NCT05234567 · Alexion Pharmaceuticals, Inc.
A Prospective Sub-Study of the Global Hypophosphatasia Registry
What this study is about
In this forward-looking 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.
View original scientific description
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
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.
Where
- Hartford, Connecticut
- Chicago, Illinois
- Boston, Massachusetts
- Kansas City, Missouri
- Mineola, New York
- Cincinnati, Ohio
- Columbus, Ohio
- Pittsburgh, Pennsylvania
- Nashville, Tennessee
- Salt Lake City, Utah
- Charlottesville, Virginia
- Madison, Wisconsin
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Feb 9, 2026 · Source of record for eligibility and locations