Another delay for Ascendis' hormone therapy as FDA extends review by 3 months

It’s been a long wait for Ascendis Pharma to score FDA approval for its hormone replacement therapy TransCon PTH (palopegteriparatide). And, now, it’ll take another three months for the U.S. regulator to decide on the treatment for the endocrine disease hypoparathyroidism.

Tuesday, the Copenhagen, Denmark-based company said the FDA has extended its review to Aug. 14, 2024, because certain information Ascendis had submitted constituted a “major amendment” to the new drug application.

With the news, Ascendis’ share price fell by 6%.

“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,” Jan Mikkelsen, Ascendis’ CEO, said in a release. “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.”

The extension comes slightly more than 12 months after the FDA issued a complete response letter to Ascendis, citing a manufacturing issue and questioning the variability of delivered doses of the treatment. In the rejection notice, the FDA did not request additional clinical data.

In November of last year, the European Commission granted marketing authorization to the drug, which is branded as Yorvipath in Europe. It also was approved in the U.K. in April. In a recent quarterly report, Ascendis said it has launched Yorvipath in Germany and Austria.

Hypoparathyroidism, which affects roughly 70,000 people in the U.S., is a condition in which the parathyroid glands don’t produce enough calcium, causing muscle aches and spasms. Four parathyroid glands in the neck control the critical balance between calcium and phosphorus. The disease can eventually lead to renal complications and cognitive impairment.

TransCon PTH proved itself in a phase 3 trial which showed that it raised the calcium levels in 79% of patients and allowed 95% of patients to be freed from conventional therapy, which includes oral calcium and active vitamin D.

Ascendis is seeking its second FDA nod in three years. Skytroka, a long-acting growth hormone for children, was endorsed in 2021. Last year, sales for the once-weekly medicine reached 179 million euros ($194 million). The company projects Skytroka sales will reach 320 million euros ($346 million) to 340 million euros ($368 million) this year.