scholarly journals Incidence, Management and Outcomes of Arterial and Venous Thromboembolism after Chimeric Antigen Receptor Modified T Cells for B-Cell Lymphoma and Multiple Myeloma

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 7-7
Author(s):  
Anna L. Parks ◽  
Swetha Kambhampati ◽  
Bita Fakhri ◽  
Charalambos Andreadis ◽  
Lissa Gray ◽  
...  

Introduction: Chimeric antigen receptor modified T Cell (CAR-T) therapy is a rapidly developing treatment for patients with relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma (NHL) or multiple myeloma (MM). Although this population is at high risk for thrombosis, there are few data about rates of venous thromboembolism (VTE) and arterial thromboembolism (ATE) with CAR-T. Additionally, treatment with anticoagulation is complicated because of the prevalence of thrombocytopenia following CAR-T. Our goal was to determine the incidence, associated risk factors, management and outcomes of VTE and ATE in the 60 days following CAR-T therapy. Methods: We performed a single-center, retrospective cohort study of all patients who received inpatient CAR-T cells at UCSF Medical Center between January 2018 and May 2020 for R/R NHL or MM as standard-of-care or on a clinical trial. The outcomes of incident VTE and ATE were identified by ICD-10 codes and medical record review. Patient characteristics, pre-existing thrombosis risk factors, laboratory results, medications, and major or clinically relevant non-major bleeding or recurrent thrombotic complications were obtained through chart review. We used descriptive statistics to delineate risk factors, incidence, management and outcomes of thrombotic events. Results: Ninety-one patients who underwent CAR-T therapy were included in the analysis, 37 with NHL and 54 with MM. For NHL, mean age was 63 (range 38-82), and 41% were women. For MM, mean age was 62 (range 33-77), and 50% were women. Patients with NHL were treated with either investigational or Federal Drug Administration-approved CD19-directed therapies, and patients with MM were treated with a variety of investigational B-cell maturation antigen-directed (BCMA) therapies. For thrombotic risk factors, 13% of patients with NHL had a history of VTE, 3% had a history of ATE, 27% had a BMI ≥30, 59% had a recent procedure including central venous catheter (CVC) placement, 14% had an intensive care unit (ICU) stay, and 22% had an infectious complication in the 30 days pre- or post-CAR-T. Forty-one percent of patients with NHL had neurotoxicity of any grade, and 59% had CRS of any grade. At 30 days, 57% had a complete response, 41% had a partial response, 3% had stable disease. For MM, 6% of patients had a pre-existing history of VTE, 2% had a history of ATE, 19% had a BMI ≥30, 96% had a recent procedure, 11% had an ICU stay and 19% had an infection. Seventeen percent had neurotoxicity, and 85% had CRS. Thirty-two percent of patients with NHL and 48% with MM received pharmacologic VTE prophylaxis while undergoing CAR-T. For those who did not receive VTE prophylaxis, thrombocytopenia was the reason for holding prophylaxis, which occurred in 51% and 50% of NHL and MM patients, respectively. In the 60 days post-CAR-T, 4 (11%) patients with NHL were diagnosed with VTE-3 pulmonary embolism (PE) and 1 lower extremity deep vein thrombosis (DVT) associated with a previously placed inferior vena cava filter. Four (7%) patients with MM were diagnosed with VTE-1 PE and 3 upper extremity DVTs associated with CVCs. Five out of these 8 (63%) patients had symptomatic VTE, while the remainder were incidental on PETCT. Mean time from CAR-T infusion to VTE diagnosis was 20 days (range 6-39 days). There were no documented ATEs. Six out of 8 (75%) were treated with therapeutic anticoagulation. Of those who were anticoagulated, 4 patients received direct oral anticoagulants and 2 received low-molecular-weight-heparin. Duration was 3 months in 3 patients, 11 days in 1, 150 days in 1, and indefinitely in 1 with atrial fibrillation. Among all 8 patients with VTE, there were no bleeding events or recurrent thromboses regardless of whether or not they received anticoagulation. Discussion: In this cohort of patients with R/R NHL or MM who received either CD19- or BCMA-directed therapies, almost 1 in 10 developed VTE in the 60 days post-CAR-T. This occurred in the context of a high prevalence of risk factors for thrombosis and low rates of pharmacologic prophylaxis. Among those who developed VTE, the majority were treated with therapeutic anticoagulation for at least 3 months, without documented bleeding or recurrent VTE. Our findings provide crucial information on a common complication that can inform patients, clinicians and researchers and should be expanded upon in larger, prospective studies to identify optimal preventive and therapeutic strategies. Disclosures Fakhri: University of California San Francisco: Current Employment. Andreadis:Jazz Pharmaceuticals: Honoraria; Karyopharm: Honoraria; Incyte: Consultancy; Merck: Research Funding; Gilead/Kite: Consultancy; Novartis: Research Funding; BMS/Celgene/Juno: Honoraria, Research Funding; Genentech: Consultancy, Current equity holder in publicly-traded company. Wong:Janssen: Research Funding; Amgen: Consultancy; Roche: Research Funding; Fortis: Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Research Funding; GSK: Research Funding. Shah:BMS, Janssen, Bluebird Bio, Sutro Biopharma, Teneobio, Poseida, Nektar: Research Funding; GSK, Amgen, Indapta Therapeutics, Sanofi, BMS, CareDx, Kite, Karyopharm: Consultancy.

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 506-506 ◽  
Author(s):  
Carlos A. Ramos ◽  
Barbara Savoldo ◽  
Enli Liu ◽  
Adrian P. Gee ◽  
Zhuyong Mei ◽  
...  

