CAR-T Cell Therapy for Lymphoma

Current Progress in EBV-Associated B-Cell Lymphomas

Epstein-Barr virus (EBV) was the first human tumor virus discovered more than 50 years ago. EBV-associated lymphomagenesis is still a significant viral-associated disease as it involves a diverse range of pathologies, especially B-cell lymphomas. Recent development of high-throughput next-generation sequencing technologies and in vivo mouse models have significantly promoted our understanding of the fundamental molecular mechanisms which drive these cancers and allowed for the development of therapeutic intervention strategies. This review will highlight the current advances in EBV-associated B-cell lymphomas, focusing on transcriptional regulation, chromosome aberrations, in vivo studies of EBV-mediated lymphomagenesis, as well as the treatment strategies to target viral-associated lymphomas.

Checkpoint inhibition and cellular immunotherapy in lymphoma

Hodgkin and non-Hodgkin lymphoma are both good targets for immunotherapy, as they are accessible to antibodies and cell-based immunotherapy, express costimulatory molecules, and express lineage-restricted, viral, and unique tumor antigens. Blockade of the programmed-death 1 (PD-1) immune checkpoint has produced very encouraging response rates in patients with Hodgkin lymphoma, whereas adoptive transfer of Epstein-Barr Virus (EBV)-specific T cells has shown clinical activity in patients with posttransplant lymphoma and other EBV-associated lymphomas. T cells can also be genetically modified with chimeric antigen receptors (CARs) to confer specificity for surface antigens, and studies of CD19 CARs in lymphoma also have had encouraging response rates. Future directions include combination of checkpoint blockade and adoptive T-cell studies.

Low Level of Blood CD4+ T Cells Is an Independent Predictor of Inferior Progression-free Survival in Diffuse Large B-cell Lymphoma

BACKGROUND

Tumor-infiltrating immune cells influence diffuse large B-cell lymphoma (DLBCL) outcomes. Relatively little, however, is known about the significance of peripheral blood immune cell numbers on DLBCL behavior.

PATIENTS AND METHODS

In the present study, 43 patients with newly diagnosed DLBCL had pretreatment multiparameter peripheral blood flow cytometry performed to assess the immune cell numbers. These cell numbers were correlated with the outcomes of progression-free survival (PFS) and overall survival.

RESULTS

After follow-up period of 0.8 to 152 months (median, 73), 25 patients (56%) were still alive. As continuous variables on univariate analysis, the predictors of PFS were patient age and absolute CD4 cell count (ACD4C), with the International Prognostic Index (IPI) marginally significant. Age was also a significant predictor of overall survival, and the IPI and ACD4C were marginally significant (P = .08). The 17 patients with a greater ACD4C (≥ 450/mm³) had better 5-year PFS than the 26 with a low ACD4C (88% vs. 50%; P = .02). Multivariable analysis, including age as a continuous variable, IPI group, and ACD4C of 450/mm³ showed that age and ACD4C were significant for PFS (P = .01 and P = .02, respectively).

CONCLUSION

Our data, although from a small series, suggest that the blood ACD4C might be a predictor of PFS for patients with DLBCL, independent of age and the IPI.

Immunotherapy for Gastroesophageal Cancer

Survival for patients with advanced oesophageal and stomach cancer is poor; together these cancers are responsible for more than a million deaths per year globally. As chemotherapy and targeted therapies such as trastuzumab and ramucirumab result in modest improvements in survival but not long-term cure for such patients, development of alternative treatment approaches is warranted. Novel immunotherapy drugs such as checkpoint inhibitors have been paradigm changing in melanoma, non-small cell lung cancer and urothelial cancers. In this review, we assess the early evidence for efficacy of immunotherapy in patients with gastroesophageal cancer in addition to considering biomarkers associated with response to these treatments. Early results of Anti- Programmed Cell Death Protein-1 (anti-PD-1), anti-PD-L1 and anti-Cytotoxic T-lymphocyte assosciated protein-4 (anti-CTLA4) trials are examined, and we conclude with a discussion on the future direction for immunotherapy for gastroesophageal cancer patients.

