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Other names | TCH346, CGP3466B |
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Formula | C19H17NO |
Molar mass | 275.351 g·mol−1 |
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Omigapil (TCH346 or CGP3466) is a drug that was developed by Novartis and tested in clinical trials for its ability to help treat Parkinson's disease (PD) [1] and amyotrophic lateral sclerosis (ALS). [2] The development for PD and ALS have been terminated due to lack of benefit, but Santhera Pharmaceuticals bought the compound for development for the treatment of congenital muscular dystrophy (CMD). [3] [4] [5] [6]
Omigapil was first synthesized at Ciba-Geigy, Basel, Switzerland. Santhera Pharmaceuticals has since taken over production of omigapil and preclinical trials for CMD. In May 2008, omigapil was granted orphan designation to commence clinical trials for. [7] Pharmacokinetic trials are scheduled to commence enrollment in the second half of 2012 to determine the appropriate pharmacokinetic profile of the drug for children with laminin-α2-deficient congenital muscular dystrophy (MDC1A) and collagen VI related myopathy. Santhera Pharmaceuticals will use the phase 1 clinical trial to determine if the drug is safe and acts with the same pharmacokinetic profile in children as it does in adults. The impending clinical trial will take place in the United States at the National Institute of Neurological Disorders and Stroke/National Institute of Health(NNDCS/NINDS) (Bethesda, Maryland) and in the United Kingdom at Great Ormond Street Hospital (UCL). [8]
Omigapil inhibits programmed cell death (apoptosis) through the enzymes glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and SIAH1. The glycolytic housekeeping enzyme GAPDH is mediated by neuronal nitric oxide synthase. [9] Once activated by nitric oxide, GAPDH binds to the ubiquitin ligase SIAH1, and is transported to the nucleus where it activates the acetyltransferases p300/CBP to enhance acetylation and subsequent transcription. GAPDH's targets proapoptotic genes such as p53, p53 upregulated modulator of apoptosis (PUMA), and p21 as well as other related targets. [10] Chemogenetic studies indicate that omigapil inhibits this proapoptotic signaling cascade by preventing GAPDH activation through S-nitrosylation, which in turn prevents the binding of SIAH1 and translocation to the nucleus (see figure). [11] Multiple binding cites on GAPDH have been suggested. [12]
Omigapil was originally developed as a structurally similar molecule to selegiline (L-deprenyl), a monoamine oxidase inhibitor (MAO) blocking the enzyme MAO type B, yet omigapil inhibit neither type of MAO. [13] Selegiline has proven problematic as a treatment for Parkinson's disease because it is metabolized to (meth)amphetamine, which gives rise to adverse effects. Due to omigapil's tricyclic nature, the drug cannot be metabolized to amphetamine derivatives. [14] Omigapil acts as a neuroprotective agent in cellular and rodent models of Parkinson's disease like selegiline, but its neuroprotective action is 100 times more potent than selegiline in both in vivo and in vitro studies. [15]
Omigapil can pass through the blood brain barrier and has oral bioavailability as omigapil mono-maleate salt. [16] Studies have demonstrated a bell-shaped dose-response curve for both rodent and primate models. The rhesus monkey dose was optimized between 0.014 and 0.14 mg/kg subcutaneous. [17] In human trials for Parkinson's disease, doses of 0.5, 2.5 and 10 mg daily were considered, which resulted in the selection of a dose range of 0.3 to 3 mg daily for a 70 kg individual. [14] Unfortunately a biomarker has not been established for omigapil, which means that clinical trials rely on blood plasma levels to measure drug distribution rather than a validated biomarker to specifically measure brain exposure. [5] [14]
The compound displayed cell-rescuing effects in various models of apoptotic neuronal death, as well as in rodent and non-rodent animal models of neurodegeneration. Omigapil rescues in vitro PC12 cells from rotenone toxicity, β-amyloid toxicity, nutrition withdrawal, and lactacystin. [14] Additionally, omigapil can prevent NMDA and kainate receptor excitotoxicity in rat cortical neurons as well as toxicity from cytosine arabinoside (ara C) in cerebellar granule cells. Omigapil also rescues rat oligodendrocytes from AMPA receptor excitotoxicity and rat embryonic mesencephalic (midbrain) dopaminergic cells from toxicity by MPP+/MPTP. [18] In human neuroblastoma (PAJU) cells, omigapil can also prevent toxicity from rotenone and GAPDH overexpression. Omigapil has an active concentration range from about 10−12 M to 10−5 M, with a maximum at about 10−9 M. Omigapil prevents neurodegeneration in facial motor neuron axotomy animal models as well as mouse models of progressive motor neuronopathy, MPTP-induced nigrostriatal degeneration, and oxidopamine-induced neuronal injury. [15] Omigapil also prevents the death of nigrostriatal dopaminergic neurons in monkeys treated with MPTP to mimic Parkinson's disease symptoms. [17] While omigapil was able to prevent programmed cell death for high-risk cells and prevent deterioration of concomitant motor deficits associated with Parkinson's symptoms, omigapil was unable to reverse pre-existing Parkinson's symptoms in MPTP monkeys. [17]