Abstract Adoptive transfer of T cells with a CD19-specific chimeric antigen receptor (CAR) to treat B-cell malignancies shows remarkable clinical efficacy. However, long-term persistence of T cells targeting CD19, a pan-B cell marker, causes sustained depletion of normal B cells and consequent severe hypogammaglobulinemia. In order to target B-cell malignancies more selectively, we exploited the clonal restriction of mature B-cell malignancies, which express either a κ or a λ-light immunoglobulin (Ig) chain. We generated a CAR specific for κ-light chain (CAR.κ) to selectively target κ+ lymphoma/leukemia cells, while sparing the normal B cells expressing the reciprocal λ-light chain, thus minimizing the impairment of humoral immunity. After preclinical validation, we designed a phase I clinical trial in which patients with refractory/relapsed κ+ non-Hodgkin lymphoma (NHL) or chronic lymphocytic leukemia (CLL) are infused with autologous T cells expressing a CAR.κ that includes a CD28 costimulatory domain. The protocol also included patients with multiple myeloma with the aim of targeting putative myeloma initiating cells. Three dose levels (DL) are being assessed, with escalation determined by a continual reassessment method: 0.2 (DL1), 1 (DL2) and 2 (DL3) ×108 T cells/m2. Repeat infusions are allowed if there is at least stable disease after treatment. End points being evaluated include safety, persistence of CAR+T cells and antitumor activity. T cells were generated for 13 patients by activating autologous PBMC with immobilized OKT3 (n=5) or CD3/CD28 monoclonal antibodies (n=8). In 2 patients with >95% circulating leukemic cells, CD3 positive selection was performed using CliniMACS. After transduction, T cells (1.2×107±0.5×107) were expanded ex vivo for 18±4 days in the presence of interleukin (IL)-2 to reach sufficient numbers for dose escalation. CAR expression was 81%±13% by flow cytometry (74,112±23,000 transgene copy numbers/mg DNA). Products were composed predominantly of CD8+ cells (78%±10%), with a small proportion of naïve (5±4%) and memory T cells (17%±12%). CAR+ T cells specifically targeted κ+ tumors as assessed by 51Cr release assays (specific lysis 79%±10%, 20:1 E:T ratio) but not κ–tumors (11%±7%) or the NK-sensitive cell line K562 (26%±13%). Ten patients have been treated: 2 on DL1, 3 on DL2 and 5 on DL3. Any other treatments were discontinued at least 4 weeks prior to T-cell infusion. Patients with an absolute leukocyte count >500/µL received 12.5 mg/kg cyclophosphamide 4 days before T-cell infusion to induce mild lymphopenia. Infusions were well tolerated, without side effects. Persistence of infused T cells was assessed in blood by CAR.κ-specific Q-PCR assay and peaked 1 to 2 weeks post infusion, remaining detectable for 6 weeks to 9 months. Although the CAR contained a murine single-chain variable fragment (scFv), we did not detect human anti-mouse antibodies following treatment and CAR.κ+T cell expansion continued to be observed even after repeated infusions. We detected modest (<20 fold) elevation of proinflammatory cytokines, including IL-6, at the time of peak expansion of T cells, but systemic inflammatory response syndrome (cytokine storm) was absent. No new-onset hypogammaglobulinemia was observed. All 10 patients are currently evaluable for clinical response. Of the patients with relapsed NHL, 2/5 entered complete remission (after 2 and 3 infusions at dose level 1 and 3, respectively), 1/5 had a partial response and 2 progressed; 3/3 patients with multiple myeloma have had stable disease for 2, 8 and 11 months, associated with up to 38% reduction in their paraprotein; and 2/2 patients with CLL progressed before or shortly after the 6-week evaluation. In conclusion, our data indicate that infusion of CAR.κ+ T cells is safe at every DL and can be effective in patients with κ+ lymphoproliferative disorders. Disclosures: Savoldo: Celgene: Patents & Royalties, Research Funding. Rooney:Celgene: Patents & Royalties, Research Funding. Heslop:Celgene: Patents & Royalties, Research Funding. Brenner:Celgene: Patents & Royalties, Research Funding. Dotti:Celgene: Patents & Royalties, Research Funding.


2019 ◽  
Vol 11 (485) ◽  
pp. eaau7746 ◽  
Author(s):  
Eric L. Smith ◽  
Kim Harrington ◽  
Mette Staehr ◽  
Reed Masakayan ◽  
Jon Jones ◽  
...  

Early clinical results of chimeric antigen receptor (CAR) T cell therapy targeting B cell maturation antigen (BCMA) for multiple myeloma (MM) appear promising, but relapses associated with residual low-to-negative BCMA-expressing MM cells have been reported, necessitating identification of additional targets. The orphan G protein–coupled receptor, class C group 5 member D (GPRC5D), normally expressed only in the hair follicle, was previously identified as expressed by mRNA in marrow aspirates from patients with MM, but confirmation of protein expression remained elusive. Using quantitative immunofluorescence, we determined that GPRC5D protein is expressed on CD138+ MM cells from primary marrow samples with a distribution that was similar to, but independent of, BCMA. Panning a human B cell–derived phage display library identified seven GPRC5D-specific single-chain variable fragments (scFvs). Incorporation of these into multiple CAR formats yielded 42 different constructs, which were screened for antigen-specific and antigen-independent (tonic) signaling using a Nur77-based reporter system. Nur77 reporter screen results were confirmed in vivo using a marrow-tropic MM xenograft in mice. CAR T cells incorporating GPRC5D-targeted scFv clone 109 eradicated MM and enabled long-term survival, including in a BCMA antigen escape model. GPRC5D(109) is specific for GPRC5D and resulted in MM cell line and primary MM cytotoxicity, cytokine release, and in vivo activity comparable to anti-BCMA CAR T cells. Murine and cynomolgus cross-reactive CAR T cells did not cause alopecia or other signs of GPRC5D-mediated toxicity in these species. Thus, GPRC5D(109) CAR T cell therapy shows potential for the treatment of advanced MM irrespective of previous BCMA-targeted therapy.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 384-384 ◽  
Author(s):  
Cameron J Turtle ◽  
Daniel Sommermeyer ◽  
Carolina Berger ◽  
Michael Hudecek ◽  
David M Shank ◽  
...  

