The calcimimetic AMG 073 reduces parathyroid hormone and calcium x phosphorus in secondary hyperparathyroidism.
BACKGROUND
A need exists for a therapy that lowers parathyroid hormone (PTH) without increasing calcium x phosphorus in patients with secondary hyperparathyroidism. The calcimimetic AMG 073 increases the sensitivity of the parathyroid calcium-sensing receptor to extracellular calcium, thereby reducing PTH secretion. Consequently, AMG 073 may provide a novel therapy for secondary hyperparathyroidism.


METHODS
Seventy-eight hemodialysis patients with secondary hyperparathyroidism were enrolled into this 18-week, double-blind, randomized, placebo-controlled, dose titration study. Daily oral AMG 073 doses were administered to determine the effect on PTH, serum calcium, phosphorus, and calcium x phosphorus.


RESULTS
The mean baseline PTH was similar in patients administered AMG 073 or placebo (632 +/- 280.1 pg/mL vs. 637 +/- 455.9 pg/mL, respectively). PTH decreased by 26.0% in the AMG 073-treated group, compared with an increase of 22.0% in the placebo group (P < 0.001). A greater proportion in the AMG 073 group (38%) had a decrease in PTH >or=30%, compared with the placebo group (8%) (P = 0.001). Decreases in PTH were independent of baseline vitamin D usage. Patients receiving AMG 073 had an 11.9% decrease in calcium x phosphorus compared with a 10.9% increase in the placebo group (P < 0.001). Use of vitamin D sterols, as well as both calcium and noncalcium-containing phosphate binders. were similar between treatment groups. Administration of AMG 073 was safe and well tolerated in this 18-week study.


CONCLUSIONS
The calcimimetic AMG 073 decreases both PTH and calcium x phosphorus levels in hemodialysis patients with secondary hyperparathyroidism.
Lindberg
Jill S
JS
Ochsner Clinical Research Center, New Orleans, Louisiana 70121, USA. jlindberg@ochsner.org
Moe
Sharon M
SM
Goodman
William G
WG
Coburn
Jack W
JW
Sprague
Stuart M
SM
Liu
Wei
W
Blaisdell
Peter W
PW
Brenner
Robert M
RM
Turner
Stewart A
SA
Martin
Kevin J
KJ
D000328:Adult; D000368:Aged; D002117:Calcitriol / Q000008:administration & dosage; D002118:Calcium / Q000097:blood*; D002120:Calcium Channel Agonists / Q000008:administration & dosage; D000069449:Cinacalcet; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000188:drug therapy*; D007676:Kidney Failure, Chronic / Q000150:complications / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009281:Naphthalenes / Q000008:administration & dosage* / Q000009:adverse effects; D010281:Parathyroid Hormone / Q000097:blood*; D010758:Phosphorus / Q000097:blood*; D006435:Renal Dialysis; D017186:Titrimetry
D002120:Calcium Channel Agonists; D009281:Naphthalenes; D010281:Parathyroid Hormone; D010758:Phosphorus; D002117:Calcitriol; D002118:Calcium; D000069449:Cinacalcet