The present invention relates to compounds of formula (I), combinations and uses thereof for disease therapy, ##STR00001## wherein: R.sup.1 represents heteroaryl, -carbocyclyl-heteroaryl, -alkenylheteroaryl or -alkylheteroaryl; R.sup.2 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, -alkoxy, -thioalkyl, --C(O)O-alkyl and --C(O)OH; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, haloalkyl, amino, halogen, hydroxyl, alkoxy-, -thioalkyl, --C(O)O-alkyl and --C(O)OH; alkenyl; alkynyl; -alkyl-aryl; -alkyl-heteroaryl; -alkyl-heterocyclyl; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -heteroaryl-heteroaryl; -aryl-aryl; -aryl (monocyclic or bicyclic); heteroaryl (monocyclic or bicyclic); heterocyclyl; or R.sup.2 together with R.sup.4 may form a carbocyclyl group optionally substituted by one or more alkyl groups; R.sup.3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, alkoxy-, -thioalkyl, --C(O)OH and --C(O)O-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, halogen, haloalkyl, hydroxyl, -alkoxy, -thioalkyl, --C(O)OH and --C(O)O-alkyl; alkenyl; -alkyl-aryl; -alkyl(aryl).sub.2, -alkyl(heteroaryl).sub.2, -alkyl(aryl)(heteroaryl), -alkyl-heteroaryl; -alkyl-heterocyclyl which heterocyclyl group may optionally be substituted by one or more groups selected from alkyl, hydroxy and oxo ; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -aryl-aryl; -aryl-O-aryl, -heteroaryl-heteroaryl; -aryl; heteroaryl; heterocyclyl; -aryl-alkyl-aryl; -aryl-O-alkyl-aryl; -alkyl-C(O)--NH-alkyl-aryl; -alkyl-C(O)--NH-alkyl-heteroaryl; -alkyl-C(O)--NH-alkyl-heterocyclyl; -alkyl-C(O)--(N-piperidinyl) or -alkyl-C(O)--(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl. R.sup.4 represents H or alkyl.