This invention relates to a group of trisubstituted and tetrasubstituted
pteridine derivatives, their pharmaceutically acceptable salts, N-oxides,
solvates, dihydro- and tetrahydro-derivatives and enantiomers, possessing
unexpectedly desirable pharmaceutical properties, in particular which are
highly active immunosuppressive agents, and as such are useful in the
treatment in transplant rejection and/or in the treatment of certain
inflammatory diseases. These compounds are also useful in preventing or
treating cardiovascular disorders, allergic conditions, disorders of the
central nervous system and cell proliferative disorders.