scholarly journals Sequential CD19- and CD22-CART Cell Therapies for Relapsed B-Cell Acute Lymphoblastic Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2126-2126 ◽  
Author(s):  
Shuangyou Liu ◽  
Biping Deng ◽  
Yuehui Lin ◽  
Zhichao Yin ◽  
Jing Pan ◽  
...  

Abstract With traditional therapies, the prognosis of relapsed acute lymphoblastic leukemia (ALL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is extremely poor. Chimeric antigen receptor (CAR) T cell therapy targeting at CD19 has demonstrated a significant efficacy on refractory/relapsed (r/r) B-ALL, but single-target CART could not maintain a long-term remission. Recently, CD22-CART has also shown an exciting result in r/r B-ALL. Here we sequentially applied CD19- and CD22-specific CART cells to treat relapsed B-ALL post-HSCT and observed the therapeutic effect. From June 30,2017 through May 31,2018, twenty-four B-ALL patients (pts) relapsing after allo-HSCT with both antigens CD19 and CD22 expression on blasts were enrolled, the median age was 24 (2.3-55) years. Seventeen pts had hematologic relapse, 6 with both bone marrow and extramedullary (EM) involvements and 1 with EM disease (EMD) only. Fourteen pts had failed to previous therapies including chemotherapy, donor lymphocyte infusion, interferon and even murinized CD19-CART in other hospitals. Recipient-derived donor T cells were collected for producing CAR-T cells, which were transfected by a lentiviral vector encoding the CAR composed of CD3ζ and 4-1BB. Eighteen pts were initially infused with murinized CD19-CART, then humanized CD22-CART; while 6 pts (5 failed to prior murinized CD19-CART and 1 had bright CD22-expression) were initially infused with humanized CD22-CART, then humanized CD19-CART. The time interval between two infusions was 1.5-6 months based on patients' clinical conditions. The average dose of infused CAR T cells was 1.4×105/kg (0.4-9.2×105/kg) for CD19 and 1.9×105/kg (0.55-6.6×105/kg) for CD22. All patients received fludarabine with or without cyclophosphamide prior to each infusion, some pts accepted additional chemo drugs to reduce the disease burden. Treatment effects were evaluated on day 30 and then monthly after each CART, minimal residual disease (MRD) was detected by flow cytometry (FCM) and quantitative PCR for fusion genes, EMD was examined by PET-CT, CT or MRI. Sixteen patients finished sequential CD19- and CD22-CART therapies. Three cases could not undergo the second round of CART infusion (1 died, 1 gave up and 1 developed extensive chronic graft-versus-host disease (GVHD)). The rest of 5 pts are waiting for the second CART. After first T-cell infusion, 20/24 (83.3%) pts achieved complete remission (CR) or CR with incomplete count recovery (CRi), MRD-negative was 100% in CR or CRi pts, 3 (12.5%) cases with multiple EMD obtained partial remission (PR), and 1 (4.2%) died of severe cytokine release syndrome (CRS) and severe acute hepatic GVHD. Sixteen patients (15 CR and 1 PR) underwent the second CART therapy. Before second infusion, 3/15 pts in CR became MRD+ and others remained MRD-. On day 30 post-infusion, 1 of 3 MRD+ pts turned to MRD-, 1 maintained MRD+ ( BCR/ABL+) and 1 had no response then hematologic relapse later. The PR patient still had not obtained CR and then disease progressed. As of 31 May 2018, at a median follow-up of 6.5 (4-10) months, among 16 pts who received sequential CD-19 and CD-22 CART therapies, 1 had disease progression, 2 presented with hematological relapse and 2 with BCR/ABL+ only, the overall survival (OS) rate was 100% (16/16), disease-free survival (DFS) was 81.3% (13/16) and MRD-free survival was 68.8% (11/16). CRS occurred in 91.7% (22/24) pts in the first round of T-cell infusion, most of them were mild-moderate (grade I-II), merely 2 pts experienced severe CRS (grade III-IV). The second CART only caused grade I or no CRS since the leukemia burden was very low. GVHD induced by CART therapy was a major adverse event in these post-HSCT patients. After the first CART, 7/24 (29.2%) pts experienced GVHD, of them, 4 presented with mild skin GVHD, 2 with severe hepatic GVHD (1 recovered and 1 died), and 1 developed extensive chronic GVHD. No severe GVHD occurred in the second infusion. Our preliminary clinical study showed that for B-ALL patients who relapsed after allo-HSCT, single CD19- or CD22- CART infusion resulted in a high CR rate of 83.3%, sequentially combined CD19- and CD22-CART therapies significantly improved treatment outcome with the rate of OS, DFS and MRD-free survival being 100%, 81.3% and 68.8%, respectively, at a median follow-up of 6.5 months. The effect of CART on multiple EMD was not good and CART induced GVHD needs to be cautious. Disclosures No relevant conflicts of interest to declare.

