A Phase 2 interventional study of Burosumab in Fibrous Dysplasia Of Bone, sponsored by National Institute of Dental and Craniofacial Research (NIDCR). Completed at 1 site in United States. Open to participants aged 1 Year to 99 Years. Per ClinicalTrials.gov, last updated 2026-02-02.
Sponsored by National Institute of Dental and Craniofacial Research (NIDCR) · Phase 2, Interventional, and Treatment
Background:
Fibrous dysplasia (FD) is a disorder that affects bone growth. Affected bone tissue is weakened, and people with FD are prone to deformities, fractures, and other problems. People with FD may also have low blood phosphate levels. This can make bones even weaker. Better treatments are needed.
Objective:
To test a study drug (burosumab) in people with FD who have low blood phosphate levels.
Eligibility:
People aged 1 year or older who have FD and low blood phosphate levels.
Design:
Participants will visit the NIH 3 times in 48 weeks. Each visit will last 5 to 7 days.
Participants will self-inject burosumab under the skin in their belly, upper arm, or thigh. They (or a caregiver) will do this at home 1 or 2 times a month. They will be trained in person on how to inject the drug. Home injections will be guided via telehealth.
During NIH visits, participants will have a physical exam with blood and urine tests. They will have x-rays of different parts of their body. They will have a radioactive tracer injected into their vein; then they will have a bone scan. They will have tests to assess their strength, walking, and movement. They will complete questionnaires about their pain, mobility, and fatigue levels.
Adult participants may have bone biopsies. These will be done under anesthesia with sedation. Small samples of FD-affected bone will be removed for study.
Between NIH visits, participants will go to a local laboratory for blood and urine tests.
Child participants will have an additional follow-up visit 2 weeks after the final NIH visit.
Study Description:
This will be a phase 2, open-label, single-arm study to evaluate the safety and efficacy of burosumab to normalize serum phosphate levels in subjects with fibrous dysplasia (FD) and fibroblast growth factor 23 (FGF23)-mediated hypophosphatemia.
Objectives:
Primary Objective:
-Evaluate the efficacy of burosumab to normalize serum phosphate levels in subjects with FD and FGF23-mediated hypophosphatemia at 48 weeks.
Secondary Objectives:
Endpoints:
Primary Endpoint:
-The proportion of subjects achieving serum phosphate levels within the target range (Z-score -1 to +2) at Week 48.
Secondary Endpoints:
Change from baseline to 48 weeks in:
Change from baseline to 48 weeks in patient reported outcomes measures:
24 studies on the registry are indexed under Fibrous Dysplasia of Bone; 6 are open to participants now.
This study's enrollment of 12 is below the median of 30 across 13 interventional studies indexed under Fibrous Dysplasia of Bone.
Browse Fibrous Dysplasia of Bone studies →National Institute of Dental and Craniofacial Research (NIDCR) is the lead sponsor of 94 studies on the registry; 9 are open to participants now.
Of its 8 completed or terminated interventional studies of FDA-regulated products, 5 (63%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
In order to be eligible to participate in this study, an individual must meet all of the following criteria:
For females of : agreement to use highly effective for during study participation. Highly effective contraception methods include:
Combination of the following (a+b or a+c, or b+c):
EXCLUSION CRITERIA:
An individual who meets any of the following criteria will be excluded from participation in this study:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Reproductive potential
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants with Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) and hypophosphatemia receive burosumab subcutaneously dosed to the nearest 10mg. Pediatric participants receive 0.8mg/kg subcutaneously every two weeks for 48 weeks. Adult participants receive 0.5mg/kg subcutaneously every four weeks, with the option to receive dose every two weeks, for 48 weeks. All participants receive a minimum dose of 10mg/dose and a maximum of 90mg/dose.
Drug: Burosumab
Human recombinant monoclonal antibody to fibroblast growth factor-23 (FGF23)
Proportion of Participants With Serum Phosphate Levels Within the Target Range at Week 48
The proportion of participants who achieved serum phosphate levels within the target range (Z-score -1 to +2) at week 48. Analysis was done by dividing the number of number of participants who achieved serum level by the number of participants analyzed.
Time frame: Week 48
Participants With Adverse Event by Grade
Number participants with any adverse events by grade, up to 4 weeks after the final burosumab dose, was assessed using the National Cancer Institute (NCI), Common Terminology Criteria for Adverse Events (CTCAE), Version 5.0. Grade 1 Mild; asymptomatic or mild symptoms; clinical or diagnostic observations only; intervention not indicated. Grade 2 Moderate; minimal, local or noninvasive intervention indicated; limiting age appropriate instrumental ADL. Grade 3 Severe or medically significant but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; limiting self care ADL. Grade 4 Life-threatening consequences; urgent intervention indicated. Grade 5 Death related to AE.
Time frame: 48 weeks for adult participants; 50 weeks for pediatric participants
Participants With Related Adverse Event
Participants with related adverse events up to 4 weeks after the final burosumab dose (48 weeks for adult subjects, 50 weeks for pediatric subjects). Adverse event was assessed using the National Cancer Institute (NCI), Common Terminology Criteria for Adverse Events (CTCAE), Version 5.0. Related adverse event means that there are available evidence that suggests that there is a reasonable possibility that the study drug caused the adverse event.
