Raptor initiates enrollment in pivotal Phase 3 clinical trial of DR Cysteamine for nephropathic cystinosis

Raptor Pharmaceutical Corp. ("Raptor" or the "Company") (Nasdaq:RPTP) announced that it has enrolled the first patient in a pivotal Phase 3 clinical trial of its proprietary delayed-release oral formulation of cysteamine bitartrate ("DR Cysteamine") in patients with nephropathic cystinosis ("cystinosis").

In November 2009, Raptor completed its Phase 2b clinical trial of DR Cysteamine in cystinosis. DR Cysteamine demonstrated improved tolerability and the potential to reduce total daily dosage and administration frequency compared to immediate-release cysteamine bitartrate. Immediate-release cysteamine bitartrate is the only drug therapy approved for marketing by the U.S. Food and Drug Administration ("FDA") and European Medicines Agency ("EMA") for this indication. Despite being a standard of care, gastrointestinal side effects and a strict around-the-clock, every 6 hour dosing schedule for immediate-release cysteamine bitartrate create tolerability and compliance issues for cystinosis patients that DR Cysteamine is designed to address.

The Phase 3 clinical trial is designed as a multi-center, randomized, crossover, outpatient study of the safety, tolerability, pharmacokinetics ("PK") and pharmacodynamics ("PD") of every 12-hour DR Cysteamine compared to immediate-release cysteamine bitartrate in cystinosis patients. The design of this clinical study is a result of discussions with the FDA under a Special Protocol Assessment ("SPA") process by which FDA provided significant guidance on trial protocol design, clinical endpoints, and statistical analyses. The primary endpoint of the study is the steady-state white blood cell ("WBC") cystine levels of patients taking DR Cysteamine compared to immediate-release cysteamine bitartrate. Secondary endpoints are the safety and tolerability of DR Cysteamine and the comparability of steady-state PK of DR Cysteamine and immediate-release cysteamine bitartrate in cystinosis patients. 

"The initiation of the Phase 3 clinical trial is a key advancement in our DR Cysteamine program and extends the positive momentum generated by the recent Orphan Medicinal Product Designation of DR Cysteamine for cystinosis from the European Medicines Agency," stated Ted Daley, president of Raptor. "We believe this study represents an important step forward in the potential treatment of cystinosis as DR Cysteamine offers the potential to improve compliance and long-term treatment outcomes for cystinosis patients by delivering what we believe is a pharmacodynamic result equivalent to immediate-release cysteamine bitartrate using a 30 percent lower daily dose, and twice-daily administration schedule."

The Phase 3 clinical trial will involve up to nine sites in North America and Europe. The Company expects to initially enroll up to 30 patients.   Patients who complete the nine-week clinical trial will be offered enrollment into a long-term follow-on study. The Company anticipates that the Phase 3 clinical trial will be completed in six months.

"We would like to thank our colleagues at the FDA for their input into this trial's design," remarked Patrice P. Rioux, M.D., Ph.D., Chief Medical Officer of Raptor. "Every night, parents of kids with cystinosis face the challenge of waking their young child in the middle of the night to take their medicine, disrupting their sleep with a drug that frequently causes nausea. Unfortunately, this means that the important nocturnal dose is often skipped and as a consequence patients do not receive the full benefit of the therapy because it is critical that the drug be administered on a strict 6-hour schedule. Our goal with DR Cysteamine is to improve the prospects of full patient compliance by allowing for twice a day dosing with what we believe is a better tolerated formulation. We believe that this dosing adjustment will have a significant impact on the quality of life of cystinosis patients and their families and enable clinicians to achieve better therapeutic control."