"Some grammar knowledge" probably also tells you the structure of the verb, namely TREAT+ING(V,present progressive). "TREAT" is the 1,118th most common word, so that gives you:

WNPHMMVF FOUND EFFECTIVE IN TREATING CUYROVGVF

And then some contextual knowledge of what sort of things get treated tells you that CUYROVGVF is a disease or injury, and WNPHMMVF is a medicine or therapy. So knowing 2,000 words and some grammar isn't quite fluent, but it's around the level of a middle-school child who has to ask what lots of nouns are.