HypophosphatasiaPhase 3HICKORYNCT06079281
Phase 3 Study of ALXN1850 Versus Placebo in Adolescent and Adult Participants With HPP Who Have Not Previously Been Treated With Asfotase Alfa
A Phase 3 study testing ALXN1850 in people with Hypophosphatasia, run by Alexion Pharmaceuticals, Inc. at 65 sites in 17 countries.
Trial 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. Read more about this study
- Who is it for?
- Ages 12 to 130 years
- Conditions the study is for
- Hypophosphatasia
- What is being tested?
- ALXN1850
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 124 participants
- Where
- 65 sitesin 17 countries
- Study dates
- 3 Jan 2024to 29 Mar 2028
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 to 130 years
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Diagnosis of HPP documented in the medical records
- Must meet 1 of the following 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)
- Must meet 1 of the following criteria without a probably cause other than HPP:
- 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.
- Two separate 6MWTs at below 85% of the predicted distance (for age, sex, weight, and height) during the Screening Period without a probable cause other than HPP
Who cannot join
- 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 (Table 9)
Trial locations and contacts
65 sites in 17 countries.
65 sites in 17 countries
China8 sites
Research Site
Beijing, 100039
Research Site
Beijing, 100730
Research Site
Changsha, 430033
Research Site
Chengdu, 610041
Research Site
Nanchang, 330006
Research Site
Qingdao, 266035
Research Site
Shanghai, 201306
Research Site
Shenzhen, 518053
Italy7 sites
Research Site
Florence, 50139
Research Site
Milan, 20122
Research Site
Milan, 20132
Research Site
Padova, 35128
Research Site
Pisa, 56126
Research Site
San Giovanni Rotondo, 71013
Research Site
Verona, 37134
Brazil6 sites
Research Site
Belo Horizonte, 30130-100
Research Site
Brasília, 71625-009
Research Site
Recife, 50740-465
Research Site
Salvador, 40050-410
Research Site
São Paulo, 01409-902
Research Site
São Paulo, 05403-900
Spain6 sites
Research Site
Barcelona, 08003
Research Site
Granada, 18016
Research Site
Madrid, 28046
Research Site
San Cristóbal de La Laguna, 38320
Research Site
Santander, 39008
Research Site
Vitoria-Gasteiz, 01009
United States5 sites
Research Site
Columbus, Ohio, 43203
Research Site
Durham, North Carolina, 27705
Research Site
Garden City, New York, 11530
Research Site
Indianapolis, Indiana, 46202
Research Site
Nashville, Tennessee, 37212
Canada5 sites
Research Site
Calgary, Alberta, T2E 7H7
Research Site
Edmonton, Alberta, T6G 2R7
Research Site
Oakville, Ontario, L6M 1M1
Research Site
Trois-Rivières, Quebec, G9A 4P3
Research Site
Winnepeg, Manitoba, R3E 3P4
Germany5 sites
Research Site
Bad Reichenhall, 83435
Research Site
Berlin, 10117
Research Site
Bonn, 53127
Research Site
Hamburg, 20251
Research Site
Würzburg, 97074
Japan5 sites
Research Site
Hiroshima, 734-8551
Research Site
Iizuka-shi, 820-8505
Research Site
Osaka, 545-8586
Research Site
Sapporo, 060-8648
Research Site
Yaizu-shi, 425-8505
Australia4 sites
Research Site
Clayton, 3168
Research Site
Herston, 4029
Research Site
Parkville, 3052
Research Site
St Leonards, 2065
South Korea3 sites
Research Site
Seoul, 03722
Research Site
Seoul, 07061
Research Site
Suwon, 16499
Turkey (Türkiye)2 sites
Research Site
Ankara, 06560
Research Site
Yakutiye, 25040
About this study
Official title: A Phase 3, Randomized, Double-blinded, Placebo-controlled, Multicenter Study to Evaluate Efficacy and Safety of ALXN1850 (Recombinant Alkaline Phosphatase) Administered Subcutaneously in Adolescent (12 to < 18 Years of Age) and Adult Participants With Hypophosphatasia Who Have Not Previously Been Treated With Asfotase Alfa
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.
