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Safety and Efficacy Study of Asfotase Alfa in Adolescents and Adults With Hypophosphatasia (HPP)

This study has been completed.
Information provided by (Responsible Party):
Alexion Pharma GmbH Identifier:
First received: June 24, 2010
Last updated: August 3, 2016
Last verified: August 2016
This clinical trial is being conducted to study hypophosphatasia (HPP), a bone disorder caused by gene mutations or changes. These gene mutations cause low levels of an enzyme needed to harden bone. The purpose of this study is to test the safety and efficacy of two doses of the study drug called asfotase alfa as compared to a control group to see what effects it has adolescents and adults with HPP.

Condition Intervention Phase
Hypophosphatasia Drug: asfotase alfa Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: A Randomized, Open-Label, Multicenter, Multinational, Dose-Ranging, Concurrent Control Study of the Safety, Efficacy, Pharmacokinetic of ENB-0040 (Human Recombinant Tissue Nonspecific Alkaline Phosphatase Fusion Protein) in Adolescents and Adults With Hypophosphatasia (HPP)

Resource links provided by NLM:

Further study details as provided by Alexion Pharma GmbH:

Primary Outcome Measures:
  • Effect of asfotase alfa on reduction in plasma inorganic pyrophosphate (PPi) and plasma pyridoxal-5' phosphate (PLP) [ Time Frame: Week 24 ]
    Blood samples will be collected to evaluate the effect of Asfotase Alfa on reduction in plasma inorganic pyrophosphate (PPi) and plasma pyridoxal-5' phosphate (PLP)

  • Safety and Tolerability of asfotase alfa [ Time Frame: Up to 96 weeks or until regulatory approval ]
    The safety and tolerability of daily subcutaneous (SC) injections of asfotase alfa will be assessed by routine monitoring of patients for adverse events (AEs) and injection-associated reactions (IARs) and monitoring changes from Baseline in physical examination findings, vital signs, clinical laboratory evaluations, renal ultrasound findings, funduscopic examinations, antibody evaluations, and results of pregnancy testing (in women of childbearing potential only). Monitoring for changes in concomitant medications and therapies will also occur.

Secondary Outcome Measures:
  • Change in bone mineral content and density as measured by dual-energy X-ray absorptiometry (DXA) [ Time Frame: Every 24 weeks ]
    A DXA scan will be performed to evaluate bone mineral content and density of the spine, hip, and whole body.

  • Change in walking ability as measured by the Six-Minute Walk Test (6MWT) [ Time Frame: Every 24 weeks ]
    The patient will be instructed to walk the length of a pre-measured hallway for 6 minutes. The primary measurement will be the distance walked (in meters).

  • Change in HPP-related osteomalacia as measured by trans-iliac crest bone biopsy [ Time Frame: Week 24, Week 48 ]
    A trans-iliac crest bone biopsy will be performed to quantify osteomalacia severity.

Enrollment: 19
Study Start Date: June 2010
Study Completion Date: June 2016
Primary Completion Date: June 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Cohort 1
Cohort 1: Daily SC injections of 0.3 mg/kg asfotase alfa (2.1 mg/kg/week total)
Drug: asfotase alfa
Cohort 1: Daily SC injections of 0.3 mg/kg asfotase alfa (tota1 of 2.1 mg/kg/week)
Experimental: Cohort 2
Cohort 2: Daily SC injections of 0.5 mg/kg asfotase alfa (3.5 mg/kg/week total)
Drug: asfotase alfa
Cohort 2: Daily SC injections of 0.5 mg/kg Asfotase Alfa (3.5 mg/kg/week total)
No Intervention: Concurrent Control
Following completion of the Week 24 visit, all patients (including those randomized to the concurrent control cohort) may be eligible to participate in an open-label extension study of asfotase alfa. In this extension period, all patients will be treated with daily SC injections of 0.5 mg/kg/day asfotase alfa (a total of 3.5 mg/kg/week) for approximately 24 weeks, then subjects will receive 1 mg/kg/day 6 days/week for an additional 48 weeks or until regulatory approval of the drug.