CRISPR-mediated genome editing and human diseases

CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) technology has emerged as a powerful technology for genome editing and is now widely used in basic biomedical research to explore gene function. More recently, this technology has been increasingly applied to the study or treatment of human diseases, including Barth syndrome effects on the heart, Duchenne muscular dystrophy, hemophilia, β-Thalassemia, and cystic fibrosis. CRISPR/Cas9 (CRISPR-associated protein 9) genome editing has been used to correct disease-causing DNA mutations ranging from a single base pair to large deletions in model systems ranging from cells in vitro to animals in vivo. In addition to genetic diseases, CRISPR/Cas9 gene editing has also been applied in immunology-focused applications such as the targeting of C-C chemokine receptor type 5, the programmed death 1 gene, or the creation of chimeric antigen receptors in T cells for purposes such as the treatment of the acquired immune deficiency syndrome (AIDS) or promoting anti-tumor immunotherapy. Furthermore, this technology has been applied to the genetic manipulation of domesticated animals with the goal of producing biologic medical materials, including molecules, cells or organs, on a large scale. Finally, CRISPR/Cas9 has been teamed with induced pluripotent stem (iPS) cells to perform multiple tissue engineering tasks including the creation of disease models or the preparation of donor-specific tissues for transplantation. This review will explore the ways in which the use of CRISPR/Cas9 is opening new doors to the treatment of human diseases.

Hematopoietic Stem Cells in Regenerative Medicine: Astray or on the Path?

Hematopoietic stem cells (HSCs) are the best characterized adult stem cells and the only stem cell type in routine clinical use. The concept of stem cell transplantation laid the foundations for the development of novel cell therapies within, and even outside, the hematopoietic system. Here, we report on the history of hematopoietic cell transplantation (HCT) and of HSC isolation, we briefly summarize the capabilities of HSCs to reconstitute the entire hemato/lymphoid cell system, and we assess current indications for HCT. We aim to draw the lines between areas where HCT has been firmly established, areas where HCT can in the future be expected to be of clinical benefit using their regenerative functions, and areas where doubts persist. We further review clinical trials for diverse approaches that are based on HCT. Finally, we highlight the advent of genome editing in HSCs and critically view the use of HSCs in non-hematopoietic tissue regeneration.

Progress of dendritic cell-based cancer vaccines for patients with hematological malignancies

INTRODUCTION

Dendritic cells (DCs) are the most professional antigen-presenting cells eliciting cellular and humoral immune responses against cancer cells by expressing these antigens on MHC class I/II complexes to T cells. Therefore, they have been employed in many clinical trials as cancer vaccines for patients with cancer. This review focuses on the use of DCs in leukemia patients expressing leukemia-associated antigens (LAAs).

AREAS COVERED

The contribution of both stimulating vs. tolerogenic DCs as well as of other factors to the milieu of anti-leukemia immune responses are discussed. Several DC vaccination strategies like leukemia lysate, proteins and peptides have been developed. Next generation DC vaccines comprise transduction of DCs with retroviral vectors encoding for LAAs, cytokines and costimulatory molecules as well as transfection of DCs with naked RNA encoding for LAAs. Published as well as ongoing clinical trials are reported and critically reviewed.

EXPERT OPINION

Future results will demonstrate whether next-generation DCs are really superior to conventional pulsing with peptide, protein or tumor lysate. However, currently available methods based on nucleic acid transfection/transduction are tempting in terms of material production costs and time for clinical application according to good manufacturing practice (GMP).

