Recruiting

Observational Study

Sponsor:

Alexion Pharmaceuticals, Inc.

Code:

NCT05234567

Conditions

Hypophosphatasia

Eligibility Criteria

Sex: All

Age: 0+

Healthy Volunteers: Not accepted

Interventions

Asfotase Alfa

Study Details

Brief summary:

In this prospective observational sub-study, participants with pediatric-onset hypophosphatasia (HPP) (perinatal/infantile- or juvenile-onset) of any age will be followed for a minimum of 5 years at sites in the United States and potentially 1 or 2 other countries.

Conditions

Hypophosphatasia

Study ID

NCT05234567

Start date

Aug 25, 2022

Status verified date

Feb, 2026

Completion date

Jul 18, 2028

Anticipated

Primary completion date

Jul 18, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 0+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Any age or sex with a confirmed diagnosis of pediatric-onset HPP (that is, first HPP sign or symptom presented at < 18 years of age).
  • Currently receiving asfotase alfa treatment at Enrollment (not treatment-naïve) or the Physician has decided to resume (not treatment-naïve) or start (treatment-naïve) the participant's asfotase alfa treatment within 6 months after Enrollment.
  • Participant must have documented alkaline phosphatase (ALP) activity below the lower limit of normal for age and sex, and a documented ALPL gene mutation (Note: An exception is made for infants with clinical features of HPP plus low ALP who need to start asfotase alfa treatment right away, at the Physician's discretion, but do not yet have a genetic result. In this case, ALPL gene documentation is not required at the time of sub-study enrollment but should be documented within 6 months after Enrollment).
  • Participant or participant's parent/legally authorized representative is able to read and/or understand the informed consent and study questionnaires in the local language.
  • Participant or participant's parent/legally authorized representative must be willing and able to give signed informed consent for this sub-study, and the participant must be willing to give written informed assent, if appropriate and required by local regulations.

Exclusion Criteria:

  • Currently participating in an Alexion-sponsored interventional clinical study. Participants who have concluded participation in an Alexion-sponsored asfotase alfa clinical study are eligible to enroll in this sub-study.

Study Design

Enrollment

30 participants

Anticipated

Interventions and Outcome Measures

Arms

Participants with Pediatric-onset HPP

Each participant will be followed for a minimum of 5 years or, if applicable, until early withdrawal. Biochemical, clinical, imaging (if clinically indicated), and functional/quality of life outcomes relevant to HPP will be assessed.

Interventions

Asfotase Alfa

All participants will receive asfotase alfa subcutaneously per standard of care. Unless otherwise specified per the Physician's standard of care, participants aged < 2 years are recommended for a clinic visit approximately every 3 months after Enrollment until 2 years of age, after which they should have a clinic visit approximately every 6 months. Participants should be followed for 5 years, as possible.

Primary outcome measure

  • Occurrence Of Immune-mediated Loss Of Effectiveness According To The Treating Physician [ Time Frame: Up to 5 years ]
  • Occurrence Of Immune-mediated Serious Adverse Events [ Time Frame: Up to 5 years ]

Central Contacts and Locations

Central contacts

Alexion Pharmaceuticals, Inc. (Sponsor)

1-855-752-2356clinicaltrials@alexion.com

Locations

Clinical Trial Site

Recruiting

Hartford, Connecticut, United States, 06106

Clinical Trial Site

Recruiting

Chicago, Illinois, United States, 60611

Clinical Trial Site

Recruiting

Boston, Massachusetts, United States, 02122

Clinical Trial Site

Recruiting

Kansas City, Missouri, United States, 64108

Clinical Trial Site

Recruiting

Mineola, New York, United States, 11501

Clinical Trial Site

Recruiting

Columbus, Ohio, United States, 43203

Clinical Trial Site

Recruiting

Nashville, Tennessee, United States, 37112

Clinical Trial Site

Recruiting

Salt Lake City, Utah, United States, 84108

Clinical Trial Site

Recruiting

Charlottesville, Virginia, United States, 22903

Clinical Trial Site

Recruiting

Madison, Wisconsin, United States, 53792

More Information

Sponsor

Alexion Pharmaceuticals, Inc.

Last update posted

Feb 9, 2026

Last verified

Feb, 2026

Keywords

  • Pediatric Onset
  • HPP
  • Asfotase alfa

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-08. This information was provided to ClinicalTrials.gov by Alexion Pharmaceuticals, Inc. on 2026-02-09.