Ataluren

Absorption

Peak plasma levels of ataluren are attained approximately 1.5 hours after dosing in subjects who received medicinal product within 30 minutes of a meal .

Description

Ataluren is a drug marketed under the trade name Translarna® which was developed by PTC Therapeutics and approved by the European Union in May 2014 for the treatment of Duchenne’s muscular dystrophy (DMD) and potentially other genetic disorders. Ataluren renders ribosomes less sensitive to premature stop or ‘read-through’ codons, which are thought to be beneficial in diseases such as DMD and cystic fibrosis.

Description

Nonsense mutations create a premature termination of mRNA translation and have been implicated in various genetic disorders, including muscular dystrophy and cystic fibrosis. PTC-124 is a nonaminoglycoside that has been reported to selectively induce ribosomes to read through premature nonsense stop signals on mRNA, thus allowing the production of full length, functional proteins. In a mouse model of cystic fibrosis caused by nonsense mutations, PTC-124 treatment (60 mg/kg s.c. injection or 0.3-0.9 mg/ml orally) has been shown to restore cystic fibrosis transmembrane conductance regulator (CFTR) protein expression and function. The target activity of PTC-124 was initially evaluated by firefly luciferase reporter cell-based nonsense codon assay (IC₅₀ = 7 nM); however, subsequent assessments using a Renilla reniformis luciferase reporter have failed to produce nonsense codon suppression activity. Thus, while PTC-124 is in clinical testing in patients with nonsense mutations within the CFTR or dystrophin genes, controversy surrounds its exact mechanism of action.

The Uses of Ataluren

Nonsense mutations create a premature termination of mRNA translation and have been implicated in various genetic disorders, including muscular dystrophy and cystic fibrosis. PTC-124 is a nonaminoglycoside that has been reported to selectively induce ribosomes to read through premature nonsense stop signals on mRNA, thus allowing the production of full-length, functional proteins. In a mouse model of cystic fibrosis caused by nonsense mutations, PTC-124 treatment (60 mg/kg s.c. injection or 0.3-0.9 mg/ml orally) has been shown to restore cystic fibrosis transmembrane conductance regulator (CFTR) protein expression and function. The target activity of PTC-124 was initially evaluated by firefly luciferase reporter cell-based nonsense codon assay (IC50 = 7 nM); however, subsequent assessments using a Renilla reniformis luciferase reporter have failed to produce nonsense codon suppression activity. Thus, while PTC-124 is in clinical testing in patients with nonsense mutations within the CFTR or dystrophin genes, controversy surrounds its exact mechanism of action.[Cayman Chemical]

The Uses of Ataluren

PTC-124 is a nonaminoglycoside that has been reported to induce ribosomes to read through premature nonsense stop signals on mRNA, allowing the production of full-length functional proteins,

Background

Ataluren is a novel, orally administered drug that targets nonsense mutations. Ataluren is approved for use by the European Medicines Agency to treat Duchenne Muscular Dystrophy in patients aged 5 years and older who are able to walk. More specifically, ataluren is used in the small group of patients whose disease is caused by a specific genetic defect (called a ‘nonsense mutation’) in the dystrophin gene.
This drug does not yet have approval by the US Food and Drug Administration or by Health Canada for any indications.

What are the applications of Application

PTC124 is a firefly luciferase inhibitor and an inducer of ribosomal read-through of mRNAs

Indications

Ataluren is approved for use by the European Medicines Agency to treat Duchenne Muscular Dystrophy in patients aged 5 years and older who are able to walk. More specifically, ataluren is used in the small group of patients whose disease is caused by a specific genetic defect (called a ‘nonsense mutation’) in the dystrophin gene.

Definition

ChEBI: 3-[5-(2-fluorophenyl)-1,2,4-oxadiazol-3-yl]benzoic acid is a ring assembly and an oxadiazole.

Synthesis

The sequence to construct ataluren, which was described by the authors at PTC Therapeutics, commenced with commercially available methyl 3-cyanobenzoate (38). This ester was exposed to hydroxylamine in aqueous tert-butanol and warmed gently until the reaction was deemed complete. Then this mixture was treated with 2-fluorobenzoyl chloride dropwise and subsequently triethylamine dropwise. To minimize exotherm and undesired side products, careful control of the addition of reagents was achieved through slow dropwise addition of these liquid reagents. Upon complete consumption of starting materials and formation of amidooxime 39, the aqueous reaction mixture was then heated to 85 ?? to facilitate 1,2,4-oxadiazole formation, resulting in the tricyclic ester 40 in excellent yield across the three steps. Finally, saponification of ester 40 through the use of sodium hydroxide followed by acidic quench gave ataluren (V) in 96% over the two-step sequence.

Metabolism

Ataluren is metabolized by conjugation via uridine diphosphate glucuronosyltransferase (UGT) enzymes, predominantly UGT1A9 in liver and intestine. In vivo, the only metabolite detected in plasma after oral administration of radio-labelled ataluren was the ataluren-O-1β-acyl glucuronide; exposure to this metabolite in humans was approximately 8% of the plasma AUC of ataluren .