Early clinical results using BCMA targeted CAR T cell therapies for advanced multiple myeloma (MM) have shown promise. However, BCMA expression can be variable, and BCMA downregulation has been ...correlated with relapse (Brudno J. JCO. 2018; Cohen A. ASH. 2017). Targeting multiple antigens may enhance response durability. We report that the orphan seven transmembrane G protein coupled receptor, GPRC5D, is an attractive additional target for CAR T cell therapy of MM.
GPRC5D mRNA expression was previously identified in bone marrow cells from patients with MM; however its protein expression could not be detected with available FACS reagents (Frigyesi I. Blood. 2014). We evaluated 83 primary marrow samples by quantitative immunofluorescence (Q-IF) for CD138, BCMA, and GPRC5D. In 98% of the samples, CD138+ cells expressed surface GPRC5D. In most samples, the majority of CD138+ cells expressed both BCMA and GPRC5D, however, in several cases the dominant CD138+ population expressed only BCMA or GPRC5D, with GPRC5D expression independent of BCMA across samples (R2=0.156; Figure 1).
The potential for “on target/off tumor” binding by targeting GPRC5D was evaluated by screening 30 essential normal tissue types by IHC (n=3 donors/type) followed by validation of any positive findings by RNA in situ hybridization and quantitative PCR. Results in non-plasma cell normal tissue were consistent with prior reports of GPRC5D off target expression restricted to cells from the hair follicle, a potentially immune privileged site.
We developed GPRC5D-targeted CARs considering immunogenicity, spacer length, and tonic signaling. To minimize potential anti-CAR immunity, a human B cell-derived phage display library was screened. Seven diverse and highly specific human single chain variable fragments (scFvs) were identified. 42 CARs were derived from the 7 scFvs by modifying scFv orientation (VH/VL; VL/VH) and incorporating a short, medium, or long IgG4 based spacer. To monitor CAR-mediated signaling, we transduced each CAR into a Jurkat reporter line with RFP inserted in-frame, downstream of endogenous NR4A1 (Nur77). Nur77 expression is an immediate-early, specific marker of CD3z signaling (Ashouri J. J Immunol. 2017). Using this reporter, we observed that (1) a long spacer provided enhanced antigen-dependent activation across all anti-GPRC5D CARs; and (2) the use of different scFvs resulted in vastly different levels of tonic signaling. We selected potential lead and backup constructs and evaluated CAR activity on primary human T cells. When co-cultured specifically with MM cell lines, anti-GPRC5D CAR T cells secreted a polyfunctional cytokine profile, proliferated, and effectively lysed target cells. CD138+/CD38hi primary MM bone marrow aspirate cells were also specifically lysed.
In vivo efficacy of GPRC5D-targeted CAR T cells was evaluated in NSG mice engrafted with a human MM cell line (ffLuc+) bone marrow xenograft. Donor T cells were gene-modified to express anti-GPRC5D CARs with either a 4-1BB or a CD28 co-stimulatory domain and membrane-anchored Gaussia luciferase (GLuc). Compared to control CAR T cells specific for an irrelevant target, anti-GPRC5D CAR T cells with either co-stimulatory domain proliferated and homed to the site of MM (Gluc imaging), eradicated MM xenograft (ffLuc imaging), and increased survival (Figure 2). One scFv that was highly functional in our GPRC5D CAR screen was evaluated for off-target binding against either >200 G protein-coupled receptors (cell based), or >4000 human transmembrane proteins (scFv-Fc based), and demonstrated binding only to GPRC5D. Studies with murine and cynomolgus cross-reactive GPRC5D targeting CARs did not show signs of alopecia or other unexpected toxicity in either species. In a murine model of post-BCMA CAR T cell treated antigen escape (CRISPR BCMA KO of a subpopulation of MM cells), anti-GPRC5D CAR T cells rescue BCMA- relapse. These results indicate that GPRC5D will be an important target for the immunotherapy of MM. We are translating this 4-1BB-containing, human-derived, GPRC5D-targeted CAR construct to the clinic.
Smith:Celgene: Consultancy, Patents & Royalties: CAR T cell therapies for MM, Research Funding. Harrington:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Masakayan:Agentus Inc: Employment. Jones:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Long:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Ghoddusi:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Do:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Pham:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Wang:Eureka Therapeutics: Employment, Equity Ownership. Liu:Eureka Therapeutics, Inc.: Employment, Equity Ownership. Xu:Eureka Therapeutics: Employment, Equity Ownership. Riviere:Juno Therapeutics, a Celgene Company: Membership on an entity's Board of Directors or advisory committees, Research Funding; Fate Therapeutics Inc.: Research Funding. Liu:Eureka Therapeutics, Inc.: Employment, Equity Ownership. Sather:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Brentjens:Juno Therapeutics, a Celgene Company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding.
