Currently we do not have an integration for ClickTeam Fusion 2.5, this is not on our roadmap at the moment either. To use FMOD in your game you would need to integrate it with the engine.
From what I can see, they have an extension SDK that supports the C/C++ programming language which is what FMOD primarily exposes.
We ship our own Unity and UE4 integrations, but there are also plenty of customers who integrate FMOD into their own custom engines.