scholarly journals Therapeutic Targeting of Monokine Production Is a Promising Strategy to Attenuate Cytokine-Release Syndrome in CAR-T Cell Therapy

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2067-2067
Author(s):  
Muneyoshi Futami ◽  
Keisuke Suzuki ◽  
Satomi Kato ◽  
Yoshio Tahara ◽  
Yoichi Imai ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Research Funding ◽  
Cytokine Production ◽  
Cytokine Release ◽  
Killing Effect ◽  
Car T Cells ◽  
Car T Cell ◽  
Tnf Α ◽  
Car T

Cancer immunotherapy using chimeric antigen receptor-armed T cells (CAR-T cells) have shown excellent outcomes in hematological malignancies. However, cytokine release syndrome (CRS), characterized by excessive activation of CAR-T cells and macrophages remains to be overcome. Steroid administration usually resolves signs and symptoms of CRS but abrogates CAR-T cell expansion and persistence. Tocilizumab, a humanized monoclonal antibody against interleukin-6 receptor (IL-6R), attenuates CRS without significant loss of CAR-T cell activities, while perfect rescue of CRS symptoms cannot be achieved by IL-6/IL-6R blockade. There is actual need for novel strategies to prevent or cure CRS. TO-207, an N-benzoyl-L-phenylalanine derivative compound, significantly inhibits inflammatory cytokine production in a human monocyte/macrophage-specific manner. Here we tested TO-207 for its ability to inhibit cytokine production without impaired CAR-T cell function in a CRS-simulating co-culture system consisting of CAR-T cells, target leukemic cells and monocytes. To observe a precise pattern of cytokine release from CAR-T cells and monocytes, we first established a co-culture system that mimics CRS using K562/CD19 cells, 19-28z CAR-T cells, and peripheral blood CD14+ cells. IFN-γ was produced exclusively from CAR-T cells, and TNF-α, MIP-1α, M-CSF, and IL-6 were produced from both CAR-T cells and monocytes, but monocytes were the major source of these cytokine production. MCP-1, IL-1β, IL-8, and IL-10 were released exclusively from monocytes. To observe the effect of drugs on cytokine production, prednisolone (PSL), TO-207, tocilizumab, and anakinra (an IL-1R antagonist) were added to the co-culture. PSL exhibited suppressive effects on TNF-α and MCP-1 production. Tocilizumab did not suppress these cytokines. Anakinra up-regulated IL-6 and IL-1β production, probably due to activation of negative feedback loops. Interestingly, TO-207 widely suppressed all of these monocyte-derived cytokines including TNF-α, IL-6, IL-1β, MCP-1, IL-8, and GM-CSF. Next, we observed whether the cytokine inhibition by TO-207 attenuates killing effect of CAR-T cells. PSL attenuated killing effect of CD4+ CAR-T cells and CD8+ CAR-T cells toward K562/CD19 cells. In contrast, TO-207 did not exhibit any change in cytotoxicity of CD4+ CAR-T cells and CD8+ CAR-T cells. To determine whether the effect of PSL and TO-207 on cytotoxicity changes in the presence of CD14+ monocytes, CD14+ cells were added to the co-culture. In the absence of CAR-T cells, PSL induced a modest attenuation of cytotoxicity, whereas to the CAR-T cells, PSL exhibited a significant attenuation of cytotoxicity. TO-207 exhibited a minimal effect on cytotoxicity in the absence or presence of CAR-T cells. These results suggested that CAR-T cells play a major role in the cytotoxicity toward leukemia cells, and drugs that do not affect CAR-T cell functions, such as TO-207, maintain their cytotoxic effects on leukemia cells. In conclusion, our present co-culture model with K562/CD19 cells, 19-28z CAR-T cells, and CD14+ monocytes accurately recapitulate killing effect and cytokine release profiles. IFN-γ was produced exclusively by CAR-T cells, but majority of other cytokines such as TNF-α, MIP-1α, M-CSF, IL-6, MCP-1, IL-1β, IL-8, and IL-10 were from CD14+ monocytes/macrophages. Because killing effect was largely dependent on CAR-T cells while cytokine production was dependent on monocytes/macrophages, selective inhibition of pro-inflammatory cytokines from monocytes by TO-207 would be ideal for treatment of CAR-T-related CRS. These results encourage us to consider a clinical application for CRS. Figure Disclosures Futami: Torii Pharmaceutical: Research Funding. Suzuki:Torii Pharmaceutical: Employment. Kato:Torii Pharmmaceutical: Research Funding. Tahara:Torii Pharmaceutical: Employment. Imai:Celgene: Honoraria, Research Funding; Janssen Pharmaceutical K.K: Honoraria, Research Funding; Bristol-Myers Squibb: Research Funding. Mimura:Torii Pharmaceutical: Employment. Watanabe:Torii Pharmaceutical: Employment. Tojo:AMED: Research Funding; Torii Pharmaceutical: Research Funding.

scholarly journals B-CLL Mediated Resistance to CAR T Cell Therapy Via Insufficient Activation Is CAR-Independent