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 19-20
Author(s):  
Yi Wang ◽  
Hui Wang ◽  
Ying Gao ◽  
Ding Zhang ◽  
Yan Zheng ◽  
...  

Introduction: It has been made great clinical progresses in hematological malignancies by chimeric antigen receptor (CAR) T cell therapy which utilizes virus vector for manufacture. However, there're still issues unresolved, for instance, sophisticated virus production process, deadly Cytokine Release Syndrome (CRS) side-effect, and high recurrence rate, which probably limit the availability of CAR-T therapy. Non-viral Genome Targeting CAR-T (nvGT CAR-T) may provide a feasible solution to those unmet needs mentioned above. We used CRISPR-Cas9 and non-viral vector to insert anti-CD19 CAR DNA to a specific genome locus in human T cells, which in theory, produces more moderate CAR-T cells compared with conventional CAR-T cells. The efficacy of anti-CD19 nvGT CAR-T cells had been demonstrated in our previous pre-clinical studies, and in this Phase I clinical trial (ChiCTR2000031942), its safety and efficacy in relapsed/refractory B-Cell Acute Lymphoblastic Leukemia (r/r B-ALL) patients were explored. Objective: The primary objective of this Phase I trial is to assess safety, including evaluation of adverse events (AEs) and AEs of special interest, such as CRS and neurotoxicity. Secondary objective is to evaluate efficacy as measured by the ratio of complete remission (CR). Method: Peripheral blood mononuclear cells were collected from patients or allogeneic donors, then CD3+ T cells were selected and modified by nvGT vector to produce anti-CD19 CAR-T, then administrated to patients with r/r B-ALL. Up to July 2020, twelve patients with r/r B-ALL had been enrolled in this study and 8 patients completed their treatments and entered follow-up period. For 8 patients with follow-up data, the median age was 33 years (range, 13 to 61), and the median number of previous regimens was 5 (range, 2 to 11). The median baseline percentage of bone marrow (BM) blast is 72% (range, 24.5% to 99%). Among those subjects, 2 patients once have been conducted autologous or allogeneic hematopoietic stem cell transplantation (Auto-HSCT or Allo-HSCT), and 2 patients experienced serious infection before CAR-T infusion. No patient has been treated by any other CAR-T therapy before enrollment. Baseline characteristics refer to Table 1. Administering a lymphodepleting chemotherapy regimen of cyclophosphamide 450-750 mg/m2 intravenously and fludarabine 25-45 mg/m2 intravenously on the fifth, fourth, and third day before infusion of anti-CD19 nvGT CAR-T, all patients received an infusion at dose of 0.55-8.21×106/kg (Table 1). Result: Until day 30 post CAR-T cell infusion, 8/8 (100%) cases achieved CR and 7/8 (87.5%) had minimal residual disease (MRD)-negative CR (Table 1). Anti-bacterial and anti-fungal were performed in patients SC-3, SC-4 and SC-5 after CAR-T cell infusion, which seems no influence on efficacy. Patient SC-7 was diagnosed as T-cell Acute Lymphoblastic Leukemia before Allo-HSCT but with recent recurrence of B-ALL, which was MRD-negative CR on day 21 post nvGT CAR-T therapy. Up to July 2020, all cases remain CR status. CRS occurred in all patients (100%) receiving anti-CD19 nvGT CAR-T cell, including 1 patient (12.5%) with grade 3 (Lee grading system1) CRS, two (25%) with grade 2 CRS, and 5 (62.5%) with grade 1 CRS. There were no cases of grade 4 or higher CRS (Table 1). The median time to onset CRS was 9 days (range, 1 to 12 days) and the median duration of CRS was 6 days (range, 2 to 9 days). None developed neurotoxicity. No fatal or life-threatening reactions happened and no Tocilizumab and Corticosteroids administered following CAR-T treatment. Data including body temperature (Figure 1), CAR-positive T cell percentage (Figure 2), Interleukin-6 (IL-6) and Interleukin-8 (IL-8) (Figure 3 and 4), C-reactive Protein (CRP) (Figure 5), Lactate Dehydrogenase (LDH) (Figure 6), and Procalcitonin (PCT) (Figure 7), are in accordance with the trend of CRS. Conclusion: This Phase I clinical trial primarily validates the efficacy of this novel CAR-T therapy, however, it still needs time to prove its durability. Surprisingly, we find that nvGT CAR-T therapy is seemingly superior than viral CAR-T therapy in terms of safety. All subjects which are high-risk patients with high tumor burden had low grade CRS, even a few patients sent home for observation post infusion with limited time of in-patient care. Furthermore, patients could tolerate a higher dose without severe adverse events, which probably bring a better dose-related efficacy. Disclosures No relevant conflicts of interest to declare.


