Adults 18 to 65, any sex, with X-linked Hypophosphatemia. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Percentage of Participants Achieving Mean Serum Phosphorus Levels Above the LLN (2.5 mg/dL [0.81 mmol/L]) at the Mid-Point of the Dose Interval, as Averaged Across Dose Cycles Between Baseline and Week 24Primary· Baseline through Week 24
Group
Value
95% CI
Placebo
7.6
3.3 – 16.5
Burosumab
92.6
83.9 – 96.8
Change From Baseline to Week 24 in Brief Pain Inventory (BPI) Question 3 (Q3; Worst Pain in Past 24 Hours) ScoreSecondary· Baseline, 24 weeks
The BPI evaluates the condition of all pain over the previous 24 hours. Two dimensions are measured: pain severity (worst, least, average, and now) and the impact of pain on functioning (pain interference with general activity, walking, work, mood, enjoyment of life, relations with others, and sleep). Question 3 of the short-form BPI (BPI-Q3) asks subjects to rate their pain at its worst in the last 24 hours on a scale of 0 (no pain) to 10 (pain as bad as you can imagine).
From the generalized estimating equation (GEE) model, which includes the change from Baseline for the endpoint of interes
Group
Value
95% CI
Placebo
-0.32
± 0.222
Burosumab
-0.79
± 0.211
Change From Baseline to Week 24 in the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) Stiffness ScoreSecondary· Baseline, 24 weeks
The WOMAC is a 24-item participant-reported questionnaire with two domains, Stiffness (2 questions) and Physical Function (17 questions) over the previous 48 hours. The WOMAC is administered in a 5-point Likert-scale format using descriptors of none, mild, moderate, severe, and extreme corresponding to an ordinal scale of 0-4. Higher scores on the WOMAC indicate worse stiffness and functional limitations. Scores are normalized to a 0-100 metric where 0 was the best health state and 100 the worst.
The GEE estimates are from the GEE model which includes the change from baseline for WOMAC Stiffn
Group
Value
95% CI
Placebo
0.46
± 3.139
Burosumab
-7.85
± 3.034
Change From Baseline to Week 24 in the WOMAC Physical Function ScoreSecondary· Baseline, 24 weeks
The WOMAC is a 24-item participant-reported questionnaire with two domains, Stiffness (2 questions) and Physical Function (17 questions) over the previous 48 hours. The WOMAC is administered in a 5-point Likert-scale format using descriptors of none, mild, moderate, severe, and extreme corresponding to an ordinal scale of 0-4. Higher scores on the WOMAC indicate worse stiffness and functional limitations. Scores are normalized to a 0-100 metric where 0 was the best health state and 100 the worst.
The GEE Estimates are from the GEE model which includes the change from baseline for WOMAC Physic
Group
Value
95% CI
Placebo
1.79
± 2.722
Burosumab
-3.11
± 2.553
Change From Baseline Over Time in BPI Worst Pain ScoreSecondary· Baseline, Weeks 12, 24, 36, 48, 72, 96
Change from baseline to post-baseline visits in BPI-Q3 (Worst Pain) score as averaged from daily diary scores recorded over 1 week and the study visit score. The BPI evaluates the condition of all pain over the previous 24 hours. Two dimensions are measured: pain severity (worst, least, average, and now) and the impact of pain on functioning (pain interference with general activity, walking, work, mood, enjoyment of life, relations with others, and sleep). Question 3 of the short-form BPI (BPI-Q3) asks subjects to rate their pain at its worst in the last 24 hours on a scale of 0 (no pain) to 1
Change at Week 12
Group
Value
95% CI
Placebo
-0.37
± 0.216
Burosumab 1 mg/kg
-0.62
± 0.208
Change at Week 24
Group
Value
95% CI
Placebo
-0.31
± 0.242
Burosumab 1 mg/kg
-0.77
± 0.228
Change at Week 36
Group
Value
95% CI
Placebo
-1.25
± 0.234
Burosumab 1 mg/kg
-0.95
± 0.228
Change at Week 48
Group
Value
95% CI
Placebo
-1.49
± 0.243
Burosumab 1 mg/kg
-1.05
± 0.230
Change at Week 72
Group
Value
95% CI
Placebo
-1.28
± 0.283
Burosumab 1 mg/kg
-1.21
± 0.316
Change at Week 96
Group
Value
95% CI
Placebo
-0.99
± 0.265
Burosumab 1 mg/kg
-1.48
± 0.299
Change From Baseline Over Time in BPI Pain Severity ScoreSecondary· Baseline, Weeks 12, 24, 36, 48, 72, 96
Change from baseline to post-baseline visits in BPI pain severity score as averaged from daily diary scores recorded over 1 week and the study visit score. The BPI evaluates the condition of all pain over the previous 24 hours. Two dimensions are measured: pain severity (worst, least, average, and now) and the impact of pain on functioning (pain interference with general activity, walking, work, mood, enjoyment of life, relations with others, and sleep). The severity of pain in the last 24 hours is rated on a scale of 0 (no pain) to 10 (pain as bad as you can imagine).
