Patient A (Northstar-2)	Patient B (Northstar-3)
Age at diagnosis, months	12	19
Annualized transfusion number (volume) 2 years prior to enrollment	24.5 (240.5 mL/kg/year)	19 (189.9 mL/kg/year)
Liver iron concentration, baseline	7.2	1.2
Cardiac T2*, baseline	35.3	39.3
Vector copy number per diploid genome/% transduced cells	3.7/83	3.4/78
Average daily busulfan area under the curve, µM*min	4988	6351
Neutrophil and platelet engraftment, days	26/44	34/50
VCN in peripheral blood (range during follow up)	1.00-1.52	1.61-2.2
Myeloid:erythroid ratio, baseline/Month 12	1:5.5/1:1.3	1:4.7/1.2:1