title: Effect of cinacalcet cessation in renal transplant recipients with persistent hyperparathyroidism.
abstract: BACKGROUND
  Persistent hyperparathyroidism after renal transplantation affects bone and allografts. Cinacalcet, a calcimimetic, reduces serum calcium and PTH in renal transplant recipients with persistent hyperparathyroidism. Here, we address the question whether this effect of cinacalcet persists after withdrawal.
  
  
  METHODS
  Therefore, cinacalcet was stopped after 12 months treatment in 10 stable renal transplant patients. Serum calcium, phosphate, PTH, creatinine and cystatin C were monitored for 3 months.
  
  
  RESULTS
  Serum calcium, normalized in nine patients before cessation of cinacalcet (2.32 +/- 0.05mmol/l, mean +/- SEM), increased after 3 months of discontinuation by 0.17 +/- 0.04mmol/l, P < 0.05, but remained within the normal range in eight patients. Compared with the time point of cessation, PTH remained unchanged or decreased further after 3 months without therapy in six patients. Measurements of cystatin C suggested an improvement of the glomerular filtration rate after cessation in 9 out of 10 patients (1.55 +/- 0.09 vs 1.33 +/- 0.12 mg/l, P < 0.01).
  
  
  CONCLUSIONS
  First, a beneficial effect of cinacalcet beyond the duration of a 12-month therapy appears to be present in some patients and second, the previously suspected influence of cinacalcet therapy on renal function is reversible. Thus, it is reasonable to consider a trial of cinacalcet cessation to identify these patients. The optimal time point for such a discontinuation is unknown. The present observations are preliminary. They clearly require a prospective randomized trial for definitive confirmation.
authors.affiliation: Department of Nephrology and Hypertension, University Hospital Bern, Inselspital, Freiburgstrasse 10, CH-3010 Berne, Switzerland.
authors.forename: Anja E
authors.initials: AE
authors.lastname: Kruse
authors.forename: Ute
authors.initials: U
authors.lastname: Eisenberger
authors.forename: Felix J
authors.initials: FJ
authors.lastname: Frey
authors.forename: Markus G
authors.initials: MG
authors.lastname: Mohaupt
mesh_terms: D000328:Adult; D000368:Aged; D002118:Calcium / Q000097:blood; D000069449:Cinacalcet; D003404:Creatinine / Q000097:blood; D055316:Cystatin C; D015891:Cystatins / Q000494:pharmacology; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000150:complications* / Q000188:drug therapy; D007668:Kidney / Q000187:drug effects; D016030:Kidney Transplantation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009281:Naphthalenes / Q000009:adverse effects / Q000627:therapeutic use*; D010281:Parathyroid Hormone / Q000097:blood; D013997:Time Factors
chemical_list: C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D009281:Naphthalenes; D010281:Parathyroid Hormone; D003404:Creatinine; D002118:Calcium; D000069449:Cinacalcet