AstraZeneca (NASDAQ: AZN) announced that its investigational drug eneboparatide met the primary endpoint in a Phase III trial for chronic hypoparathyroidism, a rare endocrine disorder.

The CALYPSO trial showed that 31.1% of patients treated with eneboparatide achieved normal serum calcium levels and independence from vitamin D and calcium supplements at 24 weeks, compared to 5.9% in the placebo group. The study included 132 patients in the treatment group and 68 in the placebo group.

Eneboparatide is a parathyroid hormone receptor agonist designed to address inadequate parathyroid hormone activity in patients with chronic hypoparathyroidism. The condition affects calcium regulation and can impact multiple body systems.

The trial also met secondary endpoints, including normalization of urinary calcium excretion in 56.6% of patients with elevated baseline levels, versus 20% in the placebo group. Patients showed improvements in physical functioning measures and disease-specific symptoms.

During the 24-week treatment period, immunogenicity was observed in most patients, which reduced treatment effects in some cases. Calcium levels were managed through supplements and dose adjustments.

An additional 28-week extension period showed maintained clinical benefits through week 52. Bone health markers remained within normal ranges, and no significant reduction in bone mineral density was observed.

The company reported that eneboparatide was well tolerated over the 52-week treatment period, with adverse events balanced between treatment and placebo groups during the initial 24 weeks.

The results were presented at the European Congress of Endocrinology in Prague, Czech Republic. AstraZeneca described the trial as the largest global study conducted in adults with chronic hypoparathyroidism.