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 44-44
Author(s):  
McKensie Collins ◽  
Weimin Kong ◽  
Inyoung Jung ◽  
Stefan M Lundh ◽  
J. Joseph Melenhorst
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Research Funding ◽  
Cytokine Production ◽  
Cell Function ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Chronic Lymphocytic Leukemia (CLL) is a B cell malignancy that accounts for nearly 1/3rd of adult leukemia diagnoses in the Western world. Conventional chemo-immunotherapies initially control progression, but in the absence of curative options patients ultimately succumb to their disease. Chimeric Antigen Receptor (CAR) T cell therapy is potentially curative, but only 26% of CLL patients have a complete response. CLL-stimulated T cells have reduced effector functions and B-CLL cells themselves are believed to be immunosuppressive. Our work demonstrates that insufficient activation of CAR T cells by CLL cells mediates some of these effects and that the results are conserved between ROR1- and CD19-targeting CARs. Results: In this study we used an in vitro system to model the in vivo anti-tumor response in which CAR T cells serially engage with CLL cells. Multiple stimulations of CD19 or ROR1-targeting CAR T cells with primary CLL cells recapitulated many aspects of known T cell dysfunction including reduced proliferation, cytokine production, and activation. While the initial stimulation induced low level proliferation, subsequent stimulations failed to elicit additional effector functions. We further found that these functional defects were not permanent, and that CAR T cell function could be restored by switching to a stimulus with an aAPC (artificial Antigen Presenting Cell) control cell line. The aAPCs are well-characterized as potent stimulators of CAR T cell effector responses. Flow cytometry revealed that CLL-stimulated CAR T cells retained a non-activated, baseline differentiation profile, suggesting that CLL cells fail to stimulate CAR T cells rather than rendering them non-functional. One mechanism that could dampen activation is immune suppression. We assessed this at a high level by stimulating CAR T cells with CLL cells and aAPCs mixed at known ratios. However, even cultures containing 75% CLL cells stimulated proliferation and cytokine production. Extensive immune-phenotyping revealed high level expression of the IL-2 Receptor on 90% (18/20) of the B-CLL cells tested. Since cytokine sinking via IL-2 receptor expression is a well-known mechanism of regulatory T cell suppression, we hypothesized that CLL cells similarly sink IL-2, blunting T cell activation. To test this, we supplemented IL-2 into CLL/CAR T cell co-cultures and showed that this rescued proliferation but only partially restored cytokine production. In contrast to our hypothesis, analysis of cytokine production by flow cytometry showed that CLL-stimulated CAR T cells did not produce IL-2 following a 6- or 12-hour stimulus, but TNFα was expressed after 12-hours. Similarly, CAR T cell degranulation, a prerequisite for target cell lysis was triggered after CLL recognition. These data again suggested that CLL cells insufficiently stimulate CAR T cell cytokine production, but also showed that cytolytic activity against CLL cells is intact. We further proposed that CLL cells express insufficient levels of co-stimulatory and adhesion molecules to activate CAR T cells. Flow cytometry showed that most CLL cells expressed co-stimulatory and adhesion molecules at low levels; we hypothesized that up-regulating these molecules would enhance CAR T cell targeting of CLL cells. CLL cells were activated with CD40L and IL-4, which increased expression of CD54, CD58, CD80, and CD86. Stimulating CAR T cells with activated CLL cells enhanced CAR T cell proliferation and induced cell conjugate formation, indicating cell activation. Therefore, improving CLL stimulatory capacity can rescue T cell dysfunctions. To assess whether IL-2 addition and CD40 ligation were synergistic, we combined the two assays; however, we saw no additional improvement over IL-2 addition alone, suggesting that the two interventions may act upon the same pathway. Importantly, we also showed that rescue of CAR T cell function via IL-2 addition or CD40 ligation was not CAR-specific, as we observed the functional defects and subsequent rescue with both a ROR1-targeting CAR and the gold standard CD19-targeting CAR. Conclusions: Together, these data show that CAR T cell "defects" in CLL are actually insufficient activation, and improving the stimulatory capacity of CLL cells may enable better clinical responses. Further, this effect is not CAR-specific and these results may therefore be broadly applicable to multiple therapies for this disease. Disclosures Melenhorst: IASO Biotherapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kite Pharma: Research Funding; Novartis: Other: Speaker, Research Funding; Johnson & Johnson: Consultancy, Other: Speaker; Simcere of America: Consultancy; Poseida Therapeutics: Consultancy.

CAR-T Therapy for Lymphoma with Prophylactic Tocilizumab: Decreased Rates of Severe Cytokine Release Syndrome without Excessive Neurologic Toxicity

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 30-31 ◽  
Author(s):  
Paolo F Caimi ◽  
Ashish Sharma ◽  
Patricio Rojas ◽  
Seema Patel ◽  
Jane Reese ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Research Funding ◽  
Advisory Board ◽  
Cytokine Release ◽  
Cytokine Release Syndrome ◽  
Car T Cells ◽  
Car T Cell ◽  
Significant Difference ◽  
Car T

INTRODUCTION: Anti-CD19 chimeric antigen receptor T (CAR-T) cells have demonstrated activity against relapsed/refractory lymphomas. Cytokine release syndrome (CRS) and CAR-T related encephalopathy syndrome (CRES/ICANS) are well-known complications of CAR-T cell therapy. Tocilizumab, a humanized monoclonal antibody targeting the interleukin 6 (IL-6) receptor, is approved for treatment of CRS. Our institutional standard was modified to administer prophylactic tocilizumab before infusion CAR-T cell products. We present the outcomes of subjects treated with locally manufactured antiCD19 CAR-T cells (TNFRSF19 transmembrane domain, CD3Zeta/4-1BB costimulatory signaling) with and without prophylactic tocilizumab. METHODS: Relapsed / refractory (r/r) lymphoma patients (pts) treated with anti-CD19 CAR-T cells at our institution were included. Baseline demographic and clinical characteristics, as well as laboratory results were obtained from our Hematologic Malignancies and Stem Cell Therapy Database. Prior to institution of prophylactic tocilizumab, pts received this agent only if they presented evidence of CRS grade 2 or higher. In May 2019, our institutional practice changed to provide tocilizumab 8mg/kg, 1 hour prior to infusion of CAR-T cell product. CRS was measured according to the ASTCT Consensus Grading, whereas CRES was measured using the CARTOX-10 criteria. Comparisons between groups were done with the Mann-Whitney U test for continuous variables and Fisher's exact test for categorical variables. RESULTS: Twenty-three relapsed / refractory lymphoma pts were treated with antiCD19 CAR-T cells; 15 pts received prophylactic tocilizumab. Median follow up was 312 days (range 64 - 679) days. Baseline characteristics are listed in table 1. Both groups were similar: There were no statistically differences in the rate of bulky, refractory disease, prior ASCT or number or prior lines of therapy. Baseline lymphocyte counts, C - reactive protein (CRP) and were also comparable between groups (Table 2). We did not observe immune adverse reactions to tocilizumab infusion. There were no differences in the incidence of cytopenias or infectious complications between groups. CRS of any grade was observed in 6/8 (75%) of pts without prophylactic tocilizumab vs. 6/15 (40%) in pts treated with prophylactic tocilizumab (p = 0.23), whereas CRS grade >1 was observed in 5 pts (62.5%) without prophylactic tocilizumab and in 3 pts (20%) treated with prophylactic tocilizumab (p = 0.02). There was no significant difference in the incidence of all grade CRES (no prophylaxis, 3/8 [38%] pts; prophylaxis 5/15 [30%] pts, p = 0.2969). There was a statistically significant difference in the peak CRP and peak ferritin without difference in the peak lymphocyte count after CAR-T infusion (Table 2, Figure 1). Patients given prophylactic tocilizumab had higher IL-6 plasma concentrations on day 2 after infusion (Figure 2). Complete response was observed in 4/8 (50%) pts without prophylactic tocilizumab vs. 12/15 (80%) pts with prophylactic tocilizumab (p = 0.18). All pts had detectable Anti-CD19 CAR-T cells on day 30, both groups had peak CAR-T expansion on day 14, with no statistically significant differences in expansion rates between groups. All evaluable subjects have had CAR-T persistence on days 60, 90, 180, and 365. CONCLUSIONS: Use of prophylactic tocilizumab prior to infusion of antiCD19 CAR-T cells is associated with reduced incidence of severe CRS and decreased levels of clinical laboratory markers of inflammation, despite increases in plasma concentration of IL-6. This decreased rate of grade ≥2 CRS is not associated with impaired disease control and did not result in increased rates of neurologic toxicity. Prophylactic tocilizumab does not appear to affect CAR-T cell expansion or persistence. Figure 1 Disclosures Caimi: ADC therapeutics: Other: Advisory Board, Research Funding; Celgene: Speakers Bureau; Amgen: Other: Advisory Board; Bayer: Other: Advisory Board; Verastem: Other: Advisory Board; Kite pharmaceuticals: Other: Advisory Board. Worden:Lentigen, a Miltenyi biotec company: Current Employment. Kadan:Lentigen, a Miltenyi biotec company: Current Employment. Orentas:Lentigen Technology, a Miltenyi Biotec Company: Research Funding. Dropulic:Lentigen, a Miltenyi Biotec Company: Current Employment, Patents & Royalties: CAR-T immunotherapy. de Lima:Celgene: Research Funding; Pfizer: Other: Personal fees, advisory board, Research Funding; Kadmon: Other: Personal Fees, Advisory board; Incyte: Other: Personal Fees, advisory board; BMS: Other: Personal Fees, advisory board. OffLabel Disclosure: Use of tocilizumab as prophylaxis for CRS is not approved, whereas use for treatment is approved and on label.