Time frame: 48 weeks for adult participants; 50 weeks for pediatric participants
Proportion of Participants With Serum Phosphate Levels Within the Target Range at Week 24
The proportion of participants who achieved serum phosphate levels within the target range (Z-score -1 to +2) at week 24. Analysis was done by dividing the number of number of participants who achieved serum level by the number of participants analyzed.
Time frame: Week 24
Proportion of Participants With Serum Phosphate Levels Above the Target Range (Z-score >+2)
The proportion of participants who achieved serum phosphate levels above the target range (Z-score \>+2) at any timepoint between baseline and week 48. Analysis was done by dividing the number of number of participants who achieved serum level above the target range by the number of participants analyzed.
Time frame: Between baseline and week 48
Change in Serum Phosphate Level
Change in serum phosphate level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Percent Change in Serum Phosphate Level
Percent change in serum phosphate level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Serum 1,25-dihydroxyvitamin D Level
Change in serum 1,25-dihydroxyvitamin D level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Percent Change in Serum 1,25-dihydroxyvitamin D Level
Percent change in serum 1,25-dihydroxyvitamin D level from baseline to 48 weeks. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = 48 weeks minus baseline.
Time frame: Week 48 minus baseline
Change in Serum Ratio of Renal Tubular Maximum Reabsorption Rate of Phosphate to Glomerular Filtration Rate (TmP/GFR)
Change in serum ratio of renal tubular maximum reabsorption rate of phosphate to glomerular filtration rate (TmP/GFR) from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Percent Change in Serum Ratio of Renal Tubular Maximum Reabsorption Rate of Phosphate to Glomerular Filtration Rate (TmP/GFR)
Percent change in serum ratio of renal tubular maximum reabsorption rate of phosphate to glomerular filtration rate (TmP/GFR) from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Fibrous Dysplasia Lesion Activity Using Fluorine-18 Sodium Fluoride Positron Emission Tomography/Computed Tomography (18F-NaF PET/CT) Scan
Change in fibrous dysplasia lesion activity using Fluorine-18 Sodium Fluoride Positron Emission Tomography/Computed Tomography (18F-NaF PET/CT) scan from baseline to week 48. 18F-NaF PET/CT scan was done at baseline and week 48 and total lesion activity units were calculated from each scan. Change in lesion activity was compared between timepoints, baseline and week 48. Change = 48 weeks minus baseline.
Time frame: Week 48 minus baseline
Change in Serum Procollagen 1 N-terminal Propeptide (P1NP) Level
Change in serum procollagen 1 N-terminal propeptide (P1NP) level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Percent Change in Serum Procollagen 1 N-terminal Propeptide (P1NP) Level
Percent change in serum procollagen 1 N-terminal propeptide (P1NP) level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Serum Beta Crosslaps C-telopeptides (CTX) Level
Change in serum beta crosslaps C-telopeptides (CTX) level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Percent Change in Serum Beta Crosslaps C-telopeptides (CTX) Level
Percent change in serum beta crosslaps C-telopeptides (CTX) level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Serum Osteocalcin Level
Change in serum osteocalcin level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Percent Change in Serum Osteocalcin Level
Percent change in serum osteocalcin level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Serum Alkaline Phosphatase Level
Change in serum alkaline phosphatase level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Percent Change in Serum Alkaline Phosphatase Level
Percent change in serum alkaline phosphatase level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Fibrous Dysplasia Lesion Cellularity
Change in fibrous dysplasia lesion cellularity was assessed by minimally invasive bone biopsies at baseline and week 48 in only adult participants with capacity to consent to procedure. Bone biopsies assessed the count of cell density. Analysis was done as change in median cell density value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Muscle Strength Using the Manual Muscle Test Scale
Muscle strength was assessed using the manual muscle test (MMT) scale. MMT is a clinical technique to assess the strength of individual muscles or muscle groups based on ability to move against gravity and resist applied external pressure on a 0-5 scale, with 0 (no contraction), 1 (trace), 2 (poor) (movement with gravity eliminated), 3 (fair) (movement against gravity), 4 (good) (movement against gravity with moderate resistance), and 5 (normal strength). Higher number indicates better muscle resistance and strength. Each muscle group was assessed at baseline and week 48. Analysis was done for each muscle as change between baseline and week 48 (week 48 - baseline).
