Ascendis’ Hormone Drug Hits Another FDA Roadblock on Path to Approval

After experiencing a regulatory delay early last month due to issues in their hormone drug’s New Drug Application (NDA), the FDA issued Denmark-based Ascendis Pharma with a Complete Response Letter (CLR), citing concerns with the drug’s manufacturing process. The hormone drug in question, TransCon PTH (palopegteriparatide), was initially set to receive an approval decision by April 30. 

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Addressing Manufacturing Concerns

In light of the CLR, Ascendis issued a press release outlining some of the issues and the next steps the company plans to take. Ascendis stated that the reason for the CLR is issues concerning the manufacturing control strategy for the variability of delivered doses in the TransCon PTH drug/device combination product.

The company plans to set up a Type A meeting with the FDA to find a solution to the problems to get the product back on the approval pathway. Fortunately, the FDA did not mention anything about the quality or quantity of clinical trial data in the most recent CLR, meaning Ascendis would not have to perform additional studies.

Ascendis’ 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 3 studies may be needed to demonstrate the product’s safety and efficacy, we believe we are well prepared to address their concerns.”

In addition to seeking American approval for TransCon PTH, Ascendis has its eyes set on European approval. The company says it expects to receive a response to its marketing authorization application (MAA) in the fourth quarter of this year. If the European Commission renders a favorable verdict, Ascendis says it plans to launch the product in Germany in early 2024. 

TransCon PTH’s Development So Far

If Ascendis’ TransCon PTH gains approval, it would mark the company’s second approved product following Skytrofa, a pediatric growth hormone treatment approved in August 2021. 

The proprietary TransCon line of technology’s name comes from the term “transient conjugation” and its ability to link a carrier to a parent drug. Ascendis’ primary focus for TransCon’s application is in rare endocrinology diseases, but the company also has programs in oncology and ophthalmology. 

Ascendis designed TransCon PTH to treat hypoparathyroidism, a rare disease characterized by the body’s lack of ability to produce enough PTH. A lack of this crucial hormone can reduce blood calcium levels and increase phosphorus levels. 

TransCon PTH underwent Phase 3 clinical trials where Ascendis said the drug was generally well tolerated among the trial participants. 145 of the 154 Phase 3 trial participants continue to take TransCon PTH, and the U.S. Expanded Access Program continues to enroll new participants. 

The most recent CLR is a blow to Ascendis, but the company is taking the letter in stride and seems confident in its abilities to overcome any of the manufacturing concerns the FDA might have. With the initial approval decision date come and gone, hopefully, the company can remediate the issues and get TransCon PTH back on track to make it to the market and treat adults with hypoparathyroidism. 

Author

Reed Slater