title: Cinacalcet reduces plasma intact parathyroid hormone, serum phosphate and calcium levels in patients with secondary hyperparathyroidism irrespective of its severity.
abstract: OBJECTIVE
  To evaluate the relationship between the severity of secondary hyperparathyroidism (SHPT) - defined in terms of baseline plasma intact parathyroid hormone (iPTH) level - and the magnitude of response to cinacalcet.
  
  
  METHODS
  In this post hoc analysis, data were pooled from three randomized, placebo-controlled trials in which dialysis patients with iPTH ≥ 300 pg/ml were dose-titrated with cinacalcet or placebo in addition to conventional treatment to achieve iPTH ≤ 250 pg/ml. In 953 patients analyzed (cinacalcet, 545; placebo, 408), baseline iPTH levels were categorized in 100 pg/ml intervals (300 - ≥ 1,000 pg/ml), and the impact of baseline iPTH on changes in iPTH, phosphate (P), calcium (Ca) and calcium- phosphate product (Ca × P) was evaluated.
  
  
  RESULTS
  Cinacalcet reduced iPTH (47% reduction), P (9%), Ca (7%), and Ca × P (15%) across all subgroups. For patients receiving cinacalcet, the mean percentage reduction from baseline in iPTH varied from 35 to 55%, being consistently decreased across the severity subgroups. The mean absolute change in iPTH was more pronounced in patients with higher baseline iPTH levels, particularly in the ≥ 1,000 pg/ml subgroup vs. the other subgroups. However, as baseline iPTH levels increased, iPTH ≤ 250 pg/ml was achieved in fewer patients. A trend towards greater absolute change from baseline was observed for P in patients with more severe disease (iPTH ≥ 800 pg/ml) treated with cinacalcet compared with patients with less severe disease (iPTH 300 - < 800 pg/ml).
  
  
  CONCLUSIONS
  Cinacalcet lowers plasma iPTH and serum P, Ca and Ca × P levels in dialysis patients with SHPT, regardless of disease severity. Patients with more severe disease experienced greater reductions in PTH and P, but fewer achieved iPTH ≤ 250 pg/ml by the efficacy assessment phase. Use of cinacalcet when baseline PTH is lower may result in more stable control of SHPT and help to control bone and mineral alterations.
authors: School of Medicine, Porto University, Porto, Portugal. jmmdfrazao@netcabo.pt
authors: J M
authors: JM
authors: Frazão
authors: P
authors: P
authors: Messa
authors: G J
authors: GJ
authors: Mellotte
authors: H
authors: H
authors: Geiger
authors: E C
authors: EC
authors: Hagen
authors: L D
authors: LD
authors: Quarles
authors: P G
authors: PG
authors: Kerr
authors: A
authors: A
authors: Baños
authors: B
authors: B
authors: Dehmel
authors: P
authors: P
authors: Urena
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D057966:Calcimimetic Agents / Q000627:therapeutic use*; D002118:Calcium / Q000097:blood*; D000069449:Cinacalcet; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009281:Naphthalenes / Q000627:therapeutic use*; D010281:Parathyroid Hormone / Q000097:blood*; D010710:Phosphates / Q000097:blood*; D016032:Randomized Controlled Trials as Topic; D055815:Young Adult
chemical_list: D057966:Calcimimetic Agents; D009281:Naphthalenes; D010281:Parathyroid Hormone; D010710:Phosphates; D002118:Calcium; D000069449:Cinacalcet