Time frame: Week 48 minus baseline
Change in Muscle Range-of-motion
Muscle range-of-motion was measured as the degree of movement of muscles. Assessment was done at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Walking Speed Measured by the 9-minute Walk Test (9MWT)
Change in walking speed was measured by the 9-minute walk test from baseline to week 48. The 9-minute walk test (9MWT) is a measure of physical capacity and participants are instructed to run or walk over a time period of nine minutes. The 9-minute walk test distance (9MWD) is the total distance walked in meters during the 9MWT and greater distance walked means better physical capacity. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Quality of Life Measured by the 36-Item Short Form Health Survey (SF-36) Score
The change in quality of life for the adult participants was assessed using the Short Form Health Survey (SF-36). SF-36 is a 36-item patient-reported survey of patient health status that consists of eight scaled scores, which are the weighted sums of the questions in their section. Each scale is directly transformed into a 0-100 scale. The higher the score, the less disability. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Health-related Quality of Life Measured by the 10-Item Short Form Health Survey (SF-10) - Physical Summary Score (PHS)
The change in quality of life for the pediatric participants was assessed using the Short-Form Health Survey-10 (SF-10). The Short-Form Health Survey (SF-10) is a 10-item parent-completed questionnaire that covers a wide range of domains affecting a child's functional health and well-being. The SF-10 is scored to produce two norm-based summary scores: a Physical Summary Score (PHS) and a Psychosocial Summary Score (PSS), each with a mean of 50 and a standard deviation of 10. Analysis was based on the PHS. The PHS scale is directly transformed into a 0-100 scale. The higher the score, the less disability. Measurements were taken for the Physical Summary Score (PHS) at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Pediatric and Parent Proxy Version 1.0) - Pain Intensity Domain
The Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity (Pediatric and Parent Proxy version 1.0) domain measures pain intensity in children, with pediatric self-report versions for ages 8-17 and parent proxy-report versions for children aged 5-17. This measure uses a standard scale to assess the level of pain over the past seven days, and for the current moment, providing a quantitative score that reflects the severity of the pain. The scale consist of three items with each scored on a 5-point Likert scale, 1-5 with lowest score of 3 and highest of 15. The raw score is converted to a T-score with a mean of 50 and standard deviation of 10. Higher scores indicates greater pain intensity. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Adult Version 2.0) - Pain Intensity Domain
The Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity (Adult version 2.0) - Pain Intensity domain is a universal, self-report measure of how much pain a person is experiencing. This measure uses a standard scale to assess the level of pain over the past seven days, and for the current moment, providing a quantitative score that reflects the severity of the pain. The scale consist of three items with each scored on a 5-point Likert scale, 1-5 with lowest score of 3 and highest of 15. The raw score is converted to a T-score with a mean of 50 and standard deviation of 10. Higher scores indicates greater pain intensity. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Pediatric and Parent Proxy Version 2.0) - Pain Inference Domain
The Patient Reported Outcome Measurement Information System (PROMIS) (Pediatric and Parent Proxy version 2.0) - Pain Inference Domain assesses how pain impacts daily life, sleep, and enjoyment in children, with the Pediatric version being self-reported by children aged 8-17 and the Parent Proxy version completed by a parent or guardian for their child aged 5-17. This measure uses a standard scale to assess the level of pain interference over the past seven days, and for the current moment, providing a quantitative score that reflects the severity of the pain interference. Each item is rated on a 5-point scale (1-5). The scores are then summed and converted into a T-score, with a mean of 50 and standard deviation of 10. Higher scores indicate greater pain interference. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Adult Version 1.1) - Pain Inference Domain
The Patient-Reported Outcomes Measurement Information System (PROMIS) (Adult version 1.1) - Pain Inference scale assesses the impact of pain on social, physical, cognitive, emotional, and recreational activities, as well as sleep and life enjoyment. The scale consists of 12 items and each item is rated on a 5-point scale (1-5). The scores are then summed and converted into a T-score, with a mean of 50 and standard deviation of 10. Higher scores indicate greater pain interference. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Pediatric and Parent Proxy Version 2.0) - Mobility Lower Extremity Domain
The Patient Reported Outcome Measurement Information System (PROMIS) (Pediatric and Parent Proxy version 2.0) Mobility Lower Extremity domain assesses self-perceived mobility in children, with the Pediatric version being self-reported by children aged 8-17 and the Parent Proxy version completed by a parent or guardian for their child aged 5-17. This measure uses a standard scale to assess lower extremity mobility by asking about activities such as getting up from a chair or running over the past seven days. Each item is rated on a 5-point scale (1-5). The scores are then summed and converted into a T-score, with a mean of 50 and standard deviation of 10. Higher scores indicate greater mobility. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Adult Version 2.0) - Mobility Lower Extremity Domain
The Patient Reported Outcome Measurement Information System (PROMIS) (Adult version 2.0) Mobility Lower Extremity Domain assesses an adult's self-perceived ability to perform physical tasks related to mobility and lower extremity function, such as getting out of a chair or walking. This measure uses a standard scale to assess lower extremity mobility by asking about mobility activities over the past seven days. Each item is rated on a 5-point scale (1-5). The scores are then summed and converted into a T-score, with a mean of 50 and standard deviation of 10. Higher scores indicate greater mobility. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48 minus baseline
Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Pediatric and Parent Proxy Version 2.0) - Fatigue Domain
The Patient Reported Outcome Measurement Information System (PROMIS) (Pediatric and Parent Proxy version 2.0) Fatigue domain assess the level and impact of fatigue in children and adolescents, with the Pediatric version being self-reported by children aged 8-17 and the Parent Proxy version completed by a parent or guardian for their child aged 5-17. This measure uses a standard scale to assess the level of fatigue over the past seven days. Each item is rated on a 5-point scale (1-5). The scores are then summed and converted into a T-score, with a mean of 50 and standard deviation of 10 based on a US general population. Higher scores indicate worsening fatigue. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48
Change in Patient Reported Outcome Measurement Information System (PROMIS) - Short Form - Fatigue 13a (Adult FACIT 13a v1.0)
The Patient Reported Outcome Measurement Information System (PROMIS) Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) Scale is a 13-item patient-reported outcome (PRO) questionnaire that captures the individual's subjective experience of their fatigue. The fatigue domain is scored on a 5-point Likert scale and converted into standardized T-scores with a mean of 50 and a standard deviation of 10 based on a US general population. Higher score indicates less fatigue. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
Time frame: Week 48
Proportion of Participants With Change in Activities of Daily Living (ADL) Questions
Proportion of participants with change in activities of daily living (ADL) questions from baseline to week 48 was assessed using a study developed questionnaire. Participants and/or caregivers were asked to provide a list of three activities of daily living that were affected by fibrous dysplasia skeletal features at home or school/work (e.g., mobility, climbing stairs, dressing, playing with peers, catching a bus, etc.) and to rate the extent of impact upon their activity level using one of the option: * Very Much Improved * Much Improved * Minimally Improved * No Change * Minimally Worse * Much Worse * Very Much Worse These activities were assessed at baseline, then reassessed at Week 24 and Week 48. Analysis was done as proportion of participants reporting "much improved" or "very much improved" in Activities of Daily Living Questions. Change = Week 48 minus baseline.
