The FDA has approved Raptor Pharmaceutical’s Procysbi(cysteamine bitartrate) delayed release capsules for 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.

"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," said Christopher M. Starr, Ph.D., CEO and co-founder of Raptor. "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. Clinical studies are ongoing in children less than six years of age to evaluate for the first time the safety and efficacy of Procysbi.

"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, M.D., 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."

The FDA approval of Procysbi triggers the second of two $25 million payments to Raptor under the terms of the HealthCare Royalty Partners $50 million loan agreement.