Etelcalcetide Hydrochloride is primarily used in the treatment of secondary hyperparathyroidism in patients with chronic kidney disease who are on hemodialysis. It works by mimicking the action of calcium in the body, helping to regulate the levels of parathyroid hormone (PTH). This is crucial for patients with kidney disease, as their kidneys cannot effectively manage calcium and phosphate levels, leading to elevated PTH and associated complications like bone disease and cardiovascular issues. By controlling PTH levels, Etelcalcetide Hydrochloride helps reduce the risk of these complications, improving overall patient outcomes. It is administered intravenously during or after hemodialysis sessions, ensuring consistent and effective treatment.