Time frame: Week 48 minus baseline
| Milestone | Treatment With Burosumab |
|---|---|
| Started | 12 |
| Completed | 12 |
| Not completed | 0 |
The proportion of participants who achieved serum phosphate levels within the target range (Z-score -1 to +2) at week 48. Analysis was done by dividing the number of number of participants who achieved serum level by the number of participants analyzed.
| Proportion of participant | Treatment With Burosumab |
|---|---|
| Proportion of Participants With Serum Phosphate Levels Within the Target Range at Week 48 | 1 |
Number participants with any adverse events by grade, up to 4 weeks after the final burosumab dose, was assessed using the National Cancer Institute (NCI), Common Terminology Criteria for Adverse Events (CTCAE), Version 5.0. Grade 1 Mild; asymptomatic or mild symptoms; clinical or diagnostic observations only; intervention not indicated. Grade 2 Moderate; minimal, local or noninvasive intervention indicated; limiting age appropriate instrumental ADL. Grade 3 Severe or medically significant but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; limiting self care ADL. Grade 4 Life-threatening consequences; urgent intervention indicated. Grade 5 Death related to AE.
| Participants | Treatment With Burosumab |
|---|---|
| Grade 1 | 9 |
| Grade 2 | 6 |
| Grade 3 | 1 |
| Grade 4 | 0 |
| Grade 5 | 0 |
Participants with related adverse events up to 4 weeks after the final burosumab dose (48 weeks for adult subjects, 50 weeks for pediatric subjects). Adverse event was assessed using the National Cancer Institute (NCI), Common Terminology Criteria for Adverse Events (CTCAE), Version 5.0. Related adverse event means that there are available evidence that suggests that there is a reasonable possibility that the study drug caused the adverse event.
| Participants | Treatment With Burosumab |
|---|---|
| Participants With Related Adverse Event | 8 |
The proportion of participants who achieved serum phosphate levels within the target range (Z-score -1 to +2) at week 24. Analysis was done by dividing the number of number of participants who achieved serum level by the number of participants analyzed.
| Proportion of participants | Treatment With Burosumab |
|---|---|
| Proportion of Participants With Serum Phosphate Levels Within the Target Range at Week 24 | 0.92 |
The proportion of participants who achieved serum phosphate levels above the target range (Z-score \>+2) at any timepoint between baseline and week 48. Analysis was done by dividing the number of number of participants who achieved serum level above the target range by the number of participants analyzed.
| Proportion of participants | Treatment With Burosumab |
|---|---|
| Proportion of Participants With Serum Phosphate Levels Above the Target Range (Z-score >+2) | 0.5 |
Change in serum phosphate level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| mg/dL | Treatment With Burosumab |
|---|---|
| Change in Serum Phosphate Level | 1.5 (0.8 to 2.2) |
Percent change in serum phosphate level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
| Percentage of change | Treatment With Burosumab |
|---|---|
| Percent Change in Serum Phosphate Level | 55.5 (29 to 106) |
Change in serum 1,25-dihydroxyvitamin D level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| ng/mL | Treatment With Burosumab |
|---|---|
| Change in Serum 1,25-dihydroxyvitamin D Level | 7.5 (-19 to 57) |
Percent change in serum 1,25-dihydroxyvitamin D level from baseline to 48 weeks. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = 48 weeks minus baseline.
