Approval Granted for New Thiola Dosage Form
June 28, 2019 – The U.S. FDA has approved Thiola® EC (tiopronin), a new dosage form of Thiola® manufactured by Retrophin. The new enteric-coated tablets are indicated for use in combination with high fluid intake as well as alkali and diet modification to prevent cystine stone formation in adults and pediatric patients weighing at least 20kg (44 pounds) who have severe homozygous cystinuria. Thiola and Thiola EC are only indicated for use by patients who are not responsive to high fluid intake and alkali and diet modification alone.
A rare genetic disease, cystinuria occurs in approximately one out of every 7,000 to 10,000 people in the United States. It causes the amino acid cystine to build up in the kidneys and bladder, forming crystals that can grow to become stones. These stones can increase the risk of bacterial infection, block the urinary tract, and reduce the kidneys’ ability to eliminate waste through urine. Thiola and Thiola EC work by increasing the solubility of cystine.
Thiola EC’s enteric coating allows patients to take the medication either with or without food. For adults, the recommended initial dose is 800mg per day. However, in clinical studies, the average dosage was approximately 1,000mg per day. Recommended dosing in pediatric patients is based on weight and should not exceed 50mg/kg per day. Thiola EC should be taken in three divided doses at the same times each day on a routine pattern with regard to meals. The enteric coating may allow patients to more easily schedule their doses, as the immediate release form of Thiola must be taken one to two hour hours before eating. Patients may also need to take fewer pills with Thiola EC compared to Thiola, as the immediate release form is only available in 100mg dosage strengths, while Thiola EC is available in both 100mg and 300mg dosage strengths.
Retrophin has launched Thiola EC at a wholesale acquisition cost (WAC) of $8,462.76 per 300 tablets, compared to $10,155.30 for Thiola.