MBX Biosciences has dosed the first patient in its Phase 3 oPTimize clinical trial, evaluating canvuparatide as a potential treatment for chronic hypoparathyroidism. The study, registered under NCT07699471, aims to enroll approximately 160 adults with the condition across sites in the U.S. and Europe.
The trial follows a 3:1 randomization ratio, assigning patients to receive either canvuparatide or a placebo once weekly over a 26-week double-blind treatment period. The regimen includes a four-week fixed-dose phase at 600 micrograms, an 18-week individualized dose-titration period up to 1,600 micrograms, and a four-week dose-maintenance phase. Participants will then enter a 78-week open-label extension period.
The primary endpoint assesses the proportion of patients achieving a composite responder definition at week 26, requiring maintenance of normal albumin-adjusted serum calcium levels, independence from active vitamin D, reduction of calcium supplementation to 600 milligrams or less daily, and no increases in study drug dose 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.
Canvuparatide is an investigational long-acting parathyroid hormone peptide prodrug designed for once-weekly administration as a parathyroid hormone replacement therapy. The drug has received Orphan Drug Designation from the U.S. Food and Drug Administration and Orphan Designation from the European Medicines Agency, reflecting its potential to address an underserved patient population. Chronic hypoparathyroidism affects over 250,000 patients in the U.S. and EU, with an estimated annual incidence exceeding 7,000 new cases.
