scholarly journals Allogeneic Hematopoietic Cell Transplantation Is Critical to Maintain Remissions after CD19-CAR T-Cell Therapy for Pediatric ALL: A Single Center Experience

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 39-40
Author(s):  
Aimee C Talleur ◽  
Renee M. Madden ◽  
Amr Qudeimat ◽  
Ewelina Mamcarz ◽  
Akshay Sharma ◽  
...  

CD19-CAR T-cell therapy has shown remarkable efficacy in pediatric patients with relapsed and/or refractory B-cell acute lymphoblastic leukemia (r/r ALL). Despite high short-term remission rates, many responses are not durable and the best management of patients who achieve a complete response (CR) post-CAR T-cell therapy remains controversial. In particular, it is unclear if these patients should be observed or proceed to consolidative allogeneic hematopoietic cell transplantation (HCT). To address this question, we reviewed the clinical course of all patients (n=22) who received either an investigational CAR T-cell product (Phase I study: SJCAR19 [NCT03573700]; n=12) or tisagenlecleucel (n=10) at our institution. The investigational CD19-CAR T cells were generated by a standard cGMP-compliant procedure using a lentiviral vector encoding a 2nd generation CD19-CAR with a FMC63-based CD19 binding domain, CD8a stalk and transmembrane domain, and 41BB.ζ signaling domain. Patients received therapy between 8/2018 and 3/2020. All products met manufacturing release specifications. Within the entire cohort, median age at time of infusion was 12.3 years old (range: 1.8-23.5) and median pre-infusion marrow burden using flow-cytometry minimal residual disease (MRD) testing was 6.8% (range: 0.003-100%; 1 patient detectable by next-generation sequencing [NGS] only). All patients received lymphodepleting chemotherapy (fludarabine, 25mg/m2 daily x3, and cyclophosphamide, 900mg/m2 daily x1), followed by a single infusion of CAR T-cells. Phase I product dosing included 1x106 CAR+ T-cells/kg (n=6) or 3x106 CAR+ T-cells/kg (n=6). Therapy was well tolerated, with a low incidence of cytokine release syndrome (any grade: n=10; Grade 3-4: n=4) and neurotoxicity (any grade: n=8; Grade 3-4: n=3). At 4-weeks post-infusion, 15/22 (68.2%) patients achieved a CR in the marrow, of which 13 were MRDneg (MRDneg defined as no detectable leukemia by flow-cytometry, RT-PCR and/or NGS, when available). Among the 2 MRDpos patients, 1 (detectable by NGS only) relapsed 50 days after CAR T-cell infusion and 1 died secondary to invasive fungal infection 35 days after infusion. Within the MRDneg cohort, 6/13 patients proceeded to allogeneic HCT while in MRDneg/CR (time to HCT, range: 1.8-2.9 months post-CAR T-cell infusion). All 6 HCT recipients remain in remission with a median length of follow-up post-HCT of 238.5 days (range 19-441). In contrast, only 1 (14.3%) patient out of 7 MRDneg/CR patients who did not receive allogeneic HCT, remains in remission with a follow up of greater 1 year post-CAR T-cell infusion (HCT vs. no HCT: p<0.01). The remaining 6 patients developed recurrent detectable leukemia within 2 to 9 months post-CAR T-cell infusion (1 patient detectable by NGS only). Notably, recurring leukemia remained CD19+ in 4 of 5 evaluable patients. All 4 patients with CD19+ relapse received a 2nd CAR T-cell infusion (one in combination with pembrolizumab) and 2 achieved MRDneg/CR. There were no significant differences in outcome between SJCAR19 study participants and patients who received tisagenlecleucel. With a median follow up of one year, the 12 month event free survival (EFS) of all 22 patients is 25% (median EFS: 3.5 months) and the 12 month overall survival (OS) 70% (median OS not yet reached). In conclusion, infusion of investigational and FDA-approved autologous CD19-CAR T cells induced high CR rates in pediatric patients with r/r ALL. However, our current experience shows that sustained remission without consolidative allogeneic HCT is not seen in most patients. Our single center experience highlights not only the need to explore maintenance therapies other than HCT for MRDneg/CR patients, but also the need to improve the in vivo persistence of currently available CD19-CAR T-cell products. Disclosures Sharma: Spotlight Therapeutics: Consultancy; Magenta Therapeutics: Other: Research Collaboration; CRISPR Therapeutics, Vertex Pharmaceuticals, Novartis: Other: Clinical Trial PI. Velasquez:St. Jude: Patents & Royalties; Rally! Foundation: Membership on an entity's Board of Directors or advisory committees. Gottschalk:Patents and patent applications in the fields of T-cell & Gene therapy for cancer: Patents & Royalties; TESSA Therapeutics: Other: research collaboration; Inmatics and Tidal: Membership on an entity's Board of Directors or advisory committees; Merck and ViraCyte: Consultancy.

