Infusion therapy can employ several routes for administering liquids with a needle or catheter, cf. parenteral, intravenous, intramuscular and intrathecal injection.

My suggestion (only!) as to infused biological therapy would be something along the lines of infuusioimmuunihoito or nesteimmunoterapia, (which I coined myself so be careful...!) as opposed to, say for example, radiation therapy that targets the malignant cells directly and not the body's own (immunological) systems. What I mean by that is that infusion therapy and infused biological therapy are two quite different things.