Effect of Camostat Mesilate on Persistent Proteinuria of IgA Nephropathy

Mitsunobu Matsubara, MD, Department of Nephrology, Sendai Shakaihoken Hospital, 3-16-1 Tsutsumimachi, Aoba-ku, Sendai 981 (Japan) Table 1. Changes in clinical data during 3 weeks of camostat mesilate administration Dear Sir, Camostat mesilate is a protease inhibitor developed for oral use. Recently we found its efficacy on proteinuria in patients with various glomerulonephritides including IgA nephropathy [1]. However, the number of the patients with IgA nephropathy in our previous study was only 3 and we have not referred to the details of these patients. In this study, we selected 9 patients with active IgA nephropathy (5 males and 4 females, aged 20-60 years) and administered camostat mesilate at a daily dose of 600 mg. All of them showed moderate proteinuria of more than 1.5 g/day even after weeks of combination therapy with prednisolone, cyclophosphamide, warfarin, and dipyridamole (fig. 1). The level of serum creatinine was less than 1.5 mg/dl and creati-nine clearance was more than 70 ml/min/1.73 m3. Focal and segmental necrotizing lesions and/or small cellular crescents were observed in addition to diffuse and moderate mesangial proliferation in every patient. Their blood pressure had been kept within the normal range with antihypertensive drugs at least 3 weeks before camostat mesilate treatment, and a thrombotest had been kept from 20 to 40% in all patients throughout the study. Urinary protein excretion significantly decreased from 2.1 ± 0.2 to 1.4 ± 0.2 g/day during 3 weeks of camostat mesilate treatment. The hematuria had already been reduced before the administration of camostat mesilate (fig. 1). Serum levels of creatinine,