MBX Biosciences (MBX) said Friday that the Avail phase 2 trial of once-weekly canvuparatide to treat chronic hypoparathyroidism met its primary composite endpoint at 12 weeks.

The primary endpoint required patients to normalize their serum calcium levels while eliminating the need for active vitamin D and reducing daily calcium supplements to less than 600 mg.

The company also released new one-year open-label extension data showing a 57% responder rate, with 90% of the entering patients continuing the treatment.

The treatment demonstrated solid initial retention, with 60 patients advancing into the two-year open-label extension after the core 12-week trial.

The company remains on track to begin the phase 3 trial in Q3 2026.

Shares of MBX Biosciences were down more than 16% pre-bell after surging 20% in Thursday's trading session.