Abstract BACKGROUND: The adoptive transfer of CD19-specific chimeric antigen receptor-modified (CD19 CAR) T cells is a promising strategy for treating patients with CD19+ B cell acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), and non-Hodgkin lymphoma (NHL). Dramatic responses have been observed in a subset of patients receiving CD19 CAR T cell therapy, and prior studies suggest that persistence of transferred T cells may correlate with the extent of tumor regression. The use of unselected T cells to prepare CAR T cells results in variation in the phenotypic composition of the infused product in individual patients, making it difficult to determine whether particular T cell subsets contribute to efficacy and/or toxicity. Studies in our lab demonstrated that genetically modified effector T cells derived from purified T cell subsets differ in the capacity to persist in vivo after adoptive transfer, and that a combination of CAR-modified CD8+ central memory (TCM) and CD4+ T cells provides optimal antitumor activity in tumor xenograft models. Based on these data, we designed the first clinical trial in which patients with CD19+ B cell malignancies receive CD19 CAR T cells comprised of a defined composition of CD8+ TCM and CD4+T cells engineered to express a CD19 CAR. METHODS: Patients with relapsed or refractory CD19+ ALL, CLL or NHL are eligible for this phase I/II study. CD8+ TCM and CD4+ T cells were separately enriched by immunomagnetic selection from a leukapheresis product from each patient, and cryopreserved. The CD8+ TCM and CD4+ T cells were stimulated in independent cultures with anti-CD3/anti-CD28 paramagnetic beads, and transduced with a lentivirus encoding the murine FMC63 anti-CD19 scFv, 4-1BB and CD3 zeta signaling domains. After in vitro expansion, the cell product for infusion was formulated in a 1:1 ratio of CD4+:CD8+ CAR+ T cells. A truncated non-functional human epidermal growth factor receptor (EGFRt) encoded in the transgene cassette allowed identification of transgene-expressing T cells by flow cytometry. Lymphodepleting chemotherapy was administered followed by infusion of EGFRt+ CAR T cells at one of three dose levels (2 x 105 EGFRt+ cells/kg, 2 x 106 EGFRt+ cells/kg, 2 x 107 EGFRt+cells/kg). RESULTS: Twenty patients with relapsed or refractory ALL (n = 9), NHL (n = 10) or CLL (n = 1), including those who failed prior autologous (n = 4) or allogeneic (n = 4) stem cell transplant have been treated on the trial. Fifteen of 20 treated patients received a product that conformed to the prescribed CD8+ T­CM:CD4 composition. Five patients received a product manufactured using a modified strategy either due to low blood lymphocyte counts (n = 3) or due to failure to propagate T cells in culture (n = 2). CD8+ TCM and CD4+ T cells have been isolated from 12 additional patients and cryopreserved for therapy. Patients have been treated at all three dose levels without acute infusional toxicity. Severe cytokine release syndrome (sCRS) consisting of fever, hypotension, and reversible neurotoxicity associated with elevated serum IFN-γ and IL-6 was only observed in ALL patients with a high tumor burden. One ALL patient treated at the highest cell dose died of complications associated with sCRS. None of the NHL patients had sCRS. Of patients who are >6 weeks after CD19 CAR T cell therapy, best responses included complete (n=1) or partial (n=5) remission in 6/9 patients with NHL and complete remission in 5/7 patients with ALL. Both CD4+ and CD8+ CAR-T cells expanded in vivo and could be detected in blood, marrow and CSF. The peak level and duration of persistence of both CD4+ and CD8+ EGFRt+ T cells were associated with clinical response. TCRBV gene sequencing of flow sorted CD4+ and CD8+ EGFRt+CAR T cells from 2 patients showed that proliferating CAR T cells were polyclonal. A subset of NHL patients in whom CAR T cells became undetectable developed a T cell immune response to sequences in the murine CD19-specific scFv component of the CAR transgene. CONCLUSION: Adoptive immunotherapy with CD19 CAR T cells of defined subset composition is feasible and safe in a majority of heavily pretreated patients with refractory B cell malignancies and has potent anti-tumor activity. Persistence of CAR-T cells may be limited in some patients by transgene product immunogenicity. Data from this ongoing clinical trial will be updated at the meeting. Disclosures Turtle: Juno Therapeutics: Research Funding. Berger:Juno Therapeutics: Patents & Royalties. Hudecek:Juno Therapeutics: Patents & Royalties. Jensen:Juno: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Riddell:Juno Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Maloney:Juno Therapeutics: Research Funding.


2018 ◽  
Vol 26 (8) ◽  
pp. 1906-1920 ◽  
Author(s):  
Julia Bluhm ◽  
Elisa Kieback ◽  
Stephen F. Marino ◽  
Felix Oden ◽  
Jörg Westermann ◽  
...  

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4810-4810
Author(s):  
Mark B. Geyer ◽  
Briana Cadzin ◽  
Elizabeth Halton ◽  
Peter Kane ◽  
Brigitte Senechal ◽  
...  