▪
Background: We have previously reported high anti-tumor activity of autologous T cells genetically modified to express 19-28z chimeric antigen receptor (CAR) targeting CD19 in adult patients with ...relapsed or refractory (R/R) ALL (Park et al. ASH 2014). Herein, we further report the long-term outcome of a larger cohort from our phase 1 clinical trial in adults with R/R ALL (NCT01044069) with a focused analysis on the role of post-treatment minimal residual disease (MRD) negativity as a predictive marker of survival as well as the effect of allogeneic hematopoietic stem cell transplant (allo-HSCT) prior to or after CAR T cell infusion on safety and clinical outcome.
Patients and Methods: Adult patients with R/R B-cell ALL (B-ALL) were enrolled. Eligible patients underwent leukapheresis, and T cells were transduced with a retroviral vector encoding a CAR comprising a CD19-specific scFv and CD28 and CD3ζ signaling domains (19-28z). All patients received lymphodepleting chemotherapy followed 2 days later by 1x106 - 3x106 19-28z CAR T cells/kg. The primary objective of the study was to evaluate the safety and anti-tumor activity of 19-28z CAR T cells. Post-treatment MRD was assessed at day 14-28 by multiparameter flow cytometry in bone marrow (BM) samples.
Results: 44 patients have been treated to date. The median age was 45 years (range, 22-74). 14 patients (32%) had Philadelphia chromosome positive (Ph+) ALL (T315I mutation in 5 patients), 17 patients (39%) had prior allo-HSCT, and 24 patients (55%) had ≥ 3 prior lines of ALL therapy.
Of the 44 patients, 43 patients were evaluable for response. At the time of 19-28z CAR T cell infusion, 22 of the 43 patients (51%) had morphologic disease (≥5% blasts in BM or measurable extramedullary disease) and the remaining 21 patients had minimal disease (<5% blasts in BM). 36 patients (84%) were in complete remission (CR) after 19-28z CAR T-cell infusion. MRD analysis was performed in 35 of 36 CR patients, and 29 of these 35 patients (83%) achieved an MRD-negative CR (MRD-CR).
As of July 13, 2015, the median follow-up was 4.2 months (range 1-45), with 16 patients having at least 6 months of follow-up. Responses appear durable with 7 patients remaining disease-free beyond 1 year up to 45 months. A median overall survival (OS) of all patients and patients who achieved MRD-CR is 8.5 months and 10.8 months, respectively. Post-treatment MRD status emerged as a strong predictive marker of OS: OS at 6 months was 76% (95% CI: 51-89) in the MRD-CR cohort vs. 14% (95% CI: 8-45) in the MRD+CR cohort. In contrast, allo-HSCT after achieving CR with CAR T cell infusion did not affect the survival rate. Of the 36 patients in CR following the T cell infusion, 12 patients underwent allo-HSCT. OS at 6 months was 70% (95% CI: 33-89) in patients who underwent post-CAR allo-HSCT vs. 64% (95% CI: 36-82) in patients who did not get allo-HSCT after CAR T cells.
Comparing baseline disease characteristics of patients who had prior allo-HSCT before the CAR T cell treatment vs. no prior allo-HSCT, patients who had prior allo-HSCT (n=17) were similar in age (median age 45 vs. 46), but had higher disease burden (65% with morphologic disease vs. 44%), were more heavily pretreated (59% of patients with ≥4 lines of therapy vs. 15%), and included more high-risk disease (41% with Ph+ ALL vs. 26%). However, there was no statistically significant difference in CR rates (75%, CI: 48-93 vs. 89%, CI: 71-98), incidences of severe cytokine release syndrome (24% vs. 22%), and OS at 6 months (57% vs. 60%) between these two cohorts. Fewer patients who had prior allo-HSCT underwent another allo-HSCT following CAR T cell infusion: 2 patients vs. 10 patients with no prior all-HSCT. Although no obvious case of graft-versus-host disease (GvHD) was noted, one patient experienced a grade 3 gastrointestinal toxicity that may have been related to GvHD.