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 4-6
Author(s):  
Xian Zhang ◽  
Junfang Yang ◽  
Wenqian Li ◽  
Gailing Zhang ◽  
Yunchao Su ◽  
...  

Backgrounds As CAR T-cell therapy is a highly personalized therapy, process of generating autologous CAR-T cells for each patient is complex and can still be problematic, particularly for heavily pre-treated patients and patients with significant leukemia burden. Here, we analyzed the feasibility and efficacy in 37 patients with refractory/relapsed (R/R) B-ALL who received CAR T-cells derived from related donors. Patients and Methods From April 2017 to May 2020, 37 R/R B-ALL patients with a median age of 19 years (3-61 years), were treated with second-generation CD19 CAR-T cells derived from donors. The data was aggregated from three clinical trials (www.clinicaltrials.gov NCT03173417; NCT02546739; and www.chictr.org.cn ChiCTR-ONC-17012829). Of the 37 patients, 28 were relapsed following allogenic hematopoietic stem cell transplant (allo-HSCT) and whose lymphocytes were collected from their transplant donors (3 HLA matched sibling and 25 haploidentical). For the remaining 9 patients without prior transplant, the lymphocytes were collected from HLA identical sibling donors (n=5) or haploidentical donors (n=4) because CAR-T cells manufacture from patient samples either failed (n=5) or blasts in peripheral blood were too high (>40%) to collect quality T-cells. The median CAR-T cell dose infused was 3×105/kg (1-30×105/kg). Results For the 28 patients who relapsed after prior allo-HSCT, 27 (96.4%) achieved CR within 30 days post CAR T-cell infusion, of which 25 (89.3%) were minimal residual disease (MRD) negative. Within one month following CAR T-cell therapy, graft-versus-host disease (GVHD) occurred in 3 patients including 1 with rash and 2 with diarrhea. A total of 19 of the 28 (67.9%) patients had cytokine release syndrome (CRS), including two patients (7.1%) with Grade 3-4 CRS. Four patients had CAR T-cell related neurotoxicity including 3 with Grade 3-4 events. With a medium follow up of 103 days (1-669days), the median overall survival (OS) was 169 days (1-668 days), and the median leukemia-free survival (LFS) was 158 days (1-438 days). After CAR T-cell therapy, 15 patients bridged into a second allo-HSCT and one of 15 patients (6.7%) relapsed following transplant, and two died from infection. There were 11 patients that did not receive a second transplantation, of which three patients (27.3%) relapsed, and four parents died (one due to relapse, one from arrhythmia and two from GVHD/infection). Two patients were lost to follow-up. The remaining nine patients had no prior transplantation. At the time of T-cell collection, the median bone marrow blasts were 90% (range: 18.5%-98.5%), and the median peripheral blood blasts were 10% (range: 0-70%). CR rate within 30 days post CAR-T was 44.4% (4/9 cases). Six patients developed CRS, including four with Grade 3 CRS. Only one patient had Grade 3 neurotoxicity. No GVHD occurred following CAR T-cell therapy. Among the nine patients, five were treated with CAR T-cells derived from HLA-identical sibling donors and three of those five patients achieved CR. One patient who achieved a CR died from disseminated intravascular coagulation (DIC) on day 16. Two patients who achieved a CR bridged into allo-HSCT, including one patient who relapsed and died. One of two patients who did not response to CAR T-cell therapy died from leukemia. Four of the nine patients were treated with CAR T-cells derived from haploidentical related donors. One of the four cases achieved a CR but died from infection on day 90. The other three patients who had no response to CAR T-cell therapy died from disease progression within 3 months (7-90 days). Altogether, seven of the nine patients died with a median time of 19 days (7-505 days). Conclusions We find that manufacturing CD19+ CAR-T cells derived from donors is feasible. For patients who relapse following allo-HSCT, the transplant donor derived CAR-T cells are safe and effective with a CR rate as high as 96.4%. If a patient did not have GVHD prior to CAR T-cell therapy, the incidence of GVHD following CAR T-cell was low. Among patients without a history of transplantation, an inability to collect autologous lymphocytes signaled that the patient's condition had already reached a very advanced stage. However, CAR T-cells derived from HLA identical siblings can still be considered in our experience, no GVHD occurred in these patients. But the efficacy of CAR T-cells from haploidentical donors was very poor. Disclosures No relevant conflicts of interest to declare.


