Skip to content
approvedBone & Joint

Etelcalcetide

Also known as: Parsabiv, AMG 416, Velcalcetide

Etelcalcetide (Parsabiv) is a synthetic 8-amino acid peptide calcimimetic agent FDA-approved in 2017 for the treatment of secondary hyperparathyroidism (SHPT) in adults with chronic kidney disease on hemodialysis. As the first peptide-based calcimimetic, it acts as a positive allosteric modulator of the calcium-sensing receptor (CaSR) on parathyroid cells, suppressing parathyroid hormone (PTH) secretion. Uniquely, it is administered intravenously at the end of hemodialysis sessions, eliminating the GI side effects and adherence problems associated with oral cinacalcet.

3 cited references·5 researched benefits

Quick Answer

Etelcalcetide (Parsabiv) is an 8-amino acid calcimimetic peptide FDA-approved for secondary hyperparathyroidism in hemodialysis patients. Administered intravenously 3 times weekly at the end of dialysis, it activates the calcium-sensing receptor on parathyroid glands to suppress excess PTH secretion. Clinical trials demonstrated superior PTH reduction compared to oral cinacalcet, with fewer GI side effects. Its long half-life of 3-5 days allows thrice-weekly dosing aligned with hemodialysis schedules.

Key Facts

Mechanism
Etelcalcetide is a linear peptide containing a D-cysteine residue linked via a disulfide bond to the L-cysteine residue of the extracellular domain of the calcium-sensing receptor (CaSR). This unique covalent binding mechanism acts as a positive allosteric modulator, enhancing the receptor sensitivity to extracellular calcium. When CaSR is activated on chief cells of the parathyroid gland, it triggers Gq-mediated phospholipase C activation and intracellular calcium mobilization, which suppresses PTH gene transcription, PTH secretion, and parathyroid cell proliferation. The D-amino acid composition confers resistance to proteolytic degradation, and its clearance occurs primarily through hemodialysis.
Research Status
approved
Half-Life
~3-5 days
Molecular Formula
C₃₈H₇₃N₁₅O₁₀S₂
Primary Use
Bone & Joint
Table of Contents

Benefits

  • Superior PTH reduction — phase 3 trials showed >30% PTH reduction in 68-76% of patients vs 22-26% for placebo, and superiority over cinacalcetstrong
  • Improved medication adherence — IV administration at dialysis ensures 100% compliance, eliminating the pill burden and missed doses seen with oral cinacalcetstrong
  • Fewer GI side effects — avoids the nausea and vomiting that affect 20-30% of cinacalcet patients due to oral route bypassstrong
  • Reduces FGF-23 levels — secondary benefit of PTH suppression, potentially reducing cardiovascular risk associated with elevated FGF-23moderate
  • Corrects disordered mineral metabolism — lowers calcium-phosphorus product, reducing risk of vascular calcification in CKDmoderate

Dosage Protocols

RouteDosage RangeFrequencyNotes
Intravenous (bolus at end of hemodialysis)5 mg initial dose; titrate by 2.5-5 mg increments3 times per week (with each hemodialysis session)Administered as IV bolus into the venous line of the dialysis circuit at the end of the session. Starting dose is 5 mg. Dose titrated every 4 weeks to a maximum of 15 mg based on PTH levels. Serum calcium must be ≥8.3 mg/dL before initiation and monitored before each dose. Hold dose if calcium <7.5 mg/dL or symptomatic hypocalcemia.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Hypocalcemia — the most significant side effect, occurring in 60-70% of patients; serum calcium must be monitored before each doseserious
  • Muscle spasms and paresthesias — related to hypocalcemia, reported in 10-15% of patientscommon
  • Nausea — occurs in approximately 10-11% (lower than cinacalcet's 28-32%) but still presentcommon
  • QT prolongation — secondary to hypocalcemia; ECG monitoring recommended in patients on QT-prolonging medicationsserious
  • Diarrhea and vomiting — gastrointestinal effects in 7-9% of patients, less frequent than with oral cinacalcetcommon
  • Worsening heart failure — rare reports of symptomatic hypocalcemia exacerbating cardiac function; avoid in patients with very low serum calciumserious

Frequently Asked Questions

How does etelcalcetide compare to cinacalcet (Sensipar)?
Both are calcimimetics that activate the calcium-sensing receptor to suppress PTH, but they differ significantly. Etelcalcetide is an 8-amino acid peptide given IV 3 times/week at dialysis, while cinacalcet is a small-molecule oral tablet taken daily. In a head-to-head phase 3 trial, etelcalcetide showed statistically superior PTH reduction. The IV route ensures compliance (a major issue with oral cinacalcet) and significantly reduces GI side effects (nausea, vomiting). However, etelcalcetide is only suitable for hemodialysis patients since it requires IV access and is cleared by dialysis.
Why is hypocalcemia so common with etelcalcetide?
Etelcalcetide potently activates the calcium-sensing receptor, which suppresses PTH — the primary hormone responsible for maintaining blood calcium levels. With PTH suppressed, calcium reabsorption from bone and kidneys decreases, and serum calcium drops. Dialysis patients are already prone to calcium dysregulation. The high rate (60-70%) reflects the drug effectiveness at PTH suppression. Management involves ensuring adequate calcium dialysate concentration, calcium and vitamin D supplementation, and careful dose titration.
Can etelcalcetide be used in non-dialysis CKD patients?
No. Etelcalcetide is approved only for hemodialysis patients. It requires IV administration through the dialysis circuit and is primarily cleared by hemodialysis. In non-dialysis CKD patients, its extremely long half-life would lead to drug accumulation and severe, prolonged hypocalcemia. Cinacalcet (oral) is also only indicated for dialysis patients. Non-dialysis CKD patients with hyperparathyroidism are typically managed with vitamin D analogs, phosphate binders, and dietary modification.
What is secondary hyperparathyroidism in kidney disease?
Secondary hyperparathyroidism (SHPT) develops in chronic kidney disease because failing kidneys cannot produce sufficient active vitamin D or excrete phosphorus. This leads to low calcium, high phosphorus, and compensatory overproduction of parathyroid hormone. Chronically elevated PTH causes bone disease (renal osteodystrophy), vascular calcification, increased cardiovascular mortality, and other complications. SHPT affects virtually all dialysis patients and is a major driver of morbidity in end-stage kidney disease.

References

  1. 1
    Effect of etelcalcetide vs cinacalcet on serum parathyroid hormone in patients receiving hemodialysis with secondary hyperparathyroidism: a randomized clinical trial(2017)PubMed ↗
  2. 2
    Effect of etelcalcetide vs placebo on serum parathyroid hormone in patients receiving hemodialysis with secondary hyperparathyroidism: two randomized clinical trials(2017)PubMed ↗
  3. 3
    Etelcalcetide: a novel peptide calcimimetic agent for secondary hyperparathyroidism(2017)PubMed ↗

Latest Research

Last updated: 2026-02-19