Adoptive T-cell therapy for Hodgkin lymphoma

Novel and multiple targets for chimeric antigen receptor-based therapies in lymphoma

Chimeric antigen receptor (CAR) T-cell therapy targeting CD19 in B-cell non-Hodgkin lymphoma (NHL) validates the utility of CAR-based therapy for lymphomatous malignancies. Despite the success, treatment failure due to CD19 antigen loss, mutation, or down-regulation remains the main obstacle to cure. On-target, off-tumor effect of CD19-CAR T leads to side effects such as prolonged B-cell aplasia, limiting the application of therapy in indolent diseases such as chronic lymphocytic leukemia (CLL). Alternative CAR targets and multi-specific CAR are potential solutions to improving cellular therapy outcomes in B-NHL. For Hodgkin lymphoma and T-cell lymphoma, several cell surface antigens have been studied as CAR targets, some of which already showed promising results in clinical trials. Some antigens are expressed by different lymphomas and could be used for designing tumor-agnostic CAR. Here, we reviewed the antigens that have been studied for novel CAR-based therapies, as well as CARs designed to target two or more antigens in the treatment of lymphoma.

Predictive and prognostic molecular biomarkers in lymphomas

Recent advances in molecular diagnostics have markedly expanded our understanding of the genetic underpinnings of lymphomas and catalysed a transformation in not just how we classify lymphomas, but also how we treat, target, and monitor affected patients. Reflecting these advances, the World Health Organization Classification, International Consensus Classification, and National Comprehensive Cancer Network guidelines were recently updated to better integrate these molecular insights into clinical practice. We summarise here the molecular biomarkers of lymphomas with an emphasis on biomarkers that have well-supported prognostic and predictive utility, as well as emerging biomarkers that show promise for clinical practice. These biomarkers include: (1) diagnostic entity-defining genetic abnormalities [e.g., B-cell acute lymphoblastic leukaemia (B-ALL) with KMT2A rearrangement]; (2) molecular alterations that guide patients' prognoses (e.g., TP53 loss frequently conferring worse prognosis); (3) mutations that serve as the targets of, and often a source of acquired resistance to, small molecular inhibitors (e.g., ABL1 tyrosine kinase inhibitors for B-ALL BCR::ABL1, hindered by ABL1 kinase domain resistance mutations); (4) the growing incorporation of molecular measurable residual disease (MRD) in the management of lymphoma patients (e.g., molecular complete response and sequencing MRD-negative criteria in multiple myeloma). Altogether, our review spans the spectrum of lymphoma types, from the genetically defined subclasses of precursor B-cell lymphomas to the highly heterogeneous categories of small and large cell mature B-cell lymphomas, Hodgkin lymphomas, plasma cell neoplasms, and T/NK-cell lymphomas, and provides an expansive summary of our current understanding of their molecular pathology.

Chimeric Antigen Receptor T Cells in Hodgkin and T-Cell Lymphomas

The authors review the current use of chimeric antigen receptor (CAR)-transduced T cells (CAR-T) in Hodgkin lymphoma (HL) and T-cell lymphomas (TCL) and discuss the data on CD30-targeting CAR-T cells, which seem to be safe and effective in HL. In addition, the authors examine the use of CAR-T cells targeting CD30, CD5, or CD7 in TCL, while highlighting the unique challenges of their use in this subset of lymphomas. Furthermore, the authors present future directions and ongoing trials investigating the use of CAR-T cells in TCL and HL.

CAR-T Cell Therapy for Classical Hodgkin Lymphoma

Classical Hodgkin lymphoma (cHL) is a malignancy characterized by the presence of Hodgkin and Reed-Sternberg (HRS) cells within a complex tumor microenvironment (TME). Despite advances in conventional therapies, a subset of cHL patients experience relapse or refractory disease, necessitating the exploration of novel treatment strategies. Chimeric antigen receptor T cell (CAR-T cell) therapy has emerged as a promising approach for the management of cHL, harnessing the power of genetically modified T cells to recognize and eliminate tumor cells. In this article, we provide an overview of the pathogenesis of cHL, highlighting the key molecular and cellular mechanisms involved. Additionally, we discuss the rationale for the development of CAR-T cell therapy in cHL, focusing on the identification of suitable targets on HRS cells (such as CD30, CD123, LMP1, and LMP2A), clonotypic lymphoma initiating B cells (CD19, CD20), and cells within the TME (CD123, CD19, CD20) for CAR-T cell design. Furthermore, we explore various strategies employed to enhance the efficacy and safety of CAR-T cell therapies in the treatment of cHL. Finally, we present an overview of the results obtained from clinical trials evaluating the efficacy of CAR-T cell therapies in cHL, highlighting their potential as a promising therapeutic option. Collectively, this article provides a comprehensive review of the current understanding of cHL pathogenesis and the rationale for CAR-T cell therapy development, offering insights into the future directions of this rapidly evolving field.

