Novel CD19 chimeric antigen receptor T cells manufactured next-day for acute lymphoblastic leukemia

Abstract

Chimeric antigen receptor-engineered T (CAR-T) cells have shown promising efficacy in patients with relapsed/refractory B cell acute lymphoblastic leukemia (R/R B-ALL). However, challenges remain including long manufacturing processes that need to be overcome. We presented the CD19-targeting CAR-T cell product GC007F manufactured next-day (FasTCAR-T cells) and administered to patients with R/R B-ALL. A total of 21 patients over 14 years of age with CD19+ R/R B-ALL were screened, enrolled and infused with a single infusion of GC007F CAR-T at three different dose levels. The primary objective of the study was to assess safety, secondary objectives included pharmacokinetics of GC007F cells in patients with R/R B-ALL and preliminary efficacy. We were able to demonstrate in preclinical studies that GC007F cells exhibited better proliferation and tumor killing than conventional CAR-T (C-CAR-T) cells. In this investigator-initiated study all 18 efficacy-evaluable patients achieved a complete remission (CR) (18/18, 100.00%) by day 28, with 17 of the patients (94.4%) achieving CR with minimal residual disease (MRD) negative. Fifteen (83.3%) remained disease free at the 3-month assessment, 14 patients (77.8%) maintaining MRD negative at month 3. Among all 21 enrolled patients, the median peak of CAR-T cell was on day 10, with a median peak copy number of 104899.5/µg DNA and a median persistence period of 56 days (range: 7–327 days). The incidence of cytokine release syndrome (CRS) was 95.2% (n = 20), with severe CRS occurring in 52.4% (n = 11) of the patients. Six patients (28.6%) developed neurotoxicity of any grade. GC007F demonstrated superior expansion capacity and a less exhausted phenotype as compared to (C-CAR-T) cells. Moreover, this first-in-human clinical study showed that the novel, next-day manufacturing FasTCAR-T cells was feasible with a manageable toxicity profile in patients with R/R B-ALL.

Early induction of cytokine release syndrome by rapidly generated CAR T cells in a preclinical mouse model

“…28 While we cannot exclude that besides the mouse strain the higher administered dose contributed to rapid CRS induction, so far the only data from clinical trials with rapidly manufactured CD19-CAR T cells documented CRS occurrence about one week post treatment. 5,6 Note, that this clinical study administered a rather low CAR T cell dose (10 4 to 10 5 cells/kg body weight), yet induced severe CRS in some patients. In comparison, we administered approximately 5x10 8 cells/kg and thus a more than 1000-fold higher (which was not certified by peer review) is the author/funder.…”

“…The CD19-directed stCAR T cells resembled a less differentiated and exhausted phenotype when compared to conventional CAR T cells as previously described. [4][5][6] Interestingly, our assay for the detection of vector components in these cells revealed that stCAR T cells consisted mainly of vector particle-bound cells with only a small fraction of cells being positive for the CAR. Only upon further cultivation and activation CAR becomes cell-surface expressed and vector particles dissapear, demonstrating that transduction is not fully completed in stCAR T cells.…”

“…6 Current preclinical data about CAR T cells with shortened manufacturing time tested in therapeutical mouse models did not reveal any concerncs regarding CRS and adverse events so far. [4][5][6][7] While CAR T cell generation followed a similar protocol, with respect to the short lentiviral vector exposure to the cells, relevant differences to our study refer to the mouse strain (NSG and NOG) and the administered CAR T cell doses, which were 3 -10 fold lower. Indeed, the NSG-SGM3 mouse model, which was only used in our study, has previously proven to be more sensitive for CRS than the parental NSG strain when assessing the safety of anti-CD28 superagonist and anti-PD1 monoclonal antibodies.…”

“…So far, preclinical studies focussed exclusively on the therapeutic activities of short-term CAR T cells. [4][5][6][7] Assay systems identifying residual vector particles as well as a careful safety assessment of these CAR T cells are therefore urgently needed.…”

Clinical Strategies for Enhancing the Efficacy of CAR T-Cell Therapy for Hematological Malignancies

“…The preparation of CAR T-cells is about 13 days, including T cells expanding for 9 days; another study shortens the preparation time to 7 days with similar effectiveness [ 50 , 51 ]. Surprisingly, Gracell Bio in China has developed a fabrication technique of FasTCAR, which shortens the preparation time of CAR T-cells to 1 day [ 52 ]. FasTCAR technology transforms the activation, transduction, and expansion steps into a single “concurrent activation-transduction” step, eliminating the time for in vitro expansion of CAR T-cells [ 53 ].…”