AstraZeneca Says Hypoparathyroidism Candidate Meets Primary Endpoint in Phase 3 Study

Rare Daily Staff

AstraZeneca said its experimental therapy eneboparatide met its primary endpoint of normalizing serum calcium at 24 weeks in its phase 3 study in adults with the rare endocrine disorder hypoparathyroidism.

The company took over the development of eneboparatide following its acquisition of Amolyt Pharma for $800 million upfront and potential milestones of up to $250 million.

Hypoparathyroidism is caused by a deficiency of parathyroid hormone and characterized by decreased calcium and elevated phosphate levels in the blood, which can lead to a variety of neuromuscular, renal, and skeletal manifestations. The primary cause in approximately 75 percent of people with hypoparathyroidism is injury to or removal of the parathyroid glands during neck surgery. Despite available treatments, people living with hypoparathyroidism continue to experience a significant unmet need.

Eneboparatide is an experimental parathyroid hormone (PTH) receptor 1 agonist for the treatment of chronic hypoparathyroidism. It is designed to bind with high affinity to a specific conformation of the PTH receptor 1 to restore PTH function to manage the symptoms of hypoparathyroidism while preserving kidney function and bone health. Eneboparatide has been granted fast track designation and orphan drug designation by the US Food and Drug Administration and orphan designation by the European Medicines Agency for the treatment of hypoparathyroidism.

High-level results from the CALYPSO Phase 3 trial showed that eneboparatide met its primary endpoint with statistical significance in adults with chronic hypoparathyroidism at 24 weeks, compared to placebo. The primary endpoint is a composite of normalization of albumin-adjusted serum calcium levels and independence from active vitamin D and oral calcium therapy.

The study will continue for 52 weeks to fully characterize the risk-benefit profile.

Eneboparatide was well tolerated. After the 24-week randomized treatment period, all patients receive eneboparatide in the ongoing long-term extension period until 52 weeks. Full efficacy and safety data will be analyzed at 52 weeks. Alexion plans to share these data with global health authorities and present them at forthcoming medical meetings.

“These results from the CALYPSO trial underscore eneboparatide’s potential to be another option for these patients,” said Marc Dunoyer, CEO, Alexion, AstraZeneca Rare Disease.