Conclusions: These data confirm the potent anti-tumor efficacy of 19-28z CAR T cells (JCAR015) in adult patients with R/R ALL. MRD negativity following the 19-28z CAR T cell treatment is highly predictive of survival, and allo-HSCT post-CAR T cell infusion had no significant impact on survival. Furthermore, 19-28z CAR T cells appear to be safe in patients who had prior allo-HSCT, and may represent an attractive alternative option to second allo-HSCT. These findings are being confirmed in an ongoing multi-center, pivotal phase 2 trial evaluating JCAR015 in adult patients with R/R ALL.
Park:Amgen: Consultancy; Genentech: Research Funding; Juno Therapeutics: Other: Advisory Board, Research Funding. Riviere:Juno Therapeutics: Other: Co-founder, stockholder and consultant. Curran:Juno Therapeutics: Consultancy. Sadelain:Juno Therapeutics: Consultancy, Equity Ownership, Other: Co-Founder, stockholder, Patents & Royalties: Licensed patents on CARs. Brentjens:Juno Therapeutics: Other: Co-founder, stockholder and consultant.
Multiple myeloma (MM) is the second most common hematologic malignancy in the US, characterized by uncontrolled proliferation of monoclonal plasma cells in the bone marrow. Although recent treatment ...options for MM patients have resulted in increased survival rates, MM remains incurable. There continue to be opportunities for advancement in treatment, and B-cell maturation antigen (BCMA) has emerged as a promising target for MM. BCMA is heterogeneously expressed on malignant plasma cells from all relapsed or newly diagnosed myeloma patients, with little expression on normal tissues. Several clinical trials using BCMA-targeting CAR T cells have shown promising results with no observed off target effects reported to date.
Juno Therapeutics is developing a (CAR) T-cell product candidate, comprised of autologous CD4+ and CD8+ T-cells transduced with a genetically-engineered lentiviral vector to express a BCMA-specific CAR. The construct comprises a BCMA-specific single chain variable fragment (scFv) with human variable regions, CD137 4 1BB co-stimulatory domain, and CD3ζ signaling domain. The binding domain was observed to specifically bind to BCMA with high affinity. No off target cell membrane staining was observed in assays for potential binding of the scFV to cryosections across a range of human tissues. BCMA CAR T cells did not bind unexpectedly to samples with an array of human plasma membrane proteins.
When the CAR was expressed on primary T cells, the cells activated, proliferated and had high lytic activity against BCMA-positive targets, with no activity against BCMA-negative targets. We compared the activity of the construct against constructs having a series of different spacer lengths between the scFV and the transmembrane domain, as well as different signaling domains and observed advantageous qualities with the specific combination of the particular components of this CAR construct. When incubated with target cells, over a range effector to target ratios (from 10 to 1 to 1 to 10), primary cells transduced with the CAR construct had comparatively robust lytic activity and produced high levels of multiple effector cytokines. These cells showed similar activity with a range of antigen densities from <1000 mol./cell (Daudi) to >100,000 mol./cell (NCI-H929,). We observed similar activity against both BCMA+ cell lines and primary CD138+ multiple myeloma cells. Additionally, the CAR-expressing primary T cells showed comparable activity against BCMA-expressing cells in the presence and absence of soluble recombinant or natural BCMA (up to 1000ng/ml). T cells engineered with the CAR derived from MM patients demonstrated similar expression, expansion and antigen-specific activities as compared to cells expressing the CAR derived from normal human donors.
Additionally, in an in vitro assay, no evidence of tonic signaling was observed in the absence of antigen, in contrast to other BCMA-specific CARs that were observed to have variable levels of tonic signaling in this assay. In the presence of increasing amounts of antigen-either plate bound or endogenously expressed on cell lines-efficient signaling through the CAR was observed, with strong signaling observed at low levels of antigen (<1000 molecules per cell) and increasing signal as antigen density increased.
Function of the construct in vivo was evaluated in NSG mouse models generated by injecting OPM2 or RPMI-8226 MM cells. Significantly improved survival and tumor growth were observed in mice in both models treated with the anti-BCMA CAR+ cells, as compared to mock T cells. In the RPMI-8226 model, mice administered both tested doses of the anti-BCMA CAR T cells exhibited complete regression of tumor growth by 20 days post CAR T-cell transfer which continued up to Day 60. Total circulating BCMA CAR T cells peaked at Day 14 post CAR T-cell transfer and greater numbers of CD8+ CAR+ T cells were observed compared to CD4+ CAR T cells.
