Ascendis Asking to Open TransCon PTH Trial for Adults in Japan

Marisa Wexler MS avatar

by Marisa Wexler MS |

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TransCon PTH trial plans

Ascendis Pharma is requesting regulatory permission to open a Phase 3 clinical trial in Japan, part of its program to assess TransCon PTH as a hormone replacement therapy for adults with hypoparathyroidism at sites worldwide.

Ascendis filed a clinical trial notification (CTN) for what it will call the PaTHway Japan Trial with that country’s Pharmaceuticals and Medical Devices Agency (PDMA).

“The CTN filing for TransCon PTH represents another milestone as we continue to lay the groundwork to make this important therapy available globally to address a significant unmet need for patients with hypoparathyroidism worldwide,” Jan Mikkelsen, president and CEO of Ascendis, said in a press release.

“The phase 3 PaTHway Japan Trial … will enroll a predetermined cohort [group] of patients so that the combined global program will support submission of a marketing authorization application in Japan,” Mikkelsen added.

Hypoparathyroidism is caused by abnormally low levels of the parathyroid hormone (PTH), which is important for regulating levels of calcium and phosphate. TransCon PTH is a prodrug — an inactive compound that is converted by the body into an active treatment — designed to mimic the effects of PTH.

The therapy is administered once per day via a subcutaneous (under-the-skin) injection from a pre-filled pen injector.

In addition to the planned trial in Japan, Ascendis is sponsoring a Phase 3 clinical trial called PaTHway (NCT04701203) that is underway at sites in Europe and North America. This trial is enrolling about 76 adults with hypoparathyroidism who will be randomized to daily injections of TransCon PTH or a placebo for 26 weeks (six months). Its main goal is to assess the effect of treatment on calcium levels in the body.

PaTHway is recruiting at multiple sites in the U.S., Canada, Denmark, Hungry and Norway; more information is available here. An open-label (no placebo group) extension study is set to follow the 26-week main study.

A long-term extension study is also underway and collecting data on hypoparathyroidism patients who took part in the Phase 2 PaTH Forward (NCT04009291) trial; are being given TransCon PTH. Results from the main Phase 2 study indicated that the treatment with TransCon PTH normalized body calcium levels and reduced the need for vitamin D or calcium supplements — the standard therapeutic regimen in hypoparathyroidism. Six-month data from the extension study, where all are on the treatment, were also positive and showed an improved quality of life.

Data from the planned PaTHway Japan Trial, in combination with the PaTHway trial and the PaTH Forward data, “should potentially enable rapid access to an important hormone replacement therapy for patients living with [hypoparathyroidism] in Japan,” Mikkelsen said.