New 3-Year Phase 3 Data Confirmed Sustained Response to TransCon® PTH (Palopegteriparatide) Therapy in Adults with Hypoparathyroidism, Including Improvements in Biochemistries, Kidney Function, and Quality of Life

Rhea-AI Summary

Ascendis Pharma (Nasdaq: ASND) announced promising 3-year Phase 3 data for TransCon PTH (palopegteriparatide) in treating adults with hypoparathyroidism. The PaTHway Trial demonstrated significant sustained efficacy with 88% of patients achieving normal calcium levels and 96% becoming independent from conventional therapy at Week 156.

Key outcomes include improved kidney function with mean eGFR increase of 8.76 mL/min/1.73 m2 across all participants, and 13.98 mL/min/1.73 m2 in patients with lower baseline eGFR. The trial showed high retention with 89% completion rate, while demonstrating sustained improvements in patient symptoms and quality of life. The treatment was generally well-tolerated with no new safety concerns identified.

Positive

• 88% of patients achieved normal albumin-adjusted serum calcium levels at Week 156
• 96% of patients became independent from conventional therapy
• Significant kidney function improvement with mean eGFR increase of 8.76 mL/min/1.73 m2
• High trial retention rate of 89% over 3.5 years
• Well-tolerated safety profile with no serious treatment-related adverse events

Negative

• None.

COPENHAGEN, Denmark, July 14, 2025 (GLOBE NEWSWIRE) -- Ascendis Pharma A/S (Nasdaq: ASND) today announced new data from Week 156 of its Phase 3 PaTHway Trial confirming that long-term treatment with TransCon PTH (palopegteriparatide) continued to provide a durable response in adults with hypoparathyroidism regardless of its cause (post-surgical, autoimmune, genetic, or idiopathic), including improvements in biochemistries, kidney function, and quality of life. Results were shared over the weekend in an oral presentation by Aliya Khan, M.D., Clinical Professor of Medicine, Division of Endocrinology and Geriatrics and Director of the Calcium Disorders Clinic at McMaster University (Canada) 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 (eGFR). Safety assessments included 24-hour urine-calcium and treatment-emergent adverse events (TEAEs). Hypoparathyroidism-related symptoms, functioning, and well-being were measured by the Hypoparathyroidism Patient Experience Scale (HPES). Overall retention in the trial was high, with 73 of the original 82 adults enrolled (89%) completing the 3.5-year trial.

At Week 156, 64 patients (88%) had normal albumin-adjusted serum calcium levels and 70 patients (96%) were independent from conventional therapy (defined as taking < 600 mg/day of calcium and not taking active vitamin D). 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 < 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.

“We are pleased to report these latest data from our second clinical trial of TransCon PTH showing sustained efficacy and improvements across key health and quality of life measures, beginning at the earliest timepoints in the Phase 3 PaTHway trial and continuing through three years of treatment,” said Aimee Shu, M.D. Executive Vice President of Endocrine & Rare Disease Medical Science and Chief Medical Officer at Ascendis Pharma. “These responses, including normalization of skeletal dynamics with significant and clinically meaningful improvements in kidney function, demonstrate the long-term benefits of this treatment option for the vast majority of adults with hypoparathyroidism, regardless of their disease etiology.”

About Hypoparathyroidism
Hypoparathyroidism is an endocrine disease caused by insufficient levels of parathyroid hormone (PTH), the primary regulator of calcium and phosphate balance in the body, acting directly on bone and kidney and indirectly on the intestine. Individuals with hypoparathyroidism may experience a range of severe and potentially life-threatening short-term and long-term complications, including neuromuscular irritability, renal complications, extra-skeletal calcifications, and cognitive impairment. Post-surgical hypoparathyroidism accounts for the majority of cases (70-80%), while other etiologies include autoimmune and idiopathic causes.

About Ascendis Pharma A/S
Ascendis Pharma is a global biopharmaceutical company focused on applying our innovative TransCon technology platform to make a meaningful difference for patients. Guided by our core values of Patients, Science, and Passion, and following our algorithm for product innovation, we apply TransCon to develop new therapies that demonstrate best-in-class potential to address unmet medical needs. Ascendis is headquartered in Copenhagen, Denmark and has additional facilities in Europe and the United States. Please visit ascendispharma.com to learn more.

Forward-Looking Statements
This press release contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, included in this press release regarding Ascendis’ future operations, plans and objectives of management are forward-looking statements. Examples of such statements include, but are not limited to, statements relating to (i) the long term benefits of TransCon PTH therapy for adults with hypoparathyroidism, regardless of disease etiology, (ii) Ascendis’ ability to apply its TransCon technology platform to make a meaningful difference for patients, and (iii) Ascendis’ application of its TransCon technologies to develop new therapies that demonstrate best-in-class potential to address unmet medical needs. Ascendis may not actually achieve the plans, carry out the intentions or meet the expectations or projections disclosed in the forward-looking statements and you should not place undue reliance on these forward-looking statements. Actual results or events could differ materially from the plans, intentions, expectations and projections disclosed in the forward-looking statements. Various important factors could cause actual results or events to differ materially from the forward-looking statements that Ascendis makes, including the following: dependence on third party manufacturers, distributors and service providers for Ascendis’ products and product candidates; unforeseen safety or efficacy results in Ascendis’ development programs or on-market products; unforeseen expenses related to commercialization of any approved Ascendis products; unforeseen expenses related to Ascendis’ development programs; unforeseen selling, general and administrative expenses, other research and development expenses and Ascendis’ business generally; delays in the development of its programs related to manufacturing, regulatory requirements, speed of patient recruitment or other unforeseen delays; Ascendis’ ability to obtain additional funding, if needed, to support its business activities; the impact of international economic, political, legal, compliance, social and business factors, including tariffs and trade policies. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to Ascendis’ business in general, see Ascendis’ Annual Report on Form 20-F filed with the U.S. Securities and Exchange Commission (SEC) on February 12, 2025, and Ascendis’ other future reports filed with, or submitted to, the SEC. Forward-looking statements do not reflect the potential impact of any future licensing, collaborations, acquisitions, mergers, dispositions, joint ventures, or investments that Ascendis may enter into or make. Ascendis does not assume any obligation to update any forward-looking statements, except as required by law.

Ascendis, Ascendis Pharma, the Ascendis Pharma logo, the company logo, and TransCon are trademarks owned by the Ascendis Pharma group. © July 2025 Ascendis Pharma A/S.

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FAQ

What are the key results from Ascendis Pharma's 3-year TransCon PTH Phase 3 trial?

The trial showed that 88% of patients achieved normal calcium levels and 96% became independent from conventional therapy. The treatment demonstrated sustained efficacy with improved kidney function and quality of life over 156 weeks.

How did TransCon PTH affect kidney function in hypoparathyroidism patients?

TransCon PTH improved kidney function with a mean eGFR increase of 8.76 mL/min/1.73 m2 across all participants, and 13.98 mL/min/1.73 m2 in patients with baseline eGFR below 60.

What was the safety profile of TransCon PTH in the PaTHway Trial?

TransCon PTH was generally well-tolerated with mostly mild to moderate treatment-emergent adverse events. No new safety signals were identified, and no serious adverse events were related to the study drug.

How many patients completed Ascendis Pharma's PaTHway Trial?

The trial showed high retention with 73 of 82 enrolled adults (89%) completing the 3.5-year study period.

What is the significance of TransCon PTH for hypoparathyroidism treatment?

TransCon PTH represents a potential breakthrough as it helped 96% of patients become independent from conventional therapy while normalizing calcium levels and improving kidney function, regardless of disease cause.