Long-Term Efficacy and Safety of TransCon PTH in Adult Hypoparathyroidism

Overview

The 52-week Phase 3 PaTHway study demonstrated that TransCon PTH provides sustained normalization of serum calcium and independence from conventional therapy in adults with hypoparathyroidism. The treatment improved quality of life and physical functioning while maintaining a favorable safety profile.

Background

Hypoparathyroidism is characterized by insufficient parathyroid hormone (PTH) leading to hypocalcemia, hyperphosphatemia, and low bone turnover. Conventional therapy with calcium and active vitamin D alleviates symptoms but does not restore normal PTH physiology and is associated with long-term complications. TransCon PTH is a once-daily prodrug designed to provide physiological PTH levels continuously, addressing the underlying hormone deficiency. The PaTHway trial evaluated its long-term efficacy and safety in adults with chronic hypoparathyroidism.

Data Highlights

Key Findings

• At week 52, 81% of participants achieved normal serum calcium and independence from conventional therapy.
• 95% of participants were independent from conventional therapy, with none requiring active vitamin D.
• Mean 24-hour urine calcium excretion decreased significantly from baseline to week 52, indicating improved calcium homeostasis.
• Bone mineral density Z-scores decreased toward age- and sex-matched norms, suggesting normalization of bone turnover.
• Patient-reported outcomes showed sustained improvements in quality of life, physical functioning, and well-being.
• Most treatment-emergent adverse events were mild or moderate, with no discontinuations due to adverse events during the open-label extension.

Clinical Implications

TransCon PTH offers a physiologic replacement therapy for hypoparathyroidism that can normalize serum calcium levels and reduce reliance on conventional calcium and vitamin D supplementation. Its favorable safety profile and improvements in quality of life support its use as a long-term treatment option. Clinicians should consider TransCon PTH for patients inadequately controlled or burdened by conventional therapy.

Conclusion

The 52-week data from the PaTHway trial confirm that TransCon PTH is an effective and well-tolerated treatment for adults with hypoparathyroidism, providing sustained biochemical control and improved patient-reported outcomes. This therapy addresses an unmet need by restoring physiological PTH activity and reducing complications associated with conventional treatment.

References

1. PaTHway Study Group 2024 -- Long-Term Efficacy and Safety of TransCon PTH in Adults With Hypoparathyroidism