2021 ◽  
pp. JCO.20.02262
Author(s):  
Nirali N. Shah ◽  
Daniel W. Lee ◽  
Bonnie Yates ◽  
Constance M. Yuan ◽  
Haneen Shalabi ◽  
...  

PURPOSE CD19 chimeric antigen receptor (CD19-CAR) T cells induce high response rates in children and young adults (CAYAs) with B-cell acute lymphoblastic leukemia (B-ALL), but relapse rates are high. The role for allogeneic hematopoietic stem-cell transplant (alloHSCT) following CD19-CAR T-cell therapy to improve long-term outcomes in CAYAs has not been examined. METHODS We conducted a phase I trial of autologous CD19.28ζ-CAR T cells in CAYAs with relapsed or refractory B-ALL. Response and long-term clinical outcomes were assessed in relation to disease and treatment variables. RESULTS Fifty CAYAs with B-ALL were treated (median age, 13.5 years; range, 4.3-30.4). Thirty-one (62.0%) patients achieved a complete remission (CR), 28 (90.3%) of whom were minimal residual disease−negative by flow cytometry. Utilization of fludarabine/cyclophosphamide–based lymphodepletion was associated with improved CR rates (29/42, 69%) compared with non–fludarabine/cyclophosphamide–based lymphodepletion (2/8, 25%; P = .041). With median follow-up of 4.8 years, median overall survival was 10.5 months (95% CI, 6.3 to 29.2 months). Twenty-one of 28 (75.0%) patients achieving a minimal residual disease−negative CR proceeded to alloHSCT. For those proceeding to alloHSCT, median overall survival was 70.2 months (95% CI, 10.4 months to not estimable). The cumulative incidence of relapse after alloHSCT was 9.5% (95% CI, 1.5 to 26.8) at 24 months; 5-year EFS following alloHSCT was 61.9% (95% CI, 38.1 to 78.8). CONCLUSION We provide the longest follow-up in CAYAs with B-ALL after CD19-CAR T-cell therapy reported to date and demonstrate that sequential therapy with CD19.28ζ-CAR T cells followed by alloHSCT can mediate durable disease control in a sizable fraction of CAYAs with relapsed or refractory B-ALL (ClinicalTrials.gov identifier: NCT01593696 ).


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 382-382 ◽  
Author(s):  
Jae H Park ◽  
Isabelle Riviere ◽  
Xiuyan Wang ◽  
Yvette J Bernal ◽  
Sarah Yoo ◽  
...  

