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Open Label Trial Assessing Safety and Efficacy of Burosumab (KRN23), in a Patient With ENS and Hypophosphatemic Rickets

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ClinicalTrials.gov Identifier: NCT03581591
Recruitment Status : Completed
First Posted : July 10, 2018
Last Update Posted : January 18, 2020
Ultragenyx Pharmaceutical Inc
Information provided by (Responsible Party):
Redwood Dermatology Sciences

Brief Summary:

A 52 week, open label trial to assess the safety and efficacy of KRN23, an investigational antibody to FGF23, in a single pediatric patient with Epidermal Nevus Syndrome(ENS) and associated hypophosphatemic rickets

A 26 weeks extension to original study to monitor patient lab results for her safety.

Condition or disease Intervention/treatment Phase
Hypophosphatemia Hypophosphatemic Rickets Pain, Chronic Biological: Burosumab Phase 3

Detailed Description:

1.1 Primary Objective

The effect of KRN23 treatment on normalizing age-adjusted serum phosphorous levels in a single pediatric patient with Epidermal Nevus Syndrome associated hypophosphatemic rickets

1.2 Secondary Objectives

  1. The PD profile of KRN23 as assessed by changes from baseline over time 1,25(OH)2D, iPTH, Serum Calcium, TRP and TmP/GFR (the ratio of renal tubular maximum phosphate reabsorption rate to glomerular filtration rate)
  2. Changes in underlying skeletal disease/rickets as assessed by standard radiographs utilizing the Radiographic Global Impression of Change (RGI-C) rating scales
  3. Effects of KRN23 on biochemical markers of bone turnover that reflect rickets severity, alkaline phosphatase (ALP)
  4. Walking ability as assessed by 6-Minute Walk Test (6MWT)
  5. Patient/parent-Reported Outcomes as assessed by PROMIS and FPS-R rating scales

1.3 Exploratory Objective

1. Dual-energy X-ray absorptiometry (DXA)

1.4 Safety Objective Assess the safety of KRN23 administration in a single patient with ENS-associated hypophosphatemic rickets, based on adverse events (AEs), laboratory assessments, cardiac imaging and renal ultrasound.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 1 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: An Open Label Trial to Assess the Safety and Efficacy of Burosumab (KRN23), an Investigational Antibody to FGF23, in a Single Pediatric Patient With Epidermal Nevus Syndrome(ENS) and Associated Hypophosphatemic Rickets
Actual Study Start Date : January 31, 2018
Actual Primary Completion Date : December 6, 2019
Actual Study Completion Date : December 6, 2019

Arm Intervention/treatment
Experimental: Primary; open label
Injection of Burosumab every two to three weeks based on Serum Phosphorus level of subject. Initial dose to be 0.3 mg/kg. Subsequent dosing will be titrated up or down depending on Serum Phosphorus level for that time period.
Biological: Burosumab
recombinant human IgG1 monoclonal antibody to fibroblast growth factor 23)

Primary Outcome Measures :
  1. The effect of KRN23 treatment on normalizing age-adjusted serum phosphorous levels in a single pediatric patient with Epidermal Nevus Syndrome associated hypophosphatemic rickets [ Time Frame: 18 months ]

Information from the National Library of Medicine

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Ages Eligible for Study:   up to 18 Years   (Child, Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Patient has confirmed ENS by physician diagnosis
  2. Patient has confirmed FGF23 elevations in the context of low serum phosphorous < 4.1 mg/dL
  3. Patient able to tolerate KRN23 treatment
  4. Have a corrected serum calcium level < 10.8mg/dL
  5. Have an eGFR >60 ml/min
  6. Must be willing in the opinion of the investigator, to comply with study procedures and schedule
  7. Provide written informed consent by a parent after the study has been explained and prior to any research related procedures begin

Exclusion Criteria:

  1. Concomitant use of active vitamin D (i.e calcitriol) and/or exogenous phosphate supplementation. Patient will be allowed OTC Vitamin D should levels drop below <20 ng/ml
  2. The use or enrollment in studies using other investigational therapies including other monoclonal antibodies
  3. Subject and their parent not willing or not able to give written informed consent
  4. In the Investigators opinion, the patient may not be able to meet all the requirements for study participation
  5. Patient has a history of hypersensitivity to KRN23 excipients that in the opinion of the investigator, places the patient at an increased risk of adverse effects
  6. Patient has a condition that in the opinion of the investigator could present a concern for subject safety or data interpretation.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03581591

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United States, Utah
The Focus Center, PC
Clinton, Utah, United States, 84015
Sponsors and Collaborators
Redwood Dermatology Sciences
Ultragenyx Pharmaceutical Inc
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Principal Investigator: Jeffrey Sugarman, MD PhD Redwood Dermatology Sciences
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Responsible Party: Redwood Dermatology Sciences
ClinicalTrials.gov Identifier: NCT03581591    
Other Study ID Numbers: ENSKRN23.1
First Posted: July 10, 2018    Key Record Dates
Last Update Posted: January 18, 2020
Last Verified: January 2020

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Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Rickets, Hypophosphatemic
Familial Hypophosphatemic Rickets
Chronic Pain
Neurologic Manifestations
Phosphorus Metabolism Disorders
Metabolic Diseases
Bone Diseases, Metabolic
Bone Diseases
Musculoskeletal Diseases
Calcium Metabolism Disorders
Vitamin D Deficiency
Deficiency Diseases
Nutrition Disorders
Hypophosphatemia, Familial
Renal Tubular Transport, Inborn Errors
Kidney Diseases
Urologic Diseases
Metal Metabolism, Inborn Errors
Metabolism, Inborn Errors
Genetic Diseases, Inborn