Efficacy and Safety of Anti-CD19 and Anti-BCMA Chimeric Antigen Receptor (CAR) T-Cell Therapies in Patients with Autoimmune Disease and Lymphoma or Myeloma

γ-Secretase inhibition increases efficacy of BCMA-specific chimeric antigen receptor T cells in multiple myeloma

Introduction: Chimeric antigen receptor (CAR) T-cells have revolutionized therapies for B-cell malignancies. However, while ethnic and racial minorities or those with obesity represent medically underserved populations for whom cancer outcomes are worse, it is unknown whether these factors also negatively impact outcomes of CAR T-cells. Methods: We conducted a retrospective review of 5 unique phase I CAR T-cell trials for children and adults with B-cell malignancies (including CD19, CD22 and BCMA targeted CAR T-cells for B-cell acute lymphoblastic leukemia (B-ALL), B-cell non-Hodgkin lymphoma (NHL) and multiple myeloma (MM)). In addition to evaluating basic demographics, complete remission (CR) rates and cytokine release syndrome (CRS) severity, graded by ASTCT, were stratified by race (white vs non-white), ethnicity and obesity, defined as BMI > 30. All individual protocols were IRB approved, and the retrospective study for this analysis is registered at: Clinicaltrials.gov NCT03827343. Statistics were done in GraphPad Prism, using non-parametric tests with p<0.05 considered significant. Results: 185 patients were treated with 1 of 5 unique CAR T-cell constructs. The median age was 22.7 years (range, 4.2-69 years). 138 had B-ALL; 23 had NHL and 24 had MM. The racial distribution was 154 (83.2%) white patients, and 31 (16.8%) non-white patients. The ethnic distribution (Hispanic versus non-Hispanic) was: 45 (24.3%) Hispanic, 139 (75.1%) non-Hispanic, and 1 unknown. Twenty-eight patients (15.1%) were obese. CR rates in those with B-ALL was 68.1% (94/138), in MM was 8.3% (2/24), and in NHL was 43.5% (10/23). CR rates did not vary by race or ethnicity. White CR rate 88/154 (57.1%) vs non-white CR rate was 18/31 (58.1%); p=not-significant (NS)) Hispanic CR rate was 26/44 (59.1%) vs Non-Hispanic CR rate of 79/136 (58.1%); p=NS. The overall CR rate in obese patients was 50% (14/28) versus 58.6% (92/157) in non-obese patients, p=NS. Grade >/= 3 CRS occurred in 35/185 (18.9%) patients and did not vary by race. Grade >/= 3 CRS in white patients was 30/154 (19.5%) vs non-White patients was 5/31 (16.1%); p=NS. Rates of Grade >/= 3 CRS were higher in Hispanic patients, (13/45, 28.9%) versus non-Hispanic patients (21/139, 15.1%), p=0.05 and in obese patients, (9/28, 32.1%) vs non-obese 26/157 (16.6%); p=NS). Conclusion: While CR rates did not vary by race (white versus non-white), ethnicity or obesity, a closer analysis by racial sub-populations and at active dose levels is a critical next step to evaluate for subtle disparities. Hispanic patients and those with obesity had a trend towards higher rates of Grade >/= 3 CRS, which needs further study. Given the tremendous potential of CAR T-cells across diverse populations and ability to overcome chemotherapeutic resistance seen in minority populations, CAR T-cells may represent an opportunity to improve outcomes for underserved populations without substantially increasing toxicity. Citation Format: Paul Borgman, John Ligon, Bonnie Yates, Haneen Shalabi, Toni Foley, Lauren Little, Jennifer Brudno, Lekha Mikkilineni, James Kochenderfer, Nirali N. Shah. The impact of race, ethnicity and obesity on CAR T-cell outcomes [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-111.

B-cell maturation antigen chimeric antigen receptor T-cell re-expansion in a patient with myeloma following salvage programmed cell death protein 1 inhibitor-based combination therapy.

Development and Evaluation of an Optimal Human Single-Chain Variable Fragment-Derived BCMA-Targeted CAR T Cell Vector.