| Percentage of change | Treatment With Burosumab |
|---|---|
| Percent Change in Serum 1,25-dihydroxyvitamin D Level | 29.3 (-0.4 to 950) |
Change in serum ratio of renal tubular maximum reabsorption rate of phosphate to glomerular filtration rate (TmP/GFR) from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| mmol/L | Treatment With Burosumab |
|---|---|
| Change in Serum Ratio of Renal Tubular Maximum Reabsorption Rate of Phosphate to Glomerular Filtration Rate (TmP/GFR) | 0.51 (0.29 to 1.15) |
Percent change in serum ratio of renal tubular maximum reabsorption rate of phosphate to glomerular filtration rate (TmP/GFR) from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
| Percentage of change | Treatment With Burosumab |
|---|---|
| Percent Change in Serum Ratio of Renal Tubular Maximum Reabsorption Rate of Phosphate to Glomerular Filtration Rate (TmP/GFR) | 68.05 (29.8 to 219) |
Change in fibrous dysplasia lesion activity using Fluorine-18 Sodium Fluoride Positron Emission Tomography/Computed Tomography (18F-NaF PET/CT) scan from baseline to week 48. 18F-NaF PET/CT scan was done at baseline and week 48 and total lesion activity units were calculated from each scan. Change in lesion activity was compared between timepoints, baseline and week 48. Change = 48 weeks minus baseline.
| Total lesion activity units | Treatment With Burosumab |
|---|---|
| Change in Fibrous Dysplasia Lesion Activity Using Fluorine-18 Sodium Fluoride Positron Emission Tomography/Computed Tomography (18F-NaF PET/CT) Scan | 8.4 (-143 to 1518) |
Change in serum procollagen 1 N-terminal propeptide (P1NP) level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| mcg/L | Treatment With Burosumab |
|---|---|
| Change in Serum Procollagen 1 N-terminal Propeptide (P1NP) Level | 8.5 (-611 to 1679) |
Percent change in serum procollagen 1 N-terminal propeptide (P1NP) level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
| Percentage of change | Treatment With Burosumab |
|---|---|
| Percent Change in Serum Procollagen 1 N-terminal Propeptide (P1NP) Level | 12.45 (-36.3 to 345) |
Change in serum beta crosslaps C-telopeptides (CTX) level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| pg/mL | Treatment With Burosumab |
|---|---|
| Change in Serum Beta Crosslaps C-telopeptides (CTX) Level | 0.515 (0.29 to 1.15) |
Percent change in serum beta crosslaps C-telopeptides (CTX) level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
| Percentage of change | Treatment With Burosumab |
|---|---|
| Percent Change in Serum Beta Crosslaps C-telopeptides (CTX) Level | 1.69 (-34.6 to 138) |
Change in serum osteocalcin level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| ng/mL | Treatment With Burosumab |
|---|---|
| Change in Serum Osteocalcin Level | 21.95 (-79.7 to 1184) |
Percent change in serum osteocalcin level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
| Percentage of change | Treatment With Burosumab |
|---|---|
| Percent Change in Serum Osteocalcin Level | 24.9 (-35 to 446) |
Change in serum alkaline phosphatase level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| U/L | Treatment With Burosumab |
|---|---|
| Change in Serum Alkaline Phosphatase Level | -531.5 (-1493 to -147) |
Percent change in serum alkaline phosphatase level from baseline to week 48. Measurements were taken at baseline and week 48. Analysis was done as percent change in median value between baseline and week 48. Change = week 48 minus baseline.
| Percentage of change | Treatment With Burosumab |
|---|---|
| Percent Change in Serum Alkaline Phosphatase Level | -48.3 (-62.5 to -33.1) |
Change in fibrous dysplasia lesion cellularity was assessed by minimally invasive bone biopsies at baseline and week 48 in only adult participants with capacity to consent to procedure. Bone biopsies assessed the count of cell density. Analysis was done as change in median cell density value between baseline and week 48. Change = week 48 minus baseline.
| Fibrosis nuclei/mcm^2 | Treatment With Burosumab |
|---|---|
| Change in Fibrous Dysplasia Lesion Cellularity | -0.0001163 (-0.001003 to 0.0001152) |
Muscle strength was assessed using the manual muscle test (MMT) scale. MMT is a clinical technique to assess the strength of individual muscles or muscle groups based on ability to move against gravity and resist applied external pressure on a 0-5 scale, with 0 (no contraction), 1 (trace), 2 (poor) (movement with gravity eliminated), 3 (fair) (movement against gravity), 4 (good) (movement against gravity with moderate resistance), and 5 (normal strength). Higher number indicates better muscle resistance and strength. Each muscle group was assessed at baseline and week 48. Analysis was done for each muscle as change between baseline and week 48 (week 48 - baseline).
