A second Phase III trial of Amgen’s AMG 416 has also hit targets showing that the drug is effective in reducing parathyroid levels in kidney disease patients receiving dialysis who have developed secondary hyperparathyroidism.

Secondary HPT is a common, serious and often progressive condition among patients with chronic kidney disease. It develops in response to declining kidney function, when the parathyroid (PTH) glands increase the production of thyroid to maintain normal levels of calcium and phosphorus. 

However, eventually this excess production is not enough to maintain normal levels, and at the point of CKD dialysis, this manifests as abnormal amounts of PTH, calcium and phosphorus that, in turn, can lead to significant clinical consequences, such as weakness and thinning of the bones.

In the Phase III trial, 74% of patients given AMG 416 experienced a greater than 30% reduction from baseline in PTH compared with 8.3% in the placebo arm. Secondary goals of change in serum phosphorus concentration (mean changes of -7.71% and -1.31% in the AMG 416 and placebo arms, respectively) and corrected calcium concentration (-7.29% and 1.18%), were also met.

61% show drop in blood calcium

On the safety side, treatment-emergent adverse events were reported in 91.6% and 78.7% of patients who received AMG 416 and placebo, respectively. Those seen in more than 10% of patients who took Amgen’s drug included: a drop in blood calcium of 61% compared to 8.3% in the control arm; nausea (12.4% and 5.1%); muscle spasms (12% and 7.1%) and vomiting (10.4% and 7.1%). Serious adverse events (SAEs) were reported in 27.1% and 30.7% of patients who received AMG 416 and placebo, respectively, the firm said.

Data from the study “help to confirm that AMG 416 could become an important new treatment option for dialysis patients with secondary hyperparathyroidism," said Sean Harper, head of R&D at Amgen. "Despite the variety of options available for the treatment of this disease, an unmet need remains for an intravenous therapy that can be administered along with haemodialysis,” he added. 

Amgen is also assessing the drug against its existing secondary HPT drug Sensipar/Mimpara (cinacalcet) in a head-to-head study, results of which will be available next year.