Description
Cysteamine bitartrate is an amino thiol and a byproduct of the cysteine degradation pathway that is an FDA-approved therapy for the treatment of nephropathic cystinosis to decrease the accumulation of lysosomal cystine (the disulfide-linked form of cysteine) by engaging in disulfide exchange. In addition, cysteamine bitartrate has been postulated to have broader antioxidant properties potentially related to a distinct role in increasing cysteine availability to support the biosynthesis of the potent antioxidant molecule glutathione[1].
References
[1] Sujay Guha. “Pre-clinical evaluation of cysteamine bitartrate as a therapeutic agent for mitochondrial respiratory chain disease.” Human molecular genetics (2019): 1837–1852.
[2] Sabrina Klank. “Enteric-Coated Cysteamine Bitartrate in Cystinosis Patients.” Pharmaceutics 15 7 (2023).
Uses
Cysteamine bitartrate (CAS# 27761-19-9) treatment of cystinosis and other metabolic and neurodegenerative diseases.
Mechanism of action
Cysteamine Bitartrate is an aminothiol salt used in the treatment of nephropathic cystinosis. Cysteamine bitartrate depletes cystine in lysosomes by reacting with cysteine and forming a mixed cysteine–cysteamine disulfide that can exit the lysosomes via lysine transporters. This prevents the accumulation of cystine crystals in the lysosomes of patients with cystinosis, which can cause considerable damage and eventual destruction of the cells, particularly in the kidneys[2].
Clinical Use
Currently, three different formulations of oral cysteamine bitartrate are available: immediate-release (IR-) cysteamine bitartrate (Cystagon, Mylan Pharmaceuticals, Canonsburg, PA and Recordati Pharma GmbH), delayed-release (DR-) enteric-coated cysteamine bitartrate, RP103 (Procysbi®, Horizon Pharma USA and Chiesi Farmaceutici S.p.A., Parma, Italy), and a third formulation in which cysteamine is encapsulated by a pharmacist for enteric release (EC-cysteamine). In Germany, this formulation was generated by the patient advocacy group due to the unbearable side effects of IR-cysteamine (Cystagon®). It was started as an alternative to Cystagon® before Procysbi® appeared on the market. Cysteamine bitartrate is filled into enteric-release capsules and sealed with a fluid. Having been used in clinical practice for many years, a delayed release effect has been described with fewer side effects than Cystagon®[2].
