Edited human CD34+ cells engrafted in NSG mice retained >90% on-target editing at 16 weeks
“At 16 weeks post-administration, engrafted cells in NSG mice demonstrated >90% on-target editing frequencies in whole blood, bone marrow, and spleen.”
✓ VerifiedFDA pharmacology/toxicology review, p. 2Source ↗
Why that model
No relevant animal disease model of TDT or SCD exists
“No in vivo proof-of-concept studies were conducted as no relevant animal disease model for TDT and SCD exists that could be used for evaluation of exa-cel.”
EMA: pharmacodynamic studies adequate to show beneficial editing and HbF levels despite lack of a disease model
“Overall, the primary pharmacodynamic studies provided adequate evidence that potential beneficial levels of genome editing and HbF expression can be reached, despite the lack of a relevant disease animal model.”
WAS-deficient mice transplanted with WAS LVV-transduced murine Lin- BM cells: increased B cells, platelets, granulocytes; improved T, B and DC function