Allogeneic Bank Cells - What Are the Challenges?

Allogeneic bank cells could be an alternative to the current commercial CD-19 autologous products. The big thing that's brought up and I think the allogeneic field that I've been challenged with a lot is what is the persistence of an allogeneic cell whether it be a petesal lineage or an encasal lineage. And if we can't improve this persistence are we going to ever get to the longevity or the durability of responses especially in hematologic malignancies with autologous current use cells?