The US Food and Drug Administration has approved Raptor Pharmaceuticals' Procysbi for the management of a rare genetic disease called nephropathic cystinosis.
Cystinosis affects 500 patients in the USA (and 3,000 worldwide) and causes a protein building block called cystine to build up in every cell of the body. The buildup of cystine causes kidney problems and the disease may lead to slow body growth and small stature, weak bones and developing and worsening kidney failure.
There are three types of cystinosis, the most severe being nephropathic cystinosis. Currently the FDA-approved drugs used to treat cystinosis include the cysteamine-based treatments Cystagon, an immediate-release tablet marketed by Mylan and approved in 1994, and Sigma-Tau's Cystaran eye drops, approved last year to treat corneal cystine crystal accumulation.
Procysbi (cysteamine bitartrate) is a delayed-release capsule intended for patients ages six and older. While Cystagon is taken every six hours around the clock to control cystine levels, Procysbi is a long-acting formulation taken every 12 hours.
The major study supporting Procysbi’s safety and effectiveness involved 43 adults and children with nephropathic cystinosis. Patients were randomly assigned to receive Cystagon or Procysbi for three weeks before being switched to the other product for an additional three weeks and blood testing showed the Raptor treatment was as effective as Cystagon in controlling cystine levels.