Disclosed is a fused heterocyclic compound of formula (I) or a salt thereof, wherein the substituents are as described within the specification. An example of a compound of formula (I) includes N-[1-(2-hydroxyethyl)piperidin-4-yl]-3-methoxy-1-methyl-4-oxo-5-(2-oxo-2-phenylethyl)-4,5-dihydro-1H-pyrrolo[3,2-c]quinoline-2-carboxamide. Further disclosed is a pharmaceutical agent comprising a compound of formula (I), a method of inhibiting Smo or prophylaxis or treatment of cancer in a non-human animal, and the use of a compound of formula (I) for the production of an Smo inhibitor or an agent for the prophylaxis or treatment of cancer.
