A Trial Investigating the Safety, Tolerability and Efficacy of TransCon PTH in Adults With Hypoparathyroidism (PaTH Forward)

May 22, 2026 updated by: Ascendis Pharma A/S

PaTH Forward: A Phase 2, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel Group Trial With an Open-Label Extension, Investigating the Safety, Tolerability and Efficacy of TransCon PTH Administered Subcutaneously Daily in Adults With Hypoparathyroidism

During the first four weeks of the trial, participants were randomly assigned to one of four groups: three groups received fixed doses of TransCon PTH and one group received placebo. TransCon PTH or placebo were administered as a subcutaneous injection using a pre-filled injection pen. Neither trial participants nor their doctors know who has been assigned to each group. After the four weeks, participants continued in the trial as part of a long-term extension period. During the extension, all participants received TransCon PTH, with the dose adjusted to their individual needs. This was a global trial that was conducted in the United States, Canada, Germany, Denmark, Italy and Norway.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
59

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Expanded Access

Expanded Access

A way for patients with serious diseases or conditions who cannot participate in a clinical trial to gain access to a medical product that has not been approved by the U.S. Food and Drug Administration (FDA). Also called compassionate use. There are different expanded access types.
Approved

Approved

  • Available: Expanded access is currently available for this investigational treatment, and patients who are not participants in the clinical study may be able to gain access to the drug, biologic, or medical device being studied.
  • No longer available: Expanded access was available for this intervention previously but is not currently available and will not be available in the future.
  • Temporarily not available: Expanded access is not currently available for this intervention but is expected to be available in the future.
  • Approved for marketing: The intervention has been approved by the U.S. Food and Drug Administration for use by the public.
 for sale to the public. See expanded access record.

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Oakville, Ontario, Canada, L6M 1M1
        • Ascendis Pharma Investigational Site
  • Denmark
      • Aalborg, Denmark, 9000
        • Ascendis Pharma Investigational Site
      • Aarhus, Denmark, 8200
        • Ascendis Pharma Investigational Site
      • Copenhagen, Denmark, 2200
        • Ascendis Pharma Investigational Site
  • Germany
      • Dresden, Germany, 01307
        • Ascendis Pharma Investigational Site
  • Italy
      • Bologna, Italy, 40138
        • Ascendis Pharma Investigational Site
      • Milan, Italy, 20132
        • Ascendis Pharma Investigational Site
      • Pisa, Italy, 56124
        • Ascendis Pharma Investigational Site
      • Rome, Italy, 00128
        • Ascendis Pharma Investigational Site
  • Norway
      • Oslo, Norway, 0176
        • Ascendis Pharma Investigational Site
  • United States
    • Illinois
      • Chicago, Illinois, United States, 60637
        • Ascendis Pharma Investigational Site
    • Minnesota
      • Rochester, Minnesota, United States, 55901
        • Ascendis Pharma Investigational Site
    • New York
      • Great Neck, New York, United States, 11021
        • Ascendis Pharma Investigational Site
      • New York, New York, United States, 10032
        • Ascendis Pharma Investigational Site
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Ascendis Pharma Investigational Site

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Males and females aged ≥18 years.
  2. Subjects with postsurgical chronic HP or auto-immune, genetic, or idiopathic HP for at least 26 weeks.

  3. On a stable dose for at least 12 weeks (or 4 weeks if on Natpara as of September 2019) prior to Screening of:

    • ≥0.25 μg BID of calcitriol (active vitamin D) or ≥0.5 μg BID or ≥1.0 μg daily of alfacalcidol (active vitamin D), and
    • ≥400 mg BID calcium citrate or carbonate.

