SCRI-CAR22v2

P1/2, N=42, Recruiting, Seattle Children's Hospital | Trial completion date: Feb 2039 --> Feb 2040 | Trial primary completion date: Jun 2024 --> Jun 2025

P1/2, N=42, Recruiting, Seattle Children's Hospital | Trial completion date: Feb 2038 --> Feb 2039 | Trial primary completion date: Apr 2023 --> Jun 2024

Following use of cetuximab-APC and biotinylated anti-human Fab antibody for surface EGFRt and CAR detection, the SCRI-CAR22v1 expresses lower levels of EGFRt but similar CAR levels on the cell surface demonstrated by MFI (Figure B). Biotinylated, soluble CD22 antigen was also used to evaluate CD22 CAR receptor activity and, as measured by MFI, a higher affinity is suggested via SCRI-CAR22v2 as compared to SCRI-CAR22v1 (Figure B)... Despite encouraging preclinical data, SCRI-CAR22v1 demonstrated poor expansion and engraftment in a Phase 1 trial. Notably, minor CAR alterations lead to encouraging in-human activity in early clinical findings. Our experience suggests a shorter linker and hinge as well as incorporation of an CD8 alpha transmembrane region improves the clinical activity of CD22 targeted CAR T cells in subjects with recurrent disease following CD19 CAR T cells.