Abstract Background: Relapsed adult acute lymphoblastic leukemia (ALL) is associated with high reinduction mortality, chemotherapy resistance, and dismal prognosis with a median overall survival (OS) < 6 months and 5-year OS ≤10%. We have previously reported a high anti-tumor activity of autologous T cells genetically modified to express 19-28z chimeric antigen receptor (19-28z CAR) targeting CD19 in adult patients with CLL and ALL (Brentjens R et al. Blood 2011; Davila M et al. Sci Transl Med2014). Herein, for the first time, we further report the long-term outcome of our phase I clinical trial in adults with relapsed/refractory (R/R) ALL (NCT01044069) with analysis on potential predictive markers of response and neurological toxicities. Patients and Methods: Adult patients with R/R B-ALL were enrolled. Eligible patients underwent leukapheresis, and T cells were transduced with a retrovirus encoding a CAR construct composed of anti-CD19 scFV linked to CD28 and CD3ζ signaling domains (19-28z). All patients received lymphodepleting chemotherapy followed 2 days later by 1x106 – 3x10619-28z CAR T cells/kg. The primary objective of the study was to evaluate the safety and anti-tumor activity of 19-28z CAR T cells in ALL. Post-treatment minimal residual disease (MRD) was assessed at day 14-28 by multiparameter flow cytometry and deep sequencing in the bone marrow (BM) samples (Adaptive Biotech Corp.) Results: 24 patients have been treated. The median age was 56 years (range, 23-74). 6 patients (25%) had Ph+ B-ALL (T315I mutation in 2 patients), 6 patients (25%) had prior allogeneic hematopoietic stem cell transplant (allo-HSCT), and 11 patients (46%) had 3 or more prior lines of ALL therapy before receiving the 19-28z CAR T cell therapy. Of the 24 patients, 22 patients were evaluable for response. At the time of 19-28z CAR T cell infusion, 12 of 22 patients had morphologic disease (6 to 97% blasts in the BM) and the remaining 10 patients had MRD. Twenty out of 22 patients (91%) were in complete remission (CR) after 19-28z CAR T-cell infusion, and 18 of these 20 patients (90%) achieved an MRD-negative CR. Ten of the 13 transplant eligible patients (77%) successfully underwent allo-HSCT following the 19-28z CAR T cell therapy. As of July 1, 2014, the median follow-up was 7.4 months (range 1-34), with 13 patients having at least 6 months of follow-up. Responses appear durable with 6 patients remaining disease-free beyond 1 year (range 12.6 – 34 months). Median overall survial (OS) is 9 months. 5 patients relapsed during the follow-up, including 1 patient with CD19 negative relapse. Three of the relapsed patients were treated again with the 19-28z CAR T cells, and two patients achieved a second CR. Comparing responders to non-responders, no association was observed between response and age (<60 vs. ≥60), prior allo-HSCT, number of prior therapies, or pre-treatment blast percentage. While none of the 10 patients with MRD at the time of T cell infusion developed cytokine release syndrome (CRS), 9 of 13 patients with morphologic disease at the time of the T cell infusion developed CRS with or without neurological symptoms that required intervention with an IL-6R antagonist or corticosteroid. A detailed analysis of serum cytokines demonstrated a consistent peak of IL-6 (22.2 to 553-fold increase) immediately prior to the development of neurological toxicities. Based on these data, we have developed a multi-disciplinary CRS management algorithm for patients at high risk in order to reduce the severity of CRS and improve safety of the 19-28z CAR T cell therapy. Conclusions: While longer follow-up is needed to confirm the durability of the observed responses, the potent induction of MRD-negative responses and successful long-term outcomes, including subsequent allo-HSCT without apparent additional post-transplant toxicities, strongly support the use of 19-28z CAR T cells in adult patients with B-ALL. A temporal relationship between serum IL-6 levels and neurological toxicities indicates that early intervention with IL-6 directed therapy may be more effective in ameliorating neurological toxicities in patients with morphologic disease at the time of T-cell infusion. These findings will need to be evaluated systematically and confirmed in a larger phase 2 trial. Disclosures Park: Juno Therapeutics: Research Funding. Riviere:Juno Therapeutics: Consultancy, scientific co-founders Other. Sadelain:Juno Therapeutics: Consultancy, Scientific co-founder and Stock holder Other. Brentjens:Juno Therapeutics: Consultancy, Scientific co-founder and Stock holder Other.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4828-4828
Author(s):  
Yusra F Shao ◽  
Dipenkumar Modi ◽  
Andrew Kin ◽  
Asif Alavi ◽  
Lois Ayash ◽  
...  

