Soma J et al. (2006) Effect of tranilast in early-stage diabetic nephropathy. Nephrol Dial Transplant 21: 2795–2799

In 2002, Soma et al. showed that tranilast, an antifibrotic drug that suppresses collagen synthesis, slowed the progression of advanced diabetic nephropathy. These researchers have now investigated whether tranilast might also be useful in early-stage diabetic nephropathy.

The study included 20 outpatients with type 2 diabetes mellitus from a hospital in Japan. Inclusion criteria included a urinary albumin excretion of 30–1,000 mg/g creatinine in the first morning urine sample, a serum creatinine level of ≤1.2 mg/dl (106 µmol/l) and no hematuria. All patients were taking an angiotensin-converting-enzyme inhibitor or an angiotensin receptor blocker. Ten patients were randomly assigned tranilast treatment (100 mg three times per day); the other patients received no additional therapy.

After 12 months, tranilast-treated patients showed significant decreases from baseline values in their excretion rates of both urinary albumin and urinary type IV collagen (P = 0.049 and P = 0.02, respectively). By contrast, excretion rates of urinary albumin and urinary type IV collagen tended to increase from baseline to 12 months in patients who did not receive tranilast. Blood pressure, serum creatinine and glycated hemoglobin levels remained stable during the study in both patient groups.

The authors conclude that tranilast might be a useful therapy for suppressing progression of early-stage diabetic nephropathy. A longer-term, prospective, controlled study is needed to further investigate the effects of this drug on diabetic nephropathy.