Protein kinase, such as CHK-1, inhibiting tricyclic compounds of the following
formula (wherein R2, R3 and R4 are as defined
in the specification)
##STR1##
pharmaceutical compositions containing effective amounts of said compounds
or their salts are useful as a single agent or in combination with an anti-neoplastic
agent or therapeutic radiation having an anti-neoplastic effect for treating diseases
or conditions such as cancers.