- Conditions
- Hypophosphatasia
- Being tested
- ALXN1850, Placebo
- Keywords
- Hypophosphatasia, HPP, Asfotase Alfa, ALXN1850
- Medical subject headings
- Hypophosphatasia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ALXN1850Drug
ALXN1850 will be administered via subcutaneous (SC) injection.
PlaceboDrug
Placebo will be administered via SC injection.
| Study group | Role | What they receive |
|---|---|---|
| Placebo Group | Placebo comparator | During the Randomized Evaluation Period, the placebo group will receive placebo on Day 1, followed by once every 2 weeks (q2w) via SC injection for 24 weeks. Participants will enter the OLE Period and receive bodyweight dependent doses of either 20mg, 35mg, or 50mg of ALXN1850 and continue q2w dosing with ALXN1850 for up to 132 weeks. Receives: Drug: Placebo |
| ALXN1850 Group | Experimental | 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 q2w via SC injection, for 24 weeks. Participants will enter the OLE Period and continue q2w dosing with ALXN1850 for up to 132 weeks. Receives: Drug: ALXN1850; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from Baseline in 6-Minute Walk Test (6MWT) at the end of the Randomized Evaluation Period (Day 169)
Measured: Baseline, Day 169
Secondary outcomes (9)
Change from Baseline in 30-second Sit to Stand (STS) Test Score at the end of the Randomized Evaluation Period (Day 169)
Measured: Baseline, Day 169
Change from Baseline in Lower Extremity Functional Scale (LEFS) Score at the end of the Randomized Evaluation Period (Day 169)
Measured: Baseline, Day 169
Change from Baseline in BPI-SF pain severity score at the end of the Randomized Evaluation Period (Day 169) (adult cohort only)
Measured: Baseline, Day 169
Change from Baseline in FACIT-Fatigue score at the end of the Randomized Evaluation Period (Day 169) (adult cohort only)
Measured: Baseline, Day 169
Change from Baseline in Timed Up-and-Go (TUG) at the end of the Randomized Evaluation Period (Day 169)
Measured: Baseline, Day 169
Change from Baseline in Percent Predicted 6MWT at the end of the Randomized Evaluation Period (Day 169)
Measured: Baseline, Day 169
Radiographic Global Impression of Change (RGI-C) Score at the end of the Randomized Evaluation Period (Day 169)
Measured: Day 169
RGI-C Responder at the end of the Randomized Evaluation Period (Day 169)
Measured: Day 169
Change from Baseline in Rickets Severity Score (RSS) at the end of the Randomized Evaluation Period (Day 169)
Measured: Baseline, Day 169
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Oct 2023
- Study start3 Jan 2024
- Primary completion9 Jul 2025
- Study completion29 Mar 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HypophosphatasiaStudies of the same condition, open and under way.
- More trials run by Alexion Pharmaceuticals, Inc.The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 124 participants (actual)
Sponsor and investigators
- Lead sponsor
- Alexion Pharmaceuticals, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06079281
- Sponsor's protocol ID
- D8590C00002
- Other IDs
- ALXN1850-HPP-301
- Acronym
- HICKORY
- Status last verified
- Jun 2026
- First submitted
- 6 Oct 2023
- Last updated
- 22 Jun 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Alexion has a public commitment to allow requests for access to study data and will be supplying a protocol, CSR, and plain language summaries.
