The present invention relates to compounds of formula (I), combinations and uses thereof for disease therapy, wherein: R1 represents heteroaryl, -carbocyclyl-heteroaryl, -alkenylheteroaryl or -alkylheteroaryl； R2 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, -alkoxy, -thioalkyl, &mdash；C(O)O-alkyl and &mdash；C(O)OH； carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, haloalkyl, amino, halogen, hydroxyl, alkoxy-, -thioalkyl, &mdash；C(O)O-alkyl and &mdash；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 R2 together with R4 may form a carbocyclyl group optionally substituted by one or more alkyl groups； R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, alkoxy-, -thioalkyl, &mdash；C(O)OH and &mdash；C(O)O-alkyl； carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, halogen, haloalkyl, hydroxyl, -alkoxy, -thioalkyl, &mdash；C(O)OH and &mdash；C(O)O-alkyl； alkenyl； -alkyl-aryl； -alkyl(aryl)2, -alkyl(heteroaryl)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)&mdash；NH-alkyl-aryl； -alkyl-C(O)&mdash；NH-alkyl-heteroaryl； -alkyl-C(O)&mdash；NH-alkyl-heterocyclyl； -alkyl-C(O)&mdash；(N-piperidinyl) or -alkyl-C(O)&mdash；(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl. R4 represent
