FDA Extends Review Period for Ascendis TransCon PTH Hypoparathyroidism Therapy

Rare Daily Staff

The U.S. Food and Drug Administration extended the review period for Ascendis Pharma’s New Drug Application for TransCon PTH as a treatment for adults with hypoparathyroidism by three months.

Hypoparathyroidism (hypopara or HP) is a rare endocrine disorder characterized by deficient or absent parathyroid hormone. Current standard of care treatment with calcium and calicitriol does not effectively address both the short-term symptoms of low calcium in the blood and long-term complications of calcium deposits in the organs, or the quality-of-life impacts of hypoparathyroidism.

Parathyroid hormone (PTH) plays a critical role in controlling calcium, phosphate and calcitriol (active vitamin D) levels in the blood and bone. Through its primary actions, PTH directly involves the kidneys, bone and other organs in maintaining key biological functions. TransCon is an investigational long-acting prodrug of parathyroid hormone (PTH) in development as a once-daily hormone replacement therapy that is designed to restore physiologic levels of PTH 24 hours a day.

FDA rejected Ascendis’ first application to market TransCon PTH in May 2023 over manufacturing issues but accepted a second submission in December 2023. TransCon PTH has orphan designation for the treatment of hypoparathyroidism in both the U.S. and Europe, and is approved in Europe and Great Britain.

“We have responded to all requests received to date from FDA and will work with the agency as they continue their review of our NDA,” said Jan Mikkelsen, Ascendis Pharma’s president and CEO. “Adults with hypoparathyroidism in the United States, who are receiving TransCon PTH in our clinical trials and our Expanded Access Program (EAP) will continue to receive their medication, and the EAP remains open for enrollment for eligible patients.”

Photo: Jan Mikkelsen, Ascendis Pharma’s president and CEO