  4. Optimization of supplements prior to randomization to achieve the target levels of:

    • 25(OH) vitamin D levels of 30-70 ng/mL (75-175 pmol/mL) and
    • Magnesium level within the normal range and
    • Albumin-adjusted or ionized serum calcium (sCa) level in the lower half of the normal range.
  5. BMI 17-40 kg/m2 at Visit 1.
  6. If ≤25 years of age, radiological evidence of epiphyseal closure based on x-ray of non-dominant wrist and hand.
  7. eGFR >30 mL/min/1.73m2 during Screening.
  8. Thyroid-stimulating hormone (TSH) within normal laboratory limits within the 12 weeks prior to Visit 1; if on suppressive therapy for thyroid cancer, TSH level must be ≥0.2 μIU/mL.
  9. If treated with thyroid hormone replacement therapy, the dose must be stable for at least 12 weeks prior to Visit 1.
  10. Able to perform daily subcutaneous self-injections of study drug (or have a designee perform injection) via a pre-filled injection pen.
  11. Written, signed, informed consent of the subject.

Exclusion Criteria:

  1. Known activating mutation in the calcium-sensing receptor (CaSR) gene.
  2. Impaired responsiveness to PTH (pseudohypoparathyroidism) which is characterized as PTH-resistance, with elevated PTH Levels in the setting of hypocalcemia.
  3. Any disease that might affect calcium metabolism or calcium-phosphate homeostasis or PTH levels other than HP, such as active hyperthyroidism; Paget's disease; hypomagnesemia; type 1 diabetes mellitus or poorly controlled type 2 diabetes mellitus; severe and chronic cardiac, liver, or renal disease; Cushing syndrome; rheumatoid arthritis; multiple myeloma; active pancreatitis; malnutrition; rickets; recent prolonged immobility; active malignancy (other than low-risk well differentiated thyroid cancer or basal cell skin cancer); parathyroid carcinoma within 5 years prior to Screening; acromegaly; multiple endocrine neoplasia types 1 and 2.
  4. Use of loop diuretics, phosphate binders (other than calcium carbonate/calcium citrate), digoxin, lithium, methotrexate, or systemic corticosteroids (other than replacement therapy).
  5. Use of thiazide diuretic within 4 weeks prior to the Screening 24-hour urine collection or the first dose adjustment of SOC during Screening.
  6. Use of PTH-like drugs (whether commercially available or through participation in an investigational trial) including PTH(1-84), PTH(1-34), or other N-terminal fragments or analogs of PTH or PTH-related protein within 5 weeks prior to Visit 1.
  7. Use of other drugs known to influence calcium and bone metabolism, such as calcitonin, fluoride tablets (> 0.5 mg/day), strontium, or cinacalcet hydrochloride within 12 weeks prior to Visit 1.
  8. Use of bisphosphonates (oral or IV) or denosumab within 2 years prior to Visit 1.
  9. Non-hypocalcemic seizure disorder with a history of a seizure within 26 weeks prior to Visit 1.
  10. Increased risk for osteosarcoma, such as those with Paget's disease of bone or unexplained elevations of alkaline phosphatase, open epiphyses, hereditary disorders predisposing to osteosarcoma, or with a prior history of substantial external beam or implant radiation therapy involving the skeleton.
  11. Pregnant or lactating women. Note: Highly effective contraception (see Appendix 7) is required for sexually active women of childbearing potential during the trial and for 2 weeks after the last dose of study drug, and pregnancy testing will be performed throughout the trial. Sexually active women of childbearing potential who are unwilling to use highly effective contraception are excluded from the trial.
  12. Diagnosis of drug or alcohol dependence within 3 years prior to Visit 1.
  13. Disease processes that may adversely affect gastrointestinal absorption including but not limited to short bowel syndrome, bowel resection, gastric bypass, tropical sprue, active celiac disease, active ulcerative colitis, gastroparesis, AIRE gene mutations with malabsorption, and active Crohn's disease.
  14. Chronic or severe cardiac disease within 26 weeks prior to Visit 1 including but not limited to congestive heart failure, myocardial infarction, QTcF >430 msec (males) or >450 msec (females), severe or uncontrolled arrhythmias, bradycardia (resting heart rate <50 beats/minute), symptomatic hypotension, systolic BP <80 mm Hg or diastolic <40 mm Hg, or poorly controlled hypertension (systolic BP >150 mm Hg or diastolic >95 mm Hg).
  15. Cerebrovascular accident within 5 years prior to Visit 1.