Taken together, these results support the development of a fully human BCMA-specific CAR T cell product candidate with a binder exhibiting little or no off target activity and observed to kill myeloma cells over a range of antigen densities and to the same degree regardless of the presence of soluble BCMA. Phase 1 clinical studies in MM patients with a BCMA CAR T cell clinical candidate, JCARH125, are planned for early 2018.
Harrington:Juno Therapeutics: Employment, Equity Ownership. Hauskins:Juno therapeutics: Employment, Equity Ownership. Amin:Juno therapeutics: Employment, Equity Ownership. Long:Juno Therapeutics, Inc.: Employment, Equity Ownership. Chen:Juno Therapeutics: Employment, Equity Ownership. Rahardjo:Juno Therapeutics: Employment, Equity Ownership. Thayer:Juno Therapeutics: Employment, Equity Ownership. Jones:Juno Therapeutics: Employment, Equity Ownership. Baturevych:Juno Therapeutics: Employment, Equity Ownership. Morkowski:Juno Therapeutics: Employment, Equity Ownership. Salmon:Juno Therapeutics: Employment, Equity Ownership. Bond:Juno Therapeutics: Employment, Equity Ownership. Liu:Eureka Therpeutics Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Liu:Eureka Therapeutics, Inc: Employment, Equity Ownership. Xu:Eureka Therapeutics, Inc: Employment, Equity Ownership. Wang:Eureka Therapeutics Inc.: Employment, Equity Ownership. Brentjens:Juno Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Smith:Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: BCMA targeted CAR T cells, Research Funding. Sather:Juno Therapeutics: Employment, Equity Ownership.
Patients with relapsed/refractory MM (RRMM) rarely obtain durable remissions with available therapies. Clinical use of BCMA targeted CAR T cell therapy was first reported in 12/2015 for RRMM, and ...based on small numbers, preliminary results appear promising. Given that host immune anti-murine CAR responses have limited the efficacy of repeat dosing (Turtle C. Sci Trans Med 2016), our goal was to develop a human BCMA targeted CAR T cell vector for clinical translation.
We screened a human B cell derived scFv phage display library containing 6x1010 scFvs with BCMA expressing NIH 3T3 cells, and validated results on human MM cell lines. 57 unique and diverse BCMA specific scFvs were identified containing light and heavy chain CDR's each covering 6 subfamilies, with HCDR3 length ranges from 5-18 amino acids. 17 scFvs met stringent specificity criteria, and a diverse set was cloned into CAR vectors with either a CD28 or a 4-1BB co-stimulatory domain. Donor T cells transduced with BCMA targeted CAR vectors that conveyed particularly desirable properties over multiple in vitro assays , including: cytotoxicity on human MM cell lines at low E:T ratios (>90% lysis, 1:1, 16h), robust proliferation after repeat antigen stimulation (up to 700 fold, stimulation q3-4d for 14d), and active cytokine profiling, were selected for in vivo studies using a marrow predominant human MM cell line model in NSG mice. A single IV injection of CAR T cells, either early (4d) or late (21d) after MM engraftment was evaluated. In both cases survival was increased when treated with BCMA targeted CAR T cells vs CD19 targeted CAR T cells (median OS at 60d NR vs 35d p<0.05). Tumor and CAR T cells were imaged in vivo by taking advantage of luciferase constructs with different substrates. Results show rapid tumor clearance, peak (>10,000 fold) CAR T expansion at day 6, followed by contraction of CAR T cells after MM clearance, confirming the efficacy of the anti-BCMA scFv/4-1BB containing construct.
Co-culture with primary cells from a range of normal tissues did not activate CAR T cells as noted by a lack of IFN release. Co-culture of 293 cells expressing this scFv with those expressing a library of other TNFRSF or Ig receptor members demonstrated specific binding to BCMA. GLP toxicity studies in mice showed no unexpected adverse events. We generated a retroviral construct for clinical use including a truncated epithelial growth factor receptor (EGFRt) elimination gene: EGFRt/hBCMA-41BBz.
