Phase 3 Study of ALXN1850 versus Placebo in Adolescent and Adult Participants with HPP who have not previously been treated with Asfotase Alfa

JRCT ID: jRCT2041230107

Registered date:19/11/2023

Basic Information

• Recruitment status: Recruiting
• Health condition(s) or Problem(s) studied: Hypophosphatasia
• Date of first enrollment: 26/01/2024
• Target sample size: 3
• Countries of recruitment: Argentina,Japan,Australia,Japan,Austria,Japan,Belgium,Japan,Brazil,Japan,Canada,Japan,China,Japan,Czech Republic,Japan,France,Japan,Germany,Japan,India,Japan,Israel,Japan,Italy,Japan,Poland,Japan,Slovakia,Japan,South Korea,Japan,Spain,Japan,Taiwan,Japan,Thailand,Japan,Turkey,Japan,United Kingdom,Japan,United States of America,Japan
• Study type: Interventional

Intervention(s)

Placebo Comparator: Placebo Group
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.

Experimental: ALXN1850 Group
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.

Outcome(s)

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

Key inclusion & exclusion criteria

• Age minimum: >= 12age old
• Age maximum: Not applicable
• Gender: Both

Include criteria

1. Participant must be 12 years or more of age at Day 1
2. Diagnosis of HPP documented in the medical records
3. Must meet 1 of the following criteria:
a) Documented ALPL gene variant (pathogenic, likely pathogenic, or variant of unknown significance) from a Clinical Laboratory Improvement Amendments (CLIA) certified laboratory
b) Plasma PLP above the upper limit of normal (ULN) during the Screening Period (central or local laboratory results allowed per local regulations)
4. Serum ALP activity below the age- and sex-adjusted normal range during the screening period, without a probable cause other than HPP
5. 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

Exclude criteria

1. 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
2. Diagnosis of primary or secondary hyperparathyroidism
3. Hypoparathyroidism, unless secondary to HPP
4. Any new fracture within 12 weeks before Day 1 (excluding pseudofractures)
5. Planned surgical intervention which may impact the results of study assessments (in the opinion of the Investigator) during the Randomized Evaluation Period
6. History of allergy or hypersensitivity to any ingredient contained in ALXN1850 or the placebo comparator

Related Information

• Primary Sponsor: Wuebbenhorst Hiroaki
• Secondary ID(s): NCT06079281