Effects of 3 different phosphate binders on the formation of calciprotein particles in participants receiving haemodialysis treatment

Calcium carbonate (oral (600mg tablets), up to 3 tablets three times a day) treatment for 12 weeks followed by randomisation to either : Calcium Carbonate, oral (800 mg tablets), up to 3 tablets three times a day Sevelamer Hydrochloride, oral (800 mg tablets), up to 3 tablets three times a day Sevelamer Carbonate, oral, up to 3 tablets three times a day for a period of 24 weeks. Starting dose when changing from calcium carbonate to either Sevelamer carbonate or Sevelamer hydrochloride is based on the number of tablets taken, 1 tablet of calcium carbonate is considered to be equivalent to 1 tablet of Sevelamer carbonate/hydrochloride in terms of binding phosphate in the gastrointestinal tract. Participants will commence the new medication taking the same number of tablets daily as they were on previously. Dosing is dependent participant's serum phosphate level and is targeted to a serum phosphate <2.0 mmol/L. Phosphate is monitored every 4 weeks in line with standard of care, study drug dose remains unchanged unless there is indication of hypo or hyper phophataemia. If serum phosphate is <0.8 mmol/L decrease dose by 1 tablet per day. Participant is withdrawn if serum phosphate is <0.8 m mol/L and not on phosphate binder medication. If serum phosphate is <0.6 mmol/L then all phosphate binders should cease and level should be checked in 3 days. If serum phosphate is above 2.6 mmol/L on maximum dose of phosphate binder (Calcium carbonate > 5.4 g/day (i.e. 9 X 600 mg tablets); Sevelamer HCL > 7.2 g/day (i.e. 9 X 800 mg tablets); Sevelamer carbonate >7.2 g/day (i.e. 9 X 800 mg tablets )then participant should be withdrawn from the study. Compliance will be monitored by package returns.