| Units on a scale | Treatment With Burosumab |
|---|---|
| NECK_FLEXORS_RIGHT | 0 (-1 to 1) |
| NECK_FLEXORS_LEFT | 0 (-1 to 1) |
| GLUTEUS_MEDIUS_RIGHT | 0 (-2 to 1) |
| GLUTEUS_MEDIUS_LEFT | 0 (-1 to 1) |
| GLUTEUS_MAXIMUS_RIGHT | 0 (-1 to 1) |
| GLUTEUS_MAXIMUS_LEFT | 0 (-3 to 1) |
| HAMSTRINGS_RIGHT | 0 (-1 to 1) |
| HAMSTRINGS_LEFT | 0 (-1 to 1) |
| ANKLE_PLANTAR_FLEXORS_RIGHT | 0 (-1 to 1) |
| ANKLE_PLANTAR_FLEXORS_LEFT | 0 (0 to 1) |
| NECK_EXTENSORS_RIGHT | 0 (0 to 0) |
| NECK_EXTENSORS_LEFT | 0 (0 to 0) |
| TRAPEZIUS_RIGHT | 0 (0 to 1) |
| TRAPEZIUS_LEFT | 0 (0 to 1) |
| DELTOID_RIGHT | 0 (0 to 1) |
| DELTOID_LEFT | 0 (0 to 1) |
| BICEPS_BRACHII_RIGHT | 0 (0 to 1) |
| BICEPS_BRACHII_LEFT | 0 (0 to 2) |
| ILIOPSOAS_RIGHT | 0 (-3 to 1) |
| ILIOPSOAS_LEFT | 0 (-3 to 3) |
| QUADRICEPS_RIGHT | 0 (-2 to 1) |
| QUADRICEPS_LEFT | 0 (-2 to 1) |
| WRIST_FLEXORS_RIGHT | 0 (0 to 1) |
| WRIST_FLEXORS_LEFT | 0 (0 to 2) |
| WRIST_EXTENSORS_RIGHT | 0 (0 to 1) |
| WRIST_EXTENSORS_LEFT | 0 (0 to 2) |
| HALLUCIS_LONGUS_EXTENSOR_RIGHT | 0 (0 to 1) |
| HALLUCIS_LONGUS_EXTENSOR_LEFT | 0 (0 to 1) |
| ANKLE_DORSIFLEX_RIGHT | 0 (0 to 1) |
| ANKLE_DORSIFLEX_LEFT | 0 (0 to 1) |
Muscle range-of-motion was measured as the degree of movement of muscles. Assessment was done at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| Degrees | Treatment With Burosumab |
|---|---|
| SHOULDER_ABDUCTION_RIGHT | 0 (0 to 17) |
| SHOULDER_ABDUCTION_LEFT | 0 (-21 to 9) |
| SHOULDER_INTERNAL_ROTATION_RIGHT | 0 (0 to 38) |
| SHOULDER_INTERNAL_ROTATION_LEFT | 0 (-22 to 45) |
| SHOULDER_EXTERNAL_ROTATION_RIGHT | 0 (-15 to 39) |
| SHOULDER_EXTERNAL_ROTATION_LEFT | 0 (0 to 12) |
| ELBOW_FLEXION_RIGHT | -5 (-17 to 10) |
| ELBOW_FLEXION_LEFT | -6 (-19 to 8) |
| ELBOW_EXTENSION_RIGHT | -0.5 (-9 to 1) |
| ELBOW_EXTENSION_LEFT | -1 (-7 to 3) |
| WRIST_FLEXION_RIGHT | 18 (-15 to 27) |
| WRIST_FLEXION_LEFT | 21 (-19 to 105) |
| WRIST_EXTENSION_RIGHT | 12.5 (-20 to 28) |
| WRIST_EXTENSION_LEFT | 5 (-15 to 87) |
| HIP_FLEXION_RIGHT | 4 (-20 to 19) |
| HIP_FLEXION_LEFT | -4 (-24 to 34) |
| HIP_EXTENSION_RIGHT | 0 (-10 to 10) |
| HIP_EXTENSION_LEFT | 2.5 (-13 to 15) |
| HIP_EXTENSION_ROTATION_RIGHT | 0 (-25 to 42) |
| HIP_EXTENSION_ROTATION_LEFT | -4.5 (-28 to 32) |
| HIP_INTERNAL_ROTATION_RIGHT | 3.5 (-17 to 39) |
| HIP_INTERNAL_ROTATION_LEFT | -4 (-11 to 38) |
| HIP_ABDUCTION_RIGHT | 8.5 (-30 to 30) |
| HIP_ABDUCTION_LEFT | 11 (-57 to 41) |
| KNEE_FLEXION_RIGHT | -3.5 (-19 to 15) |
| KNEE_FLEXION_LEFT | -5 (-25 to 6) |
| KNEE_EXTENSION_RIGHT | 0 (-15 to 5) |
| KNEE_EXTENSION_LEFT | 0 (-16 to 24) |
| ANKLE_PLANTARFLEXION_RIGHT | -2 (-18 to 17) |
| ANKLE_PLANTARFLEXION_LEFT | 8 (-14 to 29) |
| ANKLE_DORSIFLEXION_RIGHT | -0.5 (-6 to 9) |
| ANKLE_DORSIFLEXION_LEFT | -0.5 (-10 to 24) |
Change in walking speed was measured by the 9-minute walk test from baseline to week 48. The 9-minute walk test (9MWT) is a measure of physical capacity and participants are instructed to run or walk over a time period of nine minutes. The 9-minute walk test distance (9MWD) is the total distance walked in meters during the 9MWT and greater distance walked means better physical capacity. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| Meters | Treatment With Burosumab |
|---|---|
| Change in Walking Speed Measured by the 9-minute Walk Test (9MWT) | 3 (-369 to 570) |
The change in quality of life for the adult participants was assessed using the Short Form Health Survey (SF-36). SF-36 is a 36-item patient-reported survey of patient health status that consists of eight scaled scores, which are the weighted sums of the questions in their section. Each scale is directly transformed into a 0-100 scale. The higher the score, the less disability. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| Units on a scale | Treatment With Burosumab |
|---|---|
| Change in Quality of Life Measured by the 36-Item Short Form Health Survey (SF-36) Score | 5 (-10 to 25) |
The change in quality of life for the pediatric participants was assessed using the Short-Form Health Survey-10 (SF-10). The Short-Form Health Survey (SF-10) is a 10-item parent-completed questionnaire that covers a wide range of domains affecting a child's functional health and well-being. The SF-10 is scored to produce two norm-based summary scores: a Physical Summary Score (PHS) and a Psychosocial Summary Score (PSS), each with a mean of 50 and a standard deviation of 10. Analysis was based on the PHS. The PHS scale is directly transformed into a 0-100 scale. The higher the score, the less disability. Measurements were taken for the Physical Summary Score (PHS) at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| Units on a scale | Treatment With Burosumab |
|---|---|
| Change in Health-related Quality of Life Measured by the 10-Item Short Form Health Survey (SF-10) - Physical Summary Score (PHS) | 16.63 (-19.78 to 39.28) |
The Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity (Pediatric and Parent Proxy version 1.0) domain measures pain intensity in children, with pediatric self-report versions for ages 8-17 and parent proxy-report versions for children aged 5-17. This measure uses a standard scale to assess the level of pain over the past seven days, and for the current moment, providing a quantitative score that reflects the severity of the pain. The scale consist of three items with each scored on a 5-point Likert scale, 1-5 with lowest score of 3 and highest of 15. The raw score is converted to a T-score with a mean of 50 and standard deviation of 10. Higher scores indicates greater pain intensity. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| T-Score | Treatment With Burosumab |
|---|---|
| Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Pediatric and Parent Proxy Version 1.0) - Pain Intensity Domain | -1 (-7 to 0) |
The Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity (Adult version 2.0) - Pain Intensity domain is a universal, self-report measure of how much pain a person is experiencing. This measure uses a standard scale to assess the level of pain over the past seven days, and for the current moment, providing a quantitative score that reflects the severity of the pain. The scale consist of three items with each scored on a 5-point Likert scale, 1-5 with lowest score of 3 and highest of 15. The raw score is converted to a T-score with a mean of 50 and standard deviation of 10. Higher scores indicates greater pain intensity. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| T-Score | Treatment With Burosumab |
|---|---|
| Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Adult Version 2.0) - Pain Intensity Domain | 5.8 (-7.3 to 19.8) |
The Patient Reported Outcome Measurement Information System (PROMIS) (Pediatric and Parent Proxy version 2.0) - Pain Inference Domain assesses how pain impacts daily life, sleep, and enjoyment in children, with the Pediatric version being self-reported by children aged 8-17 and the Parent Proxy version completed by a parent or guardian for their child aged 5-17. This measure uses a standard scale to assess the level of pain interference over the past seven days, and for the current moment, providing a quantitative score that reflects the severity of the pain interference. Each item is rated on a 5-point scale (1-5). The scores are then summed and converted into a T-score, with a mean of 50 and standard deviation of 10. Higher scores indicate greater pain interference. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| T-Score | Treatment With Burosumab |
|---|---|
| Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Pediatric and Parent Proxy Version 2.0) - Pain Inference Domain | 0 (-27 to 1.6) |
The Patient-Reported Outcomes Measurement Information System (PROMIS) (Adult version 1.1) - Pain Inference scale assesses the impact of pain on social, physical, cognitive, emotional, and recreational activities, as well as sleep and life enjoyment. The scale consists of 12 items and each item is rated on a 5-point scale (1-5). The scores are then summed and converted into a T-score, with a mean of 50 and standard deviation of 10. Higher scores indicate greater pain interference. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| T-Score | Treatment With Burosumab |
|---|---|
| Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Adult Version 1.1) - Pain Inference Domain | 0.2 (-0.2 to 1.6) |
The Patient Reported Outcome Measurement Information System (PROMIS) (Pediatric and Parent Proxy version 2.0) Mobility Lower Extremity domain assesses self-perceived mobility in children, with the Pediatric version being self-reported by children aged 8-17 and the Parent Proxy version completed by a parent or guardian for their child aged 5-17. This measure uses a standard scale to assess lower extremity mobility by asking about activities such as getting up from a chair or running over the past seven days. Each item is rated on a 5-point scale (1-5). The scores are then summed and converted into a T-score, with a mean of 50 and standard deviation of 10. Higher scores indicate greater mobility. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| T-Score | Treatment With Burosumab |
|---|---|
| Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Pediatric and Parent Proxy Version 2.0) - Mobility Lower Extremity Domain | 11.1 (-4.3 to 21.3) |
The Patient Reported Outcome Measurement Information System (PROMIS) (Adult version 2.0) Mobility Lower Extremity Domain assesses an adult's self-perceived ability to perform physical tasks related to mobility and lower extremity function, such as getting out of a chair or walking. This measure uses a standard scale to assess lower extremity mobility by asking about mobility activities over the past seven days. Each item is rated on a 5-point scale (1-5). The scores are then summed and converted into a T-score, with a mean of 50 and standard deviation of 10. Higher scores indicate greater mobility. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| T-Score | Treatment With Burosumab |
|---|---|
| Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Adult Version 2.0) - Mobility Lower Extremity Domain | 0.5 (-8.4 to 6.3) |
The Patient Reported Outcome Measurement Information System (PROMIS) (Pediatric and Parent Proxy version 2.0) Fatigue domain assess the level and impact of fatigue in children and adolescents, with the Pediatric version being self-reported by children aged 8-17 and the Parent Proxy version completed by a parent or guardian for their child aged 5-17. This measure uses a standard scale to assess the level of fatigue over the past seven days. Each item is rated on a 5-point scale (1-5). The scores are then summed and converted into a T-score, with a mean of 50 and standard deviation of 10 based on a US general population. Higher scores indicate worsening fatigue. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| T-Score | Treatment With Burosumab |
|---|---|
| Change in Patient Reported Outcome Measurement Information System (PROMIS) Score (Pediatric and Parent Proxy Version 2.0) - Fatigue Domain | -6.5 (-28.3 to 4) |
The Patient Reported Outcome Measurement Information System (PROMIS) Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) Scale is a 13-item patient-reported outcome (PRO) questionnaire that captures the individual's subjective experience of their fatigue. The fatigue domain is scored on a 5-point Likert scale and converted into standardized T-scores with a mean of 50 and a standard deviation of 10 based on a US general population. Higher score indicates less fatigue. Measurements were taken at baseline and week 48. Analysis was done as change in median value between baseline and week 48. Change = week 48 minus baseline.