Chimeric Antigen Receptor T Cells Targeting LILRB4, an Immunoreceptor Mediating T-Cell Suppression, Are Potently Effective in Multiple Myeloma

Chimeric Antigen Receptor T Cell Therapies Clinical Trials in Pediatric Oncology: A Retrospective Analysis from Clinicaltrials.Gov

<div>Abstract<p>Chimeric antigen receptor (CAR) T-cell therapy for multiple myeloma targeting B-cell maturation antigen (BCMA) induces high overall response rates. However, relapse still occurs and novel strategies for targeting multiple myeloma cells using CAR T-cell therapy are needed. SLAMF7 (also known as CS1) and CD38 on tumor plasma cells represent potential alternative targets for CAR T-cell therapy in multiple myeloma, but their expression on activated T cells and other hematopoietic cells raises concerns about the efficacy and safety of such treatments. Here, we used CRISPR/Cas9 deletion of the <i>CD38</i> gene in T cells and developed DCAR, a double CAR system targeting CD38 and CS1 through activation and costimulation receptors, respectively. Inactivation of <i>CD38</i> enhanced the anti–multiple myeloma activity of DCAR T <i>in vitro</i>. Edited DCAR T cells showed strong <i>in vitro</i> and <i>in vivo</i> responses specifically against target cells expressing both CD38 and CS1. Furthermore, we provide evidence that, unlike anti-CD38 CAR T-cell therapy, which elicited a rapid immune reaction against hematopoietic cells in a humanized mouse model, DCAR T cells showed no signs of toxicity. Thus, DCAR T cells could provide a safe and efficient alternative to anti-BCMA CAR T-cell therapy to treat patients with multiple myeloma.</p></div>

<div>Abstract<p>Chimeric antigen receptor (CAR) T-cell therapy for multiple myeloma targeting B-cell maturation antigen (BCMA) induces high overall response rates. However, relapse still occurs and novel strategies for targeting multiple myeloma cells using CAR T-cell therapy are needed. SLAMF7 (also known as CS1) and CD38 on tumor plasma cells represent potential alternative targets for CAR T-cell therapy in multiple myeloma, but their expression on activated T cells and other hematopoietic cells raises concerns about the efficacy and safety of such treatments. Here, we used CRISPR/Cas9 deletion of the <i>CD38</i> gene in T cells and developed DCAR, a double CAR system targeting CD38 and CS1 through activation and costimulation receptors, respectively. Inactivation of <i>CD38</i> enhanced the anti–multiple myeloma activity of DCAR T <i>in vitro</i>. Edited DCAR T cells showed strong <i>in vitro</i> and <i>in vivo</i> responses specifically against target cells expressing both CD38 and CS1. Furthermore, we provide evidence that, unlike anti-CD38 CAR T-cell therapy, which elicited a rapid immune reaction against hematopoietic cells in a humanized mouse model, DCAR T cells showed no signs of toxicity. Thus, DCAR T cells could provide a safe and efficient alternative to anti-BCMA CAR T-cell therapy to treat patients with multiple myeloma.</p></div>

BackgroundChimeric antigen receptor (CAR) T-cell therapy is highly effective for treating acute lymphoblastic leukemia and non-Hodgkin’s lymphoma with high rate complete responses. However, the broad clinical application of CAR T-cell therapy has been challenging, largely due to the lack of widespread ability to produce and high cost of CAR T-cell products using traditional methods of production. Automated cell processing in a closed system has emerged as a potential method to increase the feasibility of producing CAR T cells locally at academic centers due to its minimal reliance on experienced labor, thereby making the process less expensive and more consistent than traditional methods of production.MethodIn this study, we describe the successful production of clinical grade CD19 CAR T cells using the Miltenyi CliniMACS Prodigy Automated Cell Processor at University of Colorado Anschutz Medical Campus in a rapid manner with a high frequent CD19 CAR expression.ResultsThe final CAR T-cell product is highly active, low in immune suppression, and absent in exhaustion. Full panel cytokine assays also showed elevated production of Th1 cytokines upon IL-2 stimulation when specifically killing CD19+ target cells.ConclusionThese results demonstrate the feasibility of producing CAR T cells locally in a university hospital setting using automated cell processor for future clinical applications.

