imidazopyridine derivatives as activin receptor kinase inhibitors (alk4 or alk5)

摘要

Compounds of formula (I): in free or salt or solvate form, where X, R1, R2, R3 and R4 have the meanings as indicated in the specification, are useful for treating diseases mediated by the ALK-5 and/or ALK-4 receptor. Pharmaceutical compositions that contain the compounds and processes for preparing the compounds are also described.