The article is pretty light on details, but
> Much like other CRISPR therapies, delivery is a critical challenge, i.e., getting the large genome-cutting enzyme to all the targeted cells efficiently.
makes me think this is in vitro so far. So, years to decades away from being available for actual treatment in humans. Still good news.
Basically the issue is often that gene therapies end up in the liver since its the livers job to detoxify, but that may cause a dangerous immune response if the immune system notices it in the liver and attacks the organ, since the person could die from the damage.