2021 ◽  
pp. JCO.21.00389
Author(s):  
Jing Pan ◽  
Yue Tan ◽  
Guoling Wang ◽  
Biping Deng ◽  
Zhuojun Ling ◽  
...  

PURPOSE Patients with relapsed or refractory T-cell acute lymphoblastic leukemia (r/r T-ALL) have few options and poor prognosis. The aim was to assess donor-derived anti-CD7 chimeric antigen receptor (CAR) T-cell safety and efficacy in patients with r/r T-ALL. METHODS In this single-center, phase I trial, we administered anti-CD7 CAR T cells, manufactured from either previous stem-cell transplantation donors or new donors, to patients with r/r T-ALL, in single infusions at doses of 5 × 105 or 1 × 106 (±30%) cells per kilogram of body weight. The primary end point was safety with efficacy secondary. RESULTS Twenty participants received infusions. Adverse events including cytokine release syndrome grade 1-2 occurred in 90% (n = 18) and grade 3-4 in 10% (n = 2), cytopenia grade 3-4 in 100% (n = 20), neurotoxicity grade 1-2 in 15% (n = 3), graft-versus-host disease grade 1-2 in 60% (n = 12), and viral activation grade 1-2 in 20% (n = 4). All adverse events were reversible, except in one patient who died through pulmonary hemorrhage related to fungal pneumonia, which occurred at 5.5 months, postinfusion. Ninety percent (n = 18) achieved complete remission with seven patients proceeding to stem-cell transplantation. At a median follow-up of 6.3 months (range 4.0-9.2), 15 remained in remission. CAR T cells were still detectable in five of five patients assessed in month 6, postinfusion. Although patients' CD7-positive normal T cells were depleted, CD7-negative T cells expanded and likely alleviated treatment-related T-cell immunodeficiency. CONCLUSION Among 20 patients with r/r T-ALL enrolled in this trial, donor-derived CD7 CAR T cells exhibited efficient expansion and achieved a high complete remission rate with manageable safety profile. A multicenter, phase II trial of donor-derived CD7 CAR T cells is in progress ( NCT04689659 ).


Blood ◽  
2019 ◽  
Vol 133 (21) ◽  
pp. 2291-2304 ◽  
Author(s):  
Diego Sánchez-Martínez ◽  
Matteo L. Baroni ◽  
Francisco Gutierrez-Agüera ◽  
Heleia Roca-Ho ◽  
Oscar Blanch-Lombarte ◽  
...  

