Visen Set to Start Phase 3 Trial of TransCon PTH in China

Visen Pharmaceuticals has obtained regulatory clearance to start the PaTHway China Trial, a Phase 3 study of TransCon PTH as a hormone replacement therapy for people with hypoparathyroidism in China.

The approval from China’s Center for Drug Evaluation of the National Medical Products Administration came on June 1, which also marks World Hypopara Awareness Day every year.

“It is very encouraging to obtain the [investigational new drug] approval for [the] Phase III clinical trial in China on the World Hypopara Awareness Day, which will inspire us to work hard to accelerate the development of innovative drugs and address unmet clinical needs,” Jun Yang, MD, PhD, Visen’s chief medical officer, said in a press release.

Hypoparathyroidism is caused by lower-than-normal levels of parathyroid hormone (PTH), an important regulator of the balance of calcium and phosphate in the body. For this reason, people with hypoparathyroidism have low levels of calcium (hypocalcemia) and high levels of phosphate (hyperphosphatemia) in the blood. In the short term, this imbalance can cause symptoms that include muscle cramps, pain, and twitching. Over the long term, major complications, such as impaired renal function, may arise.

Developed by Ascendis Pharma, TransCon PTH is a prodrug — an inactive compound that is converted by the body into an active treatment — given as a once-daily under-the-skin injection as a replacement for natural PTH. The therapy is designed to restore blood calcium and phosphate levels to normal and eliminate the need for standard care.

“Hormone replacement has always been the primary treatment option for hormonal deficiency states,” Yang said. “However, no effective parathyroid replacement therapy is available for hypoparathyroidism to correct [disease-related] changes and metabolic disorders.”

TransCon PTH is “designed to replace PTH at physiologic levels for 24 hours every day, and address both short-term symptoms and long-term complications of the disease,” she added.

In 2020, Ascendis Pharma conducted a global Phase 2 trial called PaTH Forward (NCT04009291), results of which supported the use of TransCon PTH in adults with hypoparathyroidism. The therapy was found to be safe, well-tolerated, and effective, with durable benefits.

Earlier this year, Ascendis asked regulatory permission to start a Phase 3 clinical trial in Japan, as part of its global PaTHway trial (NCT04701203) to test TransCon PTH. Visen is responsible for developing and marketing the therapy in Greater China.

“With exclusive rights for R&D and marketing of TransCon parathyroid hormone in Greater China, Visen Pharmaceuticals will carry out the related clinical trial in China, and we hope to provide a new option for Chinese patients with [hypoparathyroidism] as soon as possible,” said Pony Lu, Visen’s CEO.

The PaTHway China Trial seeks to compare the safety, tolerability, and efficacy of TransCon PTH versus a placebo in adults with hypoparathyroidism. In addition, it will assess changes in patient-reported scores in the Hypoparathyroidism Patient Experience Scale and the 36-Item Short Form Health Survey. According to Visen, these assessments are important as China lacks sufficient patient-reported data on the quality of life of people with hypoparathyroidism, including their employment status and the impact of the disease on their jobs.

TransCon PTH has been granted orphan drug designation by the U.S. Food and Drug Administration in 2018 and by the European Medicines Agency in 2020.