Chimeric antigen receptor (CAR) T-cell therapy for multiple myeloma targeting B-cell maturation antigen (BCMA) induces high overall response rates. However, relapse still occurs and novel strategies for targeting multiple myeloma cells using CAR T-cell therapy are needed. SLAMF7 (also known as CS1) and CD38 on tumor plasma cells represent potential alternative targets for CAR T-cell therapy in multiple myeloma, but their expression on activated T cells and other hematopoietic cells raises concerns about the efficacy and safety of such treatments. Here, we used CRISPR/Cas9 deletion of the CD38 gene in T cells and developed DCAR, a double CAR system targeting CD38 and CS1 through activation and costimulation receptors, respectively. Inactivation of CD38 enhanced the anti-multiple myeloma activity of DCAR T in vitro. Edited DCAR T cells showed strong in vitro and in vivo responses specifically against target cells expressing both CD38 and CS1. Furthermore, we provide evidence that, unlike anti-CD38 CAR T-cell therapy, which elicited a rapid immune reaction against hematopoietic cells in a humanized mouse model, DCAR T cells showed no signs of toxicity. Thus, DCAR T cells could provide a safe and efficient alternative to anti-BCMA CAR T-cell therapy to treat patients with multiple myeloma.

Introduction: Diffuse intrinsic pontine glioma (DIPG) is a universally fatal pediatric brainstem tumor with a median survival of less than one year. Despite advances in the understanding of the molecular origins of DIPG, improvement in clinical outcomes has yet to materialize. To date, there has been little target exploration for immunotherapy applications in DIPG. Methods: Patient-derived DIPG cell cultures were screened for expression of more than 350 surface antigens as potential immunotherapeutic targets. The disialoganglioside GD2 was found to have the highest expression across cell cultures and was verified by IHC on post-mortem samples. Chimeric antigen receptor (CAR) T-cell therapy against this target was explored both in vitro and in vivo. Results: We found high levels of the disialoganglioside GD2 expressed on cell cultures derived from post-mortem samples of DIPG. Quantification of the number of GD2 molecules per cell demonstrated higher GD2 expression on DIPG than any other tumors, including neuroblastoma, for which GD2 targeted immunotherapy is part of the standard of care. Most cases of DIPG are caused by a mutation in Histone 3.3 (H3K27M). GD2 is highly and uniformly expressed in patient-derived H3K27M DIPG cultures, whereas H3 wild-type pediatric high-grade gliomas, including those diagnosed as DIPG, do not express significant levels of GD2. The H3K27M mutation is associated with increased levels of enzymes in the ganglioside synthesis pathway, suggesting that expression of the target antigen is driven by H3K27M-induced transcriptional dysregulation. Anti-GD2 CAR T cells with a 4-1BB costimulatory domain demonstrate remarkable preclinical activity against H3K27M DIPG. GD2 CAR T cells specifically kill DIPG cells and produce cytokines IL-2 and IFN- upon coculture with tumor. Systemic administration of anti-GD2 CAR T cells achieves potent and durable cure compared to control T cells in multiple orthotopic xenograft models of DIPG. Using a CAR fluorescent protein fusion construct, we demonstrate significant T-cell trafficking to the brainstem where the antitumor effect is mediated. Universal response was observed across multiple cohorts, and treatment-associated toxicity was transient and tolerated during the period of peak antitumor activity. Conclusion: We have previously demonstrated that antigen density drives CAR efficacy. Extremely high expression of GD2 on DIPG makes this a particularly good disease for CAR T-cell therapy. If these results are predictive of human response, CAR T cells could have a transformative impact upon DIPG outcomes. A clinical trial of second generation anti-GD2 CAR T cells in relapsed and progressive DIPG is planned. Citation Format: Robbie G. Majzner, Christopher Mount, Shree Sundaresh, Evan Arnold, Meena Kadapakkam, Louai Labanieh, Pamelyn Woo, Michelle Monje, Crystal L. Mackall. GD2-directed chimeric antigen receptor T cells mediate potent antitumor effect and cure in xenograft models of diffuse intrinsic pontine glioma [abstract]. In: Proceedings of the AACR Special Conference: Pediatric Cancer Research: From Basic Science to the Clinic; 2017 Dec 3-6; Atlanta, Georgia. Philadelphia (PA): AACR; Cancer Res 2018;78(19 Suppl):Abstract nr PR04.