Hodgkin Lymphoma: A disease shaped by the tumor micro- and macroenvironment

The tumor microenvironment (TMicroE) and tumor macroenvironment (TMacroE) are defining features of classical Hodgkin lymphoma (cHL). They are of critical importance to clinicians since they explain the common signs and symptoms, allow us to classify these neoplasms, develop prognostic and predictive biomarkers, bioimaging and novel treatments. The TMicroE is defined by effects of cancer cells to their immediate surrounding and within the tumor. Effects of cancer cells at a distance or outside of the tumor define the TMacroE. Paraneoplastic syndromes are signs and symptoms due to effects of cancer at a distance or the TMacroE, which are not due to direct cancer cell infiltration. The most common paraneoplastic symptoms are B-symptoms, which manifest as fevers, chills, drenching night sweats, and/or weight loss. Less common paraneoplastic syndromes include those that affect the central nervous system, skin, kidney, and hematological autoimmune phenomena including hemophagocytic lymphohistiocytosis (HLH). Paraneoplastic signs such as leukocytosis, lymphopenia, anemia, and hypoalbuminemia are prognostic biomarkers. The neoplastic cells in cHL are the Hodgkin and Reed Sternberg (HRS) cells, which are preapoptotic germinal center B cells with a high mutational burden and almost universal genetic alterations at the 9p24.1 locus primarily through copy gain and amplification with strong activation of signaling via PD-L1, JAK-STAT, NFkB, and c-MYC. In the majority of cases of cHL over 95% of the tumor cells are non-neoplastic. In the TMicroE, HRS cells recruit and mold non-neoplastic cells vigorously via extracellular vesicles, chemokines, cytokines and growth factors such as CCL5, CCL17, IL6, and TGF-β to promote a feed-forward inflammatory loop, which drives cancer aggressiveness and anti-cancer immune evasion. Novel single cell profiling techniques provide critical information on the role in cHL of monocytes-macrophages, neutrophils, T helper, Tregs, cytotoxic CD8+ T cells, eosinophils, mast cells and fibroblasts. Here, we summarize the effects of EBV on the TMicroE and TMacroE. In addition, how the metabolism of the TMicroE of cHL affects bioimaging and contributes to cancer aggressiveness is reviewed. Finally, we discuss how the TMicroE is being leveraged for risk adapted treatment strategies based on bioimaging results and novel immune therapies. In sum, it is clear that we cannot effectively manage patients with cHL without understanding the TMicroE and TMacroE and its clinical importance is expected to continue to grow rapidly.

Broadening the horizon: potential applications of CAR-T cells beyond current indications

Engineering immune cells to treat hematological malignancies has been a major focus of research since the first resounding successes of CAR-T-cell therapies in B-ALL. Several diseases can now be treated in highly therapy-refractory or relapsed conditions. Currently, a number of CD19- or BCMA-specific CAR-T-cell therapies are approved for acute lymphoblastic leukemia (ALL), diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), multiple myeloma (MM), and follicular lymphoma (FL). The implementation of these therapies has significantly improved patient outcome and survival even in cases with previously very poor prognosis. In this comprehensive review, we present the current state of research, recent innovations, and the applications of CAR-T-cell therapy in a selected group of hematologic malignancies. We focus on B- and T-cell malignancies, including the entities of cutaneous and peripheral T-cell lymphoma (T-ALL, PTCL, CTCL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML), chronic lymphocytic leukemia (CLL), classical Hodgkin-Lymphoma (HL), Burkitt-Lymphoma (BL), hairy cell leukemia (HCL), and Waldenström's macroglobulinemia (WM). While these diseases are highly heterogenous, we highlight several similarly used approaches (combination with established therapeutics, target depletion on healthy cells), targets used in multiple diseases (CD30, CD38, TRBC1/2), and unique features that require individualized approaches. Furthermore, we focus on current limitations of CAR-T-cell therapy in individual diseases and entities such as immunocompromising tumor microenvironment (TME), risk of on-target-off-tumor effects, and differences in the occurrence of adverse events. Finally, we present an outlook into novel innovations in CAR-T-cell engineering like the use of artificial intelligence and the future role of CAR-T cells in therapy regimens in everyday clinical practice.

