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NCT Number: NCT06079281

Phase 3 Study of ALXN1850 Versus Placebo in Adolescent and Adult Participants With HPP Who Have Not Previously Been Treated With Asfotase Alfa

The primary objective of this study is to assess the efficacy of ALXN1850 versus placebo on functional outcomes in adolescent and adult participants with HPP who have not previously been treated with asfotase alfa.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

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Key information

Conditions

Hypophosphatasia Congenital, Hereditary, and Neonatal Diseases and Abnormalities Genetic Diseases, Inborn Metabolic Diseases Metabolism, Inborn Errors Metal Metabolism, Inborn Errors Nutritional and Metabolic Diseases

Age range

12 year–130 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Research Site, Ciudad de Buenos Aires, Argentina

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of HPP documented in the medical records
  • Must meet 1 of the following criteria:
  • Documented ALPL gene variant (pathogenic, likely pathogenic, or variant of unknown significance) from a Clinical Laboratory Improvement Amendments (CLIA) or ISO 15189 certified laboratory (Section 8.7 )
  • Plasma PLP above the upper limit of normal (ULN) during the Screening Period (central or local laboratory results allowed per local regulations)
  • Must meet 1 of the following criteria without a probably cause other than HPP:
  • Serum ALP activity below the age- and sex-adjusted normal range during the screening period as measured by the Central Laboratory
  • Two documented serum ALP activity results, at least 15 days apart, below the age- and sex-adjusted local laboratory normal range during the 24 months before the Day 1 Visit. Note: Local laboratories need to be CLIA or ISO 15189 certified, or have other local equivalent laboratory certification with Alexion's approval.
  • Two separate 6MWTs at below 85% of the predicted distance (for age, sex, weight, and height) during the Screening Period without a probable cause other than HPP

Exclusion criteria

  • History or presence of cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrinological, hematological, neurological disorders, or any other disorders that are capable of significantly altering the absorption, metabolism, or elimination of drugs; constituting a risk when taking the study intervention; or interfering with the interpretation of data as determined by the Investigator
  • Diagnosis of primary or secondary hyperparathyroidism
  • Hypoparathyroidism, unless secondary to HPP
  • Any new fracture within 12 weeks before Day 1 (excluding pseudofractures)
  • Planned surgical intervention which may impact the results of study assessments (in the opinion of the Investigator) during the Randomized Evaluation Period
  • History of allergy or hypersensitivity to any ingredient contained in ALXN1850 or the placebo comparator (Table 9)

Treatment and study plan

ALXN1850

Drug

ALXN1850 will be administered via subcutaneous (SC) injection.

Placebo

Drug

Placebo will be administered via SC injection.

Primary outcomes

  1. Change from Baseline in 6-Minute Walk Test (6MWT) at the end of the Randomized Evaluation Period (Day 169)

    Time frame: Baseline, Day 169

Secondary outcomes

  1. Change from Baseline in 30-second Sit to Stand (STS) Test Score at the end of the Randomized Evaluation Period (Day 169)

    Time frame: Baseline, Day 169

  2. Change from Baseline in Lower Extremity Functional Scale (LEFS) Score at the end of the Randomized Evaluation Period (Day 169)

    Time frame: Baseline, Day 169

  3. Change from Baseline in BPI-SF pain severity score at the end of the Randomized Evaluation Period (Day 169) (adult cohort only)

    Time frame: Baseline, Day 169

  4. Change from Baseline in FACIT-Fatigue score at the end of the Randomized Evaluation Period (Day 169) (adult cohort only)

    Time frame: Baseline, Day 169

  5. Change from Baseline in Timed Up-and-Go (TUG) at the end of the Randomized Evaluation Period (Day 169)

    Time frame: Baseline, Day 169

  6. Change from Baseline in Percent Predicted 6MWT at the end of the Randomized Evaluation Period (Day 169)

    Time frame: Baseline, Day 169

  7. Radiographic Global Impression of Change (RGI-C) Score at the end of the Randomized Evaluation Period (Day 169)

    Time frame: Day 169

  8. RGI-C Responder at the end of the Randomized Evaluation Period (Day 169)

    Time frame: Day 169

  9. Change from Baseline in Rickets Severity Score (RSS) at the end of the Randomized Evaluation Period (Day 169)

    Time frame: Baseline, Day 169

Sponsors and collaborators

Lead sponsor

Alexion Pharmaceuticals, Inc.

Industry

Registry information

Official study title

A Phase 3, Randomized, Double-blinded, Placebo-controlled, Multicenter Study to Evaluate Efficacy and Safety of ALXN1850 (Recombinant Alkaline Phosphatase) Administered Subcutaneously in Adolescent (12 to < 18 Years of Age) and Adult Participants With Hypophosphatasia Who Have Not Previously Been Treated With Asfotase Alfa

Acronym: HICKORY

Important dates

Study start
2024
Primary completion
2025
Study completion
2028
First posted
Oct 12, 2023
Registry last updated
Jun 22, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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