FDA Extends Review of Ascendis' Hormone Therapy by 3 Months

Ascendis Pharma's quest for FDA approval of its hormone replacement therapy, TransCon PTH (palopegteriparatide), for the treatment of hypoparathyroidism continues to face delays. The FDA has decided to extend its review period for the therapy by an additional three months, setting a new decision date for August 14, 2024. This extension was triggered because new data submitted by Ascendis was classified as a "major amendment" to the new drug application.

The announcement led to a 6% drop in Ascendis' share price. Despite the delay, Jan Mikkelsen, CEO of Ascendis, expressed confidence in the company's ongoing efforts to address the FDA's requests. He confirmed that patients currently enrolled in clinical trials and the Expanded Access Program (EAP) would continue to receive TransCon PTH. The EAP also remains open for new eligible patients.

This delay follows a complete response letter issued by the FDA to Ascendis about a year ago, which identified a manufacturing issue and questioned the consistency of administered doses. However, no additional clinical data was requested at that time.

TransCon PTH has already found success in Europe. The European Commission granted marketing authorization in November of the previous year, where it is sold under the brand name Yorvipath. The therapy received approval in the U.K. as well, and Ascendis has begun its commercial rollout in Germany and Austria.

Hypoparathyroidism, affecting approximately 70,000 individuals in the U.S., is characterized by insufficient production of calcium by the parathyroid glands, leading to muscle aches and spasms. The condition, if untreated, can cause severe complications including renal issues and cognitive impairments. The parathyroid glands play a crucial role in regulating calcium and phosphorus levels in the body.

In clinical trials, TransCon PTH demonstrated significant efficacy. A phase 3 trial revealed that the treatment raised calcium levels in 79% of patients and enabled 95% of them to discontinue conventional therapies, which typically involve oral calcium and active vitamin D supplements.

This pending approval is critical as Ascendis aims to secure its second FDA endorsement in just three years. The company previously received FDA approval for Skytroka, a long-acting growth hormone designed for children, in 2021. Sales of Skytroka reached 179 million euros ($194 million) last year, and Ascendis forecasts that revenues from this product will climb to between 320 million euros ($346 million) and 340 million euros ($368 million) in the current year.

The delay in TransCon PTH’s approval is a setback, but Ascendis remains committed to meeting regulatory requirements and bringing their innovative treatment to the U.S. market.