Phase 2 Study of Treatment for Hypoparathyroidism, TransCon PTH, Starts to Enroll Adults

A Phase 2 trial evaluating the efficacy and safety of TransCon PTH — designed to restore parathyroid hormone (PTH) levels within 24 hours — in people with hypoparathyroidism is now enrolling adults in North America and Europe.

Called PaTH Forward, the study (NCT04009291) is planning to enroll about 40 patients with hypoparathyroidism who are currently managing their condition with the vitamin D analog calcitriol at least twice a day or the vitamin D metabolite alfacalcidol at least once a day, along with calcium supplements (calcium citrate or calcium carbonate) taken at least twice a day.

Participants will be randomly assigned to one of three doses of Ascendis Pharma‘s TransCon PTH (15, 18, or 21 μg per day) or a placebo for four weeks, all given once daily via an under-the-skin injection using a pre-filled pen. Those who complete this study will have the option of moving in a long-term extension trial, in which they will be given doses of TransCon PTH tailored to their specific needs.

Details on contacts and study locations in the U.S., Europe, and Canada, including those yet to open, can be found here.

To meet trial’s primary endpoints, or goals, patients’ blood calcium levels and the percentage of calcium filtered by the kidneys must be within a normal range after treatment, or decrease by 50% over the course of the study without the need for vitamin D or more than 1 g of a daily calcium supplement.

Investigators will also determine the best disease-specific and patient-reported outcomes, which will be used to inform the design of future trials.

Participants will be required to keep to a schedule of clinic and laboratory visits. They will also need to keep detailed records of their use of TransCon PTH and related supplements for the first 14 weeks of the trial.

TransCon PTH is a pro-drug, a compound that needs to be processed by the body in order to release its active agent — in this case, the parathyroid hormone. PTH is normally secreted by the parathyroid gland and helps regulate levels of calcium and phosphate in the body.

The experimental therapy has been designed to restore PTH levels within 24 hours in people with hypoparathyroidism, while also promoting the normalization of calcium levels in the blood and urine, as well as serum phosphate levels, and bone turnover.

A previous Phase 1 trial (ACTRN12617001375347), also sponsored by Ascendis Pharma, found that TransCon PTH led to sustained release of PTH in the blood of healthy volunteers for more than 60 hours, supporting once-a-day administration. Safety results were also positive.