Tricyclic Compounds for Use as Kinase Inhibitors

There is provided compounds of formula (I), wherein R1, R2, R3 and R4 have meanings given in the description (and which compounds are optionally substituted as indicated in the description), and pharmaceutically-acceptable esters, amides, solvates or salts thereof, which compounds are useful in the treatment of diseases in which inhibition of a protein or lipid kinase (e.g. a PIM family kinase, such as PIM-1, PIM-2 and/or PIM-3) is desired and/or required, and particularly in the treatment of cancer or a proliferative disease. There is also provided combinations comprising the compounds of formula (I).