A new enteric-coated formulation of Thiola (tiopronin; Retrophin) has been approved by the Food and Drug Administration (FDA) for the prevention of cystine stone formation, in combination with high fluid intake, alkali, and diet modification, in adults and pediatric patients ≥20kg with severe homozygous cystinuria, who are not responsive to these measures alone.

Commenting on the approval, Eric Dube, PhD, chief executive officer of Retrophin said, “This new formulation provides patients with the freedom to administer Thiola EC with or without food, an advancement over the original formulation which has limiting food restrictions, and also provides the potential to reduce the number of tablets necessary to manage cystinuria.”

The approval of Thiola EC was based on safety and efficacy data from previous studies of Thiola. The goal of therapy is to reduce urinary cystine concentration below its solubility limit. Tiopronin is an active reducing agent which undergoes thiol-disulfide exchange with cystine to form a mixed disulfide of tiopronin-cysteine. From this reaction, a water-soluble mixed disulfide is formed and the amount of sparingly soluble cystine is reduced.

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Thiola EC is expected to be available sometime this July in 100mg and 300mg delayed-release tablets. 

According to the NIH, cystinuria affects approximately 1 in 10,000 individuals.

For more information visit thiola.com.

This article originally appeared on MPR