Abstract Background: Autologous CD19-targeted chimeric antigen receptor-modified (CAR) T-cell therapy leads to complete responses (CR) in patients (pts) with (w/) relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL, &gt;80% CR rate) and diffuse large B-cell lymphoma (DLBCL, ~40-55% CR rate). However, following fludarabine/cyclophosphamide (Flu/Cy) conditioning and CAR T-cell therapy w/ a CD28 costimulatory domain (e.g. 19-28z CAR T-cells), rates of grade ≥3 ICANS and grade ≥3 cytokine release syndrome (CRS) in pts w/ R/R DLBCL and morphologic R/R B-ALL exceed 30%. CRS and ICANS are associated w/ considerable morbidity, including increased length of hospitalization, and may be fatal. Host monocytes appear to be the major reservoir of cytokines driving CRS and ICANS post-CAR T-cell therapy (Giavradis et al. and Norelli et al., Nature Medicine, 2018). Circulating monocytic myeloid-derived suppressor cells (MDSCs) may also blunt efficacy of 19-28z CAR T-cells in R/R DLBCL (Jain et al., Blood, 2021). The CD45-targeted antibody radioconjugate (ARC) 131-I apamistamab is being investigated at myeloablative doses as conditioning prior to hematopoietic cell transplantation in pts w/ R/R acute myeloid leukemia. However, even at low doses (4-20 mCi), transient lymphocyte and blast reduction are observed. Preclinical studies in C57BL/6 mice demonstrate low-dose anti CD45 radioimmunotherapy (100 microCi) transiently depletes &gt;90% lymphocytes, including CD4/CD8 T-cells, B-cells, NK cells, and T-regs, as well as splenocytes and MDSCs, w/ negligible effect on bone marrow (BM) hematopoietic stem cells (Dawicki et al., Oncotarget, 2020). We hypothesized a higher, yet nonmyeloablative dose of 131-I apamistamab may achieve more sustained, but reversible depletion of lymphocytes and other CD45 + immune cells, including monocytes thought to drive CRS/ICANS. We additionally hypothesized this approach (vs Flu/Cy) prior to CAR T-cell therapy would promote CAR T-cell expansion while reducing CSF levels of monocyte-derived cytokines (e.g. IL-1, IL-6, and IL-10), thus lowering the risk of severe ICANS (Fig 1A). Study design and methods: We are conducting a single-institution pilot study of 131-I apamistamab in lieu of Flu/Cy prior to 19-28z CAR T-cells in adults w/ R/R BALL or DLBCL (NCT04512716; Iomab-ACT); accrual is ongoing. Pts are eligible for leukapheresis if they are ≥18 years-old w/ R/R DLBCL (de novo or transformed) following ≥2 chemoimmunotherapy regimens w/ ≥1 FDG-avid measurable lesion or B-ALL following ≥1 line of multi-agent chemotherapy (R/R following induction/consolidation; prior 2 nd/3 rd gen TKI required for pts w/ Ph+ ALL) w/ ≥5% BM involvement and/or FDG-avid extramedullary disease, ECOG performance status 0-2, and w/ appropriate organ function. Active or prior CNS disease is not exclusionary. Pts previously treated w/ CD19-targeted CAR T-cell therapy are eligible as long as CD19 expression is retained. See Fig 1B/C: Post-leukapheresis, 19-28z CAR T-cells are manufactured as previously described (Park et al., NEJM, 2018). Bridging therapy is permitted at investigator discretion. Thyroid blocking is started ≥48h pre-ARC. 131-I apamistamab 75 mCi is administered 5-7 days pre-CAR T-cell infusion to achieve total absorbed marrow dose ~200 cGy w/ remaining absorbed dose &lt;25 cGy at time of T-cell infusion. 19-28z CAR T-cells are administered as a single infusion (1x10 6/kg, B-ALL pts; 2x10 6/kg, DLBCL pts). The primary objective is to determine safety/tolerability of 131-I apamistamab 75 mCi given prior to 19-28z CAR T-cells in pts w/ R/R B-ALL/DLBCL. Secondary objectives include determining incidence/severity of ICANS and CRS, anti-tumor efficacy, and 19-28z CAR T-cell expansion/persistence. Key exploratory objectives include describing the cellular microenvironment following ARC and 19-28z CAR T-cell infusion using spectral cytometry, as well as cytokine levels in peripheral blood and CRS. The trial utilizes a 3+3 design in a single cohort. If dose-limiting toxicity (severe infusion-related reactions, treatment-resistant severe CRS/ICANS, persistent regimen-related cytopenias, among others defined in protocol) is seen in 0-1 of the first 3 pts treated, then up to 6 total (up to 3 additional) pts will be treated. We have designed this study to provide preliminary data to support further investigation of CD45-targeted ARCs prior to adoptive cellular therapy. Figure 1 Figure 1. Disclosures Geyer: Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Actinium Pharmaceuticals, Inc: Research Funding; Amgen: Research Funding. Geoghegan: Actinium Pharmaceuticals, Inc: Current Employment. Reddy: Actinium Pharmaceuticals: Current Employment, Current holder of stock options in a privately-held company. Berger: Actinium Pharmaceuticals, Inc: Current Employment. Ludwig: Actinium Pharmaceuticals, Inc: Current Employment. Pandit-Taskar: Bristol Myers Squibb: Research Funding; Bayer: Research Funding; Clarity Pharma: Research Funding; Illumina: Consultancy, Honoraria; ImaginAb: Consultancy, Honoraria, Research Funding; Ymabs: Research Funding; Progenics: Consultancy, Honoraria; Medimmune/Astrazeneca: Consultancy, Honoraria; Actinium Pharmaceuticals, Inc: Consultancy, Honoraria; Janssen: Research Funding; Regeneron: Research Funding. Sauter: Genmab: Consultancy; Celgene: Consultancy, Research Funding; Precision Biosciences: Consultancy; Kite/Gilead: Consultancy; Bristol-Myers Squibb: Research Funding; GSK: Consultancy; Gamida Cell: Consultancy; Novartis: Consultancy; Spectrum Pharmaceuticals: Consultancy; Juno Therapeutics: Consultancy, Research Funding; Sanofi-Genzyme: Consultancy, Research Funding. OffLabel Disclosure: 131-I apamistamab and 19-28z CAR T-cells are investigational agents in treatment of ALL and DLBCL


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 42-42
Author(s):  
Michael D. Jain ◽  
Bachisio Ziccheddu ◽  
Caroline A. Coughlin ◽  
Rawan Faramand ◽  
Anthony J. Griswold ◽  
...  

