Phase 3 Study of ALXN1850 in Treatment-Naïve Pediatric Participants With HPP

NCT ID: NCT06079359

Last Updated: 2026-01-14

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

ACTIVE_NOT_RECRUITING

Clinical Phase

PHASE3

Total Enrollment

30 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-05-14

Study Completion Date

2028-08-24

Brief Summary

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The primary purpose of this study is to evaluate the efficacy of ALXN1850 versus placebo on radiographic outcomes in pediatric participants with HPP who have not previously been treated with asfotase alfa.

Detailed Description

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Conditions

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Hypophosphatasia

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

QUADRUPLE

Participants Caregivers Investigators Outcome Assessors
double-blinded

Study Groups

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ALXN1850

Starting at Day 1 of the Randomized Evaluation Period, the ALXN1850 group will receive bodyweight dependent doses of either 20mg, 35mg or 50mg of ALXN1850 once every 2 weeks (q2w) via SC injection, for 24 weeks. Participants will enter the OLE Period and continue q2w dosing with ALXN1850 for up to 132 weeks.

Group Type EXPERIMENTAL

ALXN1850

Intervention Type DRUG

Participants will receive a ALXN1850 via subcutaneous (SC) injection.

Placebo

Intervention Type DRUG

Participants will receive placebo via SC injection.

Placebo

Starting at Day 1 during the Randomized Evaluation Period, participants will receive placebo q2w for a total of 24 weeks. Participants will enter the OLE Period and continue q2w dosing with ALXN1850 for up to 132 weeks.

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type DRUG

Participants will receive placebo via SC injection.

Interventions

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ALXN1850

Participants will receive a ALXN1850 via subcutaneous (SC) injection.

Intervention Type DRUG

Placebo

Participants will receive placebo via SC injection.

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* Diagnosis of HPP documented in the medical records, and the following criteria fulfilled without other probable cause than HPP:

1. Presence of HPP-related rickets on skeletal X-rays during the Screening Period, with a minimum Rickets Severity Score (RSS) of 1.0 AND
2. Serum ALP activity below the age- and sex-adjusted normal range during the Screening Period as measured by the Central Laboratory OR 2 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 Clinical Laboratory Improvement Amendments (CLIA) or ISO 15189 certified, or have other local equivalent laboratory certification with Alexion's approval.
* Must meet 1 of the following criteria:

1. Documented ALPL gene variant (pathogenic, likely pathogenic, or variant of unknown significance) from a CLIA certified laboratory (Section 8.7)
2. Plasma PLP above the upper limit of normal (ULN) during the Screening Period (central or local laboratory results allowed per local regulations)
* Tanner stage 2 or less during the Screening Period

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
Minimum Eligible Age

2 Years

Maximum Eligible Age

11 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Alexion Pharmaceuticals, Inc.

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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Research Site

Baltimore, Maryland, United States

Site Status

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Kansas City, Missouri, United States

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Durham, North Carolina, United States

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Nedlands, , Australia

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Parkville, , Australia

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Brussels, , Belgium

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Brasília, , Brazil

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Porto Alegre, , Brazil

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Recife, , Brazil

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Salvador, , Brazil

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São Paulo, , Brazil

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São Paulo, , Brazil

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Calgary, Alberta, Canada

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Winnepeg, Manitoba, Canada

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Beijing, , China

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Guangzhou, , China

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Shanghai, , China

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Shenzhen, , China

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Helsinki, , Finland

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Ashkelon, , Israel

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Chihuahua City, , Mexico

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Lodz, , Poland

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Bucharest, , Romania

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Madrid, , Spain

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Vitoria-Gasteiz, , Spain

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Stockholm, , Sweden

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Taipei, , Taiwan

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Ankara, , Turkey (Türkiye)

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Bursa, , Turkey (Türkiye)

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Erzurum, , Turkey (Türkiye)

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Istanbul, , Turkey (Türkiye)

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Birmingham, , United Kingdom

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Countries

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United States Australia Belgium Brazil Canada China Finland Israel Mexico Poland Romania Spain Sweden Taiwan Turkey (Türkiye) United Kingdom

Other Identifiers

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ALXN1850-HPP-305

Identifier Type: OTHER

Identifier Source: secondary_id

D8590C00003

Identifier Type: -

Identifier Source: org_study_id

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