Abstract Background Chimeric Antigen Receptor (CAR) T cell therapy has emerged as a promising therapeutic option for relapsed/refractory non-Hodgkin lymphoma. However, access to CAR T cell therapy remains limited as CAR T cells are routinely administered in the hospital setting. Hence, there's a growing interest in standardizing outpatient administration of CAR T cells to increase patient access and minimize costs. Here, we describe our institution's experience with outpatient administration of CAR T cells. Methods In this retrospective study, we reviewed who received CAR T cell therapy in the outpatient setting at Karmanos Cancer Center between June 2019 and June 2021.Charts were reviewed for age, disease pathology, prior lines of therapy, need for hospitalization within 30 days, development of CRS and/or neurotoxicity, need for ICU admission, need for steroids and/or tocilizumab, length of admission, and disease state at last follow up. All patients received fludarabine and cyclophosphamide as lymphodepletion (LD) therapy day -5 to -3. CAR T cells were infused on day 0. Patients subsequently followed up in clinic daily for 2 weeks and were started on allopurinol, ciprofloxacin, fluconazole, acyclovir and levetiracetam. First response was assessed by FDG PET scan 4 weeks after CAR T cell . Results A total of 12 patients received CAR T cells during the study period. All patients had a diagnosis of DLBCL and received Tisagenlecleucel. Median age at CAR T cell therapy was 69.5 years (40-78 years). Median number of prior lines of therapy was (2-3) while 2 patients had received prior stem cell transplantation. Table 1 describes patient characteristics and lines of therapy. Two patients received bridging therapy prior to LD. Overall response rate was 58.3% (complete response-3, partial response-4). Median duration of follow up was 6.7 (0.6-13.8 months). Four patients required subsequent therapy after CAR T cell for disease progression while 9 patients were alive at the time of data cut off. Figure 1 summarizes disease response and follow . Table 2 summarizes complications during follow up. Nine (75%) patients developed anemia (grade 3-4 n=4, 33.3%), 8 (66.7%) developed thrombocytopenia (grade 3-4 n= 3, 37.5%), and 8 (66.7%) developed neutropenia (grade 3-4 n=8, 66.7%). Median time to platelet recovery to &gt;,000 and neutrophil recovery to &gt;500 was 66 days (44-81 days) and 11.5 days (6-65 days), respectively. Three (25%) patients required platelet and red blood cell transfusion support. Six (50%) patients developed cytokine release syndrome (CRS) with median grade 2 (range 1-3, grade 3-4 n=1). Five (5/6) patients required hospitalization, five (5/6) required tocilizumab, and one (1/6) required steroids. One (8.3%) patient developed neurotoxicity of grade 1 severity improved without systemic therapy. Six patients required hospitalization within 30 days of CAR T cell infusion. Median day of admission from CAR T cell infusion was 4 days (range 2-12 days (range 2-12 days, admission within 3 days n=2, admission under observation n=1). Patient characteristics at admission are summarized in table 3. Of these, 5 patients were diagnosed with CRS,1 patient with colitis and none with blood stream infection. Two patients required ICU admission. Median length of hospital admission was 5.5 days (2-9 days). All patients were alive at discharge while 1 patient required subsequent admission within 30 . Conclusion Outpatient administration of Tisagenlecleucel is feasible with low risk of hospital admission within 3 days of infusion. Adoption of outpatient CAR T cell therapy may increase patient access for treatment of DLBCL and diseases such as multiple myeloma while reducing administration costs for this novel therapy. Figure 1 Figure 1. Disclosures Modi: Genentech: Research Funding; Seagen: Membership on an entity's Board of Directors or advisory committees; MorphoSys: Membership on an entity's Board of Directors or advisory committees. Deol: Kite, a Gilead Company: Consultancy.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1830-1830
Author(s):  
Xiaoyan Qu ◽  
Gang An ◽  
Weiwei Sui ◽  
Tingyu Wang ◽  
Xian Zhang ◽  
...  