Clinical investigation of this construct is underway in a dose escalation, single institution trial. Enrollment is completed on 2/4 planned dose levels (DL). On DL1 pts received cyclophosphamide conditioning (3g/m2 x1) and 72x106 mean CAR+ T cells. On DL2 pts received lower dose cyclophosphamide/fludarabine (300/30 mg/m2 x3) and 137x106 mean CAR+ T cells. All pts screened for BCMA expression by IHC were eligible. High risk cytogenetics were present in 4/6 pts. Median prior lines of therapy was 7; all pts had IMiD, PI, high dose melphalan, and CD38 directed therapies. With a data cut off of 7/20/17, 6 pts are evaluable for safety. There were no DLT's. At DL1, grade 1 CRS, not requiring intervention, occurred in 1/3 pts. At DL2, grade 1/2 CRS occurred in 2/3 pts; both received IL6R directed Tocilizumab (Toci) with near immediate resolution. In these 2 pts time to onset of fever was a mean 2d, Tmax was 39.4-41.1 C, peak CRP was 25-27mg/dl, peak IL6 level pre and post Toci were 558-632 and 3375-9071 pg/ml, respectively. Additional serum cytokines increased >10 fold from baseline in both pts include: IFNg, GM CSF, Fractalkine, IL5, IL8, and IP10. Increases in ferritin were limited, and there were no cases of hypofibrinogenemia. There were no grade 3-5 CRS and no neurotoxicities or cerebral edema. No pts received steroids or Cetuximab. Median time to count recovery after neutropenia was 10d (range 6-15d).
Objective responses by IMWG criteria after a single dose of CAR T cells were observed across both DLs. At DL1, of 3 pts, responses were 1 VGPR, 1 SD, and 1 pt treated with baseline Mspike 0.46, thus not evaluable by IMWG criteria, had >50% reduction in Mspike, and normalization of K/L ratio. At DL2, 2/2 pts had objective responses with 1 PR and 1 VGPR (baseline 95% marrow involvement); 1 pt is too early to evaluate. As we are employing a human CAR, the study was designed to allow for an optional second dose in pts that do not reach CR. We have treated 2 pts with a second dose, and longer follow up data is pending.
Display omitted
Smith:Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: BCMA targeted CAR T cells, Research Funding. Almo:Cue Biopharma: Other: Founder, head of SABequity holder; Institute for Protein Innovation: Consultancy; AKIN GUMP STRAUSS HAUER & FELD LLP: Consultancy. Wang:Eureka Therapeutics Inc.: Employment, Equity Ownership. Xu:Eureka Therapeutics, Inc: Employment, Equity Ownership. Park:Amgen: Consultancy. Curran:Juno Therapeutics: Research Funding; Novartis: Consultancy. Dogan:Celgene: Consultancy; Peer Review Institute: Consultancy; Roche Pharmaceuticals: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Liu:Eureka Therpeutics Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Brentjens:Juno Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding.
Introduction: BCMA targeted CAR T cell therapy has shown promising results in patients with relapsed/refractory multiple myeloma (MM). Herein, we report on the safety and efficacy of MCARH171, a ...second generation, human derived BCMA targeted autologous 4-1BB containing CAR T cell therapy, including a truncated epidermal growth factor receptor safety system (Smith EL. Mol Ther 2018).
Methods: This is a phase I first in human, dose escalation trial of MCARH171. Patients received conditioning chemotherapy with cyclophosphamide (Cy) 3 gm/m2 as a single dose or fludarabine 30 mg/m2 daily and Cy 300 mg/m2 daily for 3 days followed by MCARH171 infusion in 1-2 divided doses. The trial followed a standard 3+3 design with 4 dose levels where patients received the following mean doses per cohort: (1) 72x106, (2) 137x106, (3) 475x106, (4) 818x106 viable CAR+ T cells. The primary objective was to demonstrate safety, and secondary objectives included efficacy and expansion, and persistence of CAR T cells using PCR from the peripheral blood. The last accrued patient received MCARH171 on Dec 6, 2017 and the data cut-off is July 16, 2018. The study is closed to accrual.
Results: 11 patients with relapsed and/or refractory MM were treated. Median number of prior lines of therapy was 6 (range: 4-14), and all patients received prior therapy with a proteasome inhibitor, IMiD, anti-CD38 monoclonal antibody, and high dose melphalan/stem cell transplant. Nine (82%) patients had high-risk cytogenetics and 9 (82%) were refractory to their immediate prior line of treatment. One patient was not evaluable for DLTs given the need for early radiation and steroids for impending spinal cord compression by tumor. There are no DLTs reported. Cytokine release syndrome (CRS) grade 1-2 occurred in 4 patients (40%), grade 3 occurred in 2 (20%), and there was no grade 4-5 CRS. Grade 2 encephalopathy occurred in 1 patient (10%) in the setting of high fevers which resolved in less than 24 hours. There was no grade 3 or higher neurotoxicity observed. Tocilizumab was administered to 3 patients; 2 in cohort 2, and 1 in cohort 3. Laboratory values correlating with CRS reaching grade 3 or requiring Tocilizumab (N=4) compared to those with no or milder CRS (N=6) included peak CRP (mean: 28.5 vs 4.6 mg/dL, p<0.001), IFNg (mean peak fold increase: 271 vs 11-fold, p<0.0001), and peak IL6 before Tocilizumab, as IL6 elevation artificially increases after use (mean: 435 vs 68.7 pg/mL, p<0.005). No significant change was seen in ferritin or fibrinogen compared to baseline.
