MBX Biosciences has initiated a Phase 3 clinical trial for canvuparatide, an investigational long-acting parathyroid hormone peptide prodrug, dosing the first patient in the oPTimize study. The trial, registered as NCT07699471, will enroll approximately 160 adults with chronic hypoparathyroidism across the U.S. and Europe.
The double-blind, placebo-controlled trial includes a 26-week treatment period, followed by a 78-week open-label extension. Patients will receive a fixed dose of 600 micrograms once weekly or placebo during the initial four weeks, with dose titration up to 1,600 micrograms possible over the subsequent 18 weeks. The primary endpoint at week 26 assesses the proportion of patients achieving a composite responder endpoint, which requires maintenance of normal albumin-adjusted serum calcium levels, independence from active vitamin D, reduction of calcium supplementation to 600 milligrams or less per day, and no dose increases in the four weeks preceding the assessment.
Key secondary endpoints include normalization of urinary calcium excretion while maintaining normal serum calcium in patients with elevated baseline levels, as well as improvements in physical functioning and hypocalcemia-related symptoms. The trial design incorporates a four-week fixed-dose period, an 18-week individualized dose-titration period, and a four-week dose-maintenance period leading up to the primary evaluation at week 26.
Canvuparatide has received Orphan Drug Designation from the U.S. Food and Drug Administration and Orphan Designation from the European Medicines Agency. Hypoparathyroidism, the target condition, affects over 250,000 patients in the U.S. and EU, with an estimated annual incidence of more than 7,000 new cases per year.