Based on the preclinical results mentioned above, clinical trials were run for both Parkinson's disease and amyotrophic lateral sclerosis, but omigapil proved to be inefficacious for both diseases. [5] It is unclear whether the discrepancy in results between laboratory studies and clinical studies is from improper pathogenesis modeling of the disease in animal models, insufficient doses of the study drug, insensitive clinical endpoints, or abnormal sampling in the patient population. However, the drug was determined to be safe for human use with no notable serious side effects. [5]
Omigapil can ameliorate congenital muscular dystrophy (CMD) symptoms. [19] This rare yet fatal infant disease has symptoms ranging from severe neonatal hypotonia ("floppy infant syndrome") to peripheral neuropathy, inability to stand or walk, respiratory distress, and eventually premature death in early life. The majority of CMD cases result from a genetic mutation in laminin-α2, a subunit of the laminin-211 protein, which serves as an essential mechanical link between basement membrane and muscle fiber in skeletal and heart muscle. [20] The result is muscle degeneration and demyelination of peripheral nerves. [21]
The mouse model of laminin-α2-deficient congenital muscular dystrophy (MDC1A) was found to positively respond to omigapil with inhibition of apoptosis in muscle, reduction of body weight loss and skeletal deformation, increased locomotive activity, and protection from early mortality. [22] Furthermore, omigapil was found to be even more effective in improving muscle function and strength when coupled with overexpression of the extracellular matrix molecule mini-agrin in MDC1A mice. [23] Omigapil coupled with mini-agrin overexpression works as a dual treatment that enhances mechanical load bearing ability and improves regeneration of muscle in MDC1A mice. Given that the technology for mini-agrin administration to skeletal muscle in human subjects is not yet available, omigapil is ready for human clinical trials to help mediate CMD. Omigapil has undergone extensive clinical trial scrutiny for Parkinson's disease and ALS, which indicates that the drug is safe to begin clinical trials for congenital muscular dystrophy. [5] [24]
It has been investigated in vitro in the context of ketamine-like rapid acting antidepressants. [25]
MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) is an organic compound. It is classified as a tetrahydropyridine. It is of interest as a precursor to the neurotoxin MPP+, which causes permanent symptoms of Parkinson's disease by destroying dopaminergic neurons in the substantia nigra of the brain. It has been used to study disease models in various animals.
Becker muscular dystrophy (BMD) is an X-linked recessive inherited disorder characterized by slowly progressing muscle weakness of the legs and pelvis. It is a type of dystrophinopathy. This is caused by mutations in the dystrophin gene, which encodes the protein dystrophin. Becker muscular dystrophy is related to Duchenne muscular dystrophy in that both result from a mutation in the dystrophin gene, but has a milder course.
Selegiline, also known as L-deprenyl and sold under the brand names Eldepryl, Emsam, Selgin, among other names, is a medication which is used in the treatment of Parkinson's disease and major depressive disorder. It is provided in the form of a capsule or tablet taken by mouth or orally disintegrating tablets taken on the tongue for Parkinson's disease and as a patch applied to skin for depression.
Idebenone is a drug that was initially developed by Takeda Pharmaceutical Company for the treatment of Alzheimer's disease and other cognitive defects. This has been met with limited success. The Swiss company Santhera Pharmaceuticals has started to investigate it for the treatment of neuromuscular diseases. In 2010, early clinical trials for the treatment of Friedreich's ataxia and Duchenne muscular dystrophy have been completed. As of December 2013 the drug is not approved for these indications in North America or Europe. It is approved by the European Medicines Agency (EMA) for use in Leber's hereditary optic neuropathy (LHON) and was designated an orphan drug in 2007.
Neuroprotection refers to the relative preservation of neuronal structure and/or function. In the case of an ongoing insult the relative preservation of neuronal integrity implies a reduction in the rate of neuronal loss over time, which can be expressed as a differential equation. It is a widely explored treatment option for many central nervous system (CNS) disorders including neurodegenerative diseases, stroke, traumatic brain injury, spinal cord injury, and acute management of neurotoxin consumption. Neuroprotection aims to prevent or slow disease progression and secondary injuries by halting or at least slowing the loss of neurons. Despite differences in symptoms or injuries associated with CNS disorders, many of the mechanisms behind neurodegeneration are the same. Common mechanisms of neuronal injury include decreased delivery of oxygen and glucose to the brain, energy failure, increased levels in oxidative stress, mitochondrial dysfunction, excitotoxicity, inflammatory changes, iron accumulation, and protein aggregation. Of these mechanisms, neuroprotective treatments often target oxidative stress and excitotoxicity—both of which are highly associated with CNS disorders. Not only can oxidative stress and excitotoxicity trigger neuron cell death but when combined they have synergistic effects that cause even more degradation than on their own. Thus limiting excitotoxicity and oxidative stress is a very important aspect of neuroprotection. Common neuroprotective treatments are glutamate antagonists and antioxidants, which aim to limit excitotoxicity and oxidative stress respectively.
