The regulator, in its complete response letter (CRL), mentioned concerns regarding the manufacturing control strategy for variability of delivered dose in the TransCon PTH drug/device combination product.
It did not express concerns regarding the clinical data, which was submitted by the company as part of the NDA package.
The FDA also did not request for new preclinical or Phase III clinical trials for assessing efficacy or safety.
Ascendis Pharma president and CEO Jan Mikkelsen said: “We are committed to working collaboratively with the FDA and, because the agency did not suggest that additional Phase III studies may be needed to demonstrate the product’s safety and efficacy, we believe we are well prepared to address their concerns.
“People with hypoparathyroidism need new treatment options and we are working with urgency to resolve the FDA’s concerns, with the goal of bringing TransCon PTH to patients in the US.”
The investigational prodrug, TransCon PTH has been designed for replacing parathyroid hormone to physiologic levels in hypoparathyroidism patients.
It was found to be generally well tolerated and there were no discontinuations related to study drug, in the clinical trials.
The company expects to receive European Commission decision regarding the marketing authorisation application (MAA) during the fourth quarter of this year.
If approved, Ascendis Pharma intends to launch TransCon PTH in Germany early next year.