OBJECTIVES: to demonstrate the impact of Mimpara (MIM), a drug against secondary hyperparathyroidism (sHPT), on the dialysis health care budget in Belgium over time. METHODS: A Markov model was developed to compare cost of dialysis patients on standard treatment of care (SOC) with patients on MIM + SOC (add-on model). The model operates in ½ year cycles over 5 years starting with a cohort of 5,400 patients (prevalence data). Each year new cases were added to the cohort and a % dropped out due to death or renal transplant. Mortality risk was calculated from 2-year cohort dialysis database (CDB) (n=13,000)1. Patient distributions for sHPT, calcium x phosphor values, and MIM dosages were taken from phase III trials for the MIM arm and from the 2-year CDB for the SOC arm. Patients withdrawing from MIM were treated as SOC patients. According to CDB 35% of the initial cohort may receive MIM (=% of sHPT). Drug uptake was 30% in first cycle with 20% increase per added cycle. MIM drug costs were € 3,109/year in first cycle and € 2,617/year per added cycle as only drug responders (85%) remained on study drug. Other treatment costs were taken from a retrospective cost study in Belgium2 using average daily cost of € 214 per dialysis patient, plus € 50/day for sHPT. Annual 3% discount rate was applied. RESULTS: Cumulative 5-year cost difference of € 7,4 million was seen between SOC- and MIM-arm (<0.4% total cost increase with MIM). Running the analysis per year, cost savings early in MIM-treatment were observed due to reduction in treatment costs of morbidities related to shift from sHPT. Slight increase in treatment costs was seen later on due to observed survival benefit with MIM. CONCLUSION: Major budget shifts will not be seen with Mimpara in its approved indication.