Hypoparathyroidism due to surgery controlled with TransCon PTH
Results from PaTHway clinical trial presented at annual ATA meeting
The experimental therapy TransCon PTH was effective at controlling hypoparathyroidism caused by neck surgery for most patients in the PaTHway clinical trial, according to data presented at the American Thyroid Association (ATA) annual meeting by its developer Ascendis Pharma.
“We are pleased to share with thyroid surgeons and thyroidologists attending ATA this data demonstrating the safety and benefits of TransCon PTH seen in clinical trial patients whose disease arose following neck surgeries,” Aimee Shu, MD, vice president of clinical development, endocrinology medical sciences at Ascendis, said in a company press release.
Hypoparathyroidism is marked by the abnormally low production of parathyroid hormone (PTH), a signaling molecule that helps regulate the absorption of calcium. Standard treatment for hypoparathyroidism involves calcium and vitamin D, which helps absorb calcium.
TransCon PTH, which is injected under the skin once a day, contains an inactive molecule, or prodrug, that gets converted into PTH inside the body. It’s being developed to normalize calcium levels and other molecules without needing standard supplements.
The Phase 3 PATHway clinical trial (NCT04701203) tested TransCon PTH against a placebo in 82 people with hypoparathyroidism. The therapy outperformed a placebo at normalizing calcium levels after six months and recent one-year data showed continued benefits.
Results on hypoparathyroidism caused by surgery
In the new presentation, researchers shared an analysis of the 70 participants in PATHway whose hypoparathyroidism developed from surgery in the neck that damaged the parathyroid glands, which make PTH. Surgical complications are the most common cause of hypoparathyroidism.
After six months of treatment, 81% of the patients on TransCon PTH had normal calcium levels without taking vitamin D supplements and with calcium supplement levels of 600 mg/day or lower. Only 6% of patients given a placebo had normal calcium levels without the need for substantial supplements.
Scores on a standardized measure of health-related quality of life called the SF-36 improved significantly with TransCon PTH compared to the placebo after six months. Also, 81% of patients given TransCon PTH reported an improvement relative to the placebo in their ability to function in daily life.
A greater reduction in urine calcium excretion with TransCon PTH over a placebo was also seen, and the therapy was well tolerated, with no participants stopping it due to side effects resulting from treatment.
The analysis from patients with surgery-related hypoparathyroidism was similar to results from prior analyses that included all the participants in the PATHway trial, according to Ascendis.
“Our goal is to provide a treatment option that can help patients overcome the serious health and quality of life burdens associated with hypoparathyroidism, regardless of its cause,” Shu said. “We will continue to advance TransCon PTH globally as a candidate to address the urgent needs of this patient community.”