Autoimmune Outcomes in Patients with Concurrent Autoimmune Disease Receiving CD19 CAR T-Cell Therapy for Lymphoma

<div>Abstract<p>Chimeric antigen receptor (CAR) T-cell immunotherapy has revolutionized the treatment of refractory leukemias and lymphomas, but is associated with significant toxicities, namely cytokine release syndrome (CRS) and neurotoxicity. A major barrier to developing therapeutics to prevent CAR T cell–mediated neurotoxicity is the lack of clinically relevant models. Accordingly, we developed a rhesus macaque (RM) model of neurotoxicity via adoptive transfer of autologous CD20-specific CAR T cells. Following cyclophosphamide lymphodepletion, CD20 CAR T cells expand to 272 to 4,450 cells/μL after 7 to 8 days and elicit CRS and neurotoxicity. Toxicities are associated with elevated serum IL6, IL8, IL1RA, MIG, and I-TAC levels, and disproportionately high cerebrospinal fluid (CSF) IL6, IL2, GM-CSF, and VEGF levels. During neurotoxicity, both CD20 CAR and non-CAR T cells accumulate in the CSF and in the brain parenchyma. This RM model demonstrates that CAR T cell–mediated neurotoxicity is associated with proinflammatory CSF cytokines and a pan–T cell encephalitis.</p><p><b>Significance:</b> We provide the first immunologically relevant, nonhuman primate model of B cell–directed CAR T-cell therapy–mediated CRS and neurotoxicity. We demonstrate CAR and non-CAR T-cell infiltration in the CSF and in the brain during neurotoxicity resulting in pan-encephalitis, accompanied by increased levels of proinflammatory cytokines in the CSF. <i>Cancer Discov; 8(6); 750–63. ©2018 AACR.</i></p><p><i>This article is highlighted in the In This Issue feature, p. 663</i></p></div>

<div>Abstract<p>Chimeric antigen receptor (CAR) T-cell immunotherapy has revolutionized the treatment of refractory leukemias and lymphomas, but is associated with significant toxicities, namely cytokine release syndrome (CRS) and neurotoxicity. A major barrier to developing therapeutics to prevent CAR T cell–mediated neurotoxicity is the lack of clinically relevant models. Accordingly, we developed a rhesus macaque (RM) model of neurotoxicity via adoptive transfer of autologous CD20-specific CAR T cells. Following cyclophosphamide lymphodepletion, CD20 CAR T cells expand to 272 to 4,450 cells/μL after 7 to 8 days and elicit CRS and neurotoxicity. Toxicities are associated with elevated serum IL6, IL8, IL1RA, MIG, and I-TAC levels, and disproportionately high cerebrospinal fluid (CSF) IL6, IL2, GM-CSF, and VEGF levels. During neurotoxicity, both CD20 CAR and non-CAR T cells accumulate in the CSF and in the brain parenchyma. This RM model demonstrates that CAR T cell–mediated neurotoxicity is associated with proinflammatory CSF cytokines and a pan–T cell encephalitis.</p><p><b>Significance:</b> We provide the first immunologically relevant, nonhuman primate model of B cell–directed CAR T-cell therapy–mediated CRS and neurotoxicity. We demonstrate CAR and non-CAR T-cell infiltration in the CSF and in the brain during neurotoxicity resulting in pan-encephalitis, accompanied by increased levels of proinflammatory cytokines in the CSF. <i>Cancer Discov; 8(6); 750–63. ©2018 AACR.</i></p><p><i>This article is highlighted in the In This Issue feature, p. 663</i></p></div>

<div>Abstract<p>Chimeric antigen receptor (CAR) T-cell therapy is effective in the treatment of cancers of hematopoietic origin. In the immunosuppressive solid tumor environment, CAR T cells encounter obstacles that compromise their efficacy. We developed a strategy to address these barriers by having CAR T cells secrete single-domain antibody fragments [variable heavy domain of heavy chain antibodies (VHH) or nanobodies] that can modify the intratumoral immune landscape and thus support CAR T-cell function in immunocompetent animals. VHHs are small in size and able to avoid domain swapping when multiple nanobodies are expressed simultaneously—features that can endow CAR T cells with desirable properties. The secretion of an anti-CD47 VHH by CAR T cells improves engagement of the innate immune system, enables epitope spreading, and can enhance the antitumor response. CAR T cells that secrete anti–PD-L1 or anti–CTLA-4 nanobodies show improved persistence and demonstrate the versatility of this approach. Furthermore, local delivery of secreted anti-CD47 VHH-Fc fusions by CAR T cells at the tumor site limits their systemic toxicity. CAR T cells can be further engineered to simultaneously secrete multiple modalities, allowing for even greater tailoring of the antitumor immune response.</p></div>