I'm confused how this would reduce disease progression compared to a much cheaper allo bone marrow transplant then if they are only modifying hematopoietic stem cells since a BMT is just doing the exact same thing except with someone else's non affected cells. BMTs are a horrific procedure though so this definitely has an advantage in that regard.

I would also have to imagine they would have to do myeloablative chemo or radiation to make sure the fixed cells propagate more than the diseased cell line.

Edit: read the study, they do give them the same chemo used for normal transplants.