scholarly journals Biomarkers Accurately Predict Cytokine Release Syndrome (CRS) after Chimeric Antigen Receptor (CAR) T Cell Therapy for Acute Lymphoblastic Leukemia (ALL)

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1334-1334 ◽  
Author(s):  
David T Teachey ◽  
Simon F. Lacey ◽  
Pamela A Shaw ◽  
J Joseph Melenhorst ◽  
Noelle V. Frey ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Research Funding ◽  
Disease Burden ◽  
Clinical Laboratory ◽  
University Of Pennsylvania ◽  
Cytokine Release ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Abstract CAR T cells with anti-CD19 specificity have demonstrated considerable promise against highly refractory hematologic malignancies. Dramatic responses with complete remission rates as high as 90% have been reported in patients (pts) with relapsed/refractory ALL treated with CTL019 (Maude et al., NEJM 2014). Marked in vivo CAR T cell proliferation (100 to 100,000x) leads to improved efficacy but can be associated with adverse events, including cytokine release syndrome (CRS). To better understand manifestations of CRS, we studied clinical, laboratory, and biomarker data of 39 children and 12 adults with relapsed/refractory ALL treated with anti-CD19 CAR T cells. T cells were lentivirally transduced with a CAR composed of anti-CD19 single chain variable fragment/4-1BB/CD3 (Porter, NEJM 2011). 43 cytokines, chemokines, and soluble receptors (collectively termed cytokines hereafter) were serially measured, using Luminex bead array. Other biomarkers were tested in a CLIA/CAP certified lab. 48 of 51 pts developed grade 1-5 CRS (CRS1-5) (see Table). Most pts developed mild (grade 1-2) to moderate (grade 3) CRS (34/51). 14 pts developed severe (grade 4-5) CRS (12 grade 4, 2 adults with grade 5). 21 pts were treated with the IL-6 inhibitor tocilizumab, and most had rapid marked clinical improvement in CRS evidenced by quick resolution of fever and weaning of vasoactive medications. We found peak levels of 24 cytokines, including IFNg, IL6, IL8, sIL2Ra, sgp130, sIL6R, MCP1, MIP1a, and GM-CSF during the first month after CTL019 infusion were highly associated with CRS4-5 compared to CRS0-3, significant by the Holm-Bonferroni adjusted p-value. Analyzing cytokines from the first 3 days after infusion, sent before patients developed severe CRS, only 2 cytokines, sgp130 and IFNg, were strongly associated with later development of severe CRS (p<0.001) and significant by Holm-Bonferroni. With a 3 variable regression model, found by forward selection, we accurately predicted which pts developed severe CRS using IFNg, sgp130, and IL1Ra (PPV 75%, NPV 94%, sensitivity 86%, specificity 89%, AUC=0.93). For the pediatric cohort, the modeling was even more accurate; a combination of IFNg, IL13, and MIP1a had PPV 92%, NPV 100%, sensitivity 100%, and specificity 96% (AUC=0.98). In the pediatric cohort only, a bone marrow aspirate was collected immediately prior to infusion. We found disease burden was associated with CRS severity but did not improve the predictive accuracy of the models over the cytokines alone. A combination of sgp130, IFNg and disease burden yielded PPV 77%, NPV 96%, sensitivity 91%, and specificity 88% (AUC 0.95). We are validating our models in an additional cohort and will present those data. The 1-month peak of several clinical laboratory tests were strongly associated with severe CRS, including CRP, ferritin, LDH, AST, and BUN; however, they were not predictive of severe CRS. Some of these, including CRP, had a good NPV for early prediction but none had a good PPV. We hypothesized and demonstrated that children with severe CRS develop clinical and laboratory manifestations similar to macrophage activation syndrome (MAS)/hemophagocytic syndrome (HLH), including hyperferritinemia (>10,000ng/ml), splenomegaly, and hypofibrinogenemia. Of the tested cytokines, 18 have been previously studied in children with HLH. We found a near identical pattern of cytokines differentially elevated in HLH also elevated in pts with CRS4-5 compared with CRS0-3. IL6, sIL6R, and sgp130 were markedly elevated in pts with CRS4-5; this IL6 cytokine pattern, along with the pronounced response to tocilizumab, establishes that IL6 trans-signaling is clinically relevant. These data represent the largest and most comprehensive profiling of the clinical and laboratory manifestations of CAR T cell related CRS and provide novel insights into CRS biology. They represent the first data that can accurately predict which pts treated with CAR T cells have a high probability of becoming critically ill. These data have direct therapeutic relevance and may guide future cytokine directed therapy. The first 4 authors contributed equally. Table 1. CRS grading Gr1 Supportive care only Gr2 IV therapies +/- hospitalization. Gr3 Hypotension requiring IV fluids or low-dose vasoactives or hypoxemia requiring oxygen, CPAP, or BIPAP. Gr4 Hypotension requiring high-dose vasoactives or hypoxemia requiring mechanical ventilation. Gr 5 Death Disclosures Teachey: Novartis: Research Funding. Off Label Use: tocilizumab. Lacey:Novartis: Research Funding. Shaw:Novartis: Research Funding. Melenhorst:Novartis: Research Funding. Frey:Novartis: Research Funding. Maude:Novartis: Consultancy, Research Funding. Aplenc:Sigma Tau: Consultancy. Chen:Novartis: Research Funding. Gonzalez:Novartis: Research Funding. Pequignot:Novartis: Research Funding. Rheingold:Endo: Other: Husband's employer, has equity interest; Novartis: Consultancy. June:Novartis: Research Funding; University of Pennsylvania: Patents & Royalties: financial interests due to intellectual property and patents in the field of cell and gene therapy. Conflicts of interest are managed in accordance with University of Pennsylvania policy and oversight. Porter:Novartis: Patents & Royalties, Research Funding; Genentech: Other: Spouse Employment. Grupp:Novartis: Research Funding.

