The present invention relates generally to 3-(2,6-Dichloro-3,5-dimethoxy-phenyl)-1-{6-[4-(4-ethyl-piperazin-1-yl)-phenylamino]-pyrimid-4-yl}-1-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-piperazin-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.