Cinacalcet treatment of primary hyperparathyroidism: biochemical and bone densitometric outcomes in a five-year study.
BACKGROUND
Primary hyperparathyroidism (PHPT) is characterized by chronically elevated serum calcium and inappropriately normal or increased PTH.


OBJECTIVE
Our objective was to evaluate long-term tolerability, safety, and efficacy of cinacalcet in PHPT patients.


METHODS
A 4.5-yr open-label extension study was conducted at 14 study centers in the United States.


METHODS
Forty-five subjects with PHPT from a double-blind, placebo-controlled, 1-yr trial were continued into this study.


METHODS
After the parent study, all subjects were treated with 30 mg cinacalcet twice daily, increasing to 50 mg twice daily during the 12-wk titration if serum calcium levels were 10.3 mg/dl or higher and then maintained on cinacalcet for up to 4.5 yr.


METHODS
Assessments included serum calcium, PTH, phosphate and alkaline phosphatase, and areal bone mineral density (aBMD). Vital signs, safety chemistries and hematology, and adverse events were monitored throughout.


RESULTS
Compared with baseline, cinacalcet treatment improved biochemical measures of PHPT including reducing serum calcium and PTH and increasing serum phosphate with slight increases in alkaline phosphatase. No changes in z-scores of aBMD at spine, hip, or wrist were seen with annual percent changes, consistent with reports for untreated postmenopausal women or PHPT patients. Safety biochemistries remained normal, and adverse events (most commonly arthralgia, myalgia, diarrhea, respiratory infection, and nausea) were mild to moderate in severity.


CONCLUSIONS
Treatment of PHPT patients with cinacalcet for up to 5.5 yr maintained normocalcemia, reduced plasma PTH, increased serum phosphate and alkaline phosphatase with no significant effects on aBMD, and was well tolerated.
Peacock
Munro
M
Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA. mpeacock@iupui.edu
Bolognese
Michael A
MA
Borofsky
Michael
M
Scumpia
Simona
S
Sterling
Lulu Ren
LR
Cheng
Sunfa
S
Shoback
Dolores
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000469:Alkaline Phosphatase / Q000097:blood; D015519:Bone Density / Q000187:drug effects*; D002118:Calcium / Q000097:blood; D000069449:Cinacalcet; D003720:Densitometry; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009281:Naphthalenes / Q000009:adverse effects / Q000627:therapeutic use*; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D016896:Treatment Outcome
D009281:Naphthalenes; D010281:Parathyroid Hormone; D010710:Phosphates; D000469:Alkaline Phosphatase; D002118:Calcium; D000069449:Cinacalcet