Abstract Background: C-CAR088, an anti-BCMA CAR T-cell therapy, is a novel 2nd generation 4-1BB chimeric antigen receptor T (CAR-T) cell therapy targeting BCMA. Previously presented results from an ongoing study of C-CAR088 in R/R MM (NCT03751293, NCT03815383, NCT04322292, NCT04295018) included a 95.7% overall response rate (ORR) for the dose of 1.0~6.0x10 6 CAR-T cells/kg with a favorable safety profile (Lu, 2020 ASH Oral Presentation #182). Here we present the updated results of the study, with more patients and longer follow up time. Methods: Dose escalation and expansion studies were conducted at four medical centers in China to evaluate the safety and efficacy of C-CAR088 in patients with R/R MM who were previously treated with at least 2 lines of therapy, including proteasome inhibitors (PIs) and IMiDs. C-CAR088 was administered to patients as a single infusion after lymphodepletion with fludarabine (30 mg/m 2) and cyclophosphamide (300 mg/m 2) daily for 3 days. The primary endpoint was the incidence of adverse events (AEs), including dose-limiting toxicities (DLTs), and the secondary endpoints included overall response rate(ORR), duration of response (DOR), and progression-free survival (PFS) by IMWG Uniform Response Criteria. Results: As of July 2nd, 2021, 31 patients had been infused with C-CAR088. The median vein-to-vein time was 18 days. The manufacturing success rate was 100%. 4, 13 and 14 patients were infused with 1.0, 3.0 and 4.5~6.0 x10 6 CAR+ T cells/kg respectively. The median follow-up time for all patients was 8.0 months (0.1-24.2). The median age of patients was 61 years (45-74). The median number of prior lines of therapy was 4 (2-13). There were 25 (80.6%) patients with at least one high risk cytogenetic abnormality and 17 (54.8%) patients with at least two high risk cytogenetic abnormalities. 7 patients (22.6%) received bridging therapy before C-CAR088 therapy. Cytokine release syndrome (CRS) developed in 29/31 (93.5%) patients, grade 1 in 18/31 (58.1%), grade 2 in 8/31 (25.8%) and grade 3 in 3/31 (9.7%) respectively. The median time to the first onset of CRS was 6 days (1-11) and the median duration of CRS was 5 days (2-14). 9/31 (29%) patients used tocilizumab and 6/31 (19.4%) patients used corticosteroids to manage CRS. Only one patient developed a grade 1 neurotoxicity. No DLTs were observed and all adverse events were reversible. One patient died of septic shock on day 2 after receiving C-CAR088. Clinical efficacy was assessed in 28 patients with ≥ 1 month of follow up. Among the 28 patients, 3, 11 and 14 patients were infused with the dose of 1.0 x 10 6 CAR+ T cells/kg 3 x10 6 CAR+ T cells/kg, and 4.5~6x10 6 CAR+ T cells/kg respectively. The ORR was 27/28 (96.4%): 4 (14.3%) achieved CR, 12 (42.9%) achieved sCR and 9 (32.1%) achieved very good partial response (VGPR). At the dose level of 1.0 x10 6 CAR+ T cells/kg, 3(100%) patients achieved VGPR. The median DOR was 3.7 months (1.8-5.8), and the median PFS was 4.6 months (2.7-6.2). The CR rate was 54.5% (6/11) and 71.4% (10/14) in the 3.0 and 4.5~6.0 x10 6 CAR+ T cells/kg cohorts respectively. The median time to CR was 2.0 (0.5-9.5) months. Minimal residual disease (MRD) was testedbyEuroFlow-based flow cytometric analysis in 16 patients who had CR, 15/16 (93.7%) patients were MRD negative with the sensitivity of 10 -5. With a median follow-up of 9.5 months (1.9-24.2) in ≥ 3.0x10 6 CAR+ T cells/kg cohorts, the median DOR and PFS had not been reached. The Kaplan-Meier estimation of PFS at 6 and 12 months was 81.1% (95% CI:65.9% ~99.8%) and 69.5 % (95% CI:51.6 % ~93.6%) respectively. 8 patients in the ≥ 3.0x10 6 CAR+ T cells/kg cohorts discontinued the study. 7 discontinued due to disease progression (PD), and 1 discontinued for other anticancer therapy. 4 progressed within 6 months, 2 progressed within 6-12 months, and 1 progressed within 12-24 months. C-CAR088 proliferated and expanded well in patients' blood. The median C max was 734,868 copies/μg gDNA. The median AUC 0~28day was 7,468,779 day·copies/μg gDNA. The median T max was 14 days. The median T last was 84 days. 71% (95% CI: 42%~92%) of patients with C max equal to or greater than the median C max achieved CR/sCR. Conclusion: C-CAR088 has a manageable safety profile, which includes low neurotoxicity rates (with no gr ≥3 events). Deep and durable responses were observed in ≥ 3.0x10 6 CAR-T cells/kg cohorts. Doses of 3.0 and 6.0×10 6 CAR T cells/kg were selected for further study. Figure 1 Figure 1. Disclosures Zhu: CBMG: Current Employment. Huang: CBMG: Current Employment. Li: CBMG: Current Employment. Lan: CBMG: Current Employment. Chen: CBMG: Current Employment. Humphries: CBMG Ltd: Current Employment. Yao: CBMG: Current Employment, Current holder of stock options in a privately-held company.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Laura Castelletti ◽  
Dannel Yeo ◽  
Nico van Zandwijk ◽  
John E. J. Rasko

