The European Committee for Medicinal Products for Human Use (CHMP) has adopted a positive opinion regarding Raptor Pharmaceutical Corporation’s drug, Procysbi, for treating proven nephropathic cystinosis, a rare inherited genetic disorder that causes irreversible tissue damage, organ failure and premature death.

On September 20th, 2010, Procysbi was designated as an orphan medicinal product in Europe, because it targets a rare condition or disease.

Cystinosis is a very uncommon genetic condition that affects approximately 3,000 people worldwide. If not treated early on in childhood, the condition is fatal. Cystinosis causes an accumulation of cystine in every cell in the body. Cystine is a protein building block. When too much cystine builds up, it leads to kidney problems, which in turn causes the body too lose too much glucose, salts and protein through urine. Cystinosis is more common among white, blue-eyed people of European descent.

People with cystinosis may experience slow body growth, small stature, worsening renal failure and weak bones. Nephropathic cystinosis is the most severe of the three types of cystinosis.

The CHMP’s green light does not mean Procysbi (cysteamine bitartrate) 25mg and 75mg gastro-resistant hard capsules have been approved – final approval is decided by the European Commission (EC). However, the EC nearly always goes along with CHMP’s recommendations. An EC’s decision regarding drug approvals covers 27 EU countries, including Iceland and Norway.


CHMP wrote “The approved indication is: “Procysbi is indicated for the treatment of proven nephropathic cystinosis. Cysteamine reduces cystine accumulation in some cells (e.g. leukocytes, muscle and liver cells) of nephropathic cystinosis patients and, when treatment is started early, it delays the development of renal failure.”

“The CHMP, on the basis of quality, safety and efficacy data submitted, considers there to be a favourable benefit-to-risk balance for Procysbi and therefore recommends the granting of the marketing authorisation.”

CHMP proposes that only doctors experienced in treating cystinosis prescribe Procysbi.

Christopher M. Starr, Ph.D., Chief Executive Officer of Raptor, said:

“The positive opinion of the CHMP brings us an important step closer to anticipated EU approval of Procysbi subject to the European Commission review process. While this recommendation is an important milestone for Raptor, it is also good news for European patients who suffer from nephropathic cystinosis.”

Procysbi, which is taken by mouth every twelve hours, is a new therapy for the management of nephropathic cystinosis. It was designed to bypass the stomach and has an extended terminal half-life, meaning patients receive a constant level of drug supply in their bodies over the whole 12-hour dosing period.

Randomized, controlled human studies showed that extended Procysbi therapy maintained “consistent and continuous control of white blood cell cysteine”.

The most common side effects associated with Procysbi therapy include:

Procysbi was approved by the U.S. Food and Drug Administration on April 30th, 2013, for the management of nephropathic cystinosis in adults and children aged 6+ years. The drug had been granted orphan product designation because it targets a rare disease or condition.

On the likely event of the European Commission approving Procysbi, its indications, contraindications, warnings and precautions might not necessarily be the same as those stipulated by the U.S. FDA.

More information on Procysbi can be obtained at

Written by Christian Nordqvist