Raptor Pharmaceutical Corp. ("Raptor" or the "Company") (Nasdaq:RPTP), today announced it has completed enrollment in its Phase 3 clinical trial of its proprietary delayed-release oral formulation of cysteamine bitartrate ("DR Cysteamine") in patients with nephropathic cystinosis ("cystinosis").
The pivotal Phase 3 clinical trial is designed as an outpatient study of the safety, tolerability, pharmacokinetics ("PK") and pharmacodynamics ("PD") of DR Cysteamine dosed every twelve hours in patients with cystinosis, compared to the current standard of care, immediate-release cysteamine bitartrate, which requires dosing every six hours. Raptor expects over 30 patients to complete the eight-week study protocol. All patients completing the Phase 3 clinical trial have the option of enrolling in a long-term follow-on study where they continue to receive DR Cysteamine twice daily for the extent of the study.
"As defined in our statistical analysis plan, an interim statistical analysis of intra-patient variance after 20 patients had completed the study, led us to determine that our patient enrollment is complete. With enrollment completed, we anticipate that we will be able to meet our goal of reporting top line data from this clinical trial in the first quarter of 2011," remarked Patrice P. Rioux, M.D., Ph.D., Chief Medical Officer of Raptor. "Patient compliance is paramount to improving therapeutic control and achieving optimal long-term treatment outcome, and we believe twice-daily DR Cysteamine has the potential to be as efficacious as immediate-release cysteamine bitartrate for cystinosis patients, but with a more convenient dosing schedule and potentially improved tolerability."
The randomized, crossover design of the pivotal Phase 3 clinical trial is a result of discussions with the U.S. Food and Drug Administration ("FDA") through which the FDA provided significant guidance on trial protocol design, clinical endpoints, and statistical analyses plans. The primary endpoint of the multi-center, global clinical trial 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.
"DR Cysteamine has the potential to address two critical issues with the current treatment regimen for cystinosis patients, which result in sub-optimal disease control in many of them. I believe this new formulation of cysteamine bitartrate could greatly improve the quality of life and long-term health outcomes of these patients," said Craig Langman, M.D., The Isaac A Abt MD Professor of Kidney Diseases at the Feinberg School of Medicine, Northwestern University, and Lead Investigator in Raptor's Phase 3 clinical trial.
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 FDA and European Medicines Agency ("EMA") for this indication. Despite being the 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.
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