Detailed Description:

Asfotase alfa was formerly referred to as ENB-0040

Hypophosphatasia (HPP) is a life-threatening, genetic, and ultra-rare metabolic disease characterized by defective bone mineralization and impaired phosphate and calcium regulation that can lead to progressive damage to multiple vital organs, including destruction and deformity of bones, profound muscle weakness, seizures, impaired renal function, and respiratory failure. There are no approved disease-modifying treatments for patients with this disease. There is also limited data available on the natural course of this disease over time, particularly in patients with the juvenile-onset form.


Ages Eligible for Study:   13 Years to 65 Years   (Child, Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion criteria:

Patients must meet all of the following inclusion criteria to be eligible for participation in this study:

  • Patients or their legal representative(s) must provide written informed consent prior to undergoing any study-related procedures
  • Patients must be ≥ 13 and ≤ 65 years of age at the time of study enrollment
  • Female patients of childbearing potential and sexually mature males must agree to use a medically acceptable form of birth control; for the purposes of this study, females are considered of non-childbearing potential if they are surgically sterile (i.e., have undergone a total hysterectomy, bilateral salpingo-oophorectomy or tubal ligation) or are post-menopausal, defined as having complete cessation of menstruation for at least 1 year after 45 years of age
  • Patients must have a pre-established clinical diagnosis of HPP as indicated by:

    • Serum alkaline phosphatase (ALP) below the age-adjusted normal range
    • Plasma PLP at least twice the upper limit of normal (no vitamin B6 administered for at least 1 week prior to determination)
    • Evidence of osteopenia or osteomalacia on skeletal radiographs
  • Patients must have osteomalacia on bone biopsy, characterized by an MLT z-score of +2 or more (results from ENB-001-08 may be used)
  • Patients must be willing to comply with study procedures and the visit schedule

Exclusion criteria:

Patients will be excluded from participation in this study if they meet any of the following exclusion criteria:

  • Women who are pregnant or lactating
  • History of sensitivity to tetracycline
  • Serum calcium or phosphate levels below the normal range
  • Serum 25(OH) vitamin D below 20 ng/mL
  • Serum creatinine or parathyroid hormone (PTH) levels above the upper limit of normal
  • Medical condition, serious intercurrent illness, or other extenuating circumstance that, in the opinion of the Investigator, may significantly interfere with study compliance, including all prescribed evaluations and follow-up activities
  • Orthopedic surgery within 12 months prior to study entry that may interfere with the ability to perform functional assessments for the study
  • Prior treatment with bisphosphonates within 2 years of study entry for any length of time or for more than 2 years at any time point; for patients with prior bisphosphonate use that is allowed, the bone resorption markers serum C-telopeptide and urine N-telopeptide or urine deoxypyridinoline must also be within the normal range or elevated to be eligible for study participation
  • Treatment with PTH within 6 months prior to the start of asfotase alfa administration
  • Participation in an interventional or investigational drug study within 30 days prior to study participation
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01163149

United States, Missouri
Shriner's Hospital for Children
St. Louis, Missouri, United States, 63131
United States, North Carolina
Duke University Medical Center
Durham, North Carolina, United States, 27710
Canada, Manitoba
Health Sciences Centre Winnipeg, University of Manitoba
Winnipeg, Manitoba, Canada, R3A 1S1
Sponsors and Collaborators
Alexion Pharma GmbH
  More Information

Additional Information:
Responsible Party: Alexion Pharma GmbH Identifier: NCT01163149     History of Changes
Other Study ID Numbers: ENB-009-10
Study First Received: June 24, 2010
Last Updated: August 3, 2016

Keywords provided by Alexion Pharma GmbH:
Bone Disease
Soft Bones
Low Alkaline Phosphatase
genetic metabolic disorder
alkaline phosphatase
tissue-specific alkaline phosphatase (TNSALP)

Additional relevant MeSH terms:
Metal Metabolism, Inborn Errors
Metabolism, Inborn Errors
Genetic Diseases, Inborn
Metabolic Diseases
Immunoglobulin G
Immunologic Factors
Physiological Effects of Drugs processed this record on August 21, 2017