1. Sex differences of burosumab in children with X-linked hypophosphataemic rickets
- Author
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Filler, Guido, Tremblay, Olivia, Chen, Emily, Huang, Susan Shi Han, and Stein, Robert
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Rickets -- Drug therapy -- Demographic aspects -- Patient outcomes ,Sex factors in disease -- Research ,Pediatric research ,Dose-response relationship (Biochemistry) -- Research ,Health - Abstract
Background The severity of X-linked hypophosphataemic rickets (XLH) may be affected by genotype and sex. However, burosumab, a fully humanized monoclonal antibody against fibroblast growth factor 23, has the same pediatric dose recommendation for both sexes (0.8 mg/kg every 2 weeks). Patients and methods In a retrospective cohort study, we describe the burosumab response differences by sex in children with XLH. Results We treated 10 children (5 females, mean age at initiation 4.2 ± 3.5 years) with XLH with burosumab. Initial mean serum phosphate was 0.69 ± 0.18 mmol/L in males and 0.86 ± 0.22 mmol/L in females (p = 0.108). The mean ratio of tubular maximum reabsorption rate of phosphate to glomerular filtration rate (TmP/GFR) was 0.55 ± 0.11 mmol/L in males and 0.76 ± 0.23 mmol/L in females (p = 0.06). The mean starting dose of burosumab was 0.83 ± 0.19 mg/kg subcutaneously every 14 days (males: 0.79 ± 0.19 mg/kg; females: 0.87 ± 0.21 mg/kg, n.s.). Two weeks after starting burosumab, serum phosphate differed significantly between males (0.90 ± 0.21 mmol/L) and females (1.27 ± 0.25 mmol/L) (p = 0.018). All males required a dose increase to try to normalize serum phosphate. On day 140 after starting, the average dose in males increased further to 1.24 ± 0.41 mg/kg to achieve a phosphate of 0.87 ± 0.11 mmol/L while females had a normal phosphate and alkaline phosphatase on the starting dose. After a mean of 458 ± 79 days, the mean burosumab dose/kg in males was 1.68 ± 0.61 mg/kg, mean serum phosphate was 1.08 ± 0.23 mmol/L, mean TmP/GFR was 1.01 ± 0.20, mean alkaline phosphatase had normalized to 303.6 ± 40.7U/L, and mean 1.25(OH).sub.2 vitamin D level was 186.4 ± 16.6 nmol/L. Conclusions Our findings may suggest a sex difference in response to burosumab in XLH patients. Our data suggest that males may require higher doses., Author(s): Guido Filler [sup.1] [sup.2] [sup.3] [sup.4] , Olivia Tremblay [sup.5] , Emily Chen [sup.5] , Susan Shi Han Huang [sup.1] [sup.2] [sup.6] , Robert Stein [sup.1] Author Affiliations: (1) [...]
- Published
- 2023
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