| T-Score | Treatment With Burosumab |
|---|---|
| Change in Patient Reported Outcome Measurement Information System (PROMIS) - Short Form - Fatigue 13a (Adult FACIT 13a v1.0) | 0 (-9.6 to 16) |
Proportion of participants with change in activities of daily living (ADL) questions from baseline to week 48 was assessed using a study developed questionnaire. Participants and/or caregivers were asked to provide a list of three activities of daily living that were affected by fibrous dysplasia skeletal features at home or school/work (e.g., mobility, climbing stairs, dressing, playing with peers, catching a bus, etc.) and to rate the extent of impact upon their activity level using one of the option: * Very Much Improved * Much Improved * Minimally Improved * No Change * Minimally Worse * Much Worse * Very Much Worse These activities were assessed at baseline, then reassessed at Week 24 and Week 48. Analysis was done as proportion of participants reporting "much improved" or "very much improved" in Activities of Daily Living Questions. Change = Week 48 minus baseline.
| Proportion of participants | Treatment With Burosumab |
|---|---|
| Proportion of Participants With Change in Activities of Daily Living (ADL) Questions | 0.67 |
Collected over 48 weeks for adult participants; 50 weeks for pediatric participants. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Treatment With Burosumab | 0/12 (0%) | 2/12 (16.7%) | 12/12 (100%) |
| Event | Treatment With Burosumab |
|---|---|
| HospitalisationSurgical and medical procedures | 2/12 |
| AppendicitisGastrointestinal disorders | 1/12 |
| HypercalcaemiaMetabolism and nutrition disorders | 1/12 |
| Event | Treatment With Burosumab |
|---|---|
| HyperphosphataemiaMetabolism and nutrition disorders | 6/12 |
| Injection site reactionGeneral disorders | 3/12 |
| DiarrhoeaGastrointestinal disorders | 1/12 |
| HaemorrhoidsGastrointestinal disorders | 1/12 |
| Bacterial infectionInfections and infestations | 1/12 |
| Corona virus infectionInfections and infestations | 1/12 |
| HypercalcaemiaMetabolism and nutrition disorders | 1/12 |
| Back painMusculoskeletal and connective tissue disorders | 1/12 |
| Bone painMusculoskeletal and connective tissue disorders | 1/12 |
| Urinary tract infectionRenal and urinary disorders | 1/12 |
| Age, Categorical(Participants) | Treatment With Burosumab |
|---|---|
| <=18 years | 7 |
| Between 18 and 65 years | 5 |
| >=65 years | 0 |
| Sex: Female, Male(Participants) | Treatment With Burosumab |
|---|---|
| Female | 8 |
| Male | 4 |
| Ethnicity (NIH/OMB)(Participants) | Treatment With Burosumab |
|---|---|
| Hispanic or Latino | 0 |
| Not Hispanic or Latino | 12 |
| Unknown or Not Reported | 0 |
| Race (NIH/OMB)(Participants) | Treatment With Burosumab |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 1 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 2 |
| White | 8 |
| More than one race | 0 |
| Unknown or Not Reported | 1 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: Yes — This study will comply with the NIH Data Sharing Policy and the Clinical Trials Registration and Results Information Submission rule.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
Time frame: Results from this trial will be made available 12 months after the primary study completion date
Access criteria: Investigators from NIH and Ultragenyx and Kyowa Kirin will consider requests from qualified researchers for access to clinical data.
Ran from Dec 2022 to primary completion in Nov 2024, 23 months.
Results were first posted in Feb 2026, 1 year 2 months after primary completion.
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Studies of the drug tested here: Burosumab
National Institute of Dental and Craniofacial Research (NIDCR) →