FDA OKs New Drug for Treating Hypoparathyroidism

The US Food and Drug Administration (FDA) has approved palopegteriparatide (Yorvipath) for the treatment of hypoparathyroidism in adults, the drug’s manufacturer Ascendis Pharma announced. 

In hypoparathyroidism, insufficient levels of parathyroid hormone (PTH) can lead to hypocalcemia and hyperphosphatemia, with subsequent complications including neuromuscular irritability and kidney and vascular complications. Cognitive impairment is also common. Most cases (70%-80%) are post-surgical, while others result from autoimmunity or are idiopathic. The condition affects an estimated 70,000-90,000 people in the United States, according to Ascendis. 

Palopegteriparatide, developed as TransCon PTH, is a prodrug of parathyroid hormone. It is given as a once-daily subcutaneous injection designed to provide stable PTH levels within the normal physiological range over 24 hours. In contrast, conventional active vitamin D and calcium treatments are associated with fluctuations in calcium levels, hypercalciuria, renal impairment, and decreased quality of life. 

The FDA approval was based on data from the company’s phase 2 PaTH Forward trial and the Phase 3 PaTHway trial. In both, the drug was associated with normalization of serum calcium levels and independence from conventional treatments, without major adverse events. 

Adverse reactions occurring in 5% or more of treated patients included injection site reactions (39%), vasodilatory signs and symptoms (28%), headache (21%), diarrhea (10%), back pain (8%), hypercalcemia (8%) and oropharyngeal pain (7%).

Ascendis is completing manufacturing of commercial product for the US market and anticipates initial supply will be available in the first quarter of 2025 pending FDA approval of existing manufactured product, which could be introduced later in 2024. 

Miriam E. Tucker is a freelance journalist based in the Washington DC area. She is a regular contributor to Medscape, with other work appearing in The Washington Post, NPR’s Shots blog, and Diatribe. She is on X (formerly Twitter) @MiriamETucker.