Overall response rate was 64% and the median duration of response was 106 days (range: 17 to 235 days). The peak expansion and persistence of MCARH171 as well as durable clinical responses were dose dependent. Patients who were treated on the first two dose cohorts (≤150 X106 CAR T cells) had a lower peak expansion in the peripheral blood (mean 14,098 copies/µL; N=6), compared to patients who were treated on the third or fourth dose cohort 3-4 (≥450 X106 CAR T cells; N=5), where the mean peak expansion was 90,208 copies/µL (p<0.05). Among the 5 patients who received higher doses (450 X106), 5/5(100%) patients responded. The duration of responses was also related to the cell dose, with 3 of 5 patients (60%) treated in the cohorts receiving ≥450 X106 had clinical responses lasting >6 months compared to only 1 of 6 (16.7%) patients who received lower doses. Two patien have ongoing responses (VGPR) at 7.5+ and 10+ months of follow up.
To normalize for dose administered we compared the pharmacokinetics of only patients treated at dose levels 3-4 ( ≥450 X106 CAR T cells). Here, we demonstrate that peak expansion correlated to clinical efficacy, with the 3 durable responders all having peak expansion >85,000 copies/µL (mean: 131,732 copies/µL); compared to transient responders, where the maximum peak expansion was 33,213 copies/µL (mean: 27,922; Figure 1).
Conclusions: MCARH171 has an acceptable safety profile with no DLTs reported. A dose-response relationship with toxicity was not clearly observed, as noted by distribution of tocilizumab use across dose cohorts. However, a dose-response relationship was observed with promising clinical efficacy at dose levels of ≥450 X106 CAR T cells. Controlling for dose level, peak expansion correlated with durability of response. These results further support the development of CAR T cells for heavily pre-treated patients with relapsed and refractory MM.
Mailankody:Janssen: Research Funding; Takeda: Research Funding; Juno: Research Funding; Physician Education Resource: Honoraria. Korde:Amgen: Research Funding. Lesokhin:Takeda: Consultancy, Honoraria; Squibb: Consultancy, Honoraria; Janssen: Research Funding; Genentech: Research Funding; Serametrix, inc.: Patents & Royalties: Royalties; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding. Hassoun:Oncopeptides AB: Research Funding. Park:Juno Therapeutics: Consultancy, Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy; AstraZeneca: Consultancy; Adaptive Biotechnologies: Consultancy; Kite Pharma: Consultancy; Novartis: Consultancy; Shire: Consultancy. Sauter:Juno Therapeutics: Consultancy, Research Funding; Sanofi-Genzyme: Consultancy, Research Funding; Spectrum Pharmaceuticals: Consultancy; Novartis: Consultancy; Precision Biosciences: Consultancy; Kite: Consultancy. Palomba:Pharmacyclics: Consultancy; Celgene: Consultancy. Riviere:Fate Therapeutics Inc.: Research Funding; Juno Therapeutics, a Celgene Company: Membership on an entity's Board of Directors or advisory committees, Research Funding. Landgren:Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Pfizer: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Consultancy; Merck: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Research Funding. Brentjens:Juno Therapeutics, a Celgene Company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Smith:Celgene: Consultancy, Patents & Royalties: CAR T cell therapies for MM, Research Funding.
Background: Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive B-NHL. While 50-80% of patients with DLBCL are cured with standard induction therapy, a large fraction of patients ...either relapse or have primary refractory (rel/ref) disease. High-dose therapy followed by autologous stem cell transplantation (HDT-ASCT) is the established standard of care for these patients. Despite this, approximately half of all rel/ref patients that are chemosensitive to salvage therapy are cured with this approach. Relapse is the major cause of treatment failure, and ultimately death, in these patients. Our group has demonstrated encouraging activity with 19-28z chimeric antigen receptor modified T cells (19-28z CAR-T) directed against CD19 in rel/ref ALL. We hypothesize that biologic optimization of cellular therapy with 19-28z CAR-T can be met immediately post-HDT-ASCT given: lymphoproliferative cytokine availability through lymphodepletion post-HDT, depletion of prohibitive regulatory cellular elements post-HDT and achievement of minimal residual disease prior to 19-28z CAR-T consolidation. Herein, we report safety data on the first 6 patients of the phase I MSKCC #12-117: 19-28z CAR-T post HDT-ASCT for poor-risk rel/ref aggressive B-NHL.
