The late-breaking data were presented at the European Congress of Endocrinology in Prague, Czech Republic.
Hypoparathyroidism is a rare condition in which the parathyroid glands in the neck produce too little parathyroid hormone (PTH), leading to low blood calcium (hypocalcemia) and high phosphorus levels.
Treatment involves calcium and vitamin D supplements.
Eneboparatide Met Primary Endpoint
The CALYPSO trial evaluated eneboparatide, also known as AZP-3601, a parathyroid hormone 1 receptor agonist designed for patients with chronic hypoparathyroidism.
At week 24, 31.1% of patients treated with eneboparatide achieved normal albumin-adjusted serum calcium levels and independence from active vitamin D and oral calcium supplements.
In comparison, 5.9% of patients in the placebo arm met the same endpoint.
The company said immunogenicity was observed in most patients, which reduced treatment effects in some cases.
However, serum calcium levels were managed with supplements and dose adjustments.
Secondary Endpoints Also Achieved
The study also met all key secondary endpoints at week 24.
Among patients with baseline hypercalciuria, 56.6% of those receiving eneboparatide achieved normalization of urinary calcium excretion, compared with 20% in the placebo group.
Investigators also reported statistically significant improvements in patient-reported outcomes related to physical symptoms, physical functioning, and the SF-36 Physical Function Subscore.
Benefits Maintained Through 52 Weeks
Following the initial 24-week period, patients either continued eneboparatide treatment or switched from placebo to the therapy during a 28-week open-label extension phase.
Patients who remained on eneboparatide maintained clinical benefits through week 52, while some continued using oral supplements.
The company said bone health indicators remained within normal ranges during the extension period.
Biomarkers associated with bone turnover, including P1NP and CTX, increased but stayed consistent with balanced bone activity.
Researchers also reported no clinically significant decline in bone mineral density scores.
AstraZeneca said eneboparatide was generally well-tolerated over 52 weeks of treatment.
Price Action
AstraZeneca shares were up 0.80% at $183.31at the time of publication Tuesday, according to Benzinga Pro. Over the past month, AZN has declined about 9.7% versus a 8.6% rise in the S&P 500 and is down roughly 1% year-to-date compared to the index’s 7.3% gain.
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