Compounds of formula (I), combinations and uses thereof for disease therapy, or a pharmaceutically acceptable salt, solvate or polymorph thereof, including all tautomers and stereoisomers thereof wherein: A represents and B, R<;SUP>;1<;/SUP>;, R<;SUP>;2<;/SUP>;, R<;SUP>;3<;/SUP>;, R<;SUP>;4<;/SUP>;, R<;SUP>;5<;/SUP>;, R<;SUP>;6 <;/SUP>;and Z are as defined throughout the description and the claims.