scholarly journals Automated Manufacture of Matched Donor-Derived Allogeneic CD19 CAR T-Cells for Relapsed/Refractory B-ALL Following Allogeneic Stem Cell Transplantation: Toxicity, Efficacy and the Important Role of Lymphodepletion

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 776-776
Author(s):  
Claire Roddie ◽  
Maeve A O'Reilly ◽  
Maria A V Marzolini ◽  
Leigh Wood ◽  
Juliana Dias Alves Pinto ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
Advisory Committees ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Peak Car ◽  
Matched Donor

Introduction: 2nd generation CD19 CAR T cells show unprecedented efficacy in B-ALL, but several challenges remain: (1) scaling manufacture to meet patient need and (2) feasibility of generating products from lymphopenic patients post allogeneic stem cell transplant (allo-SCT). To overcome these issues we propose: (1) use of the CliniMACS Prodigy (Miltenyi Biotec), a semi-automated cGMP platform that simplifies CAR T cell manufacture and (2) the use of matched donor T cells to overcome the challenge posed by patient lymphopenia, albeit this may come with a heightened risk of graft versus host disease (GvHD). CARD (NCT02893189) is a Phase I study of matched donor derived CD19 CAR T cells generated on the CliniMACS Prodigy in 14 adult patients with relapsed/refractory (r/r) B ALL following allo-SCT. We additionally explore the requirement for lymphodepletion (LD) in the allogeneic CAR T cell setting and report on the incidence of GvHD with this therapy. Methods: Manufacturing: CARD utilises non-mobilised matched donor leucapheresate to manufacture 2nd generation CD19CAR T cells using a closed CliniMACS® Prodigy/ TransACTTM process. Study design: Eligible subjects are aged 16-70y with r/r B ALL following allo SCT. Study endpoints include feasibility of CD19CAR T cell manufacture from allo-SCT donors on the CliniMACS Prodigy and assessments of engraftment and safety including GvHD. To assess the requirement for LD prior to CD19CAR T cells in lymphopenic post-allo-SCT patients, the study is split into Cohort 1 (no LD) and Cohort 2 (fludarabine (30 mg/m2 x3) and cyclophosphamide (300mg/m2 x3)). To mitigate for the potential GvHD risk, cell dosing on study mirrors conventional donor lymphocyte infusion (DLI) schedules and is based on total CD3+ (not CAR T) cell numbers: Dose 1=1x106/kg CD3+ T cells; Dose 2= 3x106/kg CD3+ T cells; Dose 3= 1x107/kg CD3+ T cells. Results: As of 26 July 2019, 17 matched allo SCT donors were leukapheresed and 16 products were successfully manufactured and QP released. Patient demographics are as follows: (1) median patient age was 43y (range 19-64y); (2) 4/17 had prior blinatumomab and 5/17 prior inotuzumab ozogamicin; (3) 7/17 had myeloablative allo SCT and 10/17 reduced intensity allo SCT of which 6/17 were sibling donors and 12/17 were matched unrelated donors. No patients with haploidentical transplant were enrolled. To date, 12/16 patients have received at least 1 dose of CD19CAR T cells: 7/16 on Cohort 1 and 5/16 on Cohort 2 (2/16 are pending infusion on Cohort 2 and 2/16 died of fungal infection prior to infusion). Median follow-up for all 12 patients is 22.9 months (IQR 2.9-25.9; range 0.7 - 25.9). At the time of CAR T cell infusion, 7/12 patients were in morphological relapse with &gt;5% leukemic blasts. Despite this, CD19CAR T cells were administered safely: only 2/12 patients experienced Grade 3 CRS (UPenn criteria), both in Cohort 1, which fully resolved with Tocilizumab and corticosteroids. No patients experienced ≥Grade 3 neurotoxicity and importantly, no patients experienced clinically significant GvHD. In Cohort 1 (7 patients), median peak CAR expansion by flow was 87 CD19CAR/uL blood whereas in Cohort 2 (5 patients to date), median peak CAR expansion was 1309 CD19CAR/uL blood. This difference is likely to reflect the use of LD in Cohort 2. CAR T cell persistence by qPCR in Cohort 1 is short, with demonstrable CAR in only 2/7 treated patients at Month 2. Data for Cohort 2 is immature, but this will also be reported at the meeting in addition to potential mechanisms underlying the short persistence observed in Cohort 1. Of the 10 response evaluable patients (2/12 pending marrow assessment), 9/10 (90%) achieved flow/molecular MRD negative CR at 6 weeks. 2/9 responders experienced CD19 negative relapse (one at M3, one at M5) and 3/9 responders experienced CD19+ relapse (one at M3, one at M9, one at M12). 4/10 (40%) response evaluable patients remain on study and continue in flow/molecular MRD negative remission at a median follow up of 11.9 months (range 2.9-25.9). Conclusions: Donor-derived matched allogeneic CD19 CAR T cells are straightforward to manufacture using the CliniMACS Prodigy and deliver excellent early remission rates, with 90% MRD negative CR observed at Week 6 in the absence of severe CAR associated toxicity or GvHD. Peak CAR expansion appears to be compromised by the absence of LD and this may lead to a higher relapse rate. Updated results from Cohorts 1 and 2 will be presented. Disclosures Roddie: Novartis: Consultancy; Gilead: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau. O'Reilly:Kite Gilead: Honoraria. Farzaneh:Autolus Ltd: Equity Ownership, Research Funding. Qasim:Autolus: Equity Ownership; Orchard Therapeutics: Equity Ownership; UCLB: Other: revenue share eligibility; Servier: Research Funding; Bellicum: Research Funding; CellMedica: Research Funding. Linch:Autolus: Membership on an entity's Board of Directors or advisory committees. Pule:Autolus: Membership on an entity's Board of Directors or advisory committees. Peggs:Gilead: Consultancy, Speakers Bureau; Autolus: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Human CD83 Targeted Chimeric Antigen Receptor T Cell for the Prevention of Graft Versus Host Disease and Treatment of Myeloid Leukemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 196-196
Author(s):  
Bishwas Shrestha ◽  
Kelly Walton ◽  
Jordan Reff ◽  
Elizabeth M. Sagatys ◽  
Nhan Tu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
Advisory Committees ◽  
Graft Versus Host ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Fund Research

