scholarly journals Posttransplant chimeric antigen receptor therapy

Blood ◽  
2018 ◽  
Vol 131 (10) ◽  
pp. 1045-1052 ◽  
Author(s):  
Melody Smith ◽  
Johannes Zakrzewski ◽  
Scott James ◽  
Michel Sadelain

Abstract Therapeutic T-cell engineering is emerging as a powerful approach to treat refractory hematological malignancies. Its most successful embodiment to date is based on the use of second-generation chimeric antigen receptors (CARs) targeting CD19, a cell surface molecule found in most B-cell leukemias and lymphomas. Remarkable complete remissions have been obtained with autologous T cells expressing CD19 CARs in patients with relapsed, chemo-refractory B-cell acute lymphoblastic leukemia, chronic lymphocytic leukemia, and non-Hodgkin lymphoma. Allogeneic CAR T cells may also be harnessed to treat relapse after allogeneic hematopoietic stem cell transplantation. However, the use of donor T cells poses unique challenges owing to potential alloreactivity. We review different approaches to mitigate the risk of causing or aggravating graft-versus-host disease (GVHD), including CAR therapies based on donor leukocyte infusion, virus-specific T cells, T-cell receptor–deficient T cells, lymphoid progenitor cells, and regulatory T cells. Advances in CAR design, T-cell selection and gene editing are poised to enable the safe use of allogeneic CAR T cells without incurring GVHD.

Author(s):  
Saar Gill ◽  
Jennifer N. Brudno

At the time of writing, five anti-CD19 CAR T-cell products are approved by the U.S. Food and Drug Administration for seven different indications in lymphoid malignancies, including B-cell non-Hodgkin lymphoma, pediatric B-cell acute lymphoblastic leukemia, and multiple myeloma. CAR T cells for chronic lymphocytic leukemia, acute myeloid leukemia, and less common malignancies such as T-cell lymphomas and Hodgkin lymphoma are being tested in early-phase clinical trials worldwide. The purpose of this overview is to describe the current landscape of CAR T cells in hematologic malignancies, outline their outcomes and toxicities, and explain the outstanding questions that remain to be addressed.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 228-228 ◽  
Author(s):  
Shuangyou Liu ◽  
Biping Deng ◽  
Jing PAN ◽  
Zhichao Yin ◽  
Yuehui Lin ◽  
...  

