An oral adsorbent, AST-120, combined with a low-protein diet and RAS blocker, for chronic kidney disease

BACKGROUND: A low-protein diet and treatment with renin-angiotensin system (RAS) blockers can delay the progression of chronic kidney disease (CKD). The oral adsorbent AST-120 (Kremezin) has a renoprotective effect by reducing serum levels of uremic toxins. We investigated the influence of AST-120 on the preservation of renal function in patients with CKD. METHODS: Twenty-eight patients were randomized to 2 groups: 15 patients receiving 6.0 g of AST-120 daily for 12 months plus a low-protein diet and RAS blocker therapy (group A) and 13 patients who were not given AST-120 (group B). All of them had shown progressive deterioration of renal function with basal treatment. Mean baseline serum creatinine level (+/- standard deviation) was 2.4 +/- 0.8 mg/dL in group A and 2.7 +/- 0.8 mg/dL in group B. There were no significant differences in background parameters before AST-120 therapy. RESULTS: The change in the estimated glomerular filtration rate (eGFR) was significantly smaller in group A than in group B. The change was also significantly smaller in patients with a baseline serum creatinine <2.4 mg/dL and in patients with rapid progression. After 12 months, the slope of the eGFR curve was significantly less steep compared with baseline in group A (-1.77 vs. -0.52 ml/min per month), but there was no significant change in group B. The slope was also significantly less steep in patients with rapid progression. CONCLUSIONS: Adding AST-120 to a low-protein diet and RAS blocker therapy may delay the deterioration of chronic renal failure, especially in patients with early or rapid progression.