Abstract Relapsed/refractory T-cell acute lymphoblastic leukemia (T-ALL) has a dismal outcome, and no effective targeted immunotherapies for T-ALL exist. The extension of chimeric antigen receptor (CAR) T cells (CARTs) to T-ALL remains challenging because the shared expression of target antigens between CARTs and T-ALL blasts leads to CART fratricide. CD1a is exclusively expressed in cortical T-ALL (coT-ALL), a major subset of T-ALL, and retained at relapse. This article reports that the expression of CD1a is mainly restricted to developing cortical thymocytes, and neither CD34+ progenitors nor T cells express CD1a during ontogeny, confining the risk of on-target/off-tumor toxicity. We thus developed and preclinically validated a CD1a-specific CAR with robust and specific cytotoxicity in vitro and antileukemic activity in vivo in xenograft models of coT-ALL, using both cell lines and coT-ALL patient–derived primary blasts. CD1a-CARTs are fratricide resistant, persist long term in vivo (retaining antileukemic activity in re-challenge experiments), and respond to viral antigens. Our data support the therapeutic and safe use of fratricide-resistant CD1a-CARTs for relapsed/refractory coT-ALL.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 10507-10507 ◽  
Author(s):  
Mala Kiran Talekar ◽  
Shannon L. Maude ◽  
George E Hucks ◽  
Laura S Motley ◽  
Colleen Callahan ◽  
...  

10507 Background: Anti-CD19 CAR-T cell therapies have shown high efficacy in inducing durable marrow responses in patients with relapsed/refractory CD19+ ALL. We now report on outcome of 10 patients with extramedullary (EM) involvement of ALL treated with CAR-T, including 5 patients who had EM disease at time of infusion. Methods: We identified patients treated on pediatric phase 1/2a trials of murine (CTL019) or humanized (CTL119) anti-CD19 CAR-T cells for isolated EM or BM/EM relapse of ALL. EM relapse was defined as involvement of non-CNS site by imaging +/- pathology within 12 months (mos) of infusion. Post infusion, patients had diagnostic imaging done at 1, 3, 6, 9, and 12 mos. Results: Among 97 patients receiving CAR-T, ten (CTL019, n=6; CTL119, n=4) were identified who had EM involvement on average 2.3 mos (range 0-9 mos) prior to infusion; including 5/10 at time of infusion. Sites of EM relapses included testes, sinus, parotid, bone, uterus, kidney and skin, and 5 patients had multiple sites of EM involvement. Patients ranged from 2-4 relapses of their ALL pre-CAR-T. Two had isolated EM relapse (sites were parotid and multifocal bony lesions in one; testis and sinus in second). All 10 patients had undergone hematopoietic stem cell transplantation prior to EM relapse, 2 had received radiation directed to the EM site prior to CAR-T. Five patients evaluated by serial imaging had objective responses: 2 had resolution of EM disease by day 28; 2 had resolution by 3 mos; 1 had continued decrease in size of uterine mass at 3 and 6 mos and underwent hysterectomy at 8 mos with no evidence of disease on pathology. In the 4 patients with prior history of skin or testicular involvement, there was no evidence by exam at day 28. One patient had progressive EM disease within 2 weeks of CAR-T cell infusion and died at 6 weeks. Three relapsed with CD19+ disease [1 skin/medullary- died at 38 mos post CAR-T; 2 medullary (1 died at 17 mos, 1 alive at 28 mos)]. The remaining 6 are alive and well at median follow-up of 10 mos (range 3-16 mos) without recurrence of disease. Conclusions: Single agent CAR-T immunotherapy can induce potent and durable responses in patients with EM relapse of their ALL. Clinical trial information: NCT01626495, NCT02374333.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1115-1115
Author(s):  
Elad Jacoby ◽  
Haiying Qin ◽  
Yinmeng Yang ◽  
Christopher Daniel Chien ◽  
Terry J Fry