  16. History of renal colic or acute gout within 52 weeks prior to Visit 1.
  17. Any disease or condition that, in the opinion of the investigator, may make the subject unlikely to fully complete the trial, or any condition that presents undue risk from the investigational product or procedures, including treated malignancies that are likely to recur within the approximate 1-year duration of the trial.
  18. Known allergy or sensitivity to PTH or any of the excipients.
  19. Participation in another clinical trial in which receipt of investigational drug or device occurred within 8 weeks (or at least 5.5 times the half-life of the investigational drug) prior to Visit 1.
  20. Likely to be non-compliant with respect to trial conduct.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Placebo Comparator: Placebo
Placebo mimicking 15, 18, or 21 mcg of TransCon PTH delivered once daily by subcutaneous injection
Combination product: Placebo for TransCon PTH
Placebo is supplied as a clear solution containing the formulation buffer for TransCon PTH in a pre-filled pen intended for subcutaneous injection.
Experimental: Double Blind: TransCon PTH 15 mcg
TransCon PTH 15 mcg delivered once daily by subcutaneous injection
Combination product: TransCon PTH
TransCon PTH drug product is supplied as a clear solution containing TransCon PTH with a nominal PTH(1-34) content of 0.3 mg/mL in a pre-filled pen intended for subcutaneous injection.
Experimental: Double Blind: TransCon PTH 18 mcg
TransCon PTH 18 mcg delivered once daily by subcutaneous injection
Combination product: TransCon PTH
TransCon PTH drug product is supplied as a clear solution containing TransCon PTH with a nominal PTH(1-34) content of 0.3 mg/mL in a pre-filled pen intended for subcutaneous injection.
Experimental: Double Blind: TransCon PTH 21 mcg
TransCon PTH 21 mcg delivered once daily by subcutaneous injection
Combination product: TransCon PTH
TransCon PTH drug product is supplied as a clear solution containing TransCon PTH with a nominal PTH(1-34) content of 0.3 mg/mL in a pre-filled pen intended for subcutaneous injection.
Experimental: Open-Label Extension Period: TransCon PTH
Participants who completed the 4-week double-blind period, continued into the open-label extension period and received treatment with TransCon PTH up to Week 266, with up to an initial 14 weeks of TransCon PTH titration and standard of care optimization, followed by approximately 248 weeks of individualized doses of TransCon PTH (allowable dose range: 6 to 60 mcg/day).
Combination product: TransCon PTH
TransCon PTH drug product is supplied as a clear solution containing TransCon PTH with a nominal PTH(1-34) content of 0.3 mg/mL in a pre-filled pen intended for subcutaneous injection.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Efficacy - Primary Endpoint During the Blinded Period
Time Frame: Week 4
The percentage of subjects with albumin-adjusted serum calcium within the normal range, and spot morning fractional excretion of calcium (spot AM FECa) within normal range (≤2%) or a reduction by at least 50% from baseline, and not taking active vitamin D supplements, and taking ≤1000 mg/day of calcium supplements
Week 4

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Efficacy - Key Secondary Endpoint During the Blinded Period
Time Frame: Week 4
The percentage of subjects with albumin-adjusted serum calcium within the normal range, and spot AM FECa within the normal range (≤2%) or a reduction by at least 50% from baseline, and not taking active vitamin D supplements, and taking ≤ 500 mg/day of calcium supplements
Week 4

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Ascendis Pharma A/S

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Medical Director, MD, Ascendis Pharma A/S

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
August 27, 2019

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 6, 2020

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 17, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 20, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 2, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 5, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 18, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 22, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • TransCon PTH TCP-201

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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