DR Cysteamine for Cystinosis

Raptor's DR Cysteamine product candidate is a delayed-release oral formulation of cysteamine bitartrate. We are investigating DR Cysteamine as a potential improvement in the management of nephropathic cystinosis (cystinosis), a serious lysosomal storage disease. The disease is primarily diagnosed in early childhood.

Cysteamine therapy may be effective at preventing or delaying kidney transplants in cystinosis patients.1,2,3,4 However, patient compliance is challenging due to frequent dosing and gastrointestinal side effects.2,4,5,6

Raptor's DR Cysteamine for cystinosis was designed to potentially mitigate some of these difficulties. It is expected to be dosed twice daily, compared to the current every-six-hour dosing schedule. In addition, DR Cysteamine is designed to pass through the stomach and deliver the drug directly to the small intestine, where it may be more easily absorbed into the bloodstream and may result in fewer gastrointestinal side effects.7

Development Status for DR Cysteamine for Cystinosis

Scientists at the University of California, San Diego Medical School (UCSD) have been studying the use of various forms of cysteamine for treating cystinosis for over 20 years. Dr. Jerry Schneider, Professor Emeritus and now medical advisor to Raptor, was the principal clinical investigator responsible for the 1994 clearance of immediate release cysteamine.

With support from the Cystinosis Research Foundation, investigators at UCSD conducted research indicating that delivery of cysteamine to the small intestine instead of the stomach has a variety of potential advantages, including less frequent dosing and a reduction in gastrointestinal side effects.7 The UCSD investigators followed up on this research with a study in cystinosis patients with enterically coated cysteamine capsules. Raptor's DR Cysteamine program builds upon the promising results of these initial UCSD studies.

The FDA granted orphan drug designation for DR Cysteamine for the treatment of cystinosis in 2006. Raptor plans to initiate a pivotal clinical trial of DR Cysteamine in collaboration with UCSD in 2009.


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References:

  1. Gahl WA, Balog JZ, Kleta R. Nephropathic cystinosis in adults: natural history and effects of oral cysteamine therapy. Annals of Internal Medicine. 2007;147:242-250.
  2. Levtchenko EN, van Dael CM, de Graaf-Hess AC, Wilmer MJ, van den Heuvel LP, Monnens LA, Blom HJ. Strict cysteamine dose regimen is required to prevent nocturnal cystine accumulation in cystinosis. Pediatr Nephrol. 2006;21:110–113.
  3. Markello TC, Bernardini IM, Gahl WA. Improved renal function in children with cystinosis treated with cysteamine. N Engl J Med. 1993;328:1157-1162.
  4. Kleta R, Bernadini IM, Ueda M, Varade WS, Phornphutkul C, Krasnewich D, Gahl WA. Long-term follow-up of well-treated nephropathic cystinosis patients. J Pediatr. 2004; 145:555-60.
  5. Kleta R, Gahl WA. Pharmacological treatment of nephropathic cystinosis with cysteamine. Expert Opin. Pharmacother. 2004;5(11):2255-2262.
  6. http://www.fda.gov/medwatch/SAFETY/2007/Jun_PI/Cystagon_PI.pdf
  7. Dohil R, Fidler M, Barshop BA, Martin M, Gangoiti J, Deutsch R, Schneider JA. Understanding intestinal cysteamine bitartrate absorption. J Pediatr. 2006;148:764-769.