© SSIEM and Kluwer Academic Publishers. Printed in the Netherlands Recent advances in the treatment of cystinosis

Summary: Cysteamine bitartrate capsules (Cystagon) have been approved by the US Food and Drug Administration for use in patients with nephropathic cystinosis. Plasma cysteamine concentrations were virtually identical at various times follow-ing ingestion of either cysteamine hydrochloride orCystagon capsules in 24 normal control subjects. A transfer study was done with eight eystinosis patients who had been receiving either cysteamine hydrochloride or phosphocysteamine for many years. The plasma cysteamine concentration was significantly higher 2h after Cystagon and the leukocyte cystine content was significantly lower at all times after Cystagon compared to older forms of the drug. These differences are probably the result of greater patient compliance in taking the capsules compared to the older, liquid forms of the drug. A new method for following the course of renal glomerular deterioration i diseases uch as cystinosis has been published recently. This method was used to re-analyse data on the efficacy of cysteamine treatment and to re-analyse new data on treating cystinosis patients with either of two doses of cysteamine (1.30g/m 2 per day and 1.95 g/m 2 per day). This new method agrees well with othe