AP301 Efficacy and Safety in Chinese Dialysis Patients With Hyperphosphatemia

This study has two primary efficacy objectives. The primary efficacy objective 1 is to evaluate the superiority of maintenance dose versus low dose of AP301 on serum P control in dialysis patients with hyperphosphatemia. The primary efficacy objective 2 is to evaluate the non-inferiority of AP301 versus sevelamer carbonate on serum phosphorus control. Besides these two primary efficacy objectives, this study will also evaluate the serum phosphorus control equivalence and the safety for AP301 produced from two APIs (Active Pharmaceutical Ingredient) in the last 8 weeks of drug exposure. Patients will start dosed after eligibility confirmation. The treatment period will last 52 weeks in total, including: A) A 24-week sevelamer carbonate active control phase in which serum phosphorus level at the end of Week 12 will be measured for the analysis of primary efficacy endpoint 2, B) A 3-week AP301 low dose control phase in which serum phosphorus level at the end of Week 27 will be measured for the analysis of primary efficacy endpoint 1, and C) A 25 or 28-week extension treatment phase The investigational treatments will be AP301. Sevelamer carbonate will be provided as active control in active control and extension treatment phase and AP301 125 mg as ineffective control in low dose control phase. A) The starting dose of AP301 is one 700 mg capsule 3 times daily. The dosage is to be adjusted based on their serum phosphorus level and safety assessmentsevery two or four weeks. The maximal dose is to be 10 capsules daily. B) The starting dose of sevelamer carbonate will be one to two 800 mg capsules 3 times daily. The dosage is to be adjusted based on their serum phosphorus level every and safety assessments two or four weeks. The maximal dose is to be 12 capsules daily. Then, a 2-week safety observation will be followed after the last dosing.