<qa>  What is the effect of combination Cinacalcet with Vitamin D analogue?This is a single arm, open-labelled study to determine the effectiveness of combination Cinacalcet with Vitamin D analogue in the treatment of severe hyperparathyroidism in patients with ESRF on haemodialysis. Patients will be started on PO Cinacalcet 25mg OD POIV active Vitamin D analogues adjusted by incrementsdecrements in steps of 1 mcg 3x per week every 1-4 weeks until the corrected calcium level is within 2.4-2.54 mmolL. After iPTH has reached 2-9x ULN, patient enters maintenance phase. If serum calcium falls below 2.1mmolL, active Vit D dose will be increased and if it is above 2.54 mmolL, the dose will be decreased. 