Effect of camostat mesilate on heavy proteinuria in various nephropathies

Camostat mesilate, a developed derivative of gabexate mesilate for oral use, was administered in a daily dose of 600 mg for 4 weeks to 17 patients with heavy proteinuria due to various nephropathies. Five patients had glomerulonephritis (3 patients with IgA nephropathy, one each with membranoproliferative GN and membranous nephropathy) and 3 had systemic vasculitis. These patients had been treated with glucocorticoid, cyclophosphamide, anticoagulants, and dipyridamole. Five patients had diabetic nephropathy and had been treated with conventional therapy including angiotensin converting enzyme inhibitors. Two cases with benign nephrosclerosis, one with Alport syndrome, and the rest with end-stage renal failure of undetermined cause were also included in this study. Urinary protein decreased promptly within 2 weeks (from 5.2 ± 0.7 to 3.5 ± 0.5, mean ± SE, p < 0.005), and serum total protein and albumin levels increased significantly. Serum creatinine levels did not change. Decreases in urinary protein excretion of more than 50% were observed in five out of eight patients with glomerulonephritis or systemic vasculitis, two out of five with diabetic nephropathy, and one with chronic renal failure. However, urinary protein excretion values remained at the same level in two patients with benign nephrosclerosis and a patient with Alport syndrome. We suggest that camostat mesilate caused a change in glomerular capillary permeability for macromolecules through its inhibitory effects on the kallikrein-kinin system, complement system, coagulation system, and platelet function, which contributed to the treatment of the various nephropathies.