Ascendis Pharma reports five-year Phase 2 data for TransCon PTH
Ascendis Pharma has published five-year data from its Phase 2 PaTH Forward Trial evaluating TransCon PTH (palopegteriparatide) in adults with hypoparathyroidism, reporting durable efficacy across kidney, bone, and quality-of-life measures. The results were presented at the European Congress of Endocrinology in 2026 and represent the longest continuous dataset so far generated for a PTH replacement approach in this indication.
At Week 266, 82% of patients met the trial's multi-component response endpoint, defined as normal serum calcium, independence from active vitamin D, and calcium supplementation below 600 mg per day. Fifty-six of the original 59 enrolled participants completed the full five years, a 95% completion rate that the company described as indicative of tolerability. No new safety signals were identified and treatment-emergent adverse events were predominantly mild or moderate, with no drug-related discontinuations.
Clinical outcomes in detail
Kidney function improvements were among the more clinically notable findings. Mean estimated glomerular filtration rate rose by 9.4 mL/min/1.73 m² from baseline to reach 78.0 mL/min/1.73 m² at Week 266. The release noted that this gain held against the expected age-related decline in eGFR, citing a published BMJ Open reference. Mean 24-hour urine calcium normalised within 26 weeks and remained within the normal range throughout the study.
Bone mineral density Z-scores, which were elevated at baseline, corrected downward toward normal by Week 26 and remained above zero through Week 266. Patient-reported outcomes measured by the Hypoparathyroidism Patient Experience Scales and the SF-36 showed rapid improvement that was sustained across the five-year period.
Andrea Palermo, an endocrinologist at Campus Bio-Medico University in Rome who presented the data, said that normalising PTH biology had met "the high bar for the treatment of chronic hypoparathyroidism" and described TransCon PTH as "the emerging standard of care" for the condition. The company's chief medical officer Aimee Shu said the drug was "working as designed" to replicate endogenous PTH action across its main target organ systems.
Market context and regulatory standing
TransCon PTH is already approved, marketed under the brand name YORVIPATH, in the United States, the European Union, and the European Economic Area. The five-year Phase 2 dataset therefore adds long-term durability evidence to a product that has cleared the major regulatory hurdles rather than representing a pre-approval milestone.
Hypoparathyroidism is a rare endocrine disease affecting an estimated 70,000 to 90,000 patients in the United States alone, with post-surgical cases accounting for roughly 70 to 80% of diagnoses. Conventional management with active vitamin D and calcium supplementation does not address the underlying hormone deficiency and is associated with progressive renal and extra-skeletal complications, leaving a clear unmet need for a hormone-replacement strategy.
The competitive landscape remains relatively uncrowded. YORVIPATH's main approved comparator in the replacement-therapy category is Natpara (rhPTH 1-84, from Takeda), which has faced intermittent supply constraints in the United States. Ascendis positions TransCon PTH's once-daily subcutaneous prodrug design, which is intended to deliver stable PTH levels within the physiological range over 24 hours, as a differentiating feature versus pulsatile approaches. Longer-term, the dataset strengthens the commercial narrative for payers and health technology assessment bodies in markets where reimbursement negotiations are ongoing.