Raptor Pharmaceutical Corp., a biopharmaceutical company, has received the US Food and Drug Administration (FDA) approval for Procysbi (cysteamine bitartrate) delayed release capsules in the treatment of nephropathic cystinosis in adults and children six years and older.

In a phase III study, Procysbi showed consistent cystine depletion over the full 12-hour dosing period. Sustained levels of cysteamine have not historically been achieved in the majority of patients in this population. Studies have shown that sustained cystine depletion in patients may significantly delay disease progression, including kidney dysfunction, dialysis, kidney transplant, organ failure and premature death.

Christopher M Starr, CEO and co-founder of Raptor said, "PROCYSBI's approval advances Raptor closer to its goal of becoming an integrated, commercial-stage biopharmaceutical company. It is especially gratifying for us that patients and caregivers in the cystinosis community now have a long-anticipated treatment available to them." Starr further added, "Procysbi is the result of a decade-long patient- and physician-initiated effort to improve the treatment and lives of cystinosis patients. We are very grateful to have worked together on the development, manufacturing and regulatory submission of this important treatment for the cystinosis community."

Procysbi is the culmination of early research funded by the patient advocacy group Cystinosis Research Foundation. The FDA approval of Procysbi was based on a New Drug Application (NDA) comprising data from six clinical trials, including a multi-center randomized, active-controlled phase III trial of 43 patients with nephropathic cystinosis and extension data from that trial. The most commonly reported adverse reactions were vomiting, abdominal pain/discomfort, headaches, nausea, diarrhea, anorexia/decreased appetite, breath odor, fatigue, dizziness, skin odor and rash.  Clinical studies are ongoing in children less than six years of age to evaluate for the first time the safety and efficacy of PROCYSBI. Over 90 per cent of the cystinosis population is six years or older.

“Sustaining appropriate levels of cysteamine in the body is the key to maintaining organ function and lowering the likelihood of kidney transplantation. Most patients don't take their cystinosis medication consistently as a result of severe stomach side effects and a burdensome dosing schedule," said Craig Langman, MD, The Isaac A Abt, MD Professor of Kidney Diseases Feinberg School of Medicine and Head of Kidney Diseases at Ann & Robert H Lurie Children's Hospital of Chicago. "In addition to providing sustained control of cystine levels, PROCYSBI's dosing schedule and side effect profile may help patients stay the course with their treatment. The fact that 40 of 41 patients from the phase III trial elected to enroll in the extension study and have been followed for two years now demonstrates their motivation to be on Procysbi therapy."

Physicians can now prescribe Procysbi by calling RaptorCares at 1-855-888-4004. RaptorCares provides individualized services to help patients access Procysbi through education, support, extensive case management and a commitment to the principle that no eligible US patient with nephropathic cystinosis will be denied access to Procysbi based on inability to pay. Raptor intends to begin shipping Procysbi within six to eight weeks.

The FDA approval of Procysbi triggers the second of two $25 million payments to Raptor under the terms of the HealthCare Royalty Partners (HC Royalty) $50 million loan agreement. The loans mature on December 31, 2019, bear interest at an annual fixed rate of 10.75 per cent, and a Synthetic Royalty variable rate, tiered down, based on a percentage of future Procysbi sales. Raptor signed the loan agreement with HC Royalty in December 2012 and received the first $25 million payment upon closing. The loan is interest-only for the first two years.

Nephropathic cystinosis comprises 95 per cent of cystinosis, a rare, life-threatening metabolic lysosomal storage disorder that causes toxic accumulation of cystine in all cells, tissues, and organs in the body. Elevated cystine leads to progressive, irreversible tissue damage and multi-organ failure, including kidney failure, blindness, muscle wasting and premature death. Nephropathic cystinosis is usually diagnosed in infancy and requires lifelong therapy. Left untreated, the disease is usually fatal by the end of the first decade of life.

Cystine depletion is the primary treatment strategy for nephropathic cystinosis. However, poor adherence to therapy has been a major challenge resulting in poor sustained control of cystine levels, and patients consequently experience poor clinical outcomes, including kidney insufficiency leading to dialysis and kidney transplantation, muscle wasting and in some cases, premature death. Even brief interruptions in daily therapy can permit toxic accumulation of cystine, exposing tissues to renewed, progressive deterioration.

Raptor Pharmaceutical Corp. is focused on developing and commercializing life-altering therapeutics that treat rare, debilitating and often fatal diseases.