CRS, TLS, MAS deemed not investigable nonclinically; CD19-dependent cytokine release in vitro
“These toxic effects cannot be investigated in non-clinical studies as they are general effects of CAR T cells and the extent of expected toxicities are largely based on patient-specific parameters such as the individual tumour load.”
No biodistribution studies; surrogate CAR-T in spleen Day 8, undetectable Day 63
“No biodistribution studies with KTE-C19 were conducted.”
✓ VerifiedFDA pharmacology/toxicology review, p. 16Source ↗
Modality-specific risk
Insertional oncogenesis from gamma-retroviral vector with full-length LTRs; on-target B-cell aplasia; RCR
“The combination of both the use of a γ-retroviral vector with full-length viral LTRs and the high proliferative potential of the transduced T cells provides a certain risk of insertional oncogenesis.”
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
Anti-drug antibodies: patients
Screening ELISA positives occurred, but a confirmatory cell-based assay found all of them antibody-negative
“Results of a confirmatory cell-based assay, leveraging a properly folded and expressed extracellular portion of the CAR (ScFv, hinge and linker) demonstrated that all patients treated with YESCARTA that had a positive result in the screening ELISA were antibody negative at all time points tested.”