The GEE Estimates are f
Change at Week 12
Group
Value
95% CI
Placebo
-0.32
± 0.166
Burosumab 1 mg/kg
-0.43
± 0.163
Change at Week 24
Group
Value
95% CI
Placebo
-0.10
± 0.211
Burosumab 1 mg/kg
-0.53
± 0.172
Change at Week 36
Group
Value
95% CI
Placebo
-0.97
± 0.214
Burosumab 1 mg/kg
-0.62
± 0.184
Change at Week 48
Group
Value
95% CI
Placebo
-1.13
± 0.205
Burosumab 1 mg/kg
-0.79
± 0.162
Change at Week 72
Group
Value
95% CI
Placebo
-1.36
± 0.216
Burosumab 1 mg/kg
-1.24
± 0.231
Change at Week 96
Group
Value
95% CI
Placebo
-1.18
± 0.195
Burosumab 1 mg/kg
-1.42
± 0.229
Change From Baseline Over Time in BPI Pain Interference ScoreSecondary· Baseline, Weeks 12, 24, 36, 48, 72, 96
Change from baseline to post-baseline visits in BPI pain interference score as recorded on the day of the study visit. The BPI evaluates the condition of all pain over the previous 24 hours. Two dimensions are measured: pain severity (worst, least, average, and now) and the impact of pain on functioning (pain interference with general activity, walking, work, mood, enjoyment of life, relations with others, and sleep). Pain interference in the last 24 hours is rated on a scale of 0 (does not interfere) to 10 (completely interferes).
The GEE Estimates are from the GEE model which includes the c
Change at Week 12
Group
Value
95% CI
Placebo
-0.29
± 0.215
Burosumab 1 mg/kg
-0.51
± 0.207
Change at Week 24
Group
Value
95% CI
Placebo
-0.28
± 0.242
Burosumab 1 mg/kg
-0.41
± 0.207
Change at Week 36
Group
Value
95% CI
Placebo
-1.30
± 0.260
Burosumab 1 mg/kg
-0.79
± 0.221
Change at Week 48
Group
Value
95% CI
Placebo
-1.28
± 0.251
Burosumab 1 mg/kg
-1.04
± 0.235
Change at Week 72
Group
Value
95% CI
Placebo
-1.22
± 0.247
Burosumab 1 mg/kg
-1.24
± 0.263
Change at Week 96
Group
Value
95% CI
Placebo
-1.08
± 0.260
Burosumab 1 mg/kg
-1.43
± 0.234
Change From Baseline Over Time in WOMAC Stiffness ScoreSecondary· Baseline, Weeks 12, 24, 36, 48, 72, 96, 120, 144
The WOMAC is a 24-item participant-reported questionnaire with two domains, Stiffness (2 questions) and Physical Function (17 questions) over the previous 48 hours. The WOMAC is administered in a 5-point Likert-scale format using descriptors of none, mild, moderate, severe, and extreme corresponding to an ordinal scale of 0-4. Higher scores on the WOMAC indicate worse stiffness and functional limitations. Scores are normalized to a 0-100 metric where 0 was the best health state and 100 the worst.