Cytokine release syndrome (CRS) is the most prominent and potentially life-threatening toxicity caused by chimeric antigen receptor (CAR) T cell therapy, therefore, effectively controlling severe CRS is critical to ensure patient safety. Tocilizumab, an interleukin-6 receptor antagonist, has been widely used to treat CRS, whereas it is not clear if corticosteroids could be as another optimal choice for managing CRS. We applied corticosteroids instead of tocilizumab as the first-line agent to control CRS in patients with relapsed/refractory B-cell acute lymphoblastic leukemia during CAR-T therapy. The impacts of steroids on treatment efficiency and kinetics of CAR-T cells were assessed by comparing two groups of patients who did (42 cases) or did not (26 cases) receive steroids. Patients followed up less than one month (went to other hospitals for transplantation or died within one month) were excluded. Treatment effects were evaluated on day 30 after T-cell infusion and then monthly in follow-up patients. Minimal residual disease (MRD) was detected by multiparameter flow cytometry (FCM) and quantitative PCR for fusion genes. The dynamic monitoring of CAR-T cells was performed through flow cytometric quantitation of FITC+CD3+ T cells. B-cell aplasia (BCA) was assayed by FCM. Dexamethasone or methylprednisolone or both (alternately) were administrated. Dexamethasone was used in most cases especially for patients with neurologic symptoms; methylprednisolone was preferred for patients with pulmonary or liver dysfunction, and patients accepting high dose steroids. Steroids started with low dose and could be increased if symptoms were not resolved, for severe CRS, steroids would be escalated up to dexamethasone 20mg/m2/d or more higher up to methylprednisolone 10mg/kg/d. Once CRS was improved, steroids were rapidly reduced and stopped. A total of 68 patients (28 adults and 40 children younger than 18 years) were included, 22 (32.4%) presented with extramedullary diseases (EMD), bone marrow blasts in patients without EMD varied between 5%-96.5%, 31 (45.6%) patients had an allogeneic transplantation, 54 (79.4%) cases received CD19-specific and 14 (20.6%) received CD22-specific CAR-T therapy. Forty-two (61.8%) cases, including all (10) of grade III CRS, 68.2% (30/44) of grade II CRS and 2 patients with no CRS but with GVHD (1 case) or neurotoxicity (1 case), were administered steroids, among them, 23/42 (54.8%) received high dose steroids (>10mg/m2/d dexamethasone or equivalent), the duration of steroid use was 1-16 days (78.6% <= 7 days); whereas 26 (38.2%) patients were not given any steroids but the supportive care. We found that there was no difference either in complete remission (CR) rate (95.2% vs 92.3%, p=.344) or in MRD negative CR rate (80.0% vs 79.2%, p=.249) between steroid and non-steroid group, verified that corticosteroids even high dose steroids did not influence the treatment response. Furthermore, we investigated the dynamics of CAR-T cells. Firstly, the expansion of CAR-T cells in peripheral blood (PB) was evaluated, the average CAR-T cell counts in steroid group were significantly higher than those in non-steroid group on D11 (p=.0302), D15 (p=.0053), D20 (p=.0045) and D30 (p=.0028), except for D7 when CAR-T cells began to expand (p=.9815), this demonstrated that steroids did not suppress the proliferation of CAR-T cells in PB. Secondly, the percentages of patients with detectable CAR-T cells in bone marrow (BM) and cerebrospinal fluid (CSF) were compared between steroid and non-steroid group, there were no differences both in BM (85.2% vs 78.6%, p=.923) and in CSF (68.6% vs 57.9%, p=.433), which implied steroids did not influence the trafficking of T-cells to BM and CSF. Thirdly, we monitored B-cell aplasia (BCA) in part of patients followed-up more than 2 months without further treatments, the percentages of patients with BCA in steroid group had no significant differences compared to non-steroid group at 2-month (p=.086) and 3-month (p=.146). Later, although limited cases left, in the steroid group, 100% of patients (4-month, 7/7; 5-month, 7/7; 6-month, 5/5) still maintained BCA and CR, indicating that corticosteroids did not impact the duration of functional CAR-T cells. In conclusion, corticosteroids do not compromise the treatment efficacy and kinetics of CAR-T cells, could be as a feasible and effective approach to manage CAR-T associated CRS. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 99-99 ◽  
Author(s):  
Jennifer N Brudno ◽  
Robert Somerville ◽  
Victoria Shi ◽  
Jeremy J. Rose ◽  
David C. Halverson ◽  
...  

