RESUMO
ABSTRACT Burosumab, a monoclonal antibody directed against the fibroblast growth factor 23 (FGF23), has been approved for the treatment of X-linked hypophosphatemia (XLH). We conducted a systematic review to compare the efficacy and safety of burosumab versus conventional therapy (phosphorus and calcitriol) on XLH treatment. After a comprehensive literature search on MEDLINE/PubMed and Embase, we found nine studies for inclusion in the analysis. Risk of bias was assessed, and a random-effects model was used to determine the effect size. Clinical, biochemical, and radiological parameters of disease severity before and after treatment were analyzed and expressed in standardized mean difference (SMD). Burosumab resulted in normalization of phosphate homeostasis with an increase in renal tubular phosphate reabsorption and significant resolution of skeletal lesions (change in Thacher's total rickets severity score SMD: −1.46, 95% confidence interval [CI]: −1.76 to −1.17, p < 0.001, improvement in deformities, and decline in serum alkaline phosphatase levels [SMD: 130.68, 95% CI: 125.26-136.1, p < 0.001)]. Conventional therapy led to similar improvements in all these parameters but to a lower degree. In adults, burosumab normalized phosphorus levels (SMD: 1.23, 95% CI: 0.98-1.47, p < 0.001) with resultant clinical improvement. Burosumab treatment was well tolerated, with only mild treatment-related adverse effects. The present review indicates a potential role for burosumab in improving rickets, deformities, and growth in children with XLH. Given its superior efficacy and safety profile, burosumab could be an effective therapeutic option in children. We suggest further studies comparing burosumab versus conventional therapy in children and adults with XLH.
RESUMO
We studied the patients diagnosed with X-linked hypophosphatemicrickets(XLH) and treated with burosumab in Peking Union Medical College Hospital from January 2021 to December 2022. In addition, we described the clinical characteristics of the patients, the changes of clinical indexes before and after burosumab treatment, and the adverse drug reactions during treatment. We also evaluated the efficacy and safety of burosumab for XLH. The results showed that three children XLH patients and one adult XLH patients received burosumab treatment. After treatment, the serum phosphorus level of all patients increased; the serum phosphorus of 3 children patients increased above the lower limit of the reference value range; the serum alkaline phosphatase(ALP) of all patients was lower than that of before treatment; the serum ALP of one adult patient was close to the normal range after 2.5 years of treatment. One child patient showed small crystals in kidney through ultrasound 48 weeks after treatment; one child and one adult showed increased serum parathyroid hormone(PTH)level before treatment and serum PTH continued increasing after treatment. Finally, it may be concluded that burosumab increased serum phosphorus levels in XLH patients, kept the level relatively stable, and reduced serum ALP levels. No serious adverse reactions occurred during treatment, in order to provide reference for the use of burosumab in patients with XLH.
RESUMO
Abstract Phosphorus is one of the most abundant minerals in the human body; it is required to maintain bone integrity and mineralization, in addition to other biological processes. Phosphorus is regulated by parathyroid hormone, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], and fibroblast growth factor 23 (FGF-23) in a complex set of processes that occur in the gut, skeleton, and kidneys. Different molecular mechanisms - overproduction of FGF-23 by tumors responsible for oncogenic osteomalacia, generation of an FGF-23 mutant that is resistant to cleavage by enzymes, and impaired FGF-23 degradation due to a reduction in or loss of the PHEX gene - can lead to FGF-23-stimulating activity and the consequent waste of urinary phosphate and low levels of 1,25(OH)2D3. Conventional treatment consists of multiple daily doses of oral phosphate salts and vitamin D analogs, which may improve radiographic rickets but do not normalize growth. Complications of the conventional long-term treatment consist of hypercalcemia, hypercalciuria, nephrolithiasis, nephrocalcinosis, impaired renal function, and potentially chronic kidney disease. Recently, burosumab, an antibody against FGF-23, was approved as a novel therapy for children and adults with X-linked hypophosphatemia and patients with tumor-induced osteomalacia. Burosumab showed good performance in different trials in children and adults. It increased and sustained the serum phosphorus levels, decreased the rickets severity and pain scores, and improved mineralization. It offers a new perspective on the treatment of chronic and disabling diseases. Arch Endocrinol Metab. 2022;66(5):658-65