Abstract Introduction: Anti-CD-19 chimeric antigen receptor-reprogrammed autologous T cells are breakthrough immunotherapies for heavily pretreated patients with aggressive B-cell lymphomas; however, across CAR-19 products, ~60% of patients do not achieve remission or relapse and unfortunately typically progress and rapidly die. Factors associated with impaired response to CAR-19 include inflammatory markers such as interferon signaling and clinical factors such as the need for bridging therapy and high pre-CAR-19 tumor burden, but cell-intrinsic driver of CAR-19 resistance remain largely undefined. Methods: To characterize the genomic mechanisms involved in diffuse large B cell lymphoma (DLBCL) resistance to CAR-19, we interrogated whole genome sequencing (WGS) from 28 relapsed/refractory (r/r) aggressive lymphoma patients treated with axicabtagene ciloleucel (axi-cel). The median coverage was 44.8X. To increase statistical power of analyses, we included also 50 newly diagnosed DLBCL patients from the Pan-Cancer Analysis of Whole Genomes (PCAWG). Results: As reported in other series, neither double hit cytogenetics nor MYC-BCL2 double expression associated with CAR-19 resistance, despite their negative predictive power for newly diagnosed DLBCL patients. Chapuy and LymphGen classification algorithms also demonstrated no prognostic significance. Among known mutated driver genes, only TP53 was significantly enriched in our cohort in comparison to the PCAWG cohort (p=0.002), but it did not predict poor CAR-19 outcome. Among other genes known to be involved in DLBCL pathogenesis, only mutations in NFKBIA or MYC, associated with worse PFS (p=0.04, p=0.025 respectively). Next, we identified 12 single base substitution (SBS) mutational signatures detected in our cohort of r/r lymphomas, four of which are caused by exposure to distinct chemotherapies (Landau et al., 2020, Nat Comm). The melphalan-related signature (SBS-MM1) was identified in 4 out 5 patients who received high dose melphalan followed by autologous stem cell transplant, and 75% of patients exposed to platinum had evidence of one of the three known platinum signatures. Across different SBS signatures, only presence of APOBEC (SBS2 and SBS13) associated with worse PFS with 4/5 patients progressing (p=0.03). We compared newly diagnosed and r/r DLBCL by GISTIC2.0 copy number variation (CNV) analysis, revealing three gene deletions significantly enriched in our r/r cohort: TP53, RHOA and RB1. Interestingly, the deletions involving RHOA and RB1 both independently predicted poor outcome (p=0.0007 and p=0.05 respectively) with 5/5 and 6/8 patients progressing respectively. The third, involving TP53 (46.4% of patients), had no prognostic impact but reflected the high-risk nature of the heavily pretreated tumors. WGS allows detailed identification of structural variants and complex events. Indeed, we found evidence of chromothripsis, a catastrophic event in which one or more chromosomes are shattered and aberrantly reassembles generating multiple aneuploidies, in 39.3% of r/r DLBCL. This strongly associated with poor CAR-19 outcome, with 9/11 affected cases experiencing early progression (p=0.041). Finally, reduced expression (n=3) or genomic alteration (n=3) of CD19 did not associate with poor outcome. We found one case, with durable response, containing a sub-clonal mutation in CD19 (L174V) at baseline, previously reported as associated with CAR-19 resistance. In line with recent evidence, these findings indicate that antigen-mediated tumor killing is not the only mechanism of tumor eradication, and CD19-independent resistance mechanisms predominate. Conclusions: Leveraging the high resolution of WGS, we observed that markers of genomic complexity (chromothripsis and APOBEC) and specific genomic alterations (RHOA and RB1 deletion) associate with resistance to CAR-19 immunotherapy for aggressive B-cell lymphomas. Fifteen out of sixteen patients (93.8%) who relapsed on CAR-19 contained at least one of the described genomic alterations. Recent data demonstrate that an immunosuppressed TME leads to CAR-19 failure in patients, and animal studies show activation of host T cells by CAR-T cells. Combining these findings with these genomics findings, successful CAR-19 therapy must overcome the immune-exhausted tumor microenvironment to mobilize the host immune system and eliminate the tumor. Figure 1 Figure 1. Disclosures Jain: Takeda: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Kite/Gilead: Consultancy, Honoraria. Faramand: Novartis: Research Funding; Kite/Gilead: Research Funding. Landgren: Amgen: Research Funding; Janssen: Research Funding; Amgen: Honoraria; Celgene: Research Funding; Janssen: Other: IDMC; Janssen: Honoraria; Takeda: Other: IDMC; GSK: Honoraria. Locke: Iovance Biotherapeutics: Consultancy, Other: Scientific Advisory Role; Gerson Lehrman Group: Consultancy; Calibr: Consultancy, Other: Scientific Advisory Role; Janssen: Consultancy, Other: Scientific Advisory Role; Umoja: Consultancy, Other; Novartis: Consultancy, Other, Research Funding; Bluebird Bio: Consultancy, Other: Scientific Advisory Role; Allogene Therapeutics: Consultancy, Other: Scientific Advisory Role, Research Funding; Kite, a Gilead Company: Consultancy, Other: Scientific Advisory Role, Research Funding; Takeda: Consultancy, Other; Emerging Therapy Solutions: Consultancy; EcoR1: Consultancy; Cowen: Consultancy; Wugen: Consultancy, Other; Legend Biotech: Consultancy, Other; GammaDelta Therapeutics: Consultancy, Other: Scientific Advisory Role; Cellular Biomedicine Group: Consultancy, Other: Scientific Advisory Role; BMS/Celgene: Consultancy, Other: Scientific Advisory Role; Amgen: Consultancy, Other: Scientific Advisory Role; Moffitt Cancer Center: Patents & Royalties: field of cellular immunotherapy. Maura: Medscape: Consultancy, Honoraria; OncLive: Honoraria. Davila: Precigen: Research Funding.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4576-4576
Author(s):  
Louise Roulin ◽  
Elsa Poullot ◽  
Paul Blanc-Durand ◽  
Cyrielle Robe ◽  
Francois Lemonnier ◽  
...  