Introduction Progressive malignancy is the leading cause of death after allogeneic hematopoietic stem cell transplantation (alloHSCT). After alloHSCT, B-cell malignancies are often treated with infusions of unmanipulated donor lymphocytes (DLIs) from the transplant donor. DLIs are frequently not effective at eradicating malignancy, and DLIs often cause graft-versus-host disease (GVHD), which is a potentially lethal allogeneic immune response against normal recipient tissues. Methods We conducted a clinical trial of allogeneic T cells that were genetically engineered to express a chimeric antigen receptor (CAR) targeting the B-cell antigen CD19. The CAR was encoded by a gamma-retroviral vector and included a CD28 costimulatory domain. Patients with B-cell malignancies after alloHSCT received a single infusion of CAR T cells. No chemotherapy or other therapies were administered. The T cells were obtained from each recipient's alloHSCT donor. Findings Eight of 20 treated patients obtained remissions, including 6 complete remissions (CR) and 2 partial remissions. The response rate was highest for acute lymphoblastic leukemia with 4/5 patients obtaining minimal-residual-disease-negative CRs, but responses also occurred in chronic lymphocytic leukemia (CLL) and lymphoma. The longest ongoing CR is 30+ months in a patient with CLL. No patient developed new-onset acute GVHD after CAR T-cells were infused. Toxicities included fever, tachycardia, and hypotension. Median peak blood CAR T-cell levels were higher in patients who obtained remissions (39 CAR+ cells/mL) than in patients who did not obtain remissions (2 CAR+ cells/mL, P=0.001). Presence of endogenous normal or malignant blood B lymphocytes before CAR T-cell infusion was associated with higher post-infusion median blood CAR T-cell levels (P=0.04). Compared to patients who did not obtain a remission of their malignancies, patients obtaining remissions had a higher CD8:CD4 ratio of blood CAR+ T cells at the time of peak CAR T-cell levels (P=0.007). The mean percentage of CAR+CD8+ T cells expressing the programmed cell death-1 (PD-1) protein increased from 12% at the time of infusion to 82% at the time of peak blood CAR T-cell levels (P<0.0001). The mean percentage of CAR+CD4+ T cells expressing PD-1 increased from 32% at the time of infusion to 91% at the time of peak blood CAR T-cell levels (P<0.0001). Interpretation Infusion of allogeneic anti-CD19 CAR T cells is a promising approach for treating B-cell malignancies after alloHSCT. Our findings point toward a future in which antigen-specific T-cell therapies will be an important part of the field of allogeneic hematopoietic stem cell transplantation. Table. PatientNumber Malignancy Transplant type Total T cellsinfused/kg Anti-CD19CAR-expressingT cells infused/kg Malignancyresponseat last follow-up(interval from infusion to last follow-up in months) 1 CLL URD 10/10 HLA match 1x106 0.4x106 SD (3) 2 DLBCL Sibling 2x106 0.7x106 SD (1) 3 CLL Sibling 4x106 2.4x106 PD 4 DLBCL Sibling 4x106 2.2x106 SD (31+) 5 CLL URD 10/10 HLA match 1.5x106 1.0x106 CR (30+) 6 MCL Sibling 7x106 4.6x106 SD (3) 7 CLL URD 10/10 HLA match 1x106 0.7x106 PD 8 MCL Sibling 7x106 3.9x106 SD (24+) 9 MCL URD 10/10 HLA match 4x106 2.2x106 PR (3) 10 MCL Sibling 10x106 7.8x106 SD (2) 11 CLL URD 9/10 HLA match 5x106 3.1x106 PR (12+) 12 ALL Ph+ Sibling 7x106 5.2x106 MRD-negative CR (15+) 13 MCL Sibling 10x106 7.1x106 SD (9) 14 ALL Ph-neg Sibling 10x106 7.0x106 MRD-negative CR (5) 15 ALL Ph-neg Sibling 10x106 6.9x106 MRD-negative CR (3) 16 ALL Ph-neg Sibling 7x106 5.6x106 PD 17 DLBCL Sibling 10x106 8.2x106 CR (6+) 18 DLBCL Sibling 10x106 3.1x106 SD (2) 19 FL transformed to DLBCL URD 10/10 HLA match 5x106 4.3x106 PD 20 ALL Ph-neg URD 9/10 HLA match 5x106 4.2x106 MRD-negative CR (3+)^ CLL, chronic lymphocytic leukemia; ALL Ph+, Philadelphia chromosome positive acute lymphoblastic leukemia; ALL Ph-neg, Philadelphia chromosome negative acute lymphoblastic leukemia; MCL, mantle cell lymphoma; DLBCL, diffuse large B-cell lymphoma; FL, follicular lymphoma; Sibling, human leukocyte antigen-matched sibling donor; URD, unrelated donor; HLA, human leukocyte antigen; PD, progressive disease; SD, stable disease; PR, partial remission; CR, complete remission; MRD-negative, minimal residual disease negative. ^Patient 20 underwent a second alloHSCT 3.5 months after anti-CD19 CAR T-cell infusion while in MRD-negative CR. Disclosures Goy: Celgene: Consultancy, Research Funding, Speakers Bureau; Allos, Biogen Idec, Celgene, Genentech, and Millennium. Gilead: Speakers Bureau. Rosenberg:Kite Pharma: Other: CRADA between Surgery Branch-NCI and Kite Pharma.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 7028-7028 ◽  
Author(s):  
Lei Xiao ◽  
He Huang ◽  
Xiaojun Huang ◽  
Xiaoyan Ke ◽  
Yu Hu ◽  
...  

7028 Background: r/r B-ALL was reported as the most-threatening disease because of the low disease free survival even treatment with allogeneic hematopoietic stem cell transplantation. For overcoming conventional therapies limitation, autologous CD19CAR-T was performed in our clinical trials to induce remission in patients with r/r disease. 30 patients (from 7 clinical centers, in China) as volunteers with r/r B-ALL were treated by autologous CD19 CAR-T. Methods: 5 juveniles and 25 adults with r/r ALL received autologous CD19 targeted CAR-T, the doses between 1.03 × 106 CAR-T cells/kg and 10.09 × 106CAR-T cells/kg. These 30 cases(from 7 clinical centers, in China) were treated with CAR-T cells from May. 8 2015 to January. 4 2017 (Table1). Patients were monitored for a response. Highly standardized CAR T cell preparation protocol and manageable CRS in most were kept for no significant difference in 7 clinical centers. Results: After treated with CAR-T, a total of 30 cases (5 juveniles and 25 adults coming from 7 clinical centers, in China) with r/r B-ALL were all detected the CAR-T cells proliferated in the blood and bone marrow. The results showed that complete remission (CR) is 26/30(86.67% ) between day7-14 after CD19 CART cell infusion, and 25/30(83.33%) cases arrived at MRD negative. There is about 1/3 of the total cases receiving a repeat infusions following initial ones since these patients have no safety concerns. Additionaly, the severe Cytokine release syndrome (CRS) was 8/30(26.67%) of cases and 24/30(80%) of cases was seen CRS. The anti-IL6R agent tocilizumab and Methylprednisolone were effective confrontation Severe CRS. Conclusions: This is the first multicentre report to our knowledge of successful treatment of r/r ALL with anti-CD19 CAR T cells in China. Even r/r B-ALL with high-burden leukemia patients also was effective and associated with a high remission rate after infused autologous CD19 CAR-T).(NCT 02813837).


