PA21 Safety and Efficacy in Adult Chinese Subjects

Primary Objective is to evaluate the efficacy of PA21 in comparison with sevelamer carbonate (Renvela®) in lowering and maintaining serum phosphorus in adult Chinese subjects with CKD on dialysis after 12 weeks of treatment. In addition , secondary objectives include evaluating the efficacy of PA21 and sevelamer carbonate over time as the percentage of subjects with serum phosphorus within the target range of 1.13 to 1.78 mmol/l (3.5 to 5.5 mg/dl) and to compare the safety and tolerability of PA21 versus sevelamer carbonate (Renvela®). In total, 286 patients (143 patients to PA21 treatment and 143 patients to sevelamer carbonate treatment) will be randomised with a screening period: up to 4 weeks and a washout period of up to 3 weeks. Treatment period (total duration 12 weeks) will include a dose titration period and a maintenance period of an open-label, active-controlled comparison of PA21 versus sevelamer carbonate for 4 weeks. The primary efficacy assessment will be a non-inferiority assessment of the 2 groups of subjects at Week 12 in terms of serum phosphate lowering capability. There will be a follow-up period of 30 days after last dosing. The investigational treatments will be a PA21 dose group of PA21 chewable tablets standardised to contain 500 mg of iron. PA21 contains approximately 20% m/m of elemental iron. All doses of PA21 are expressed in mg of iron. The Starting dose will be 1,500 mg/day (3 tablets/day (1 tablet per meal)). Dose increases or decreases of 500 mg/day (1 tablet/day) are permitted , provided a subject has been receiving that dose for a minimum of 2 weeks and for safety or tolerability reasons at any time. The maximum dose of PA21 will be 3,000 mg/day (6 x 500 mg tablets/day) and the minimum dose will be 1,000 mg/day (2 x 500 mg tablets/day). The active control is sevelamer carbonate, Renvela®, tablets, containing 800 mg of sevelamer carbonate. The starting dose will be 2.4 g/day (3 tablets/day). Dose increases or decreases of 2.4 g/day (3 tablets/day (1 tablet per meal)) are permitted, provided a subject has been receiving that dose for a minimum of 2 weeks, and for safety or tolerability reasons at any time. The maximum dose of sevelamer carbonate will be 14.4 g/day (18 tablets/day) and the minimum dose will be 2.4 g/day (3 tablets/day).