Ascendis Reports Kidney Improvement in 68.9% of Patients With Hypoparathyroidism
Key Facts
Ascendis Pharma announced on October 26, 2026, results from a pooled analysis of data on TransCon PTH treatment in adults with hypoparathyroidism, showing improvement in kidney function measures and continued stability during follow-up. By week 52, 68.9% of patients had an increase in estimated glomerular filtration rate (eGFR) of at least 5 mL/min/1.73 m², while 49.6% recorded an increase of more than 10 mL/min/1.73 m². The company said the early improvement continued through five years of treatment and follow-up in the Phase 2 PaTH Forward and Phase 3 PaTHway studies. The results were presented in a poster at Kidney Week 2026, the annual meeting of the American Society of Nephrology. The poster was presented by nephrologist Elvira Guseynova, professor of medicine at Albany Medical College.
From week 52 to week 266, the average eGFR slope was about 0.28 mL/min/1.73 m² per year, according to the company. This measure represents the change in the indicator during the extended follow-up period, while Ascendis said stability continued through the end of the trials. The kidney analysis included 139 patients who received at least one dose of treatment, out of 141 adults who participated in the two studies. A total of 129 patients completed the final visit, the measurement point at which the company reported calcium results and discontinuation of some supplements. The company said researchers pooled data from the two studies in a post hoc analysis after data collection had ended, so the results should be read in the context of the stated analysis design and available follow-up periods.
Average 24-hour urinary calcium excretion fell from 396 mg/day at baseline to 206 mg/day at week 26, then to 170 mg/day at week 52. Ascendis said the improvement continued through the end of the trials. At the final visit, 98% of patients were off active vitamin D, while 95% achieved independence from therapeutic calcium doses, which the company defined as less than 600 mg/day. Average blood calcium was 8.9 mg/dL, within the normal range, and albumin-corrected calcium levels were normal in 88% of patients. These measures place the kidney-function results alongside changes in calcium and supplement requirements in the group of patients who completed the final visit.
The studies differed in design and in the duration of their controlled comparison periods. In PaTH Forward, the randomized, double-blind, placebo-controlled period ran through week 4, followed by an open-label extension through week 266. In PaTHway, the controlled period ran through week 26, and the open-label extension through week 182. Eligibility required participants to have an eGFR of at least 30 mL/min/1.73 m² at study entry; the pooled analysis reported a baseline average of 69 (17) mL/min/1.73 m². Results from PaTHway published in 2025 had previously shown an improvement in average eGFR of 8.76 mL/min/1.73 m² at week 156 for all participants, and 13.98 among those who began the study with a level below 60 mL/min/1.73 m². Those results provide an earlier comparison within follow-up of the same treatment, while Ascendis' current data add a longer follow-up period in the pooled analysis.
The company said TransCon PTH was generally well tolerated in both studies and that it had observed no new safety signals. It added that most treatment-emergent adverse events were mild to moderate, or Grade 1 or 2. The company describes the treatment as a prodrug of PTH (1-34) administered once daily and marketed as YORVIPATH. The product has been approved to treat adults with hypoparathyroidism in the United States, the European Union, the European Economic Area and other jurisdictions. The U.S. Food and Drug Administration approved YORVIPATH for this use on August 9, 2024, and Ascendis announced in December 2024 that it was available by prescription in the United States.