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 ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 151-151 ◽  
Author(s):  
James N Kochenderfer ◽  
Mark E. Dudley ◽  
Robert O. Carpenter ◽  
Sadik H Kassim ◽  
Jeremy J. Rose ◽  
...  

Abstract Progressive malignancy is a leading cause of death in patients undergoing allogeneic hematopoietic stem cell transplantation (alloHSCT). To improve treatment of B-cell malignancies that persist despite alloHSCT, we conducted a clinical trial of allogeneic T cells genetically modified to express a chimeric antigen receptor (CAR) targeting the B-cell antigen CD19. Ten patients were treated on this trial. Four patients were recipients of human-leukocyte-antigen (HLA)-matched unrelated donor (URD) transplants and 6 patients were recipients of HLA-matched sibling transplants. T cells for genetic modification were obtained from each patient’s healthy alloHSCT donor. Patients received a single infusion of anti-CD19-CAR T cells. Cell doses ranged from 1x106 to 10x106 T cells/kg. A mean of 58% of the infused cells expressed the CAR. Patients did not receive chemotherapy or other anti-malignancy therapy with the CAR-T-cell infusions, so the responses observed in these patients are not confounded by the effects of chemotherapy. In contrast to other reports of successful treatment of B-cell malignancies with anti-CD19-CAR T cells, the patients on this study were not lymphocyte-depleted at the time of the CAR-T-cell infusions. Two patients with chronic lymphocytic leukemia (CLL) refractory to standard unmanipulated allogeneic donor lymphocyte infusions (DLIs) had regressions of large malignant lymph node masses after infusion of allogeneic anti-CD19-CAR T cells. One of these CLL patients obtained a complete remission that is ongoing 9 months after treatment with allogeneic anti-CD19-CAR T cells. This patient also had complete eradication of blood B cells within 9 days after her CAR-T-cell infusion. Another patient had tumor lysis syndrome requiring rasburicase treatment as his CLL dramatically regressed in lymph nodes, bone marrow, and blood within 2 weeks of his anti-CD19-CAR-T-cell infusion. A patient with mantle cell lymphoma obtained a partial remission that is ongoing 3 months after infusion of anti-CD19-CAR T cells. A fourth patient with diffuse large B-cell lymphoma has ongoing stable disease 11 months after infusion of anti-CD19-CAR T cells. The other 6 treated patients all had short periods of stable malignancy or progressive disease after their CAR-T-cell infusions. Specific eradication of blood B cells occurred after infusion of CAR T cells in 3 of 4 patients with measurable blood B cells pretreatment. None of the patients treated on this study developed GVHD after their anti-CD19-CAR-T-cell infusions, despite the fact that 6 of 10 treated patients had experienced GVHD at earlier time-points after their most recent alloHSCT. One patient, who had a history of cardiac dysfunction with prior acute illnesses, had temporary cardiac dysfunction after infusion of anti-CD19-CAR T cells. The most prominent toxicities experienced by patients were fever and hypotension; these peaked 5 to 12 days after CAR-T-cell infusions and resolved within 14 days after the T-cell infusions. Two patients had Grade 3 fever, and 2 patients had Grade 3 hypotension. No patients experienced Grade 4 toxicities that were attributable to the CAR-T-cell infusions. Elevated levels of serum interferon gamma were detected in 3 patients at the time that they were experiencing toxicities. We detected cells containing the anti-CD19-CAR gene in the blood of 8 of 10 patients. The peak blood levels of CAR T cells varied from undetec to 2.8% of peripheral blood mononuclear cells. The persistence of the CAR T cells in the blood of patients was limited to one month or less. When we assessed T cells from the blood of patients ex vivo, we found elevated levels of the T-cell inhibitory molecule programmed cell death protein-1 (PD-1) on CAR+ T cells compared to CAR-negative T cells. These results show for the first time that small numbers of donor-derived allogeneic anti-CD19-CAR T cells can cause regression of highly treatment-resistant B-cell malignancies after alloHSCT without causing GVHD. Malignancies that were resistant to standard DLIs regressed after anti-CD19-CAR-T-cell infusions. Future goals for improving this approach include enhancing the persistence of anti-CD19-CAR T cells and reducing toxicities. Infusion of allogeneic T cells genetically modified to recognize malignancy-associated antigens is a promising approach for treating residual malignancy after alloHSCT. 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 ◽  
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 ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4817-4817
Author(s):  
Haiping Dai ◽  
Yang Lin ◽  
Huimin Meng ◽  
Qingya Cui ◽  
Wenjuan Zhu ◽  
...  