The GEE Estimates are from the GEE model which includes the change from baseline for WOMAC Stiffn
Change at Week 12
Group
Value
95% CI
Placebo
-1.24
± 2.929
Burosumab 1 mg/kg
-7.86
± 3.622
Change at Week 24
Group
Value
95% CI
Placebo
0.20
± 3.289
Burosumab 1 mg/kg
-8.01
± 2.968
Change at Week 36
Group
Value
95% CI
Placebo
-13.50
± 3.422
Burosumab 1 mg/kg
-12.58
± 3.411
Change at Week 48
Group
Value
95% CI
Placebo
-15.83
± 3.488
Burosumab 1 mg/kg
-16.63
± 3.302
Change at Week 72
Group
Value
95% CI
Placebo
-18.02
± 3.613
Burosumab 1 mg/kg
-15.47
± 3.111
Change at Week 96
Group
Value
95% CI
Placebo
-17.67
± 3.737
Burosumab 1 mg/kg
-15.32
± 3.577
Change at Week 120
Group
Value
95% CI
Placebo
-19.23
± 3.404
Burosumab 1 mg/kg
-20.57
± 3.371
Change at Week 144
Group
Value
95% CI
Placebo
-30.64
± 4.407
Burosumab 1 mg/kg
-25.88
± 4.501
Change From Baseline Over Time in WOMAC Physical Function ScoreSecondary· Baseline, Weeks 12, 24, 36, 48, 72, 96, 120, 144
The WOMAC is a 24-item participant-reported questionnaire with two domains, Stiffness (2 questions) and Physical Function (17 questions) over the previous 48 hours. The WOMAC is administered in a 5-point Likert-scale format using descriptors of none, mild, moderate, severe, and extreme corresponding to an ordinal scale of 0-4. Higher scores on the WOMAC indicate worse stiffness and functional limitations. Scores are normalized to a 0-100 metric where 0 was the best health state and 100 the worst.
The GEE Estimates are from the GEE model which includes the change from baseline for WOMAC Stiffn
Change at Week 12
Group
Value
95% CI
Placebo
-1.40
± 2.418
Burosumab 1 mg/kg
-3.96
± 1.787
Change at Week 24
Group
Value
95% CI
Placebo
1.14
± 2.531
Burosumab 1 mg/kg
-3.45
± 2.193
Change at Week 36
Group
Value
95% CI
Placebo
-5.47
± 2.694
Burosumab 1 mg/kg
-7.14
± 2.133
Change at Week 48
Group
Value
95% CI
Placebo
-7.15
± 2.801
Burosumab 1 mg/kg
-8.42
± 2.057
Change at Week 72
Group
Value
95% CI
Placebo
-8.68
± 2.835
Burosumab 1 mg/kg
-8.66
± 2.523
Change at Week 96
Group
Value
95% CI
Placebo
-8.41
± 2.752
Burosumab 1 mg/kg
-9.02
± 2.270
Change at Week 120
Group
Value
95% CI
Placebo
-11.93
± 2.685
Burosumab 1 mg/kg
-11.98
± 2.291
Change at Week 144
Group
Value
95% CI
Placebo
-19.49
± 3.892
Burosumab 1 mg/kg
-17.67
± 4.061
Change From Baseline Over Time in BFI Worst Fatigue ScoreSecondary· Baseline, Weeks 12, 24, 36, 48, 72, 96
Change from baseline to post-baseline visits in Brief Fatigue Inventory Question 3 (Worst Fatigue in Past 24 Hours; BFI-Q3) as averaged from daily diary scores recorded over 1 week and the study visit score. The BFI is a self-reported questionnaire consisting of 9 items related to fatigue rated on a 0 to 10 numerical scale with a recall period of 24 hours. Two dimensions are measured: fatigue severity and the interference of fatigue on daily life (activity, mood, walking ability, work, relations with others, and enjoyment of life). Participants are asked to rate their worst fatigue over the pa
Change at Week 12
Group
Value
95% CI
Placebo
-0.53
± 0.266
Burosumab 1 mg/kg
-0.44
± 0.261
Change at Week 24
Group
Value
95% CI
Placebo
-0.45
± 0.298
Burosumab 1 mg/kg
-0.65
± 0.280
Change at Week 36
Group
Value
95% CI
Placebo
-1.23
± 0.305
Burosumab 1 mg/kg
-0.90
± 0.271
Change at Week 48
Group
Value
95% CI
Placebo
-1.21
± 0.317
Burosumab 1 mg/kg
-0.99
± 0.295
Change at Week 72
Group
Value
95% CI
Placebo
-0.79
± 0.352
Burosumab 1 mg/kg
-0.58
± 0.309
Change at Week 96
Group
Value
95% CI
Placebo
-0.82
± 0.362
Burosumab 1 mg/kg
-0.75
± 0.306
Change From Baseline Over Time in BFI Global Fatigue ScoreSecondary· Baseline, Weeks 12, 24, 36, 48, 72, 96
