciences, Inc. |
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