The USA's Raptor Pharmaceutical Corp has been boosted by the news that the Food and Drug Administration has accepted its filing for the firm's potential treatment of the rare disease nephropathic cystinosis.

The treatment in question is RP103 (cysteamine bitartrate) delayed-release capsules and the FDA has granted standard review designation for the drug. It is already being evaluated by the European Medicines Agency and Raptor expects a decision in the first half of 2013.

Nephropathic cystinosis is an orphan disease estimated to effect 2,000 patients worldwide, including 500 in the USA and 800 in Europe. Sufferers have inherited a defective cystine transporter gene which results in body-wide cellular toxicity resulting from the abnormal buildup of the amino acid cystine in the lysosomes.

Cystinosis is usually diagnosed in the first year of life, Raptor noted, and requires lifelong therapy. Cystine crystals accumulate in various tissues and organs, including the kidneys, brain, liver, thyroid, pancreas, muscles and eyes and left untreated, the disease is fatal by the first decade of life.

Raptor chief executive Christopher Starr said "we are focused and working hard to build our internal and external infrastructure in order to support a robust commercial launch so that Raptor can quickly provide this important therapeutic to the cystinosis community in the USA and the European Union."

In December 2007, Raptor obtained a licence from the University of California, San Diego for the development of RP103 for nephropathic cystinosis and for cysteamine for other potential indications including Huntington's Disease (currently in a Phase II/III) and non-alcoholic steatohepatitis (in Phase IIb).