Methods: Eligibility for this study includes rel/ref aggressive B-NHL appropriate for HDT-ASCT as defined by chemosensitivity to salvage therapy and poor risk features including: 1) FDG-PET positivity following 2 cycles of salvage therapy or 2) bone marrow involvement of B-NHL at the time of rel/ref clinical restaging. Patients underwent separate apheresis for CD34+ progenitor cells and CD3+ T cells. T cells were transduced with a retrovirus encoding a CAR construct composed of anti-CD19 scFV linked to CD28 and CD3ζ signaling domains (19-28z). Patients were admitted for BEAM conditioned HDT and ASCT occurred day 0. Pegfilgrastim was administered on day+1 and 19-28z CAR-T dose per phase I study was split on days +2 and +3.
Results: This analysis includes the first six patients, all male, on the phase I study. The median age is 61 (range 34-68) years at the time of HDT-ASCT. Diagnoses included: n=2 relapsed and transformed follicular lymphoma (one with double-hit biology), n=3 relapsed DLBCL (one CD5+) and one subject with relapsed and transformed marginal zone lymphoma involving the bone marrow. Five patients were treated at dose level #1 (5 x106 19-28z CAR-T/kg) with no dose-limiting toxicity (DLT) observed. Four of the five patients at dose level #1 experienced grade 3 febrile neutropenia and one patient met-criterion for non-severe cytokine-release syndrome (nCRS) effectively treated with tocilizumab 4 mg/kg x1. One patient was treated at dose-level #2, 1 x107 CAR-T/kg, and experienced a DLT of grade 4 severe CRS (sCRS) manifested with acute kidney injury, hypotension and mental status changes effectively treated and fully recovered with tocilizumab in combination with dexamethasone. Peak CRP in all patients was observed at a median of 3.5 days (range 3-4 days) post-19-28z CAR-T infusion (median peak CRP= 17 mg/dL, range: 5-43.1 mg/dL), with CRP >20 mg/dL identified in the two patients that experienced CRS (nCRS=27 mg/dL, sCRS=43 mg/dL). Previously associated serum cytokine elevations (Davila et al Sci Trans Med, 2014) were observed in the two patients that experienced CRS (Figure). All patients engrafted neutrophils at a median of 10 days (range: 9-10 days) post-ASCT, and achieved a complete remission at first post-HDT-ASCT restaging. No sequelae of autoimmune phenomenon were observed. At a median follow-up of six months, with 2 patients >one year post HDT-ASCT, all patients remain alive and in remission.
Conclusions: This is the first report of 19-28z CAR-T cells in conjunction with consolidative HDT-ASCT for poor-risk rel/ref aggressive B-NHL. No DLTs have been observed at dose level #1, 5 x106 19-28z CAR-T/kg, while sCRS was observed in n=1 at 1 x107 CAR-T/kg resulting in a DLT. CRS was associated with pro-inflammatory serum cytokine elevation. CRS was aborted with tocilizumab with (sCRS=1) or without (nCRS=1) dexamethasone. All patients engrafted neutrophils at the expected time point. The use of 19-28z CAR T cells is a promising approach in this small group of poor-risk PET+ NHL patients undergoing autologous transplant. This is an ongoing trial and updated data will be presented.
Display omitted
Riviere:Juno Therapeutics: Consultancy, scientific co-founders Other. Sadelain:Juno Therapeutics: Consultancy, Scientific co-founder and Stock holder Other. Brentjens:Juno Therapeutics: Consultancy, scientific co-founder Other.
▪
Although most adults diagnosed with B-ALL can be induced into a first complete remission (CR1 rates of approximately 80-90%), a majority will relapse and develop chemorefractory disease. Novel, ...non-chemotherapy based treatments are needed for this group of patients.
