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Phase 3 Study of ALXN1850 in Treatment-Naïve Pediatric Participants with HPP
EU CTIS ID: 2023-505675-73-00
What this study is testing
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
- Therapeutic confirmatory (Phase III)
A plain-language read of the study's public EU CTIS listing. The study team confirms the details.
Who can take part
You may be able to join if
- Participant must be ≥ 2 and < 12 years of age at Day 1
- Diagnosis of HPP documented in the medical records, and the following criteria fulfilled without other probable cause than HPP: a. Presence of HPP-related rickets on skeletal X-rays during the Screening Period, with a minimum Rickets Severity Score (RSS) of 1.0 AND b. 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: a. Documented ALPL gene variant (pathogenic, likely pathogenic, or variant of unknown significance) from a CLIA or ISO 15189 certified laboratory (Section 8.7) b. 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
- Female participants of childbearing potential and male participants must follow contraception requirements and guidance as defined in the protocol.
- The participant’s legal guardian must be willing and able to provide written informed consent (as defined in the protocol) and the participant must be willing to give written informed assent (if applicable as determined by the central or local Institutional Review Board [IRB]/Institutional [or independent] Ethics Committee [IEC]). Written informed consent/assent includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol.
You likely can't join if
- 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
- Received oral bisphosphonate within 6 months before Day 1
- Received IV bisphosphonate within 12 months before Day 1
- Received a parathyroid hormone (PTH)-related protein analog (eg, abaloparatide) or PTH analog (eg, teriparatide) within 2 weeks before Day 1
- Received strontium within 6 months before Day 1
- Received sclerostin inhibitors within 6 months before Day 1
See the full eligibility criteria
Who can join
- Participant must be ≥ 2 and < 12 years of age at Day 1
- Diagnosis of HPP documented in the medical records, and the following criteria fulfilled without other probable cause than HPP: a. Presence of HPP-related rickets on skeletal X-rays during the Screening Period, with a minimum Rickets Severity Score (RSS) of 1.0 AND b. 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: a. Documented ALPL gene variant (pathogenic, likely pathogenic, or variant of unknown significance) from a CLIA or ISO 15189 certified laboratory (Section 8.7) b. 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
- Female participants of childbearing potential and male participants must follow contraception requirements and guidance as defined in the protocol.
- The participant’s legal guardian must be willing and able to provide written informed consent (as defined in the protocol) and the participant must be willing to give written informed assent (if applicable as determined by the central or local Institutional Review Board [IRB]/Institutional [or independent] Ethics Committee [IEC]). Written informed consent/assent includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol.
What rules you out
- 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
- Received oral bisphosphonate within 6 months before Day 1
- Received IV bisphosphonate within 12 months before Day 1
- Received a parathyroid hormone (PTH)-related protein analog (eg, abaloparatide) or PTH analog (eg, teriparatide) within 2 weeks before Day 1
- Received strontium within 6 months before Day 1
- Received sclerostin inhibitors within 6 months before Day 1
- Received growth hormone therapy within 6 months before Day 1
- Received estrogen or estrogen agonist/antagonist/inhibitor within 2 months before Day 1 unless used as contraception or for treatment of dysmenorrhea
- Received a receptor activator of nuclear factor kappa B ligand (RANKL) inhibitor within 6 months before Day 11
- Participation in any other clinical study involving an investigational study intervention within 30 days before initiation of the first dose of study intervention. Participants involved in interventional studies are not eligible unless the time since last treatment has exceeded 30 days or 5 half-lives of the study intervention, whichever is longer.
- Corrected calcium levels (adjusted for albumin) below age-adjusted normal range during Screening
- Diagnosis of primary or secondary hyperparathyroidism
- Serum phosphorus levels below the age-adjusted normal range during Screening
- Evidence of a treatable form of rickets (eg, vitamin D deficiency) other than HPP during Screening
- Serum 25-hydroxy (25-OH) vitamin D below 20 ng/mL during Screening
- PTH > ULN of the laboratory reference range during Screening
- Participants who are unwilling to undergo genetic testing for the ALPL gene
- Participants who are pregnant, planning to become pregnant, or breastfeeding during the course of the study
- Investigational site personnel involved directly in the study and/or their immediate families. Immediate family is defined as a spouse, parent, child, or sibling, whether biological or legally adopted.
- 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
- Body weight < 10 kg during the Screening Period
- Received asfotase alfa or ALXN1850 at any time before Day 1
- Received vitamin B6 (including vitamin supplements that contain vitamin B6) within 6 weeks before Day 1
The study team makes the final eligibility decision.
Where it's taking place
- Israel
- United States
- United Kingdom
- Brazil
- Mexico
- Turkey
- Argentina
- China
- Taiwan
- Canada
- Australia
- Korea, Republic of
Questions & answers
Do participants get paid in this trial?
This listing doesn't specify compensation. Many trials still reimburse travel or offer a stipend, so it's worth asking the study team when you connect.
Is it free to join, and do I need insurance?
Searching and applying through BridgeMD is free. In clinical trials the study-related treatment and visits are generally provided at no cost to you. You usually don't need insurance to take part - confirm specifics with the study team.
How long does this study last?
The listing doesn't state an exact length. The study team walks you through the schedule and number of visits before you decide to enroll.
Who can join this trial?
This study is enrolling all sexes, 0-17 years. The study team makes the final eligibility decision.
Where is this trial taking place?
Study sites include Israel; United States; United Kingdom; Brazil; Mexico; Turkey and 6 more location(s). Enter your location above to see the nearest site and check your eligibility.
Explore other conditions
BridgeMD is an information and trial-matching tool - not medical advice, and not the study sponsor. Details come from EU CTIS; the study team decides eligibility.