Abstract A significant portion of patients with relapsed acute lymphoblastic leukemia (ALL) who are eligible for treatment with chimeric-antigen-receptor (CAR) T cells have undergone a previous hematopoietic stem cell transplantation. We and others have previously demonstrated that the allogeneic environment, even in the presence mild graft-versus-host disease (GVHD), severely impairs tumor-directed T-cell immunity. To study the behavior of CAR cells in the allogeneic setting we chose a murine model of minor mismatched allogeneic T-cell depleted bone marrow transplantation (BMT) followed by CAR T (CD19-28-z) cell infusion in recipients bearing a murine B-precursor ALL model (positive for CD19). Importantly, the leukemia persists following myeloablative radiation thus mimicking post-transplant minimal residual disease. Donor-derived, post-transplant injection of CD19 CAR T cells eliminated residual leukemia in the syngeneic as well as the allogeneic settings. CD19 CAR T cells harvested from allogeneic recipients maintained in-vitro ability to produce IFN-gamma and degranulate in the presence of ALL ex vivo, at levels comparable to syngeneic CD19 CAR T cells. However, CAR T cells administered in the allogeneic environment had the potential to mediate severe acute GVHD with early mortality of recipients not typically seen in this minor mismatch model. This occurred across multiple T cell doses capable of clearing leukemia (0.3e6-5e6), in transduced CD19 CAR T cells generated from donors tolerized to allogeneic antigens, and when CD19 CAR T cell infusion was delayed following BMT. In-vivo tracking of transferred cells showed comparable expansion and persistence of the CD19 CAR T cells in the allogeneic and syngeneic environments. However, syngeneic CAR T cells tended to develop later into central memory T cells (CD62L+CD44+), whereas the profile of allogeneic cells was significantly skewed toward effector T cells (CD62L-CD44+). Remarkably, the process of CAR-driven acute GVHD in this minor mismatch model was only seen in the presence of leukemia, indicating a CAR-target interaction influences the induction of GVHD. Indeed, pro-inflammatory cytokines IFN-gamma and IL-6 were elevated only in the presence of both ALL and CAR T cells, whereas TNF alpha levels were undetectable in all instances. We are currently testing whether neutralization of cytokines can prevent GVHD in these models. Altogether, these data demonstrate efficacy of CD19 CAR to clear residual leukemia in an immunocompetent mouse model, and maintain initial cytotoxicity despite the potentially suppressive allogeneic environment. However, we demonstrated potential risks of allogeneic CAR T cells aggravating GVHD in the presence of residual leukemia, likely via cytokine-mediated manner. Clinically, as IL-6 was shown to be significant in cytokine release syndrome, this may represent a murine model to study potential interventions. Disclosures No relevant conflicts of interest to declare.


2020 ◽  
Vol 21 (11) ◽  
pp. 3906 ◽  
Author(s):  
Aamir Ahmad ◽  
Shahab Uddin ◽  
Martin Steinhoff

Chimeric Antigen Receptor (CAR)-T cell therapy is an exciting development in the field of cancer immunology, wherein immune T-cells from patients are collected, engineered to create ‘CAR’-T cells, and infused back into the same patient. Currently, two CAR-T-cell-based therapies, Tisagenlecleucel and Axicabtagene ciloleucel, are approved by FDA for the treatment of hematological malignancies, acute lymphoblastic leukemia and large B-cell lymphomas. Their approval has been a culmination of several phase I and II clinical studies, which are the subject of discussion in this review article. Over the years, CAR-T cells have evolved to be significantly more persistent in patients’ blood, resulting in a much-improved clinical response and disease remission. This is particularly significant given that the target patient populations of these therapies are those with relapsed and refractory disease who have often progressed on multiple therapies. Despite the promising clinical results, there are still several challenges that need to be addressed. Of particular note are the associated toxicities exemplified by cytokine release syndrome (CRS) and the neurotoxicity. CRS has been addressed by an FDA-approved therapy of its own—tocilizumab. This article focuses on the progress related to CAR-T therapy: the pertinent clinical studies and their major findings, their associated adverse effects, and future perspective.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 657-657
Author(s):  
Kai Hu ◽  
Fan Yang ◽  
Rui Liu ◽  
Teng Xu ◽  
Peihao Zheng ◽  
...  

