The present invention relates generally to 3-(2,6-Dichloro-3,5-dimethoxy-phenyl)-1-{6-[4-(4-ethyl-piperazi n-1-yl)-phenylamino]-pyrimid-4-yl}-l-methyl-urea or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition comprising 3-(2,6-Dichloro-3,5-dimethoxy-phenyl)-1-{6-[4-(4-ethyl-piperazi n-1-yl)-phenylamino]-pyrimid-4-yl}-1-methyl-urea or a pharmaceutically acceptable salt or solvate thereof for use in the treatment of X-linked hypophosphatemic rickets (XLH), autosomal dominant hypophosphatemic rickets (ADHR), autosomal recessive hypophosphatemic rickets (ARHR), tumor-induced osteomalacia, post-renal transplant hypophosphatemia, epidermal nevus syndrome, osteoglophonic dysplasia or McCune-Albright syndrome.La presente invención se refiere en general a la 3-(2,6-dicloro-3,5-dimetoxi-fenil)-1-{6-[4-(4-etil-piperazin-1-il )-fenil-amino]-pirimid-4-il}-1-metil-urea o a una sal o solvato farmacéuticamente aceptable de la misma, o a una composición farmacéutica que comprende la 3-(2,6-dicloro-3,5-dimetoxi-fenil)-1 -{6-[4-(4-etil-piperazin-1-il)-fenil-amino]-pirimid-4-iI}-1-metil -urea o una sal o solvato farmacéuticamente aceptable de la misma, para su uso en el tratamiento de raquitismo hipofosfatémico ligado al cromosoma X (XLH), raquitismo hipofosfatémico autosómico dominante (ADHR), raquitismo hipofosfatémico autosómico recesivo (ARHR), osteomalacia inducida por tumores, hipofosfatemia posterior al trasplante renal, síndrome del nevo epidérmico, displasia osteoglofónica o síndrome de McCune-Albright.