Distinct from pharmacologic immunosuppression, we designed a programmed cytolytic effector T cell that prevents graft versus host disease (GVHD). CD83 is expressed on allo-activated conventional T cells (Tconv) and pro-inflammatory dendritic cells (DCs), which are implicated in GVHD pathogenesis. Therefore we developed a novel human CD83 targeted chimeric antigen receptor (CAR) T cell for GVHD prophylaxis. Here we demonstrate that human CD83 CAR T cells eradicate cell mediators of GVHD, significantly increase the ratio of regulatory T cells (Treg) to allo-activated Tconv, and provide lasting protection from xenogeneic GVHD. Further, we show human, acute myeloid leukemia (AML) expresses CD83 and can be targeted by CD83 CAR T cells. A 2nd generation CD83 CAR was generated with CD3ζ and 41BB costimulatory domain that was retrovirally transduced in human T cells to generate CD83 CAR T cells. The CD83 CAR construct exhibited a high degree of transduction efficiency of about 60%. The CD83 CAR T cells demonstrated robust IFN-γ and IL-2 production, killing, and proliferation when cultured with CD83+ target cells. To test whether human CD83 CAR T cells reduce alloreactivity in vitro, we investigated their suppressive function in allogeneic mixed leukocyte reactions (alloMLR). CD83 CAR T cells were added to 5-day alloMLRs consisting of autologous T cells and allogeneic monocyte-derived DCs at ratios ranging from 3:1 to 1:10. The CD83 CAR T cells potently reduced alloreactive T cell proliferation compared to mock transduced and CD19 CAR T cells. We identified that CD83 is differentially expressed on alloreactive Tconv, compared to Tregs. Moreover, the CD83 CAR T cell efficiently depletes CD83+ Tconv and proinflammatory DCs with 48 hours of engagement. To test the efficacy of human CD83 CAR T cells in vivo, we used an established xenogeneic GVHD model, where mice were inoculated with human PBMCs (25x106) and autologous CD83 CAR (1-10x106) or mock transduced T cells. The CD83 CAR T cells were well tolerated by the mice, and significantly improved survival compared to mock transduced T cells (Figure 1A). Mice treated with CD83 CAR T cells exhibited negligible GVHD target organ damage at day +21 (Figure 1B). Mice inoculated with CD83 CAR T cells demonstrated significantly fewer CD1c+, CD83+ DCs (1.7x106 v 6.2x105, P=0.002), CD4+, CD83+ T cells (4.8x103 v 5.8x102, P=0.005), and pathogenic Th1 cells (3.1x105 v 1.1x102, P=0.005) at day +21, compared to mice treated with mock transduced T cells. Moreover, the ratio of Treg to alloreactive Tconv (CD25+ non-Treg) was significantly increased among mice treated with CD83 CAR T cells (78 v 346, P=0.02), compared to mice injected with mock transduced T cells. Further, CD83 appears to be a promising candidate to target myeloid malignancies. We observed CD83 expression on malignant myeloid K562, Thp-1, U937, and MOLM-13 cells. Moreover, the CD83 CAR T cells effectively killed AML cell lines. Many AML antigens are expressed on progenitor stem cells. Thus, we evaluated for stem cell killing in human colony forming unit (CFU) assays, which demonstrated negligible on-target, off-tumor toxicity. Therefore, the human CD83 CAR T cell is an innovative cell-based approach to prevent GVHD, while providing direct anti-tumor activity against myeloid malignancies. Figure Disclosures Blazar: Kamon Pharmaceuticals, Inc: Membership on an entity's Board of Directors or advisory committees; Five Prime Therapeutics Inc: Co-Founder, Membership on an entity's Board of Directors or advisory committees; BlueRock Therapeutics: Membership on an entity's Board of Directors or advisory committees; Abbvie Inc: Research Funding; Leukemia and Lymphoma Society: Research Funding; Childrens' Cancer Research Fund: Research Funding; KidsFirst Fund: Research Funding; Tmunity: Other: Co-Founder; Alpine Immune Sciences, Inc.: Research Funding; RXi Pharmaceuticals: Research Funding; Fate Therapeutics, Inc.: Research Funding; Magenta Therapeutics and BlueRock Therapeuetics: Membership on an entity's Board of Directors or advisory committees; Regeneron Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Davila:Atara: Research Funding; Celgene: Research Funding; Precision Biosciences: Consultancy; Bellicum: Consultancy; GlaxoSmithKline: Consultancy; Adaptive: Consultancy; Anixa: Consultancy; Novartis: Research Funding.

scholarly journals Treatment with Acalibrutinib, Ibrutinib and CD19 CAR T Cells Restore the Number of Granulocytic Myeloid Derived Supressor Cells in CLL-Bearing Mice

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3032-3032
Author(s):  
Arantxa Romero-Toledo ◽  
Robin Sanderson ◽  
John G. Gribben
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Population ◽  
Research Funding ◽  
Cell Function ◽  
Car T Cells ◽  
Car T Cell ◽  
T Cell Function ◽  
Car T ◽  
Secondary Lymphoid Organs

