Effectiveness of burosumab in children with X-linked hypophosphatemia with low rickets severity: SUNFLOWER analysis
Abstract
Burosumab provides treatment benefits in children with X-linked hypophosphatemia (XLH). However, children with low rickets severity (Rickets Severity Score [RSS] < 2) were excluded from a previous phase 3, multicenter, active comparator-controlled randomized clinical trial. This descriptive interim analysis of the prospective SUNFLOWER (Study of longitUdinal observatioN For patients with X-Linked hypOphosphatemic rickets/osteomalacia in collaboration With Asian partnERs) cohort study included 69 children with XLH aged ≤13 yr at enrollment. The burosumab and non-burosumab groups included 48 and 65 participants, respectively, with some overlap due to switching. Longitudinal changes in height and biochemical parameters (overall and stratified by disease severity [RSS <2/≥2; alkaline phosphatase </≥ upper limit of normal]) were assessed. In the burosumab all-patients analysis (irrespective of treatment duration or missing follow-up data), height Z-score (initiation: −2.04 ± 1.08; 3 yr: −1.58 ± 1.09), serum phosphate Z-score (initiation: −4.07 ± 1.77; 3 yr: −2.30 ± 1.45), 1,25(OH)2D (initiation: 39.79 ± 22.78 pg/mL; 3 yr: 84.35 ± 28.26 pg/mL), and ratio of tubular maximum phosphate reabsorption to glomerular filtration rate Z-score (initiation: −4.51 ± 2.60; 3 yr: −0.93 ± 2.50) tended to be higher at 3 yr following burosumab treatment. Rickets Severity Score (initiation: 2.38 ± 1.44; 3 yr: 0.83 ± 0.53) and alkaline phosphatase Z-score (initiation: 3.11 ± 1.79; 3 yr: 1.71 ± 1.14) tended to be lower at 3 yr. The subgroup analyses by RSS also showed similar results. Height Z-score, phosphate Z-score, and 1,25(OH)2D tended to be higher at 3 yr in both subgroups, while alkaline phosphatase Z-score tended to be lower. In the subgroup analysis by alkaline phosphatase status, height Z-score tended to be higher at 3 yr only in the ≥upper limit of normal subgroup; the other results were comparable. Overall, height, phosphate homeostasis, and bone health may improve in children with XLH (including RSS <2) following burosumab treatment.
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BibTeX
@article{kang2026effectiveness,
title = {{Effectiveness of burosumab in children with X-linked hypophosphatemia with low rickets severity: SUNFLOWER analysis}},
author = {Hee Gyung Kang and Toshimi Michigami and Noriyuki Namba and Nobuaki Ito and Takuo Kubota and Osamu Miyazaki and Masanori Kanematsu and Chikako Hayashi and Haruka Ishii and Seiji Fukumoto and Keiichi Ozono},
journal = {JBMR Plus},
year = {2026},
month = oct,
doi = {10.1093/jbmrpl/ziag168},
url = {https://doi.org/10.1093/jbmrpl/ziag168},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Effectiveness of burosumab in children with X-linked hypophosphatemia with low rickets severity: SUNFLOWER analysis
AU - Hee Gyung Kang
AU - Toshimi Michigami
AU - Noriyuki Namba
AU - Nobuaki Ito
AU - Takuo Kubota
AU - Osamu Miyazaki
AU - Masanori Kanematsu
AU - Chikako Hayashi
AU - Haruka Ishii
AU - Seiji Fukumoto
AU - Keiichi Ozono
PY - 2026
DA - 2026/10/15
JO - JBMR Plus
DO - 10.1093/jbmrpl/ziag168
UR - https://doi.org/10.1093/jbmrpl/ziag168
AB - Burosumab provides treatment benefits in children with X-linked hypophosphatemia (XLH). However, children with low rickets severity (Rickets Severity Score [RSS] < 2) were excluded from a previous phase 3, multicenter, active comparator-controlled randomized clinical trial. This descriptive interim analysis of the prospective SUNFLOWER (Study of longitUdinal observatioN For patients with X-Linked hypOphosphatemic rickets/osteomalacia in collaboration With Asian partnERs) cohort study included 69 children with XLH aged ≤13 yr at enrollment. The burosumab and non-burosumab groups included 48 and 65 participants, respectively, with some overlap due to switching. Longitudinal changes in height and biochemical parameters (overall and stratified by disease severity [RSS <2/≥2; alkaline phosphatase </≥ upper limit of normal]) were assessed. In the burosumab all-patients analysis (irrespective of treatment duration or missing follow-up data), height Z-score (initiation: −2.04 ± 1.08; 3 yr: −1.58 ± 1.09), serum phosphate Z-score (initiation: −4.07 ± 1.77; 3 yr: −2.30 ± 1.45), 1,25(OH)2D (initiation: 39.79 ± 22.78 pg/mL; 3 yr: 84.35 ± 28.26 pg/mL), and ratio of tubular maximum phosphate reabsorption to glomerular filtration rate Z-score (initiation: −4.51 ± 2.60; 3 yr: −0.93 ± 2.50) tended to be higher at 3 yr following burosumab treatment. Rickets Severity Score (initiation: 2.38 ± 1.44; 3 yr: 0.83 ± 0.53) and alkaline phosphatase Z-score (initiation: 3.11 ± 1.79; 3 yr: 1.71 ± 1.14) tended to be lower at 3 yr. The subgroup analyses by RSS also showed similar results. Height Z-score, phosphate Z-score, and 1,25(OH)2D tended to be higher at 3 yr in both subgroups, while alkaline phosphatase Z-score tended to be lower. In the subgroup analysis by alkaline phosphatase status, height Z-score tended to be higher at 3 yr only in the ≥upper limit of normal subgroup; the other results were comparable. Overall, height, phosphate homeostasis, and bone health may improve in children with XLH (including RSS <2) following burosumab treatment.
SN - 2473-4039
ER -