CD62L+ NKT cells have prolonged persistence and antitumor activity in vivo

Vα24-invariant natural killer T cells (NKTs) localize to tumors and have inherent antitumor properties, making them attractive chimeric antigen receptor (CAR) carriers for redirected cancer immunotherapy. However, clinical application of CAR-NKTs has been impeded, as mechanisms responsible for NKT expansion and the in vivo persistence of these cells are unknown. Here, we demonstrated that antigen-induced expansion of primary NKTs in vitro associates with the accumulation of a CD62L+ subset and exhaustion of CD62L- cells. Only CD62L+ NKTs survived and proliferated in response to secondary stimulation. When transferred to immune-deficient NSG mice, CD62L+ NKTs persisted 5 times longer than CD62L- NKTs. Moreover, CD62L+ cells transduced with a CD19-specific CAR achieved sustained tumor regression in a B cell lymphoma model. Proliferating CD62L+ cells downregulated or maintained CD62L expression when activated via T cell receptor alone or in combination with costimulatory receptors. We generated HLAnull K562 cell clones that were engineered to express CD1d and costimulatory ligands. Clone B-8-2 (HLAnullCD1dmedCD86high4-1BBLmedOX40Lhigh) induced the highest rates of NKT expansion and CD62L expression. B-8-2-expanded CAR-NKTs exhibited prolonged in vivo persistence and superior therapeutic activities in models of lymphoma and neuroblastoma. Therefore, we have identified CD62L as a marker of a distinct NKT subset endowed with high proliferative potential and have developed artificial antigen-presenting cells that generate CD62L-enriched NKTs for effective cancer immunotherapy.

Allogeneic hematopoietic cell transplantation as curative therapy for non-transformed follicular lymphomas

Allogeneic hematopoietic cell transplantation (HCT) offers the chance of cure for patients with non-transformed follicular lymphoma (FL), but is associated with the risk of non-relapse mortality (NRM). The aim of this study was to identify subgroups of FL patients who benefit from HCT. The European Society for Blood and Marrow Transplantation (EBMT) Minimum-Essential-A Data of 146 consecutive patients who received HCT for FL between 1998 and 2008 were extracted from the database of the German Registry 'DRST'. Diagnosis of FL was verified by contact with the reference pathologists. Estimated 1-, 2- and 5-year overall survivals (OS) were 67%, 60% and 53%, respectively. Day 100 NRM was 15%. Thirteen out of 33 patients (40%) with treatment-refractory disease (RD) at the time of transplantation survived long term. Univariate statistical analysis suggested limited chronic GvHD, donor age ⩽42 years and TBI-based conditioning in treatment refractory patients to correlate with favorable OS. Independent prognostic factors for OS were treatment-sensitive disease and limited chronic GvHD for the whole cohort, and additionally TBI-based conditioning for the treatment refractory subgroup. In contrast, patient age ⩾55 years had no impact on outcome. Thus, HCT for FL is associated with acceptable NRM, and offers a substantial chance of cure for patients with RD or advanced age. Donors ⩽42 years should be preferred if available.

CD19 chimeric antigen receptor (CD19 CAR)-redirected adoptive T-cell immunotherapy for the treatment of relapsed or refractory B-cell Non-Hodgkin's Lymphomas

Recovery rates for B-cell Non-Hodgkin's Lymphoma (NHL) are up to 70% with current standard-of-care treatments including rituximab (chimeric anti-CD20 monoclonal antibody) in combination with chemotherapy (R-CHOP). However, patients who do not respond to first-line treatment or develop resistance have a very poor prognosis. This signifies the need for the development of an optimal treatment approach for relapsed/refractory B-NHL. Novel CD19- chimeric antigen receptor (CAR) T-cell redirected immunotherapy is an attractive option for this subset of patients. Anti-CD19 CAR T-cell therapy has already had remarkable efficacy in various leukemias as well as encouraging outcomes in phase I clinical trials of relapsed/refractory NHL. In going forward with additional clinical trials, complementary treatments that may circumvent potential resistance mechanisms should be used alongside anti-CD19 T-cells in order to prevent relapse with resistant strains of disease. Some such supplementary tactics include conditioning with lymphodepletion agents, sensitizing with kinase inhibitors and Bcl-2 inhibitors, enhancing function with multispecific CAR T-cells and CD40 ligand-expressing CAR T-cells, and safeguarding with lymphoma stem cell-targeted treatments. A therapy regimen involving anti-CD19 CAR T-cells and one or more auxiliary treatments could dramatically improve prognoses for patients with relapsed/refractory B-cell NHL. This approach has the potential to revolutionize B-NHL salvage therapy in much the same way rituximab did for first-line treatments.