Study at a glance
From the registry record, last updated by the sponsor on 22 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 3, Randomized, Double-blinded, Placebo-controlled, Multicenter Study to Evaluate Efficacy and Safety of ALXN1850 (Recombinant Alkaline Phosphatase) Administered Subcutaneously in Adolescent (12 to < 18 Years of Age) and Adult Participants With Hypophosphatasia Who Have Not Previously Been Treated With Asfotase Alfa
- ClinicalTrials.gov ID
- NCT06079281
- Acronym / sponsor ID
- HICKORY / D8590C00002
- Conditions
- Hypophosphatasia
- Keywords
- Hypophosphatasia, HPP, Asfotase Alfa, ALXN1850
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 124 participants (actual)
- Lead sponsor
- Alexion Pharmaceuticals, Inc.Industry (pharma, biotech, devices)
- Study start
- 3 Jan 2024 (actual)
- Primary completion
- 9 Jul 2025 (actual)
- Study completion
- 29 Mar 2028 (estimated)
- First posted
- 12 Oct 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Placebo Group | Placebo comparator | Drug: PlaceboDuring the Randomized Evaluation Period, the placebo group will receive placebo on Day 1, followed by once every 2 weeks (q2w) via SC injection for 24 weeks. Participants will enter the OLE Period and receive bodyweight dependent doses of either 20mg, 35mg, or 50mg of ALXN1850 and continue q2w dosing with ALXN1850 for up to 132 weeks. |
| ALXN1850 Group | Experimental | Drug: ALXN1850, Drug: PlaceboStarting 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 q2w via SC injection, for 24 weeks. Participants will enter the OLE Period and continue q2w dosing with ALXN1850 for up to 132 weeks. |
Who may qualify
- Ages
- 12 to 130 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (8 listed)
- Diagnosis of HPP documented in the medical records
- Must meet 1 of the following criteria:
- Must meet 1 of the following criteria without a probably cause other than HPP:
- Two separate 6MWTs at below 85% of the predicted distance (for age, sex, weight, and height) during the Screening Period without a probable cause other than HPP
Key exclusion criteria (6 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ALXN1850ALXN1850 will be administered via subcutaneous (SC) injection. | Drug | ALXN1850 Group |
| PlaceboPlacebo will be administered via SC injection. | Drug | ALXN1850 Group, Placebo Group |
Primary outcome
Change from Baseline in 6-Minute Walk Test (6MWT) at the end of the Randomized Evaluation Period (Day 169)
Time frame: Baseline, Day 169
9 secondary outcomes
Change from Baseline in 30-second Sit to Stand (STS) Test Score at the end of the Randomized Evaluation Period (Day 169)
Time frame: Baseline, Day 169
Change from Baseline in Lower Extremity Functional Scale (LEFS) Score at the end of the Randomized Evaluation Period (Day 169)
Time frame: Baseline, Day 169
Change from Baseline in BPI-SF pain severity score at the end of the Randomized Evaluation Period (Day 169) (adult cohort only)
Time frame: Baseline, Day 169
Change from Baseline in FACIT-Fatigue score at the end of the Randomized Evaluation Period (Day 169) (adult cohort only)
Time frame: Baseline, Day 169
Change from Baseline in Timed Up-and-Go (TUG) at the end of the Randomized Evaluation Period (Day 169)
Time frame: Baseline, Day 169
Change from Baseline in Percent Predicted 6MWT at the end of the Randomized Evaluation Period (Day 169)
Time frame: Baseline, Day 169
Radiographic Global Impression of Change (RGI-C) Score at the end of the Randomized Evaluation Period (Day 169)
Time frame: Day 169
RGI-C Responder at the end of the Randomized Evaluation Period (Day 169)
Time frame: Day 169
Change from Baseline in Rickets Severity Score (RSS) at the end of the Randomized Evaluation Period (Day 169)
Time frame: Baseline, Day 169
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Jun 2026.
- Routing the applicable forms for final approval prior to submission by the CTIS ExpertLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. Alexion has a public commitment to allow requests for access to study data and will be supplying a protocol, CSR, and plain language summaries.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
65 sites in 17 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing ALXN1850 in people with Hypophosphatasia, run by Alexion Pharmaceuticals, Inc. at 65 sites in 17 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 22 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 65 sites in China, Italy, Brazil, Spain, United States and 12 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change from Baseline in 6-Minute Walk Test (6MWT) at the end of the Randomized Evaluation Period (Day 169) (time frame: Baseline, Day 169). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Jun 2026.