Protein kinase inhibitors are disclosed having utility in the treatment of protein kinase-mediated diseases and conditions, such as cancer. The compounds of this invention have the following structure: including steroisomers, prodrugs and pharmaceutically acceptable salts thereof, wherein A is a ring moiety selected from: and wherein R1, R2, R3, X, Z, L1, Cycl1, L2 and Cycl2 are as defined herein. Also disclosed are compositions containing a compound of this invention, as well as methods relating to the use thereof.