The complex crosstalk between malignant chronic lymphocytic leukemia (CLL) cells and the tumor microenvironment (TME) is not fully understood. CLL is associated with an inflammatory TME and T cells exhibit exhaustion and multiple functional defects, fully recapitulated in Eµ-TCL1 (TCL1) mice and induced in healthy mice by adoptive transfer (AT) of murine CLL cells, making it an ideal model to test novel immunotherapies for this disease. Myeloid-derived suppressor cells (MDSCs), a non-leukemic cell type within the TME, are immature myeloid cells with the ability to suppress T cell function and promote Treg expansion. In humans, CLL cells can induce conversion of monocytes to MDSCs provoking their accumulation in peripheral blood (PB). MDSCs include two major subsets granulocytic (Gr) and monocytic (M)-MDSC. In mice, Gr-MDSCs are defined as CD11b+Ly6G+Ly6Clo and M-MDSC as CD11b+Ly6G-Ly6Chi. Both murine and human MDSCs express BTK. We observed that in CLL-bearing mice, MDSCs cells are lost in PB as disease progresses. Treatment with both BTK inhibitors (BTKi), ibrutinib (Ibr) and acalabrutinib (Acala), result in shift of T cell function from Th2 towards Th1 polarity and increase MDSC populations in vivo. We aimed to determine whether combination treatment with BTKi and chimeric antigen receptor (CAR) T cells renders recovery of the MDSC population in CLL-bearing mice. To address this question we designed a two-part experiment, aiming to mimic the clinically relevant scenario of pre-treatment of CLL with BTKi to improve CAR T cell function. Part 1 of our experiment consisted of 4 groups (n=12) of 2.5 month old C57/Bl6 mice. Three groups had AT with 30x106 TCL1 splenocytes. A fourth group of WT mice remained CLL-free as a positive control and donors for WT T cells. When PB CLL load reached >10% (day 14) animals were randomized to either Ibr or Acala at 0.15 mg/l in 2% HPBC or no treatment for 21 days. All animals from part 1 were culled at day 35 post-AT and splenic cells were isolated, analyzed and used to manufacture CAR T cells. WT, CLL, Ibr and Acala treated T cells were activated and transduced with a CD19-CD28 CAR to treat mice in part 2. Here, 50 WT mice were given AT with 20x106 TCL1 splenocytes for CLL engraftment. All mice were injected with lymphodepleting cyclophosphamide (100mg/kg IP) one day prior to IV CAR injection. At day 21 post-AT, mice were treated with WT CAR, CLL CAR, IbrCAR, AcalaCAR or untransduced T cells. MDSC sub-populations were monitored weekly in PB and SP were analysed by flow cytometry. As malignant CD19+CD5+ cells expands in PB, the overall myeloid (CD19-CD11b+) cell population was not affected, but MDSCs significantly decreased (p<0.0001). Treatment with Acala, but not Ibr restores total MDSCs. However, MDSC impairment occurs in the Gr- but not M- MDSC population and both Acala and Ibr restores this population (Figure 1a). When we examined the spleen, treatment with both Ibr (p<0.001) and Acala (p<0.001) reduced CD5+CD19+ cells, whereas neither BTKi affected the overall myeloid (CD19-CD11b+) cell population. Gr-MDSCs were restored by both treatments whilst M-MDSCs were only restored after Ibr treatment (p<0.001 in each case). In part 2 of this experiment we observed that treatment with all CAR-T cell groups provokes the clearance of all CD19+CD5+ cells. The overall CD19-CD11b+ population stays the same across all mice groups 35 days after treatment in PB with any group of CAR and untransduced T cells. Overall MDSC population is maintained following all CAR T cells compared to CLL-bearing mice (p<0.0001) and it is the Gr- but not the M- MDSC population which is recovered in PB (Figure 1b). These parts of the experiments can of course be influenced by treatment with cyclophosphamide. We conclude that novel therapies for CLL treatment have an effect not only in CLL cells but also in non-malignant cell components of the TME. In this animal model of CLL, the rapid expansion of CLL cells in PB and secondary lymphoid organs provokes loss of MDSC, particularly the Gr-MDSC subpopulation is affected. Treatment with BTKi and CAR T cells provokes clearance of CLL cells in PB and spleen allowing MDSC recovery; suggesting this may be BTK and ITK independent. We continue to explore secondary lymphoid organs to further characterize the shift of the CLL microenvironment from an immunosuppressive to an immune effective one and its impact on immune function in this model. Disclosures Sanderson: Kite/Gilead: Honoraria. Gribben:Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Acerta/Astra Zeneca: Consultancy, Honoraria, Research Funding.

