This is a randomized, dose-ranging, efficacy and tolerability study in chronic kidney disease patients with hyperphosphatemia on hemodialysis. Patient participation in the study is approximately 10 weeks in duration.

Hyperphosphatemia is associated with abnormally high blood concentrations of phosphorus. Normally, phosphorus in the body is excreted into urine via the kidneys, but this process is impaired when renal function is reduced. Hyperphosphatemia occurs in many patients with renal insufficiency, especially those on dialysis. High blood phosphorus concentrations trigger various complications caused by phosphorous interaction with blood calcium or parathyroid hormones, and makes patients more prone to calcium deposition in soft tissues such as the coronary arteries, increasing the risk of ischemic heart disease. ILY101 is a non-absorbed, metal-free polymer that binds phosphorus in the gastrointestinal tract, allowing for excretion of phosphorus. It is therefore anticipated to ameliorate hyperphosphatemia by reducing the absorption of phosphorus from the gastrointestinal tract.

Inclusion Criteria:

• CKD patients on dialysis
• Prior successful use of phosphate binder
• Signed informed consent

Exclusion Criteria:

• Previous intolerance to polymer-based phosphate binders
• Kidney transplant planned within 3 months
• Pregnant or lactating women, or women of child bearing potential not using an acceptable form of birth control
• Clinically significant liver disease
• History of bowel obstruction or other significant gastrointestinal disorder

Additional study entry criteria will be evaluated during initial screening.