For any compound to work transdermally, it must be small enough to penetrate through multiple skin layers and achieve therapeutic concentrations in the bloodstream
The FDA titration schedule is built on pharmacokinetic modeling and GI safety data from SURMOUNT trials

2014 A Qualitative Study to Understand the Supportive Care Needs of Adolescents with X-Linked Hypophosphatemia during the Transition to Adulthood Angela Rylands 1 , Vrinda Saraff 2 , Pedro Arango Sancho 3 , Justine Bacchetta 4 , Annemieke Boot 5 , Christine Burren 6 , Amish Chinoy 7 , Poonam Dharmaraj 8 , Adele Barlassina 9 , Agns Linglart 10 , Maria Amelia Gmez Llorente 11 , Juan David Gonzlez Rodrguez 12 , Iva Gueorguieva 13 , Wesley Hayes 14 , Hctor Ros Duro 15 , Emily Hardie 16 , Dirk Schnabel 17 , Santhani Selveindran 18 1 Kyowa Kirin Ltd, Marlow, UK, 2 Birmingham Womens and Childrens Hospital, Birmingham, UK, 3 Sant Joan de Du Barcelona Hospital, Barcelona, Spain, 4 Hospices Civils de Lyon, INSERM1033 Research Unit, Lyon, France, 5 University Medical Center Groningen, University of Groningen, Groningen, Netherlands, 6 University Hospitals Bristol and Weston NHS Foundation Trust, Briston, UK, 7 Royal Manchester Childrens Hospital, Manchester, UK, 8 Alder Hey Childrens Hospital, Liverpool, UK, 9 Open Health Ltd, Rotterdam, Netherlands, 10 AP-HP, Paris Saclay University, Paris, France, 11 Hospital Virgen de Las Nieves, Granada, Spain, 12 Department of Pediatric Nephrology, Santa Lucia General University Hospital, Cartagena, Spain, 13 Centre Hospitalier Universitaire de Lille, Lille, France, 14 Great Ormond Street Hospital, London, UK, 15 Pediatric Nephrology, Vall dHebron Universitary Hospital, Barcelona, Spain, 16 Kyowa Kirin International, Marlow, UK, 17 Center for Chronic Sick Children, Pediatric Endocrinology, Charit University Medicine Berlin, Berlin, Germany, 18 Open Health Ltd, London, UK Journal of Patient-Reported Outcomes 2026 , 10(Suppl 1) :2014 Aims X-linked hypophosphatemia (XLH) is a rare, genetic disorder caused by pathogenic variants in the phosphate-regulating endopeptidase homologue X-linked (PHEX) gene

Abbreviations BBB: Blood brain barrier cAMP: Cyclic adenosine monophosphate CD163: Cluster of differentiation 163 CD86: Cluster of differentiation 86 CREB: CAMP response element (CRE)-binding protein DM: Diabetes mellitus DRG: Dorsal root ganglia ERK: Extracellular signal-regulated kinase FM: Fibromyalgia GLP-1: Glucagon-like peptide-1 GLP-1R: Glucagon-like peptide-1 receptor HD of Sema: High dose of semaglutide IR: Insulin resistance i-NOS: Inducible nitric oxide synthase ID of Sema: Intermediate dose of semaglutide IL-4: Interleukin-4 IL-1: Interleukin-1 IL-1R: Interleukin -1 receptor LD of Sema: Low dose of semaglutide M1: Macrophage 1 M2: Macrophage 2 MAPK: Mitogen activated protein kinase NO: Nitric oxide PKA: Protein kinase A Res: Reserpine ROS: Reactive oxygen species Sema: Semaglutide TBST: Tris-buffered saline with Tween 20 TNF- : Tumor necrosis factor- TNFR: Tumor necrosis factor receptor References An N, Yang J, Wang H et al (2021) Mechanism of mesenchymal stem cells in spinal cord injury repair through macrophage polarization
