MULBERRY: Phase 3 Study of ALXN1850 in Treatment-Naïve Pediatric Participants With HPP

Sponsor

Alexion (Industry)

Overall Status

Not yet recruiting

CT.gov ID

NCT06079359

Collaborator

(none)

Enrollment

Locations

Arms

Anticipated Duration (Months)

0.8

Patients Per Site

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

The primary purpose of this study is 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.

Condition or Disease	Intervention/Treatment	Phase
Hypophosphatasia	Drug: ALXN1850 Drug: Placebo	Phase 3

Study Design

Study Type:

Interventional

Anticipated Enrollment :

30 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)

Masking Description:

double-blinded

Primary Purpose:

Treatment

Official Title:

A Phase 3, Randomized, Double-blinded, Placebo-controlled, Multicenter Study to Evaluate Efficacy and Safety of ALXN1850 Versus Placebo Administered Subcutaneously in Pediatric (2 to < 12 Years of Age) Participants With Hypophosphatasia Who Have Not Received Previous Treatment With Asfotase Alfa

Anticipated Study Start Date :

Feb 28, 2024

Anticipated Primary Completion Date :

May 28, 2025

Anticipated Study Completion Date :

Nov 28, 2027

Arms and Interventions

Arm	Intervention/Treatment
Experimental: ALXN1850 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 every 2 weeks (q2w) via SC injection, for 24 weeks. Participants will enter the OLE Period and continue q2w dosing with ALXN1850 for up to 132 weeks.	Drug: ALXN1850 Participants will receive a ALXN1850 via subcutaneous (SC) injection. Drug: Placebo Participants will receive placebo via SC injection.
Placebo Comparator: Placebo Starting at Day 1 during the Randomized Evaluation Period, participants will receive placebo q2w for a total of 24 weeks. Participants will enter the OLE Period and continue q2w dosing with ALXN1850 for up to 132 weeks.	Drug: Placebo Participants will receive placebo via SC injection.

Arm

Intervention/Treatment

Experimental: ALXN1850

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 every 2 weeks (q2w) via SC injection, for 24 weeks. Participants will enter the OLE Period and continue q2w dosing with ALXN1850 for up to 132 weeks.

Drug: ALXN1850

Participants will receive a ALXN1850 via subcutaneous (SC) injection.

Drug: Placebo

Participants will receive placebo via SC injection.

Placebo Comparator: Placebo

Starting at Day 1 during the Randomized Evaluation Period, participants will receive placebo q2w for a total of 24 weeks. Participants will enter the OLE Period and continue q2w dosing with ALXN1850 for up to 132 weeks.

Drug: Placebo

Participants will receive placebo via SC injection.

Outcome Measures

Primary Outcome Measures

Radiographic Global Impression of Change (RGI-C) Score at the end of the Randomized Evaluation Period (Day 169) [Day 169]

Secondary Outcome Measures

Change from Baseline in Rickets Severity Score (RSS) at the end of the Randomized Evaluation Period (Day 169) [Baseline, Day 169]
Change from Baseline in 6-Minute Walk Test (6MWT) at the end of the Randomized Evaluation Period (Day 169) [Baseline, Day 169]
Change from Baseline in Percent Predicted 6MWT at the end of the Randomized Evaluation Period (Day 169) [Baseline, Day 169]
Change from Baseline in Bruininks Oseretsky Test of Motor Proficiency, Second Edition (BOT2) Score at the end of the Randomized Evaluation Period (Day 169) [Baseline, Day 169]
Change from Baseline in Peabody Developmental Motor Scales, Third Edition (PDMS-3) Score at the end of the Randomized Evaluation Period (Day 169) [Baseline, Day 169]
RGI-C Responder at the end of the Randomized Evaluation Period (Day 169) [Day 169]

Eligibility Criteria

Criteria

Ages Eligible for Study:

2 Years to 11 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Diagnosis of HPP documented in the medical records, and the following criteria fulfilled during the Screening Period without other probable cause than HPP:

Presence of HPP-related rickets on skeletal X-rays, with a minimum Rickets Severity Score (RSS) of 1.0 AND
Serum ALP activity below the age- and sex-adjusted normal range

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) 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)

Tanner stage 2 or less during the Screening Period

Exclusion Criteria:

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

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Research Site	Baltimore	Maryland	United States	21287
2	Research Site	Kansas City	Missouri	United States	64108
3	Research Site	Durham	North Carolina	United States	27705
4	Research Site	Buenos Aires		Argentina	C1425BPE
5	Research Site	Ciudad Autónoma de Buenos Aires		Argentina	C1199
6	Research Site	Mar del Plata		Argentina	B7600FYK
7	Research Site	Mar del Plata		Argentina	B7600
8	Research Site	Nedlands		Australia	6009
9	Research Site	Parkville		Australia	3052
10	Research Site	Westmead		Australia	2145
11	Research Site	Brasilia		Brazil	71625-009
12	Research Site	Porto Alegre		Brazil	90610-261
13	Research Site	Recife		Brazil	50740-465
14	Research Site	São Paulo		Brazil	01409-902
15	Research Site	Calgary	Alberta	Canada	T2E 7Z4
16	Research Site	Edmonton	Alberta	Canada	T6G 2H7
17	Research Site	Ottawa	Ontario	Canada	K1H 8L1
18	Research Site	Beijing		China	100045
19	Research Site	Guangzhou		China	510623
20	Research Site	Shenzhen		China	518053
21	Research Site	Le Kremlin Bicêtre		France	94270
22	Research Site	Paris		France	75015
23	Research Site	Homburg		Germany	66421
24	Research Site	Ashkelon		Israel	7830604
25	Research Site	Beer Sheva		Israel	8410101
26	Research Site	Petach-Tikva		Israel	4920235
27	Research Site	Ramat Gan		Israel	52621
28	Research Site	Bologna		Italy	40138
29	Research Site	Genova		Italy	16147
30	Research Site	Milano		Italy	20133
31	Research Site	Roma		Italy	00190
32	Research Site	Rome		Italy	00050
33	Research Site	Zapopan		Mexico	45040
34	Research Site	Vitoria		Spain	01009
35	Research Site	Taipei		Taiwan	100
36	Research Site	Taoyuan		Taiwan	333
37	Research Site	Bangkok		Thailand	10400
38	Research Site	Muang		Thailand	50200
39	Research Site	Songkla		Thailand	90110
40	Research Site	Manchester		United Kingdom

Sponsors and Collaborators

Alexion

Investigators

None specified.

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

Responsible Party:

Alexion

ClinicalTrials.gov Identifier:

NCT06079359

Other Study ID Numbers:

D8590C00003
ALXN1850-HPP-305

First Posted:

Oct 12, 2023

Last Update Posted:

Oct 12, 2023

Last Verified:

Oct 1, 2023

Individual Participant Data (IPD) Sharing Statement:

Yes

Plan to Share IPD:

Yes

Studies a U.S. FDA-regulated Drug Product:

Yes

Studies a U.S. FDA-regulated Device Product:

Keywords provided by Alexion

Hypophosphatasia

HPP

ALXN1850

Additional relevant MeSH terms:

Hypophosphatasia

Study Results

No Results Posted as of Oct 12, 2023