ESPE Abstracts

Background: Variants in SH2B1 or a 220–kilobase pair distal deletion of chromosome 16p11.2, including SH2B1, are associated with severe, early-onset obesity and hyperphagia. The melanocortin-4 receptor (MC4R) agonist setmelanotide is being investigated in individuals with rare variants in genes in the MC4R pathway.Methods: This ongoing, Phase 2 study (NCT03013543) enrolled individuals aged ≥6...

Background: Silver Russell syndrome (SRS) is a heterogeneous disorder characterised by intrauterine and post-natal growth retardation, relative macrocephaly, protruding forehead, feeding difficulties and body asymmetry. Variants in HMGA2 are a rare cause of SRS and despite strong evidence for the crucial role of HMGA2 in growth regulation, its functional role in human linear growth is unclear.Methods: Patients w...

In XLH, excess fibroblast growth factor 23 (FGF23) causes hypophosphatemia and consequent rickets, skeletal deformities, and growth impairment. The efficacy and safety of burosumab, a fully human monoclonal antibody against FGF23, was evaluated in two Phase 2 trials in children with XLH. In CL201, 52 children with XLH (5–12 years old, Tanner ≤2) were randomized 1:1 to receive subcutaneous burosumab every 2 (Q2W) or 4 (Q4W) weeks, with doses titrated up to 2 mg/kg to...

Background: In X-linked hypophosphatemia (XLH), abnormally elevated serum fibroblast growth factor 23 (FGF23) results in low renal maximum threshold for phosphate reabsorption (TmP/GFR), low serum phosphorus (Pi), inappropriately normal 1,25-dihydroxyvitamin D (1,25(OH)2D) and development of rachitic deformities.Methods: Up to four s.c. KRN23 doses were given every 28 days to 28 adults with XLH according to a dose-escalation algorithm (0.05&#1...

Background: In X-linked Hypophosphatemia (XLH), abnormally elevated serum Fibroblast Growth Factor 23 (FGF23) results in low renal maximum threshold for phosphate reabsorption (TmP/GFR), low serum phosphorus (Pi), inappropriately normal 1,25-dihydroxyvitamin D (1,25(OH)2D) and development of rachitic deformities.Methods: Up to four SC KRN23 doses were given every 28 days to 28 adults with XLH (26 completed) according to a dose-escalation algorithm (0.05&...

Objectives: In X-linked hypophosphatemia (XLH), abnormally elevated serum Fibroblast growth Factor 23 (FGF23) results in low renal maximum threshold for phosphate reabsorption, low serum phosphorus, inappropriately normal 1,25-dihydroxyvitamin D, and development of rachitic deformities. The effect of KRN23 on health-related quality of life (HRQL) was assessed.Methods: Open-label KRN23 was given s.c. every 28 days up to four doses to 28 adults with XLH (2...

The melanocortin-4 receptor (MC4R) pathway is critical for the regulation of hunger, energy balance, and weight regulation. Individuals who carry variants in MC4R pathway genes may present with early-onset severe obesity and hyperphagia. Historically, genetic testing in individuals with severe obesity has been limited. The Rare Obesity Advanced Diagnosis™ genetic testing program aims to enhance access to genetic testing for European individuals with suspected rare geneti...

In children with XLH, excess FGF23 causes hypophosphatemia with consequent rickets, skeletal deformities, and impaired growth and mobility. We previously reported that burosumab improved phosphate homeostasis and rickets in children with XLH. Here, we report final data from this Phase 2 Study CL201 (NCT02163577).Fifty-two children with XLH (5-12 years old, Tanner ≤ 2) were randomized 1:1 to receive subcutaneous burosumab every 2 (Q2W) or 4 (Q4W) we...

In children with XLH, excess FGF23 causes hypophosphatemia with consequent rickets, skeletal deformities, and impaired growth and mobility. We reported that burosumab improved phosphate homeostasis and rickets in children with XLH. Here, we present data on 11/52 subjects (all girls) who developed fused growth plates during the phase 2 study CL201 (NCT02163577).In CL201, 52 subjects (Baseline: 5-12 years-old, Tanner ≤ 2) were randomized 1:1 to recei...

In children with X-linked hypophosphatemia (XLH), excess circulating fibroblast growth factor 23 (FGF23) causes hypophosphatemia with consequent rickets, skeletal deformities, and impairments in growth and mobility. Compared to continuation with conventional therapy (oral phosphate and active vitamin D [Pi/D]), switching to treatment with burosumab, a fully human monoclonal antibody against FGF23, showed significantly greater improvement in phosphate homeostasis, rickets sever...