Cystine-binding medication is poorly accessible for the treatment of cystinuria

Introduction Cystinuria is a rare inherited disorder characterized by recurrent cystine stone formation. When lifestyle modification and urine alkalinization fail, cystine-binding medication such as tiopronin and D-penicillamine are indicated. Despite proven benefit, their accessibility across Europe appears limited. We hypothesized that access to this medication is restricted and varies substantially between European countries. Methods We surveyed physicians affiliated with the European Reference Network for Rare Kidney Diseases (ERKNet) regarding access barriers and prescribing practices. The online questionnaire was completed by 40 clinicians from 15 countries. Results Eighty-five percent of respondents had prescribed cystine-binding medication in the past two years, with tiopronin being the preferred agent. However, 30% reported having no access to tiopronin at all, and 83% of recent prescribers experienced accessibility problems, including high costs and unfilled prescriptions. Substantial differences were observed both between and within countries. Prescription rates correlated with physicians' cystinuria caseload. Discussion Cystine-binding medication is poorly and inconsistently accessible across Europe. Coordinated efforts are urgently needed to stabilize supply and ensure equitable, affordable access.