TransCon PTH Available to Adults in US Under Expanded Access Program

FDA expected to decide about OK'ing hypoparathyroidism treatment by April

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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The U.S. Food and Drug Administration (FDA) has greenlit an expanded access program (EAP) for Ascendis Pharma to allow certain adults with hypoparathyroidism to receive TransCon PTH, an investigational parathyroid hormone (PTH) replacement therapy.

An EAP allows patients with life-threatening or serious diseases access to investigational therapies outside clinical trials. A discussion with a physician is needed to determine whether a patient can participate in an EAP.

To qualify, a patient must not have satisfactory alternatives among commercial products or clinical trials, and they must live in the U.S. and have experience with PTH treatments. Physicians must submit requests on patients’ behalf. Those interested can know more at

“We are pleased to work with the FDA to expand access to TransCon PTH for eligible patients and look forward to sharing more details about this program soon,” said Edward Trott, MD, Ascendis’ vice president of global medical affairs, in a press release.

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Ascendis sought approval of TransCon PTH for adults with hypoparathyroidism in the U.S. in September. The application was given priority review. The FDA is expected to decide whether to approve the treatment by April 30.

A similar request was submitted in November to the European Medicines Agency.

“Recognizing the hypopara community’s urgent need, we remain committed to making TransCon PTH, if approved, more broadly available as quickly as possible,” Trott said.

Hypoparathyroidism is marked by abnormally low levels of PTH, a key player in regulating calcium and phosphorus.

TransCon PTH contains a long-lasting precursor of PTH. The therapy is a prodrug — an inactive compound converted by the body into an active therapy — designed to be administered once daily via under-the-skin (subcutaneous) injection to normalize PTH levels.

Positive findings from two trials — the Phase 2 PaTH Forward trial (NCT04009291) and the Phase 3 clinical trial PaTHway (NCT04701203) — supported both applications.

Results from the Phase 2 trial showed that after nearly a month, TransCon PTH was better than a placebo at eliminating the need for conventional therapies, and in normalizing calcium levels in the blood and urine. Also, after more than 1.5 years on TransCon PTH, most patients continue to show normal calcium levels with no need for vitamin D supplements or high doses of calcium.

In the Phase 3 trial, participants were given TransCon PTH or a placebo daily for six months with the therapy outperforming the placebo at normalizing calcium levels without the need for standard treatments (78.7% vs. 4.8%). The therapy also was better at easing patient-reported symptoms and improving or stabilizing physical function.

Most participants joined the study’s open-label extension, where they will receive TransCon PTH for up to three years.

In both trials, the therapy was generally well tolerated, with no one stopping it due to side effects attributable to it.