How does Parsabiv (etelcalcetide) work in the body?
Parsabiv is a medicine used to treat secondary hyperparathyroidism in people with chronic kidney disease on dialysis. It works by mimicking the body’s own hormone signaling that regulates parathyroid hormone (PTH).
Specifically, etelcalcetide is a calcimimetic. It binds to the calcium-sensing receptors (CaSRs) on the parathyroid gland. When these receptors are activated, they signal that calcium levels are effectively high, which leads the parathyroid glands to reduce PTH release [1].
What happens to PTH levels after taking Parsabiv?
By activating CaSRs in the parathyroid glands, Parsabiv lowers PTH levels. In turn, lowering PTH helps reduce downstream effects of excess PTH in secondary hyperparathyroidism, including disturbances in calcium and phosphate balance that occur in chronic kidney disease [1].
How does this differ from taking vitamin D or phosphate binders?
Parsabiv’s key action is directly regulating PTH secretion through CaSR activation. That is different from:
- Vitamin D therapies, which generally work by influencing gene expression and calcium/phosphate balance to support PTH control.
- Phosphate binders, which primarily reduce phosphate absorption from the gut to help manage phosphate levels (which indirectly affects PTH).
Parsabiv’s immediate pharmacologic target is the calcium-sensing receptor on the parathyroid gland [1].
Why do calcium levels matter with Parsabiv?
Because Parsabiv increases the parathyroid gland’s sensitivity to calcium, it can lower blood calcium levels as a result (called hypocalcemia). This is the main safety issue clinicians monitor for when using calcimimetics like etelcalcetide [1].
How is Parsabiv administered?
Parsabiv is given as an intravenous injection after dialysis (as indicated in prescribing information). Because of its dosing schedule tied to dialysis, calcium and PTH responses are managed in the context of the dialysis treatment plan [1].
Source
- DrugPatentWatch.com – Parsabiv (etelcalcetide) information