scholarly journals B Cell Maturation Antigen-Specific CAR T Cells for Relapsed or Refractory Multiple Myeloma: A Meta-Analysis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3113-3113 ◽  
Author(s):  
Nico Gagelmann ◽  
Francis Ayuketang Ayuk ◽  
Djordje Atanackovic ◽  
Nicolaus Kroeger
Keyword(s):  
T Cells ◽  
T Cell ◽  
High Risk ◽  
Research Funding ◽  
Response Rates ◽  
Overall Response ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Background Cellular immunotherapies represent an enormously promising strategy for relapsed/refractory multiple myeloma (RRMM). Chimeric antigen receptor (CAR) T cells targeting B cell maturation antigen (BCMA) have shown impressive results in early-phase clinical studies. Here, we summarize the current body of evidence on the role of anti-BCMA CAR T cell therapy for RRMM. Methods We performed a systematic literature review to identify all publicly available prospective studies. We searched Medline, Cochrane trials registry, and www.clinicaltrials.gov. To include the most recent evidence, meeting abstracts from international hematology congresses were added. A conventional meta-analysis was conducted using meta and metafor packages in R statistical software. Pooled event rates and 95% confidence intervals (CIs) were calculated using the inverse variance method within a random-effects framework. Main efficacy outcomes were overall response, complete response (CR), and minimal residual disease (MRD). Furthermore, relapse rates, progression-free survival, and overall survival were evaluated. In terms of safety, outcomes were cytokine release syndrome (CRS), neurotoxicity, and hematologic toxic effects. Results Fifteen studies comprising a total of 285 patients with heavily pretreated RRMM were included in quantitative analyses. Patients received a median of seven prior treatment lines (such as proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies, stem cell transplantation) which included autologous stem cell transplantation in 90% of patients. The median age of patients was 59 years and median follow-up duration ranged from 1.1 to 11.3 months. Most studies used 4-1BB (or CD137), a member of the TNF receptor superfamily, as an activation-induced T-cell costimulatory molecule. Most studies used fludarabine and cyclophosphamide for lymphodepletion while one study used busulfan and cyclophosphamide and one study used cyclophosphamide only. Most studies used the former Lee criteria for CRS grading. Anti-BCMA CAR T cells resulted in a pooled overall response of 82% (95% CI, 74-88%). The pooled proportion of CR in all evaluable patients was 36% (95% CI, 24-50%). Within responders, the pooled proportion of MRD negativity was 77% (95% CI, 67-85%). Higher dose levels of infused CAR+ cells were associated with higher overall response rates resulting in a pooled proportion of 88% (95% CI, 78-94%). In addition, peak CAR T cell expansion appeared to be associated with responses.The presence of high-risk cytogenetics appeared to be associated with lower overall response rates resulting in a pooled proportion of 68% (95% CI, 47-83%). The presence of extramedullary disease at time of infusion did not influence outcome and was associated with similar response rates compared with RRMM patients who did not have extramedullary disease, resulting in a pooled proportion of 78% (95% CI, 47-93%). The pooled relapse rate of all responders was 45% (95% CI, 27-64%) and the median progression-free survival was 10 months. In terms of overall survival, pooled survival rates were 84% (95% CI, 60-95%) at last follow-up (median, 11 months). In terms of safety, the pooled proportion of CRS of any grade was 69% (95% CI, 51-83%). Notably, the pooled proportions of CRS grades 3-4 and neurotoxicity were 15% (95% CI, 10-23%) and 18% (95% CI, 10-31%). Peak CAR T cell expansion appeared to be more likely in the setting of more severe CRS in three studies. Most hematologic toxic effects of grade 3 or higher were neutropenia (85%), thrombocytopenia (70%), and leukopenia (60%). Conclusion Anti-BCMA CAR T cells showed high response rates, even in high-risk features such as high-risk cytogenetics and extramedullary disease at time of CAR T cell infusion. Toxicity was manageable across all early-phase studies. However, almost half of the patients who achieved a response eventually relapsed. Larger studies with longer follow-up evaluating the association of response and survival are needed. Disclosures Ayuk: Novartis: Honoraria, Other: Advisory Board, Research Funding. Kroeger:Medac: Honoraria; Sanofi-Aventis: Honoraria; Neovii: Honoraria, Research Funding; Riemser: Research Funding; JAZZ: Honoraria; Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; DKMS: Research Funding.

scholarly journals Combination of NKTR-255, a Polymer Conjugated Human IL-15, with CD19 CAR T Cell Immunotherapy in a Preclinical Lymphoma Model

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2866-2866 ◽  
Author(s):  
Cassie Chou ◽  
Simon Fraessle ◽  
Rachel Steinmetz ◽  
Reed M. Hawkins ◽  
Tinh-Doan Phi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Research Funding ◽  
Board Member ◽  
Ad Hoc ◽  
Advisory Board ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Equity Ownership

Background CD19 CAR T immunotherapy has been successful in achieving durable remissions in some patients with relapsed/refractory B cell lymphomas, but disease progression and loss of CAR T cell persistence remains problematic. Interleukin 15 (IL-15) is known to support T cell proliferation and survival, and therefore may enhance CAR T cell efficacy, however, utilizing native IL-15 is challenging due to its short half-life and poor tolerability in the clinical setting. NKTR-255 is a polymer-conjugated IL-15 that retains binding affinity to IL15Rα and exhibits reduced clearance, providing sustained pharmacodynamic responses. We investigated the effects of NKTR-255 on human CD19 CAR T cells both in vitro and in an in vivo xenogeneic B cell lymphoma model and found improved survival of lymphoma bearing mice receiving NKTR-255 and CAR T cells compared to CAR T cells alone. Here, we extend upon these findings to further characterize CAR T cells in vivo and examine potential mechanisms underlying improved anti-tumor efficacy. Methods CD19 CAR T cells incorporating 4-1BB co-stimulation were generated from CD8 and CD4 T cells isolated from healthy donors. For in vitro studies, CAR T cells were incubated with NKTR-255 or native IL-15 with and without CD19 antigen. STAT5 phosphorylation, CAR T cell phenotype and CFSE dilution were assessed by flow cytometry and cytokine production by Luminex. For in vivo studies, NSG mice received 5x105 Raji lymphoma cells IV on day (D)-7 and a subtherapeutic dose (0.8x106) of CAR T cells (1:1 CD4:CD8) on D0. To determine optimal start date of NKTR-255, mice were treated weekly starting on D-1, 7, or 14 post CAR T cell infusion. Tumors were assessed by bioluminescence imaging. Tumor-free mice were re-challenged with Raji cells. For necropsy studies mice received NKTR-255 every 7 days following CAR T cell infusion and were euthanized at various timepoints post CAR T cell infusion. Results Treatment of CD8 and CD4 CAR T cells in vitro with NKTR-255 resulted in dose dependent STAT5 phosphorylation and antigen independent proliferation. Co-culture of CD8 CAR T cells with CD19 positive targets and NKTR-255 led to enhanced proliferation, expansion and TNFα and IFNγ production, particularly at lower effector to target ratios. Further studies showed that treatment of CD8 CAR T cells with NKTR-255 led to decreased expression of activated caspase 3 and increased expression of bcl-2. In Raji lymphoma bearing NSG mice, administration of NKTR-255 in combination with CAR T cells increased peak CAR T cell numbers, Ki-67 expression and persistence in the bone marrow compared to mice receiving CAR T cells alone. There was a higher percentage of EMRA like (CD45RA+CCR7-) CD4 and CD8 CAR T cells in NKTR-255 treated mice compared to mice treated with CAR T cells alone and persistent CAR T cells in mice treated with NKTR-255 were able to reject re-challenge of Raji tumor cells. Additionally, starting NKTR-255 on D7 post T cell infusion resulted in superior tumor control and survival compared to starting NKTR-255 on D-1 or D14. Conclusion Administration of NKTR-255 in combination with CD19 CAR T cells leads to improved anti-tumor efficacy making NKTR-255 an attractive candidate for enhancing CAR T cell therapy in the clinic. Disclosures Chou: Nektar Therapeutics: Other: Travel grant. Fraessle:Technical University of Munich: Patents & Royalties. Busch:Juno Therapeutics/Celgene: Consultancy, Equity Ownership, Research Funding; Kite Pharma: Equity Ownership; Technical University of Munich: Patents & Royalties. Miyazaki:Nektar Therapeutics: Employment, Equity Ownership. Marcondes:Nektar Therapeutics: Employment, Equity Ownership. Riddell:Juno Therapeutics: Equity Ownership, Patents & Royalties, Research Funding; Adaptive Biotechnologies: Consultancy; Lyell Immunopharma: Equity Ownership, Patents & Royalties, Research Funding. Turtle:Allogene: Other: Ad hoc advisory board member; Novartis: Other: Ad hoc advisory board member; Humanigen: Other: Ad hoc advisory board member; Nektar Therapeutics: Other: Ad hoc advisory board member, Research Funding; Caribou Biosciences: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; T-CURX: Membership on an entity's Board of Directors or advisory committees; Juno Therapeutics: Patents & Royalties: Co-inventor with staff from Juno Therapeutics; pending, Research Funding; Precision Biosciences: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Eureka Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Kite/Gilead: Other: Ad hoc advisory board member.

