Effect of camostat mesilate on urinary protein excretion in three patients with advanced diabetic nephropathy

Effective treatment has not yet been established for patients with persistent proteinuria and hypoproteinemia related to advanced diabetic nephropathy. We report three patients with diabetic nephropathy presented with the nephrotic syndrome who showed a marked decrease in proteinuria following the administration of camostat mesilate, a protease inhibitor. Each patient was resistant to treatment with an angiotensin-converting enzyme (ACE) inhibitor and a platelet-aggregation inhibitor. Camostat mesilate, 600 mg/day, orally, caused a marked decrease in urinary protein excretion after the 7th consecutive day of drug administration. There were no serious adverse effects. Its mechanism of action in this respect is not known. Camostat mesilate thus merits clinical trials in the treatment of nephrotic syndrome related to diabetic nephropathy.