Change from baseline to post-baseline visits in BFI global fatigue score, calculated by averaging all 9 BFI items as recorded on the day of the study visit. The BFI is a self-reported questionnaire consisting of 9 items related to fatigue that are rated on a numerical scale with a recall period of 24 hours. Two dimensions are measured: fatigue severity and the interference of fatigue on daily life (activity, mood, walking ability, work, relations with others, and enjoyment of life). BFI Global Fatigue score was calculated by averaging all 9 items on the BFI. Global scores range from 0 to 10, w
Change at Week 12
Group
Value
95% CI
Placebo
-0.14
± 0.262
Burosumab 1 mg/kg
-0.18
± 0.261
Change at Week 24
Group
Value
95% CI
Placebo
-0.08
± 0.292
Burosumab 1 mg/kg
0.05
± 0.261
Change at Week 36
Group
Value
95% CI
Placebo
-0.69
± 0.315
Burosumab 1 mg/kg
-0.54
± 0.283
Change at Week 48
Group
Value
95% CI
Placebo
-0.75
± 0.303
Burosumab 1 mg/kg
-0.45
± 0.275
Change at Week 72
Group
Value
95% CI
Placebo
-0.72
± 0.304
Burosumab 1 mg/kg
-0.78
± 0.266
Change at Week 96
Group
Value
95% CI
Placebo
-0.86
± 0.291
Burosumab 1 mg/kg
-0.80
± 0.285
Change From Baseline Over Time in Biochemical Marker of Bone Remodeling Procollagen Type 1 N-Propeptide (P1NP)Secondary· Baseline, Weeks 12, 24, 36, 48, 72, 96
Change at Week 12
Group
Value
95% CI
Placebo
-1.86
± 5.958
Burosumab 1 mg/kg
96.22
± 14.264
Change at Week 24
Group
Value
95% CI
Placebo
2.95
± 6.423
Burosumab 1 mg/kg
63.50
± 7.239
Change at Week 36
Group
Value
95% CI
Placebo
100.00
± 10.562
Burosumab 1 mg/kg
49.71
± 6.786
Change at Week 48
Group
Value
95% CI
Placebo
85.12
± 11.037
Burosumab 1 mg/kg
40.07
± 7.292
Change at Week 72
Group
Value
95% CI
Placebo
48.98
± 7.286
Burosumab 1 mg/kg
18.04
± 9.186
Change at Week 96
Group
Value
95% CI
Placebo
22.98
± 7.075
Burosumab 1 mg/kg
12.48
± 8.661
Adverse events — posted to ClinicalTrials.gov
Time frame: From first dose of study drug through the end of study plus 4 weeks (+ 5 days). Mean (SE) duration of exposure to burosumab for all periods combined through EOS II was 771.3 (21.97) days (range: 167 - 957) in the burosumab->burosumab group and 625.7 (19.40) days (range: 165 - 844) in the placebo->burosumab group..
Reporting threshold: 5%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
Placebo (DB Period)
Serious: 1/66 (2%)
Deaths: 0/66
Placebo -> Burosumab (OL Period)
Serious: 10/66 (15%)
Deaths: 0/66
Burosumab -> Burosumab (Combined DB and OL Period)
The primary efficacy objective of this study is to establish the effect of burosumab treatment compared with placebo on increasing serum phosphorus levels in adults with XLH.
Publications & conference data
8 peer-reviewed publications reference this trial (live from Europe PMC):
NCT02915705 — Efficacy and Safety of Burosumab Versus Oral Phosphate and Active Vitamin D Treatment in Pediatric Patients With XLH
· Phase 3
· completed
NCT02537431 — Open Label Study of KRN23 on Osteomalacia in Adults With X-linked Hypophosphatemia (XLH)
· Phase 3
· completed
NCT02163577 — Study of KRN23 (Burosumab), a Recombinant Fully Human Monoclonal Antibody Against Fibroblast Growth Factor 23 (FGF23), i
· Phase 2
· completed
Other recruiting trials for X-linked Hypophosphatemia
Currently open trials in the same condition.
NCT06525636 — A First-in-human Study of KK8123 in Adults With X-linked Hypophosphatemia
· Phase 1, PHASE2
· recruiting
Other Kyowa Kirin, Inc. trials
Trials by the same sponsor.
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NCT04147910 — Phase 1, Open-label Study of the Absorption, Metabolism, and Excretion of [14C]-KW-6356
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NCT03703102 — Study of an Anti-OX40 Monoclonal Antibody (KHK4083) in Subjects With Moderate to Severe Atopic Dermatitis
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Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Kyowa Kirin, Inc.
Last refreshed: 18 June 2024
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT02526160.