Abstract Background : High grade B cell lymphoma (HGBL) either Not Otherwise Specified (NOS) or either Double Hit (DH MYC/BCL2 or DH MYC/BCL6) or Triple Hit (TH) have been considered as separate entities from Diffuse Large B-Cell Lymphoma (DLBCL) NOS in the 2016 WHO classification. Until now, treatment of these particularly aggressive histological sybtypes remains unclear and most of patients (pts) still have a poor outcome because of chemoresistance or early relapse. Except IPI score, prognosis factors are not completely clarified. Since few years, treatment with Chimeric Antigen Receptor T (CAR-T) cells has changed the prognosis of relapsed refractory DLBCL and could represent a promising therapeutic approach - early in the course of the disease - to improve survival of HGBL. The aim of the present study is to describe a « real life » cohort of pts treated in our institution and to evaluate the prognostic impact of clinical, histological, genetic and imaging characteristics and treatment. Methods : We collected data of 45 pts diagnosed between January 2009 and October 2020. BCL2, BCL6 and MYC break were analyzed by Interphase Fluorescence In Situ Hybridization (FISH) with break-apart probes. When MYC was rearranged, MYC partner gene was analyzed with double fusion probes (MYC/IgH, MYC/IgL, MYC/IgK). Total metabolic tumor volume (TMTV) was calculated using fully automatic segmentation of lymphoma lesions by an artificial intelligence (P. Blanc-Durand, Eur J Nucl Med Mol Imaging, 2021). All pts were treated with rituximab R-CHOP/CHOP-like regimens. Treatment was reinforced (intensive regimen) with high dose methotrexate (14 pts treated with RCOPADM and one with R-ACVBP) when they were considered fit enough. Autologous stem cell transplantation at 1st relapse was performed in 3 pts and 5 pts were treated with CAR-T cells at 2 nd relapse. Results : Baseline characteristics were as follows: median age 60 y (28-80), IPI 3-5 : n=33 (73%), CNS localization : n=8/42 (19%), bone marrow involvement : n=10/34 (22%). Twenty-seven pts were DH lymphoma (MYC/BCL2: 18; MYC/BCL6: 9), 8 patients were TH-lymphoma and 10 were HGBL-NOS. MYC rearrangement was detected in 40 cases with an immunoglobulin partner gene (IgH, IgL or IgK) in 14 (52%) of 27 evaluable cases. TMTV was calculated for 29 pts with a median TMTV of 1019 ml (2-4536 ml). Fifteen pts were treated with an intensive regimen. With a median follow-up of alive pts of 17 months, 2-y progression-free survival (PFS) and overall survival (OS) were 42% [26.4 ; 56.8] and 62% [43.7 ; 75.5] respectively. PFS and OS were significantly affected by IPI 3-5 (PFS: p= 0.006, HR=3.37 ; OS: p= 0.01, HR=3.71) and CNS involvement (PFS : p=0.006, HR=6.93 ; OS: p=0.006, HR=7.44). TMTV&gt;1000ml (PFS: p=0.051, HR 2.99 ; OS: p=0.033, HR=4.13) was associated with a significantly inferior OS. Prognosis of HGBL DH/TH and HGBL-NOS was similar (PFS: p= 0.89, HR=0.93 ; OS: p=0.64, HR=1.32). Immunoglobulin as MYC partner gene had no significant impact on prognosis (PFS: p=0.47, HR=1.48 ; OS: p=0.32, HR=1.73). Intensive regimens did not improve significantly prognosis (PFS: p=0.26, HR=1.71 ; OS: p=0.08, HR=2.86). Conclusion: This monocentric study confirms previous reports on the poor prognosis of HGBL (DH/TH and NOS) especially for patients for both high IPI or high TMTV and in case of initial CNS involvement. We confirm that intensive regimen don't improve prognosis supporting the need of alternative strategies incorporating bispecific monoclonal antibodies or consolidative CAR-T cells in very high risk pts. Disclosures Roulin: Janssen: Other: Travel and meetings. Lemonnier: Institut Roche: Research Funding; Gilead: Other: travel grant. Le Bras: Novartis: Honoraria; Takeda: Honoraria, Research Funding; Kite Gilead: Honoraria; Celgene BMS: Research Funding. Gaulard: Innate Pharma: Research Funding; Sanofi: Research Funding; Alderaan: Research Funding; Gilead: Consultancy; Takeda: Consultancy, Honoraria. Haioun: Miltenyi: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; F. Hoffmann-La Roche Ltd: Honoraria, Research Funding; Servier: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding.


Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 740-740 ◽  
Author(s):  
Jesus G. Berdeja ◽  
Yi Lin ◽  
Noopur Raje ◽  
Nikhil Munshi ◽  
David Siegel ◽  
...  

Abstract Introduction: Chimeric antigen receptor (CAR) T cell therapies have demonstrated robust and sustained clinical responses in several hematologic malignancies. Data suggest that achieving acceptable benefit:risk profiles depends on several factors, including the specificity of the antigen target and characteristics of the CAR itself, including on-target, off-tumor activity.To test the safety and efficacy of CAR T cells in relapsed and/or refractory multiple myeloma (RRMM), we have designed a second-generation CAR construct targeting B cell maturation antigen (BCMA) to redirect T cells to MM cells. BCMA is a member of the tumor necrosis factor superfamily that is expressed primarily by malignant myeloma cells, plasma cells, and some mature B cells. bb2121 consists of autologous T cells transduced with a lentiviral vector encoding a novel CAR incorporating an anti-BCMA scFv, a 4-1BB costimulatory motif and a CD3-zeta T cell activation domain. Methods: CRB-401 (NCT02658929) is a multi-center phase 1 dose escalation trial of bb2121 in patients with RRMM who have received ≥ 3 prior regimens, including a proteasome inhibitor and an immunomodulatory agent, or are double-refractory, and have ≥ 50% BCMA expression on malignant cells. Peripheral blood mononuclear cells are collected via leukapheresis and shipped to a central facility for transduction, expansion, and release testing prior to being returned to the site for infusion. Patients undergo lymphodepletion with fludarabine (30 mg/m2) and cyclophosphamide (300 mg/m2) daily for 3 days then receive 1 infusion of bb2121. The study follows a standard 3+3 design with planned dose levels of 50, 150, 450, 800, and 1,200 x 106 CAR+ T cells. The primary outcome measure is incidence of adverse events (AEs), including dose-limiting toxicities (DLTs). Additional outcome measures were quality and duration of clinical response assessed according to the IMWG Uniform Response Criteria for Multiple Myeloma, evaluation of minimal residual disease (MRD), overall and progression-free survival, quantification of bb2121 in blood, and quantification of circulating soluble BCMA over time. Results: Asof May 4, 2017, 21 patients (median 58 [37 to 74] years old) with a median of 5 (1 to 16) years since MM diagnosis, had been infused with bb2121, and 18 patients were evaluable for initial (1-month) clinical response. Patients had a median of 7 prior lines of therapy (range 3 to 14), all with prior autologous stem cell transplant; 67% had high-risk cytogenetics. Fifteen of 21 (71%) had prior exposure to, and 6 of 21 (29%) were refractory to 5 prior therapies (Bort/Len/Car/Pom/Dara). Median follow-up after bb2121 infusion was 15.4 weeks (range 1.4 to 54.4 weeks). As of data cut-off, no DLTs and no treatment-emergent Grade 3 or higher neurotoxicities similar to those reported in other CAR T clinical studies had been observed. Cytokine release syndrome (CRS), primarily Grade 1 or 2, was reported in 15 of 21 (71%) patients: 2 patients had Grade 3 CRS that resolved in 24 hours and 4 patients received tocilizumab, 1 with steroids, to manage CRS. CRS was more common in the higher dose groups but did not appear related to tumor burden. One death on study, due to cardiopulmonary arrest more than 4 months after bb2121 infusion in a patient with an extensive cardiac history, was observed while the patient was in sCR and was assessed as unrelated to bb2121. The overall response rate (ORR) was 89% and increased to 100% for patients treated with doses of 150 x 106 CAR+ T cells or higher. No patients treated with doses of 150 x 106 CAR+ T cells or higher had disease progression, with time since bb2121 between 8 and 54 weeks (Table 1). MRD negative results were obtained in all 4 patients evaluable for analysis. CAR+ T cell expansion has been demonstrated consistently and 3 of 5 patients evaluable for CAR+ cells at 6 months had detectable vector copies. A further 5 months of follow up on reported results and initial data from additional patients will be presented. Conclusions: bb2121 shows promising efficacy at dose levels above 50 x 106 CAR+ T cells, with manageable CRS and no DLTs to date. ORR was 100% at these dose levels with 8 ongoing clinical responses at 6 months and 1 patient demonstrating a sustained response beyond one year. These initial data support the potential of CAR T therapy with bb2121 as a new treatment paradigm in RRMM. CT.gov study NCT02658929, sponsored by bluebird bio and Celgene Disclosures Berdeja: Teva: Research Funding; Janssen: Research Funding; Novartis: Research Funding; Abbvie: Research Funding; Celgene: Research Funding; BMS: Research Funding; Takeda: Research Funding; Vivolux: Research Funding; Amgen: Research Funding; Constellation: Research Funding; Bluebird: Research Funding; Curis: Research Funding. Siegel: Celgene, Takeda, Amgen Inc, Novartis and BMS: Consultancy, Speakers Bureau; Merck: Consultancy. Jagannath: MMRF: Speakers Bureau; Bristol-Meyers Squibb: Consultancy; Merck: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Medicom: Speakers Bureau. Turka: bluebird bio: Employment, Equity Ownership. Lam: bluebird bio: Employment, Equity Ownership. Hege: Celgene Corporation: Employment, Equity Ownership. Morgan: bluebird bio: Employment, Equity Ownership, Patents & Royalties. Quigley: bluebird bio: Employment, Equity Ownership, Patents & Royalties. Kochenderfer: Bluebird bio: Research Funding; N/A: Patents & Royalties: I have multiple patents in the CAR field.; Kite Pharma: Research Funding.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4193-4193 ◽  
Author(s):  
Nirav N Shah ◽  
Fenlu Zhu ◽  
Carolyn Taylor ◽  
Dina Schneider ◽  
Winfried Krueger ◽  
...  

