Nice post, it looks like LentiGlobin BB305 was given it's "Breakthrough Drug Status" in 2015 and has been in clinical trial for the past 3 years. They ( https://www.bluebirdbio.com/patients-families/beta-thalassemia/ ) just need enough data to release it and then we'll see the cost. That paper looks pretty promising for results and I think the gene editing part pretty cheap. Once they have what they need it's basically just a chemical bath and then back it goes. It's all about how easy it is to extract those CD 34+ cells and as far as I know you gotta split the white cells out of the blood as just the first step so that's not gonna be cheap ... those blood banks are making bank when they resale the blood/plasma the pull and separate.