The point I was trying to make about biological (at least compared to traditional small molecule drugs) is that patent protection is not as important to the commercialisation. Plenty of biologics that are on the market are out of patent, but they still don't have any generic competition. This is a really good thing if you are developing new biologics since you have a much longer time to charge a premium price.
I am quite optomistic about exosomes too, the downside is they are not anywhere near as mature as MABs or even the stem cell therapies. The next 10 years is going to bring a lot of breakthroughs in the exosome area.