Abstract Background: CAR-T cell therapy directed against the CD19 antigen is a breakthrough treatment for patients (pts) with relapsed/refractory (R/R) B-cell NHL. Despite impressive outcomes, not all pts respond and many that respond still relapse. Affordability and accessibility are further considerations that limit current commercial models of CAR-T products. Commercial CAR-T manufacturing is complex, time consuming, and expensive with a supply chain starting at the treating center with apheresis of mononuclear cells, cryopreservation, and shipping to and from a centralized third-party manufacturing site. We addressed these limitations in a Phase 1 clinical trial evaluating a first-in-human bispecific tandem CAR-T cell directed against both CD19 and CD20 (CAR-20.19-T) antigens for pts with R/R B-cell NHL. Through dual targeting we hope to improve response rates and durability of response while limiting antigen escape. We eliminated third party shipping logistics utilizing the CliniMACS Prodigy, a compact tabletop device that allows for automated manufacturing of CAR-T cells within a GMP compliant environment within the hospital. Most materials and reagents used to produce the CAR-T cell product were single-sourced from the device manufacturer. Methods: Phase 1 (NCT03019055), single center, dose escalation + expansion study to demonstrate feasibility and safety of locally manufactured second generation 41BB + CD3z CAR-20.19-T cells via the CliniMACS Prodigy. Feasibility was measured by ability to generate a target CAR-20.19-T cell dose for a minimum of 75% of subjects. Safety was assessed by the presence of dose limiting toxicities (DLTs) through 28 days post-infusion. Dose was escalated in a 3+3 fashion with a starting dose of 2.5 x 10^5 cells/kg, a target DLT rate <33%, and a goal treatment dose of 2.5 x 10^6 cells/kg. Adults with R/R Diffuse Large B-cell Lymphoma (DLBCL), Follicular Lymphoma (FL), Mantle Cell Lymphoma (MCL) or Chronic Lymphocytic Leukemia (CLL) were eligible. CAR-T production was set for a 14-day manufacturing process. Day 8 in-process testing was performed to ensure quality and suitability of CAR-T cells for a potential fresh infusion. On Day 10, pts eligible for a fresh CAR-T infusion initiated lymphodepletion (LDP) chemotherapy with fludarabine 30 mg/m2 x 3 days and cyclophosphamide 500 mg/m2 x 1 day, and cells were administered after harvest on Day 14. Pts ineligible for fresh infusion received cryopreserved product and LDP was delayed accordingly. Results: 6 pts have been enrolled and treated with CAR-20.19-T cells: 3 pts at 2.5 x 10^5 cells/kg and 3 pts at 7.5 x 10^5 cells/kg. Median age was 53 years (48-62). Underlying disease was MCL in 3 pts, DLBCL in 2 pts, and CLL in 1 patient. Baseline data and prior treatments are listed in Table 1. CAR-T production was successful in all runs and all pts received their target dose. Three pts received fresh CAR-T cells and 3 pts received CAR-T cells after cryopreservation. To date there are no DLTs to report. No cases of Grade 3/4 cytokine release syndrome (CRS) or neurotoxicity (NTX) were observed. One patient had Grade 2 CRS and Grade 2 NTX requiring intervention. The other had self-limited Grade 1 CRS and Grade 1 NTX. Median time to development of CRS was Day +11 post-infusion. All pts had neutrophil recovery (ANC>0.5 K/µL) by Day 28. Response at Day 28 (Table 2) is as follows: 2/6 pts achieved a complete response (CR), 2/6 achieved a partial response (PR), and 2/6 had progressive disease (PD). One subject with a PR subsequently progressed at Day 90. The 3 pts who did progress all underwent a repeat biopsy, and all retained either CD19 or CD20 positivity. Pts are currently being enrolled at the target dose (2.5 x 10^6 cells/kg) and updated results will be provided at ASH. Conclusions: Dual targeted anti-CD19 and anti-CD20 CAR-T cells were successfully produced for all pts demonstrating the feasibility of a point-of-care manufacturing process via the CliniMACS Prodigy device. With no DLTs or Grade 3-4 CRS or NTX to report, and 2/6 heavily pre-treated pts remaining in CR at 3 and 9 months respectively our approach represents a feasible and promising alternative to existing CAR-T models and costs. Down-regulation of both target antigens was not identified in any patient following CAR-T infusion, and in-process studies suggest that a shorter manufacturing timeline is appropriate for future trials (10 days). Disclosures Shah: Juno Pharmaceuticals: Honoraria; Lentigen Technology: Research Funding; Oncosec: Equity Ownership; Miltenyi: Other: Travel funding, Research Funding; Geron: Equity Ownership; Exelexis: Equity Ownership. Zhu:Lentigen Technology Inc., A Miltenyi Biotec Company: Research Funding. Schneider:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Krueger:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Worden:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Hamadani:Sanofi Genzyme: Research Funding, Speakers Bureau; Merck: Research Funding; Janssen: Consultancy; MedImmune: Consultancy, Research Funding; Cellerant: Consultancy; Celgene Corporation: Consultancy; Takeda: Research Funding; Ostuka: Research Funding; ADC Therapeutics: Research Funding. Johnson:Miltenyi: Research Funding. Dropulic:Lentigen, A Miltenyi Biotec company: Employment. Orentas:Lentigen Technology Inc., A Miltenyi Biotec Company: Other: Prior Employment. Hari:Takeda: Consultancy, Honoraria, Research Funding; Janssen: Honoraria; Kite Pharma: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Spectrum: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Amgen Inc.: Research Funding; Sanofi: Honoraria, Research Funding.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 898-898 ◽  
Author(s):  
Liora M Schultz ◽  
Kara L. Davis ◽  
Christina Baggott ◽  
Christie Chaudry ◽  
Anne Cunniffe Marcy ◽  
...  