AbstractMalignant mesothelioma (MM) is a treatment-resistant tumor originating in the mesothelial lining of the pleura or the abdominal cavity with very limited treatment options. More effective therapeutic approaches are urgently needed to improve the poor prognosis of MM patients. Chimeric Antigen Receptor (CAR) T cell therapy has emerged as a novel potential treatment for this incurable solid tumor. The tumor-associated antigen mesothelin (MSLN) is an attractive target for cell therapy in MM, as this antigen is expressed at high levels in the diseased pleura or peritoneum in the majority of MM patients and not (or very modestly) present in healthy tissues. Clinical trials using anti-MSLN CAR T cells in MM have shown that this potential therapeutic is relatively safe. However, efficacy remains modest, likely due to the MM tumor microenvironment (TME), which creates strong immunosuppressive conditions and thus reduces anti-MSLN CAR T cell tumor infiltration, efficacy and persistence. Various approaches to overcome these challenges are reviewed here. They include local (intratumoral) delivery of anti-MSLN CAR T cells, improved CAR design and co-stimulation, and measures to avoid T cell exhaustion. Combination therapies with checkpoint inhibitors as well as oncolytic viruses are also discussed. Preclinical studies have confirmed that increased efficacy of anti-MSLN CAR T cells is within reach and offer hope that this form of cellular immunotherapy may soon improve the prognosis of MM patients.


Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1229
Author(s):  
Ali Hosseini Rad S. M. ◽  
Joshua Colin Halpin ◽  
Mojtaba Mollaei ◽  
Samuel W. J. Smith Bell ◽  
Nattiya Hirankarn ◽  
...  

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized adoptive cell therapy with impressive therapeutic outcomes of >80% complete remission (CR) rates in some haematological malignancies. Despite this, CAR T cell therapy for the treatment of solid tumours has invariably been unsuccessful in the clinic. Immunosuppressive factors and metabolic stresses in the tumour microenvironment (TME) result in the dysfunction and exhaustion of CAR T cells. A growing body of evidence demonstrates the importance of the mitochondrial and metabolic state of CAR T cells prior to infusion into patients. The different T cell subtypes utilise distinct metabolic pathways to fulfil their energy demands associated with their function. The reprogramming of CAR T cell metabolism is a viable approach to manufacture CAR T cells with superior antitumour functions and increased longevity, whilst also facilitating their adaptation to the nutrient restricted TME. This review discusses the mitochondrial and metabolic state of T cells, and describes the potential of the latest metabolic interventions to maximise CAR T cell efficacy for solid tumours.


2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi102-vi103
Author(s):  
Tomás A Martins ◽  
Marie-Françoise Ritz ◽  
Tala Shekarian ◽  
Philip Schmassmann ◽  
Deniz Kaymak ◽  
...  

Abstract The GBM immune tumor microenvironment mainly consists of protumoral glioma-associated microglia and macrophages (GAMs). We have previously shown that blockade of CD47, a ‘don't eat me’-signal overexpressed by GBM cells, rescued GAMs' phagocytic function in mice. However, monotherapy with CD47 blockade has been ineffective in treating human solid tumors to date. Thus, we propose a combinatorial approach of local CAR T cell therapy with paracrine GAM modulation for a synergistic elimination of GBM. We generated humanized EGFRvIII CAR T-cells by lentiviral transduction of healthy donor human T-cells and engineered them to constitutively release a soluble SIRPγ-related protein (SGRP) with high affinity towards CD47. Tumor viability and CAR T-cell proliferation were assessed by timelapse imaging analysis in co-cultures with endogenous EGFRvIII-expressing BS153 cells. Tumor-induced CAR T-cell activation and degranulation were confirmed by flow cytometry. CAR T-cell secretomes were analyzed by liquid chromatography-mass spectrometry. Immunocompromised mice were orthotopically implanted with EGFRvIII+ BS153 cells and treated intratumorally with a single CAR T-cell injection. EGFRvIII and EGFRvIII-SGRP CAR T-cells killed tumor cells in a dose-dependent manner (72h-timepoint; complete cytotoxicity at effector-target ratio 1:1) compared to CD19 controls. CAR T-cells proliferated and specifically co-expressed CD25 and CD107a in the presence of tumor antigen (24h-timepoint; EGFRvIII: 59.3±3.00%, EGFRvIII-SGRP: 52.6±1.42%, CD19: 0.1±0.07%). Differential expression analysis of CAR T-cell secretomes identified SGRP from EGFRvIII-SGRP CAR T-cell supernatants (-Log10qValue/Log2fold-change= 3.84/6.15). Consistent with studies of systemic EGFRvIII CAR T-cell therapy, our data suggest that intratumoral EGFRvIII CAR T-cells were insufficient to eliminate BS153 tumors with homogeneous EGFRvIII expression in mice (Overall survival; EGFRvIII-treated: 20%, CD19-treated: 0%, n= 5 per group). Our current work focuses on the functional characterization of SGRP binding, SGRP-mediated phagocytosis, and on the development of a translational preclinical model of heterogeneous EGFRvIII expression to investigate an additive effect of CAR T-cell therapy and GAM modulation.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A133-A133
Author(s):  
Cheng-Fu Kuo ◽  
Yi-Chiu Kuo ◽  
Miso Park ◽  
Zhen Tong ◽  
Brenda Aguilar ◽  
...  

