CRYSVITA® (burosumab) is the first and only disease-modifying biologic treatment that targets the pathophysiology of XLH¹

CRYSVITA is a fully human monoclonal antibody (IgG1) that binds to and inhibits excess FGF23 activity1

Excess levels of FGF23 in XLH lead to:2

  • Decreased renal phosphate reabsorption, which increases urinary phosphate excretion
  • Decreased active vitamin D (1,25[OH]2D) production, which reduces intestinal phosphate absorption.

The effects of the excess FGF23 leads to chronic hypophosphataemia resulting in impaired bone mineralisation, leading to rickets in children with XLH.2

CRYSVITA is the first and only disease-modifying biologic treatment that targets the pathophysiology of XLH1

Mode of action of CRYSVITA

Conventional therapy for XLH

Conventional therapy for XLH is based on oral phosphate and active vitamin D supplementation,3 but is associated with variable improvement in clinical features and may led to adverse effects like hyperparathyroidism and nephrocalcinosis.4 Conventional therapy does not address the excess levels of FGF23 that underlie the pathophysiology of XLH.3

Taking oral phosphate and active vitamin D supplements has been associated with increases in FGF23 levels, which may diminish their therapeutic effect in XLH.3

Conventional therapy is also associated with low compliance and the multiple daily dosing regimen places a significant burden on patients with XLH and their carers.2,6

Conventional therapy may be poorly tolerated, with many patients experiencing gastrointestinal side effects such as abdominal pain, diarrhoea and nausea.2,5,6 Potential adverse effects of conventional therapy include nephrocalcinosis and hyperparathyroidism.3

CRYSVITA restores phosphate homeostasis and improves bone mineralisation in children with XLH, by inhibiting excess FGF23 activity1,6

Based on pre-clinical studies, CRYSVITA helps restore phosphate homeostasis by:1,7

  • Decreasing renal phosphate excretion by increasing expression of sodium phosphate cotransporters (NaPi-2a/NaPi-2c)
  • Increasing intestinal phosphate absorption by increasing 1-α hydroxylase levels and active vitamin D production.

The normalisation of serum phosphate levels improves healing of rickets in paediatric patients with XLH

1. CRYSVITA (burosumab). Summary of Product Characteristics. February 2019. 2. Linglart A, et al. Endocr Connect. 2014;3:R13–R30. 3. Beck-Nielsen SS, et al. Orphanet J Rare Dis. 2019;14(1):58. 4. Imel EA, et al. Br J Clin Pharmacol. 2019; 85: 1188–1198. 5. Carpenter, TO et al. J Bone Miner Res. 2011;26(7): 1381–1388. 6. Imel EA, et al. Lancet. 2019; 393: 2416-2427. 7. Hernando, N and Wagner, C. Compr. Physiol. 2018;8:1065-1090.

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