The Study Of Exploratory Clinical Therapy Of CD19 CAR T-cell Therapy For Philadelphia Chromosome-positive Acute Lymphoblastic Leukemia

Part Ⅰ CD19 chimeric antigen receptor T-cell therapy as a bridge therapy for allo-HSCT in patients with relapsed Ph+ALLObjectiveTo explore the clinical efficacy of CD 19-targeting CAR T-cell therapy bridging to allogeneic hematopoietic stem cell transplantation(allo-HSCT)in patients with relapsed Philadelphia chromosome-positive(Ph+)acute lymphoblastic leukemia(ALL),and analyze its prognostic factors.Methods1、Clinical data:From Jan 01,2017 to Dec 31,2020,17 relapsed Ph+ALL patients who received CAR T-cell therapy and proceeded to bridging to allo-HSCT at the First Affiliated Hospital of Soochow University were enrolled.Results were compared with 23 patients who treated with traditional salvage therapy.2、Manufacturing,infusion and criteria for the assessment of efficacy and toxicity of CAR T-cells(1)CAR T-cells used a CAR construct comprising a CD 19-specific single-chain variable fragment,a 4-1BB costimulatory domain and a CD3ζ signaling domain and were manufactured by Unicar-Therapy Bio-Medicine Technology Co.(Shanghai,China).(2)Lymphodepletion with FC regimen was used prior to CAR T-cell infusion.(3)Response assessment:BCR-ABL1 transcripts was detected by real-time PCR(RT-PCR)and measurable residual disease(MRD)negativity of complete molecular response(CMR)was defined as the absence of BCR-ABL1 transcripts.(4)CAR T-cell-related toxicity was graded using American Society for Transplantation and Cellular Therapy(ASTCT)consensus criteria.3、Allo-HSCT regimen and efficacy evaluation(1)All patients received myeloablative transplantation with a modified Bu/Cy conditioning regimen or a TBI/Cy regimen.(2)Donors include HLA matched sibling(Sib),matched unrelated donors(MUD),and haploidentical donors(Haplo).(3)The graft was donor bone marrow or(and)peripheral blood stem cells mobilized with G-CSF.(4)Cyclosporine and short-course methotrexate were used for prophylaxis graft-versus-host disease(GVHD),antithymocyte globulin and mycophenolate mofetil were given as an additional immunosuppressive treatment in MUD-HSCT and Haplo-HSCT.(5)Acute GVHD and chronic GVHD were graded according to published criteria.4、Statistical analysis:SPSS 23.0 or R were used for statistical analysis.Overall survival(OS)and event-free survival(EFS)were estimated by the Kaplan-Meier method and compared by Log-rank test.Cox regression model was used to evaluate risk factors for EFS.p<0.05 was considered statistically significant.Results1、Patient characteristics:Seventeen patients were enrolled in the study group,with a median age of 41 years,12 males and 5 females;Eight patients received>2 tyrosine kinase inhibitors(TKIs)before salvage therapy.The average proportion of BM blasts at salvage treatment 47.5%.Fourteen patients had a T315I mutation.There was no statistically significant difference of the clinical baseline characteristics of the 23 patients in the control group compared with the study group.2、Evaluation of efficacy and adverse events of CAR T-cells:All 17 patients in the study group achieved remission after CAR T-cell infusion,of which 11 patients were MRD negative and 6 were MRD positive.Eleven patients developed grade 0-1 cytokine release syndrome(CRS)while grade 2-3 CRS occurred in 6 patients.All patients recovered after treatment.No neurotoxicity was observed.3、Assessment of allo-HSCT efficacy:The median time from CAR T-cell infusion to transplantation in 17 patients in the study group was 58 days.All patients achieved neutrophil engraftment after allo-HSCT.The median time to neutrophil and platelet engraftment was 12 days(range,10 to 20)and 15 days(range,10 to 34),respectively.The cumulative incidence of grade Ⅱ-Ⅳ acute GVHD was 29.4%.Of the 14 evaluable patients,6 developed chronic GVHD.Five patients had transplant-related deaths.Three patients relapsed after allo-HSCT.The median follow-up was 33 months.The estimated 2-year OS and EFS were 58.8%and 52.9%,respectively,which showed a trend toward a higher EFS and OS rate than in patients in the control group,but did not reach statistical significance.Multivariate analysis showed that the level of MRD before transplantation was an independent risk factor for EFS(p=0.006,HR=0.1 7).ConclusionCAR T-cell therapy bridging to allo-HSCT can achieve deeper remission prior to allo-HSCT and improve the long-term outcome after allo-HSCT,and is a feasible treatment strategy for patients with relapsed Ph+ALL.Part Ⅱ CD19 chimeric antigen receptor T-cell therapy in adult patients with Ph+ALL without CMR at 3 monthsObjectiveTo investigate whether CAR T-cell therapy can improve the prognosis of Ph+ALL who did not achieve a complete molecular response(CMR)for 3 months.Methods1、Clinical data:From Jan 01,2017 to Sep 30,2021,13 Ph+ALL patients who did not achieve CMR at 3 months and treated with CD 19 CAR T-cell therapy at the First Affiliated Hospital of Soochow University were included in this study.2、Manufacturing,infusion and criteria for the assessment of efficacy and toxicity of CAR T-cellsCAR T-cells were manufactured by Unicar-Therapy Bio-Medicine Technology Co.(Shanghai,China).Patients received lymphodepletion with FC regimen prior to CAR T-cell infusion.CAR T-cell-related toxicity was graded using American Society for Transplantation and Cellular Therapy(ASTCT)consensus criteria.The response assessment was performed by bone marrow examination between Days 28 and 42 after infusion.Measurable residual disease(MRD)negativity of complete molecular response(CMR)was defined as the absence of BCR-ABL1 transcripts by real-time quantitative PCR(RT-PCR).3、Follow-up and statistical analysis:Follow-up was conducted by telephone interview or data collection of the inpatient and outpatient records.Kaplan-Meier method was used to estimate the survival probability.Results1、Patient characteristics:Among the 13 patients,7 were males and 6 were females,with a median age of 32 years;There were 8 cases of P190 transcript and 5 cases of P210 transcript;Seven patients had complex chromosomal changes.The median BCR-ABL1 proliferation level were 70 copies/10000 ABL copies.The median duration between diagnosis and infusion was 130 days(range,122 to 160).2、Evaluation of efficacy and adverse events of CAR T-cells:Cytokine release syndrome(CRS)occurred in 6(46.2%)patients,and grade 3 CRS occurred in 2 patients.The median duration of CRS was 3 days.Only one grade 1 neurological events were observed.CMR was achieved in 9 patients at Day 30 after infusion.3、CAR T-cell in vivo expansion:The median peak expansion day was 9 days(rang,l to 14)after the last infusion and proliferation level was 6.79 × 104 copies/μg genomic DNA(1.47 × 104-7.50×106).4、Follow-up of survivalNine patients received allo-HSCT.The median time to allo-HSCT was 53 days(rang,35 to 106)after CAR T-cell infusion.All patients achieved engraftment with full donor chimerism.Two patients died of infection after transplant,but no patient relapsed.Four patients(3 with CMR)received only TKIs maintenance therapy after CAR T-cell reinfusion.Two patients were still in ongoing CMR,while 2 patients relapsed.The median follow-up of the living patients was 23.5 months.2-year OS was 83.3%.ConclusionAnti-CD 19 CAR T-cell therapy is a safe and effective therapeutic strategy for Ph+ALL patients without 3-month CMR.Validation in large prospective studies is warranted.