Active — Not RecruitingPhase 3

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

United States, Argentina, Australia124 participantsStarted 2024-01-03

Plain-language summary

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.

Who can participate

Age range

12 Years – 130 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion 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)
. 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.

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

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

Timeframe: Baseline, Day 169

Trial details

NCT IDNCT06079281

SponsorAlexion Pharmaceuticals, Inc.

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2025-07-09

View on ClinicalTrials.gov More Hypophosphatasia trials