A Failure to Start: Aborted Activation of CAR T Cells in Chronic Lymphocytic Leukemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 681-681
Author(s):  
McKensie Collins ◽  
Weimin Kong ◽  
Inyoung Jung ◽  
Meng Wang ◽  
Stefan M Lundh ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Research Funding ◽  
Cell Dysfunction ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
T Cell Dysfunction ◽  
Low Levels

Introduction: Chronic Lymphocytic Leukemia (CLL) is a CD19+ B-cell malignancy that accounts for approximately 25% of adult leukemia diagnoses in the developed world. While conventional therapies have some efficacy, there are few curative therapeutic options and many patients ultimately progress to relapsed or refractory disease. CD19-targeting chimeric antigen receptor (CAR) T cell therapy has provided some hope, but induces complete remission in only 26% of patients. This suboptimal response rate is believed to be due to T cell dysfunction and immune-suppression by CLL cells, the mechanisms of which are poorly understood. Results: To understand the causes of CAR T cell dysfunction in CLL we investigated the defects that CLL cells induced in normal donor CD19-targeting CAR T cells. CAR T cells were repeatedly stimulated at 5-day intervals with either primary CLL cells from patients or a CD19-expressing control cell line (aAPC). Repeat stimulation of CAR T cells with aAPCs resulted in 5.36 ± .94 population doublings after three stimulations, whereas CLL cells only evoked 2.39 ± .92 population doublings. We performed phenotyping, proliferation analysis, and cytokine analysis of stimulated CAR T cells. CLL-stimulated T cells appeared un-activated, with low levels of PD-1, LAG3, and TIM3, low levels of cytokine production, and a high proportion of non-cycling cells as measured by Ki67 staining. We first hypothesized that CLL cells induce an altered epigenetic program that prevents effector function and is stabilized by successive stimulations. To test this, we stimulated CAR T cells with CLL cells or aAPCs as indicated in Fig. 1A. CLL-stimulated CAR T cells failed to proliferate or produce cytokines, but subsequent stimulation with aAPCs rescued these functions (Fig. 1B). Further, CLL-stimulated CAR T cells did not differentiate, suggesting that CLL cells do not induce stable defects but rather insufficiently activate CAR T cells (Fig. 1C). These cells also appeared un-activated as indicated by low levels of PD-1 and Ki67. We then used flow cytometry to assess expression of costimulatory and inhibitory molecules on the primary CLL samples. We found that the levels of co-stimulatory and adhesion molecules, namely CD80/CD86 and CD54/CD58 respectively were found at low frequencies, and where present were expressed at low levels. This suggested that one mechanism behind the lack of CAR T cell effector responses may be that a lack of co-stimulation prevents proper CAR T cell targeting of these cells. Towards this, we incubated CLL cells with a murine fibroblast line expressing CD40 ligand for 24 hours with IL-4 to activate the CLL cells. We found that this activation significantly increased expression of CD80, CD86, CD54, and CD58 on the CLL cells. We then used these cells to stimulate CAR T cells in our re-stimulation assay and found that CAR T cells were able to proliferate in response to these activated CLLs (Fig. 1D). In addition, CAR T cells stimulated with activated CLL cells formed more cell-to-cell conjugates than those stimulated with un-activated CLL cells. These data suggest not only that insufficient activation of CAR T cells may be responsible for the poor response rates to CAR T cell therapy in CLL, but also implicate a need for additional co-stimulation in this CAR T cell setting. Another contributing factor may be immune suppression by CLL cells. To determine if CLL cells are immune-suppressive, we used a co-culture assay to stimulate CAR T cells with aAPCs and CLL cells mixed at known ratios. Interestingly, all mixed cultures proliferated similarly, suggesting that CLL cells did not prevent T cell activation in the presence of a strong activation signal. We also found that CLL cells are responsive to IL-2, as addition of this cytokine to culture media prolongs survival of CLL cells out to 10 days depending on the dose. This suggests that CLL cells express a functional IL-2 receptor and may be taking up IL-2 from the culture media, further impairing T cell activation. In support of this, supplementing IL-2 into our CLL/CAR T cell co-cultures rescued T cell proliferative capacity. Taken together, these data suggest that T cell dysfunction in CLL is the result of insufficient activation rather than true functional defects. Disclosures June: Novartis: Research Funding; Tmunity: Other: scientific founder, for which he has founders stock but no income, Patents & Royalties. Melenhorst:National Institutes of Health: Research Funding; Parker Institute for Cancer Immunotherapy: Research Funding; Novartis: Research Funding, Speakers Bureau; IASO Biotherapeutics, Co: Consultancy; Simcere of America, Inc: Consultancy; Shanghai Unicar Therapy, Co: Consultancy; Colorado Clinical and Translational Sciences Institute: Membership on an entity's Board of Directors or advisory committees; Genentech: Speakers Bureau; Stand Up to Cancer: Research Funding; Incyte: Research Funding.

scholarly journals Iomab with Adoptive Cellular Therapy (Iomab-ACT): A Pilot Study of 131-I Apamistamab Followed By CD19-Targeted CAR T-Cell Therapy for Patients with Relapsed or Refractory B-Cell Acute Lymphoblastic Leukemia or Diffuse Large B-Cell Lymphoma

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4810-4810
Author(s):  
Mark B. Geyer ◽  
Briana Cadzin ◽  
Elizabeth Halton ◽  
Peter Kane ◽  
Brigitte Senechal ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
B Cell ◽  
Research Funding ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

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

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