Abstract Patients with relapsed/refractory early T-cell precursor lymphoblastic leukemia/lymphoma (ETP-ALL/LBL) respond poorly to traditional therapy and have dismal prognosis. CD7 expresses in almost all blasts of T-cell lymphoma/leukemia and represents one of the most promising therapeutic targets for T-ALL/LBL by CD7 targeted chimeric antigen receptor modified T cell therapy (CD7-CART). Because of shared CD7 expression in the majority of normal T-cell surfaces, we utilized an non-gene editing strategy by co-transducing CAR-T cells with a CD7 protein expression blocker (PEBL), and successfully overcame the fratricide as well as maintain the proliferation and cytotoxicity of CD7-CART-cells. Here, we presented the efficacy and safety results of CD7-CART therapy in a pediatric patient with TP53 mutated ETP-ALL/LBL. The patient was diagnosed with ETP-ALL/LBL at 2016, achieved and maintained complete remission (CR) for 2 years with traditional chemotherapy. The disease relapsed at a month after discontinuation of chemotherapy. He underwent haploidentical HSCT at the second CR, but suffered relapse again 2 years post haplo-HSCT. TP53 mutation(VAF:96.5%) and extensive extramedullary infiltration was detected at relapse. The patient was resistant to venetoclax combined with decitabine, homoharringtonine, aclarubicin, cytarabine and granulocyte colony stimulating factor (G-CSF), high-dose cytarabine combined with cladribine, G-CSF, chidamide and CD38 CART therapy. Nanobody derived CD7-CART cells were manufactured from lymphocytes of the donor. The CART cells were negative for CD7, CD223 and CD279. 70.5% of blasts in the bone marrow aspirates were observed prior to CAR T-cells infusion. A total of 5×10 6/kg CD7-CART-cells were infused. CR was confirmed at day 30 bone marrow evaluation and maintained at the last followup at day 91. Partial remission was achieved as evaluated by PET-CT scan at day 93. Persistence of CD7-CART-cells can be detected with flowcytometry until day 96 post CAR T-cells infusion. Grade 3 cytokine release syndrome with high fever and hypotension were observed, which was relived by tocilizumab and dexamethosone. No organ dysfuction and immune effector cell-associated neurotoxicity syndrome were observed. In general, we showed for the first time that the nanobody derived CD7-CART with PEBL technology was a potent and safe salvage therapy in a relapsed/refractory ETP-ALL/LBL patient with high tumor burden. Disclosures No relevant conflicts of interest to declare.


2021 ◽  
Author(s):  
Alijah A. Griffith ◽  
Kenneth P. Callahan ◽  
Nathan Gordo King ◽  
Qian Xiao ◽  
Xiaolei Su ◽  
...  

AbstractChimeric antigen receptor (CAR) is a single-pass transmembrane receptor designed to specifically target and eliminate cancers. While CARs prove highly efficacious against B cell malignancies, the intracellular signaling events which promote CAR T cell activity remain elusive. To gain further insight into both CAR T cell signaling and the potential signaling response of cells targeted by CAR, we analyzed phosphopeptides captured by two separate phopshoenrichment strategies from third generation CD19-CAR T cells cocultured with SILAC labeled Raji B cells by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Here, we report that CD19-CAR T cells upregulated several key phosphorylation events also observed in canonical T cell receptor (TCR) signaling while Raji B cells exhibited a significant decrease in B cell receptor-signaling related phosphorylation events in response to coculture. Our data suggest that CD19-CAR stimulation activates a mixture of unique CD19-CAR-specific signaling pathways and canonical TCR signaling while global phosphorylation in Raji B cells is reduced after association with the CD19-CAR T cells.


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