We have developed a novel CD19-targeted T cell-based therapy for patients with B cell malignancies. We isolate T cells from patients with relapsed/refractory B-ALL and genetically modify them with a chimeric antigen receptor (CAR) construct, termed 19-28z, which comprises a CD19 binding domain fused to the signaling domains of the CD28 costimulatory receptor and the ζ chain of the CD3 complex. CD19 is a universal B cell antigen expressed on all normal and malignant B cells. Expression of the 19-28z CAR by a T cell promotes binding of the CD19 antigen and triggers cytotoxicity, cytokine release and proliferation upon engagement of CD19.
We are conducting a Phase I clinical protocol in adults with relapsed/refractory B-ALL (NCT01044069). Enrolled patients are leukapheresed and then re-induced with salvage chemotherapy. A T cell infusion (3 x 106 19-28z CAR T cells/kg) is administered following conditioning chemotherapy. We now describe the results from this Phase I protocol. Thirteen adults have been treated to date: eleven were enrolled with relapsed/refractory disease, while the other 2 were enrolled and leukapheresed during CR1, but not treated until they relapsed. The age of the patients ranged from 23 to 74 with a median age of 42. Three of the 13 patients had Philadelphia-chromosome positive B-ALL, which is considered the most negative genetic risk factor for adults with B-ALL. We were able to achieve the required T cell dose, despite collecting patients with high blast counts or marked lymphopenias, in all but one patient. Seven of the 13 patients were infused with 19-28z CAR T cells while they had gross residual disease (>5 to 70% blasts in the BM). The remaining patients had MRD, detected by flow cytometry or deep sequencing, at the time of 19-28z CAR T cell infusion.
Six patients developed toxicities including high-grade fevers (>40°C), hypotension, hypoxia, mental status changes, and seizures. These episodes ran for approximately one week before they were halted by treatment with steroids or tocilizumab. The other 7 patients did not experience toxicities. All patients completely recovered and were able to leave the hospital. The occurrence of toxicities correlated with tumor burden so that patients with gross residual disease (>5% blasts in BM) developed toxicities, while patients with MRD had no evidence of toxicities.
Ten out of the 12 patients with detectable disease before T cell infusion developed MRD- responses such that 5 of the patients with gross residual disease (blasts > 5% in BM) became MRD- and 5 MRD+ patients became MRD-. The rapidity of the responses was quite remarkable with MRD- results obtained as early as 7 -14 days after T cell infusion. Furthermore, despite the poor predicted outcomes of relapsed Ph+ B-ALL we were able to get these patients MRD-, as detected by both deep sequencing for the IgH rearrangement and qPCR for the bcr-abl transcript.
The potent induction of MRD- responses and the reversibility of toxicities occurring in a subset of patients strongly support integrating this therapy in the modern paradigm for B-ALL therapy, by facilitating access to allogeneic-stem cell transplantation (SCT) for patients with relapsed B-ALL. Indeed, out of the 13 patients treated to date, 4 underwent an allo-SCT and 5 are being prepared for an allo-SCT. Of the remaining 4 patients, 1 is a non-responder (a patient with extramedullary disease, but no disease in the bone marrow), 1 relapsed (not eligible for allo-SCT), 1 is in CR2 (medically not eligible for allo-SCT), and 1 has not been evaluated for treatment response yet. Overall, the results from this Phase I protocol demonstrate that toxicities associated with this therapy are predictable and manageable. Furthermore, the remarkable MRD- re-induction rate and facilitation for allo-SCT we report here warrant further evaluation of this therapy in a Phase II protocol.
No relevant conflicts of interest to declare.
Epigenetics has become a fast-growing area of study in cellular biology. An epigenetic trait is defined as a stably inherited phenotype resulting from changes in a chromosome without alterations in ...the DNA sequence (1). These types of modifications are essential for normal cellular function, assisting in the activation or repression of necessary genes in various stages of development. There are instances, though, in which the modifications can be altered to induce irregular gene transcription. In these cases, the results can provoke various forms of disease. In mammals, epigenetic methylation has been found to play an important part in all forms of cancer, with two key areas of alteration. These are the specific methylation of sequences of DNA, as well as modifications on the histones surrounding DNA. Since the discovery of their involvement in the change of gene expression, histone modifications and DNA methylation have been implicated in diseases other than cancer, such as neurological disorders including schizophrenia and Alzheimer’s disease. One very important aspect of epigenetic methylation is its reversibility. This key property has created a promising field of epigenetic therapy, which has led to the development of several FDA approved drugs for cancer treatment. It has also generated several new and exciting ideas for future paths of treatment.
PDF