Abstract Background: The prognosis of refractory/relapsed aggressive B-cell non-Hodgkin lymphoma (r/r B-NHL) is extremely poor especially for the patients who failed to CD19-Specific chimeric antigen receptor-T (CAR-T) cells therapy.Even sequentially autologous hematopoietic stem cell transplantation(ASCT) could not maintain a durable remission in most patients. Aims: To prolong relapse-free survival, we combined ASCT and another target humanized CAR-T cells to treat r/r B-NHL patients failed to murinized CD19-CAR-T cells therapy with either CD22 or CD20 antigen expression on tumor cell.The safety and efficacy will be evaluated. Methods: From December 2019 to March 2021, 12 patients were enrolled. The median age was 38 (16-68) years old. The diagnosis included DLBCL (n=8) ,BL(n=3) and PMBCL (n=1). The median IPI score was 3 (range,2-4).There were 9 patients(9/12,75%) with extranodal lesions. Six cases(6/12,50%) were with TP53 mutations. The disease status was progressive disease in all patients who failed to multi-line therapies and murinized CD19-CAR-T cells therapy.In order to further reduce the tumor burden, all patients were treated with combined chemotherapy before transplantation. Before the trial, the expression of CD20 and CD22 antigen in tumor tissue was positive confirmed by immunohistochemistry,and the target was selected according to the antigen expression. Conditioning with BEAM-based regimen was applied. The kinetics and function of CAR-T cells was monitored by quantitative PCR and flow cytometry. The efficacy was evaluated by PET-CT every 3 month after transplantation. Results: The autologous peripheral blood stem cells were infused with the median CD34 + cells 3.91(range,0.46-9.46)×10 6/kg.Humanized CAR-T cells with the median 1.85 (range,0.13-3.26)×10 6/kg were infused 2 day after stem cells,including target antigen CD20(7/12,58.3%) and CD22(5/12,41.7%). Cytokine release syndrome (CRS) occurred in 11 cases with 5 cases in grade I, 3 case in grade II and 3 cases in grade III.One case developed immune effector cell-associated neurotoxicity syndrome (ICANS) in grade IV. The peak of cytokine IFN-γ and IL-6 post baseline in patients with grade III CRS were significantly higher than those in patients with grade I-II CRS,especially in ICANS patient.Six cases with grade II and III were relieved with glucocorticoid. The neutrophil and platelets engraftment was achieved in all cases on median days 14 (range,9-22) and 14(range,8-35) respectively post-transplant .Seven cases of bacterial enteritis were seen. Pneumonia occurred in 7 cases.For CAR-T cells expansion,the peak time in vivo was on median 11(range,7-28) days after CAR-T cells infusion.The median peak lever of CAR-T cells was 20.3 (range,0.13-60.4)×10 6/L, which was positively correlated with the number of CART infused. The tumor burden before transplantation was not significantly associated with CAR-T cells expansion.The median duration of CAR-T cells in vivo was 30 days, and the longest lasting time was 139 days post-transplant so far. B-cell aplasia was documented in all cases(7/7,100%) of CD20-CART group and two cases(2/5,40%) of CD22-CART group during the follow-up. With the median follow-up 266 (range,118-565) days, 9/12(75%) patients survived,seven cases(7/12,58.3%) achieved complete remission(CR),2 cases(2/12,16.7%) achieved PD and survival with tumor.Kaplan-Meier survival analysis showed that OS and PFS rates were 71.3% and 66.6% respectively at 9 months after transplantation.Two cases(2/12,16.7%) with BL and one with DLBCL (1/12,8.3%)died of PD.Significantly lower levels of Cumulative CAR T cell levels (AUC) during the first 1 month post transplantation were observed in patients with disease progression compared with those who had durable responses (P<0.0001). Conclusion: CRS is manageable and has no influence on hematopoiesis reconstitution.With current protocol, complication was mild and encouraging disease control was found. ASCT combined with another target humanized CAR-T therapy is a safe and effective salvage strategy for r/r B-NHL after failure of murinized CD19-CAR-T. Long-term follow-up is needed. [Key words] refractory/relapsed B-cell non-Hodgkin lymphoma; failure of CD19-CAR-T; another target CAR-T cell; autologous hematopoietic stem cell transplantation Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3872-3872 ◽  
Author(s):  
Jiang Cao ◽  
Hai Cheng ◽  
Kunming Qi ◽  
Wei Chen ◽  
Ming Shi ◽  
...  

