Ascendis Pharma announces new data from PaTHway Trial at ENDO 2025

Ascendis Pharma (ASND) announced new data from Week 156 of its Phase 3 PaTHway Trial confirming that long-term treatment with TransCon PTH continued to provide a durable response in adults with hypoparathyroidism regardless of its cause, including improvements in biochemistries, kidney function, and quality of life. Results were shared at ENDO 2025, the annual meeting of the Endocrine Society being held in San Francisco. PaTHway was a Phase 3, randomized, double-blind, placebo-controlled 26-week trial of 82 adults with chronic hypoparathyroidism, followed by an open-label extension period through Week 182. During the initial 26-week blinded period, participants were randomized 3:1 TransCon PTH:placebo. Renal function was assessed by estimated glomerular filtration rate. Safety assessments included 24-hour urine-calcium and treatment-emergent adverse events. Hypoparathyroidism-related symptoms, functioning, and well-being were measured by the Hypoparathyroidism Patient Experience Scale. Overall retention in the trial was high, with 73 of the original 82 adults enrolled completing the 3.5-year trial. At Week 156, 64 patients had normal albumin-adjusted serum calcium levels and 70 patients were independent from conventional therapy. Reflecting clinically meaningful improvements in kidney function, improvements in eGFR from baseline were sustained through Week 156: mean eGFR increased by 8.76 mL/min/1.73 m2 across all participants and by 13.98 mL/min/1.73 m2 in participants with baseline eGFR less than 60. Patients in the trial reported continued improvements from baseline in their hypoparathyroidism-related symptoms and health-related quality of life and showed continued normalization of 24-hour urine calcium excretion through Week 156. In the trial, TransCon PTH treatment was generally well-tolerated, with no new safety signals identified. TEAEs were mostly mild or moderate and no serious TEAEs or discontinuations were related to study drug.