Phosphate Binding of Chitosan Chewing Gum in Patients With Chronic Kidney Disease (CKD)

The current treatment for elevated serum phosphorus levels in chronic kidney disease (CKD) consists of dietary restriction of P and the provision of phosphate binders that act at the level of the intestinal absorption of phosphorus (P) when ingested with meals. This paradigm has proven to be inadequate to achieve normo-phosphatemia as indicated by elevated serum P levels in patients receiving renal replacement therapy. Salivary phosphate levels are elevated in patients with CKD and salivary P represents a large source of otherwise hidden non-dietary phosphate that is easily absorbed and may contribute to persistent elevations in serum P despite standard therapy. Savica et al performed a preliminary study, in a small population (n-13) of hyperphosphatemic patients receiving hemodialysis, phosphate restriction and phosphate binders, and given K2CG chewing gum 20 mg. The chewing gum was administered twice per day for 60 minutes during fasting periods (between meals) for 15 days. In addition to a significant reduction in salivary P, serum P was reduced by 2 mg/dL (31%) over the treatment period. Both salivary and serum P returned to baseline values after K2CG discontinuation. The authors concluded that adding salivary P binding to traditional phosphate binders could be a useful approach for improving treatment of hyperphosphatemia in patients receiving renal replacement therapy (RRT). Given the public health importance of increased P levels in the general population and specifically in patients with chronic kidney disease, it is of great importance to evaluate the ability of a medical food such as K2CG to reduce elevated serum P levels. In patients with CKD receiving RRT it has been estimated that sustained control of serum P may result in an approximate 17% reduction in mortality. The specific purpose of this study is to compare the total P recovered per piece of chewing gum with 20 mg and 60 mg versions of the reformulated K2CG with or without the extender in the gum core. Additionally, the unique P binding of the reformulated gum will be assessed in comparison with the total P entrapped per piece of chewing gum in the matching placebos. Subjects will be assigned to one of 3 different groups as shown in the table below. The study will be a single blind study. Subjects will be blinded as to the strength/formulation of the chewing gum and the active/placebo assignment. Group Active Chewing Week 1 Active Chewing Week 2 20 mg with extender 20 mg Placebo 20 Placebo 60 60 mg with extender 60 mg Subjects will chew the K2CG gum of a single strength/formulation for 7 days (Active Chewing Week 1) twice a day (BID). K2CG gum must be chewed at least 60 minutes in fasting conditions. This will be followed by a second 7 days of chewing K2CG gum (Active Chewing Week 2) of a different strength/formulation as described above. There will be no run-in period and no wash out period between Active Chewing Week 1 and Active Chewing Week 2.