Introduction: Adoptive infusion of CD19-targeted chimeric antigen receptor T (CAR-T) cells has showed promising treatment effects for relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL). While immune response induced by murine single-chain variable fragment (scFv) of the CAR leads to its premature elimination, and thus increases the risk of leukemia relapse. Humanized scFv is expected to reduce the immunogenicity of CAR, thereby promoting the survival time as well as improving the therapeutic efficacy of CAR-T treatment. We developed a humanized anti-CD19 scFv domain and now report on treatment with humanized CD19 CAR-T cells (hCART19s). Methods: A pilot phase 1 study of CAR-modified T cells containing a humanized anti-CD19 scFv domain (hCART19s) was performed with recruitment of children and adults with R/R B-ALL with or without prior exposure to a murine CD19 CAR-T cell product. Patient-derived T cells were transduced ex vivo with a lentiviral vector encoding a CAR composed of humanized anti-CD19 scFv, the human CD8 transmembrane, CD8 hinge, 4-1BB costimulatory domain, CD3ζ intracellular regions and T2A-EGFRt sequence. After lymphodepletion chemotherapy with cyclophosphamide (750 mg/m2, day -5) and fludarabine (30 mg/m2/day, days -5 to -2), patients received a single dose of autologous hCART19s infusion at a dose of 1×106 cells/kg (body weight) on day 0. The post-infusion responses, toxicities, expansion and persistence of hCART19s in patients were observed and monitored. Results: 51 R/R B-ALL patients aged 3-69 yr were treated with hCART19s. 5 patients was diagnosed as Ph+ B-ALL. 2 patients had received prior allogeneic stem cell transplant (SCT). A total of 8 patients had central nervous system leukemia (CNSL), and 1 had testicular leukemia (TL). Among 46 patients without previous CAR-T therapy, 38 (82.6%) achieved complete remission (CR) or CR with incomplete count recovery (CRi) on day 30, while 2 of 5 patients, who relapsed after murine CAR-T infusion, achieved CR after hCART19s infusion. The rates of event-free survival and overall survival were 63% (95% confidence interval [CI], 46 to 75) and 79% (95% CI, 64 to 88), respectively, at 6 months and 44% (95% CI, 27 to 59) and 67% (95% CI, 51 to 79) at 12 months. Among the 40 patients with CR or CRi, 17 had a relapse before receiving additional anticancer therapy. 12 patients underwent allogeneic hematopoietic stem-cell transplantation (HSCT) while in remission, 10 were alive without relapse and 2 had a relapse after HSCT. During treatment, 37 (72.5%) patients developed grade 1-2 cytokine release syndrome (CRS), and 11 (21.6%) patients developed grade 3-5 CRS. Neurologic events occurred in 4 (7.8%) patients within 8 weeks after infusion. 2 (3.9%) patients had grade 3 neurologic events; no grade 4 events or cerebral edema were reported. Conclusions: This study demonstrated that hCART19s have high therapeutic efficacy and safety in children and adults with R/R B-ALL. More importantly, hCART19s was confirmed to exert anti-leukemic activities in patients who relapsed after murine CAR-T infusion. HSCT is a potential approach to reduce leukemia relapse in patients who achieved CR after CAR-T therapy. Disclosures No relevant conflicts of interest to declare.


Author(s):  
Mohsen Sheykhhasan ◽  
Hamed Manoochehri ◽  
Paola Dama

AbstractAcute lymphoblastic leukemia (ALL) is a cancer-specific lymphoid cell. Induction and consolidation chemotherapy alone or in combination with different therapeutic approaches remain the main treatment. Although complete or partial remission of the disease can be achieved, the risk of relapse or refractory leukemia is still high. More effective and safe therapy options are yet unmet needs. In recent years’ new therapeutic approaches have been widely used. Hematopoietic Stem Cell Transplantation (HSCT) presents significant limitations and the outcome of the consolidation treatment is patient dependent. Side effects such as Graft versus Host Disease (GvHD) in allogeneic hematopoietic stem cell transplantation are extremely common, therefore, using alternative methods to address these challenges for treatment seems crucial. In the last decade, T cells genetically engineered with Chimeric Antigen Receptor (CAR) treatment for the ALL are largely studied and represent the new era of strategy. According to the Phase I/II clinical trials, this technology results seem very promising and can be used in the next future as an effective and safe treatment for ALL treatment. In this review different generations, challenges, and clinical studies related to chimeric antigen receptor (CAR) T-cells for ALL treatment are discussed.


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