Abstract

Aims: Cinacalcet lowers plasma parathyroid hormone (PTH) levels in patients with secondary hyperparathyroidism (sHPT), but the bone histologic response has not been described. This prospective, double-blind, placebo-controlled trial assessed the effects of cinacalcet on bone histology and serum markers of bone metabolism in dialysis patients with sHPT. Methods: Patients with intact PTH (iPTH) >= 300 pg/ml were randomly assigned 2:1 to receive cinacalcet or placebo with concurrent vitamin D and/or phosphate binder therapy. Cinacalcet (30 – 180 mg/day) was used to achieve iPTH levels <= 200 pg/ml. Bone biopsies were performed before and after one year of treatment. Results: Baseline and end-of-study data were available from 32 patients (19 cinacalcet, 13 placebo). Baseline bone turnover was elevated in 27, reduced in 3 and normal in 2 patients. Serum bone-specific alkaline phosphatase (BSAP) and N-telopeptide (NTx) were elevated. Cinacalcet treatment decreased PTH and diminished activation frequency, bone formation rate/bone surface, and fibrosis surface/bone surface. Adynamic bone was observed in three patients receiving cinacalcet; in two of these, PTH levels were persistently low (< 100 pg/ml). The histomorphometric parameter changes in bone corresponded to PTH, BSAP and NTx reductions. Bone mineralization parameters remained normal. Conclusions: Treatment with cinacalcet lowered PTH and reduced bone turnover and tissue fibrosis among most dialysis patients with biochemical evidence of sHPT.

Author Details

Authors

• H.H. Malluche
• M.-C. Monier-Faugere
• G. Wang
• J.M. Frazão
• C. Charytan
• J.W. Coburn
• D.W. Coyne
• M.R. Kaplan
• N. Baker
• L.C. McCary
• S.A. Turner
• W.G. Goodman

Departments

• ¹ University of Kentucky, Division of Nephrology, Bone and Mineral Metabolism, Lexington, KY, USA,
• ² Nephrology Research and Development Unit, School of Medicine, Porto University, Portugal,
• ³ New York Hospital Medical Center of Queens, Flushing, NY,
• ⁴ VA Greater Los Angeles Health Care System, Los Angeles, CA,
• ⁵ Washington University School of Medicine, St. Louis, MO,
• ⁶ Nephrology Associates, Nashville, TN,
• ⁷ Amgen, Thousand Oaks, CA,
• ⁸ David Geffen School of Medicine at UCLA, Los Angeles, CA, USA

Address

H.H. Malluche, MD; Division of Nephrology, Bone and Mineral Metabolism, University of Kentucky, Room MN 564, 800 Rose Street, Lexington, KY 40536-0084, USA
Email: [email protected]

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