FDA Delays Review by Three Months for Ascendis’ Hypoparathyroidism Therapy


Pictured: FDA signage at its office in Washington, DC/iStock, JHVEPhoto

Ascendis Pharma on Tuesday announced that the FDA has extended its review of the company’s investigational hypoparathyroidism treatment TransCon PTH (palopegteriparatide). The new target action date is Aug. 14, 2024.

The delay comes after Ascendis submitted additional information to support its New Drug Application (NDA), which the regulator considered a major amendment.

“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,” CEO Jan Mikkelsen said in a statement, adding that patients who are currently receiving TransCon PTH through clinical trials or Ascendis’ Expanded Access Program will still be able to get their treatment.

Tuesday’s delay adds to TransCon PTH’s regulatory woes. Ascendis first tried for an approval in 2022 but was rejected by the FDA in May 2023. At the time, the regulator did not identify problems with the candidate’s clinical or safety data but took issue with the biotech’s “manufacturing control strategy” for dose variabilities in the final drug-device product.

Ascendis filed its resubmission in November 2023, which the FDA accepted a month later and set a target action date of May 14, 2024. The regulator considered the resubmission a “complete, class 2 response,” according to the biotech.

TransCon PTH is approved in the European Union and in the U.K., where it carries the brand name Yorvipath.

Designed as a once-daily subcutaneous injection, TransCon PTH is a long-acting prodrug of the parathyroid hormone. It works by raising hormone levels to physiologic levels for 24 hours, which could help address hypoparathyroidism, a rare disorder characterized by low calcium and high phosphate concentrations linked to parathyroid hormone insufficiency.

Hypoparathyroidism manifests as weakness, headaches and muscle cramps. When left unchecked, the condition can lead to calcium deposits in the brain, kidneys and eyes. Hypoparathyroidism is currently managed through high-dose calcium and active vitamin therapy, though these do not adequately control the condition.

Results of the Phase III PaTHway trial, published online in January 2023 in the Journal of Bone Mineral Research, showed TransCon PTH met its composite primary endpoint, which included achieving normal levels of albumin-adjusted serum calcium, independence from conventional vitamin D therapy and no increase in the study drug over four weeks.

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. Reach out to him on LinkedIn or email him at tristan@tristanmanalac.com or tristan.manalac@biospace.com.

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