BackgroundMeditope is a small cyclic peptide that was identified to bind to cetuximab within the Fab region. The meditope binding site can be grafted onto any Fab framework, creating a platform to uniquely and specifically target monoclonal antibodies. Here we demonstrate that the meditope binding site can be grafted onto chimeric antigen receptors (CARs) and utilized to regulate and extend CAR T cell function. We demonstrate that the platform can be used to overcome key barriers to CAR T cell therapy, including T cell exhaustion and antigen escape.MethodsMeditope-enabled CARs (meCARs) were generated by amino acid substitutions to create binding sites for meditope peptide (meP) within the Fab tumor targeting domain of the CAR. meCAR expression was validated by anti-Fc FITC or meP-Alexa 647 probes. In vitro and in vivo assays were performed and compared to standard scFv CAR T cells. For meCAR T cell proliferation and dual-targeting assays, the meditope peptide (meP) was conjugated to recombinant human IL15 fused to the CD215 sushi domain (meP-IL15:sushi) and anti-CD20 monoclonal antibody rituximab (meP-rituximab).ResultsWe generated meCAR T cells targeting HER2, CD19 and HER1/3 and demonstrate the selective specific binding of the meditope peptide along with potent meCAR T cell effector function. We next demonstrated the utility of a meP-IL15:sushi for enhancing meCAR T cell proliferation in vitro and in vivo. Proliferation and persistence of meCAR T cells was dose dependent, establishing the ability to regulate CAR T cell expansion using the meditope platform. We also demonstrate the ability to redirect meCAR T cells tumor killing using meP-antibody adaptors. As proof-of-concept, meHER2-CAR T cells were redirected to target CD20+ Raji tumors, establishing the potential of the meditope platform to alter the CAR specificity and overcome tumor heterogeneity.ConclusionsOur studies show the utility of the meCAR platform for overcoming key challenges for CAR T cell therapy by specifically regulating CAR T cell functionality. Specifically, the meP-IL15:sushi enhanced meCAR T cell persistence and proliferation following adoptive transfer in vivo and protects against T cell exhaustion. Further, meP-ritiuximab can redirect meCAR T cells to target CD20-tumors, showing the versatility of this platform to address the tumor antigen escape variants. Future studies are focused on conferring additional ‘add-on’ functionalities to meCAR T cells to potentiate the therapeutic effectiveness of CAR T cell therapy.


Author(s):  
Ya.Yu. Kiseleva ◽  
A.M. Shishkin ◽  
A.V. Ivanov ◽  
T.M. Kulinich ◽  
V.K. Bozhenko

Adoptive immunotherapy that makes use of genetically modified autologous T cells carrying a chimeric antigen receptor (CAR) with desired specificity is a promising approach to the treatment of advanced or relapsed solid tumors. However, there are a number of challenges facing the CAR T-cell therapy, including the ability of the tumor to silence the expression of target antigens in response to the selective pressure exerted by therapy and the dampening of the functional activity of CAR T cells by the immunosuppressive tumor microenvironment. This review discusses the existing gene-engineering approaches to the modification of CAR T-cell design for 1) creating universal “switchable” synthetic receptors capable of attacking a variety of target antigens; 2) enhancing the functional activity of CAR T cells in the immunosuppressive microenvironment of the tumor by silencing the expression of inhibiting receptors or by stimulating production of cytokines.


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