Safety and Efficacy of AST-120 in Patients With GERD Who Continue to be Symptomatic on a Standard Dose of PPI

This is a double-blind, randomized, placebo-controlled, crossover trial where 20 patients with confirmed persistent GERD symptoms (at least twice weekly) after a standard course of PPI, with abnormal bile reflux levels but normal esophageal acid exposure are randomized to initially receive either AST-120 or placebo for a period of 4 weeks after a two week screening period. After a washout period of one week, patients will cross over to the opposite blinded treatment. The experimental drug AST-120 is composed of black, odorless spherical carbon particles in 2g sachets (aluminum foil pouches). The placebo consists of microcrystalline cellulose spheres, Celphere CP-305, stained to match the appearance of AST-120, in 2g sachets (aluminum foil pouches). Both AST-120 and placebo are oral (taken by mouth) preparations. Both are tasteless. Take the product, patients will tear open the sachet, drop the contents directly on their tongue and wash it down with 8 ounces of water. Patients will continue to receive the previously prescribed PPI throughout the duration of the trial. In addition, patients will be allowed up to 6 Gelusil tablets daily as a "rescue medication". Patients will be expected to participate in approximately 5 in-clinic visits. During these visits, patients will undergo a number of tests including: comprehensive physical, hematology panel, a urine pregnancy test for pre-menopausal females, completion of the Gastroesophageal Reflux Disease Symptom Assessment Scale (GSAS) and Short-Form-36 (SF-36)Quality of Life Form and an upper endoscopy will be performed to determine the extent of esophageal inflammation. Patients will be allowed to continue on their previously prescribed PPI with no changes and may take up to 6 Gelusil tablets per day. The following therapies must be discontinued and should not be taken during the trial: H2receptor antagonists, NSAIDs, Baclofen and Antacids (OTC or prescription).