British-Swedish multinational pharmaceutical and biotechnology company AstraZeneca (LSE:AZN)(STO:AZN)(Nasdaq:AZN) announced on Monday that eneboparatide (AZP-3601), an investigational parathyroid hormone (PTH) receptor 1 agonist, demonstrated statistically significant results in the CALYPSO Phase III trial, meeting the primary endpoint in adults with chronic hypoparathyroidism (HypoPT) after 24 weeks.

This primary endpoint involved normalisation of albumin-adjusted serum calcium levels and independence from active vitamin D and oral calcium therapy. HypoPT, a rare endocrine disorder affecting over 200,000 people in the United States and the European Union, is caused by a deficiency of PTH, leading to dysregulated calcium and phosphate levels. Eneboparatide was well tolerated and all patients will continue treatment in an ongoing long-term extension period for up to 52 weeks. Efficacy and safety data will be fully analysed at 52 weeks.

The CALYPSO trial was a global, randomised, double-blind, placebo-controlled study that included 202 patients receiving standard of care, who were randomly assigned to receive either eneboparatide or placebo. The primary efficacy endpoint focused on the proportion of patients achieving normal serum calcium levels and discontinuation of standard treatment. Secondary endpoints included normalisation of 24-hour urinary calcium in hypercalciuria patients and patient-reported outcomes reflecting physical symptoms and quality of life. Eneboparatide is designed to restore PTH function, supporting kidney and bone health and has received fast track and orphan drug designations from the FDA and EMA for HypoPT treatment. Alexion, AstraZeneca Rare Disease is committed to addressing rare disease challenges and continues to expand its portfolio globally.