Abstract Chimeric Antigen Receptor (CAR) therapy targeting CD19 achieves complete remission (CR) rates of 70%-90% in relapsed/refractory B-ALL. Relapse due to loss of the CD19 targeted epitope presents a therapeutic challenge as evidenced by the largest global pediatric CD19-CAR experience which showed 15 of 16 relapses to be explained by CD19 downregulation (Maude et al, NEJM 2018). Alternatively targeting CD22 using CD22-CAR therapy has demonstrated a CR rate of approximately 70% in both CD19+ and CD19- B-ALL, however relapse due to CD22 downregulation limits the curative potential of singularly-targeting CD22 (Fry et al, Nat Med. 2018). We hypothesized that simultaneous targeting of CD19 and CD22 via a bispecific CAR-T cell would be a safe and tolerable treatment strategy in relapsed/refractory B-cell ALL and address immune evasion. Here, we report the first clinical experience in pediatric patients using bispecific CD19-CD22 CAR T cells. We describe a single institution phase I dose escalation study in pediatric patients with relapsed or refractory B cell ALL. We utilized lentiviral transduction of a bivalent CAR construct incorporating the fmc63 CD19 and m971 CD22 single chain variable fragments (scFvs) used in clinically tested CAR constructs and a 41BB costimulatory endodomain (Fry et al, Nat Med. 2018). Our primary objectives are feasibility of production of this bivalent CAR and safety at 3 dose escalation levels (1x106, 3x106 and 1x107 CAR T cells/kg). Clinical response assessment is evaluated as a secondary aim. All patients described received lymphodepletion with fludarabine (25mg/m2 x 3 days) and cyclophosphamide (900mg/m2 x 1) followed by fresh or cryopreserved CAR T cell infusion after a 7-9 day production time. Patients were prospectively monitored at predefined intervals for disease response and correlative assessments. Four pediatric patients with precursor-B ALL, age 2-17, have been enrolled and treated with CD19/CD22 bispecific CAR T cells at dose level 1 (1x106) [Table 1]. Three patients entered CAR therapy with low disease burden detected by minimal residual disease (MRD) alone and 1 patient initiated therapy with 12% bone marrow blasts. All patients were CNS1 at time of treatment. The toxicity profile mirrored that of the singular CD19 and CD22 CAR experience with 3 patients experiencing reversible CRS (2 Grade I, 1 Grade II), onset day 3-8, and 2 patients experiencing grade I neurotoxicity, onset day 3-9. In our cohort, we experienced lower grade toxicities than previously reported, likely due to a mean lower disease burden. Only 1 patient with CRS met criteria for tocilizumab and this patient was the singular study patient treated with higher burden disease. Neurotoxicity was managed with supportive care and fully reversible. Peripheral blood flow cytometry analysis detects circulating CAR by day 6 in all patients and demonstrates peak CAR expansion between day 6-10. Peak CAR T expansion reached levels of 10-25% of total T cells with inter-patient variability in CD4 and CD8 predominance, favoring CD8 expansion in 3 of 4 patients. Clinical symptoms and inflammatory markers expectedly correlate with peak CAR expansion. Four of 4 patients achieved complete remission (CR) at day 28 post-CD19/CD22 bispecific CAR therapy. Three of 4 patients demonstrated MRD- remissions by flow cytometry and of these, next generation sequencing (NGS) was negative where available (N=2). Multi-parametric CyTOF studies permitting CAR T cell phenotyping in conjunction with single cell TCR tracking, proteomics, epigenomics and cytokine profiling are ongoing and will be used to further characterize persisting CAR T cells and define inter-product and inter-patient variability. In this phase I study, we demonstrate safety and tolerability of this bispecific CD19/CD22 CAR at a dose of 1x106 CAR T cells/kg in pediatric patients with relapsed/refractory B cell ALL. The CD19/22-bispecific CAR mediated antileukemic activity in 100% of patients studied thus far. Long-term follow up and further accrual will be required to inform the effect of bispecific CAR targeting on surface antigen remodeling. Disclosures Muffly: Adaptive Biotechnologies: Research Funding; Shire Pharmaceuticals: Research Funding. Miklos:Genentech: Research Funding; Kite - Gilead: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Pharmacyclics - Abbot: Consultancy, Research Funding; Adaptive Biotechnologies: Consultancy, Research Funding; Novartis: Consultancy, Research Funding.


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