Levomethamphetamine is the levorotatory (L-enantiomer) form of methamphetamine. Levomethamphetamine is a sympathomimetic vasoconstrictor that is the active ingredient in some over-the-counter (OTC) nasal decongestant inhalers in the United States.
Glyceraldehyde 3-phosphate dehydrogenase is an enzyme of about 37kDa that catalyzes the sixth step of glycolysis and thus serves to break down glucose for energy and carbon molecules. In addition to this long established metabolic function, GAPDH has recently been implicated in several non-metabolic processes, including transcription activation, initiation of apoptosis, ER-to-Golgi vesicle shuttling, and fast axonal, or axoplasmic transport. In sperm, a testis-specific isoenzyme GAPDHS is expressed.
Congenital muscular dystrophies are autosomal recessively-inherited muscle diseases. They are a group of heterogeneous disorders characterized by muscle weakness which is present at birth and the different changes on muscle biopsy that ranges from myopathic to overtly dystrophic due to the age at which the biopsy takes place.
Rasagiline is an irreversible inhibitor of monoamine oxidase-B used as a monotherapy to treat symptoms in early Parkinson's disease or as an adjunct therapy in more advanced cases.
In the management of Parkinson's disease, due to the chronic nature of Parkinson's disease (PD), a broad-based program is needed that includes patient and family education, support-group services, general wellness maintenance, exercise, and nutrition. At present, no cure for the disease is known, but medications or surgery can provide relief from the symptoms.
Benzofuranylpropylaminopentane is a drug with an unusual monoamine-release potentiating mechanism of action. It can loosely be grouped with the stimulant or antidepressant drug families, but its mechanism of action is quite different.
Laminin subunit alpha-2 is a protein that in humans is encoded by the LAMA2 gene.
Alpha-7 integrin is a protein that in humans is encoded by the ITGA7 gene. Alpha-7 integrin is critical for modulating cell-matrix interactions. Alpha-7 integrin is highly expressed in cardiac muscle, skeletal muscle and smooth muscle cells, and localizes to Z-disc and costamere structures. Mutations in ITGA7 have been associated with congenital myopathies and noncompaction cardiomyopathy, and altered expression levels of alpha-7 integrin have been identified in various forms of muscular dystrophy.
Pikachurin, also known as AGRINL (AGRINL) and EGF-like, fibronectin type-III and laminin G-like domain-containing protein (EGFLAM), is a protein that in humans is encoded by the EGFLAM gene.
Ullrich congenital muscular dystrophy (UCMD) is a form of congenital muscular dystrophy. There are two forms: UCMD1 and UCMD2.
Collagen VI (ColVI) is a type of collagen primarily associated with the extracellular matrix of skeletal muscle. ColVI maintains regularity in muscle function and stabilizes the cell membrane. It is synthesized by a complex, multistep pathway that leads to the formation of a unique network of linked microfilaments located in the extracellular matrix (ECM). ColVI plays a vital role in numerous cell types, including chondrocytes, neurons, myocytes, fibroblasts, and cardiomyocytes. ColVI molecules are made up of three alpha chains: α1(VI), α2(VI), and α3(VI). It is encoded by 6 genes: COL6A1, COL6A2, COL6A3, COL6A4, COL6A5, and COL6A6. The chain lengths of α1(VI) and α2(VI) are about 1,000 amino acids. The chain length of α3(VI) is roughly a third larger than those of α1(VI) and α2(VI), and it consists of several spliced variants within the range of 2,500 to 3,100 amino acids.
Losmapimod (GW856553X) is an investigational drug being developed by Fulcrum Therapeutics for the treatment of facioscapulohumeral muscular dystrophy (FSHD); a phase III clinical trial is pending approval. Losmapimod selectively inhibits enzymes p38α/β mitogen-activated protein kinases (MAPKs), which are modulators of DUX4 expression and mediators of inflammation.
Ifetroban is a potent and selective thromboxane receptor antagonist. It has been studied in animal models for the treatment of cancer metastasis, myocardial ischemia, hypertension, stroke, thrombosis, cardiomyopathy, and for its effects on platelets. Clinical trials are evaluating the therapeutic safety and efficacy of oral ifetroban capsules for the treatment of cancer metastasis, cardiovascular disease, aspirin exacerbated respiratory disease, systemic sclerosis, and Duchenne muscular dystrophy.
Markus Rüegg is a Swiss neurobiologist and professor at the Biozentrum of the University of Basel.
Phenserine is a synthetic drug which has been investigated as a medication to treat Alzheimer's disease (AD), as the drug exhibits neuroprotective and neurotrophic effects.