The impact of calcimimetic agents on the use of different classes of phosphate binders: results of recent clinical trials.
Calcimimetic agents bind to and activate the calcium-sensing receptor in the parathyroid glands, lowering the threshold for its activation by extracellular calcium and diminishing parathyroid hormone release from parathyroid cells. In three large randomized, controlled trials, cinacalcet given at doses of 30 to 180 mg orally each day was associated with effective reduction in parathyroid hormone levels over 26 weeks compared with placebo, and was consistently associated with a decrement in serum calcium, phosphorus levels, as well as a decrement in calcium-phosphorus product. In one study, there was a 5% incidence of hypocalcemia (serum calcium levels < 7.5 mg/dL on at least two consecutive measurements) among patients receiving cinacalcet, and less than 1% of patients receiving standard therapy (P < 0.0001). While there were no demonstrated differences between groups with regard to use of phosphate binders and vitamin D sterols in these randomized controlled trials, arguably, the combination of the effects on serum calcium, phosphorus, and calcium-phosphorus product may bring increased focus on the increased mortality risk associated with hypocalcemia.
Division of Nephrology, Department of Medicine, Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA. szcz001@mc.duke.edu
Lynda Anne
LA
Szczech
D002118:Calcium / Q000097:blood; D000069449:Cinacalcet; D006801:Humans; D006961:Hyperparathyroidism / Q000188:drug therapy* / Q000378:metabolism; D009281:Naphthalenes / Q000627:therapeutic use*; D010710:Phosphates / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism; D016032:Randomized Controlled Trials as Topic; D014807:Vitamin D / Q000627:therapeutic use
D009281:Naphthalenes; D010710:Phosphates; D014807:Vitamin D; D010758:Phosphorus; D002118:Calcium; D000069449:Cinacalcet