Disease status and treatment characteristics at CART1 and CART2
| Characteristic | CART1 n=18 (%) | CART2 n=18 (%) |
| Disease status pre-CART Infusion | ||
| Bone marrow | ||
| MRD-negative CR | 0 | 2 (11.1)* |
| M1 | 5 (27.8) | 4 (22.2) |
| M2/M3 | 13 (72.2) | 12 (66.7) |
| CNS | ||
| CNS1 | 11 (61.1) | 14 (72.2) |
| CNS1 with flow +disease | 7 (38.8) | 3 (16.7) |
| CNS3 | 0 | 1 (5.6) |
| Non-CNS extramedullary disease | 5 (27.8) | 4 (22.2) |
| CART dose | ||
| CART1=CART2 dose | 15 (83.3) | |
| CART1 >CART2 dose | 2 (11.1) | |
| CART1 <CART2 dose | 1 (5.6) | |
| Lymphodepletion pre-CART | ||
| Standard LD at CART1 and CART2 | 7 (38.9) | |
| Standard LD at CART1, intensified LD at CART2 | 8 (44.4) | |
| Intensified LD at CART1, standard LD at CART2 | 1 (5.6) | |
| Combination standard LD and FLAG† | 2 (11.1) | |
| Indication for CART2 | ||
| Stable disease following CART1 | 7 (38.9) | |
| Relapse post-CART1 | 11 (61.1) | |
| Time elapsed between CART1 and CART2, median (range), days | 116.5 (35–373) | |
MRD-negative CR, <0.01% (1×10–4) ALL blasts/MNC by flow cytometry; bone marrow classifications by morphology: M1 bone marrow, <5% blasts; M2 marrow, 5%–25% blasts; M3 marrow, >25% blasts. CNS1, 0 blasts detectable on cytospin; CNS2, WCC < 5/μL, cytospin positive for blasts; CNS3,WCCs ≥ 5 μL, cytospin positive for blasts.
*Concurrent CNS disease (one patient with stable disease, one patient with relapsed disease). Standard LD: fludarabine 25 mg/m2 × 3 days (−4, −3, −2), cyclophosphamide 900 mg/m2 × 1 day (−2). Intensified LD: fludarabine 30 mg/m2 × 4 days (−5, −4, −3, −2), cyclophosphamide 600 mg/m2 × 2 days (−3, −2). FLAG: fludarabine 25 mg/m2 × 5 days (1–5), cytarabine 2000 mg/m2 × 5 days (1–5), filgrastim 5µg/kg (day −1 through ANC>1000 ×2 days after nadir).
†Two CD19 CART patients received standard LD and FLAG: one with FLAG pre-CART1 and standard LD pre-CART2 and the other with standard LD pre-CART1 and FLAG pre-CART2.
ALL, acute lymphoblastic leukemia; CAR, chimeric antigen receptor; CNS, central nervous system; CR, complete remission; FLAG, fludarabine, cytarabine, filgrastim; LD, lymphodepletion; MRD, minimal residual disease.