CD22-CART

All patients received lymphodepletion with fludarabine (30 mg/m2 /d) and cyclophosphamide (300 mg/m2 /d) -based conditioning regimens on day −5 to −3...Among them, 8 patients with CML-LBC and 92 ph+ ALL patients received single CD19 CAR T therapy, others received tandem CD19/CD22 CAR T. The baseline characteristics of all patients were shown in Table 1... Worser sustained antitumor efficacy and long-term survival with CAR T-cells therapy in patients with CML-LBC compared to ph+ ALL patients, and ABL kinase region mutation is an independent risk factor for CR and LFS.

A total of 5 patients with severe cytokine release syndrome (Grade ≥ 3) were observed, including 2 patients in the single CD19 CAR-T group, 2 patients in the tandem CD19/CD22 CAR-T group, and 1 patient in the sequential CD19 and CD22 CAR-T group. Of the 23 patients who achieved CR, 4 patients bridged to allogeneic hematopoietic stem cell transplantation (allo-HSCT) and 3 patients received decitabine (DAC) consolidation.With the median follow-up of 25.5 months (range, 1.1 to 33.5), the 2-year overall survival, leukemia-free survival (LFS) and cumulative incidence of relapse rates were 23.7%, 30.5% and 69.5%, respectively. Multivariate Cox regression analyses showed that a better LFS related to the absence of high-risk cytogenetics and genetic characteristics, DAC combination with fludarabine and cyclophosphamide lymphodepletion regimen, and bridging allo-HSCT or DAC consolidation. Our study showed that the second infusion of tandem CD19/CD22 CAR-T therapy obtains a better response than other infusion strategies. Bridging allo-HSCT or DAC consolidation had a significant survival benefit in patients with CR after the second CAR-T therapy.

This case represents the first successful treatment of multiline resistant refractory PCNSL with long-term CR and without inducing ICANS under tandem CD19/CD22 bispecific CAR-T therapy followed by maintenance therapy with PD-1 and BTK inhibitors. This study shows tremendous potential in the treatment of PCNSL and offers a look toward ongoing clinical studies.

Our retrospective study showed that DAC consolidation after CD19/CD22 CAR-T therapy was a novel maintenance strategy to improve the prognosis of r/r B-ALL patients. CAR-T, B cell acute lymphoblastic leukemia, Consolidation, decitabine

Multivariable analysis in CR patients showed that a low frequency of relapse, a low tumor burden, minimal residual disease-negative CR and bridging to transplantation were independently associated with better leukemia-free survival. Our findings suggested that tandem CD19/CD22 CAR T-cell therapy obtains a better response than CD19 CAR T-cell therapy and a similar response to sequential CD19/CD22 CAR T-cell therapy.

Here, we speculated that decitabine (DAC) in combination with fludarabine and cyclophosphamide (FC) as a lymphodepletion regimen may improve the efficacy of CD19/CD22 CAR T-cell therapy. All adverse events were reversible and manageable. In conclusion, DAC in combination with the FC lymphodepletion regimen may be a new treatment option that can improve the efficacy of CAR T-cell therapy in r/r B-ALL.