Quantitative PET-based biomarkers in lymphoma: getting ready for primetime

The use of functional quantitative biomarkers extracted from routine PET-CT scans to characterize clinical responses in patients with lymphoma is gaining increased attention, and these biomarkers can outperform established clinical risk factors. Total metabolic tumour volume enables individualized estimation of survival outcomes in patients with lymphoma and has shown the potential to predict response to therapy suitable for  risk-adapted treatment approaches in clinical trials. The deployment of machine learning tools in molecular imaging research can assist in recognizing complex patterns and, with image classification, in tumour identification and segmentation of data from PET-CT scans. Initial studies using fully automated approaches to calculate metabolic tumour volume and other PET-based biomarkers have demonstrated appropriate correlation with calculations from experts, warranting further testing in large-scale studies. The extraction of computer-based quantitative tumour characterization through radiomics can provide a comprehensive view of phenotypic heterogeneity that better captures the molecular and functional features of the disease. Additionally, radiomics can be integrated with genomic data to provide more accurate prognostic information. Further improvements in PET-based biomarkers are imminent, although their incorporation into clinical decision-making currently has methodological shortcomings that need to be addressed with confirmatory prospective validation in selected patient populations. In this Review, we discuss the current knowledge, challenges and opportunities in the integration of quantitative PET-based biomarkers in clinical trials and the routine management of patients with lymphoma.

Impact of risk factors and long term survival analysis of patients with primary refractory Hodgkin lymphoma who underwent high dose chemotherapy and autologous stem cell transplant

BACKGROUND

Patients with primary refractory Hodgkin lymphoma (ref-HL) can still be salvaged with high dose chemotherapy (HDC) and autologous stem cell transplantation (auto-SCT). Outcome of patients with ref-HL is poorer than those with relapsed HL, but most studies have included patients with both relapsed and refractory diseases, and separate analyses or studies on patients with ref-HL are limited.

OBJECTIVE

This study aimed to evaluate the outcomes of HDC auto-SCT and impact of various prognostic factors on patients with ref-HL both at the time of primary treatment failure and also on subsequent survival at the time of failure post HDC auto-SCT.

STUDY DESIGN

This was a retrospective, single-institution, cohort analysis using HDC and auto-SCT database, approved by the Institutional Research Advisory Counsel and Ethics Committee for identifying patients. We used Fine and Gray competing risk analysis method, regression model for outcome analysis and Kaplan-Meier method (KM) for survival.

RESULTS

Two hundred consecutive ref-HL patients underwent HDC auto-SCT between 1996 to 2019. Median age was 22.75 years, median follow-up 106 months. Post auto-SCT, disease status was complete remission (CR), partial remission, and progressive disease in 122 (61%), 22 (11%), and 47 (23.5%) patients, respectively. KM median progression-free survival (PFS) after auto-SCT was 43.9 months (5:10 years, 49.3%:45.5%). Median overall survival (OS) was 168.6 months (5:10 years, 61.2%:56.2%). Eighty-five patients (44.5%) died - 69 (34.5%) due to disease. For both PFS and OS, multivariate analysis identified similar adverse factors. For PFS, stage III-IV at relapse (HR=1.65, P=0.045), mediastinal involvement (HR=2.01, P=0.009), and no CR after salvage chemotherapy (HR=2.2, P=0.001) as adverse factors. PFS with 0-1 (not reached), 2 (40.8), 3 adverse factors (5.4 months) were significant (p<0.001). For OS, stage III-IV at relapse (HR=1.68, P=0.045), mediastinal involvement (HR=2.52, P=0.007), and no CR after salvage chemotherapy (HR=2.15, P=0.004) were significant. OS with 0-1 (not reached), 2 (148.5) 3 adverse factors (34.4 months) were significant (p<0.001). Median OS after auto-SCT failure was 23.6 months; patients received post auto-SCT brentuximab/second SCT (not reached), other treatments (22.5 months), and supportive care (8.4) (p<0.001). OS with five risk factors, present at HDC auto-SCT failure, (stage III-IV, failure <12 months, tumor >5 cm, B-symptoms, low albumin) showed that 0-1:2:3-5 risk factors had 152:30.9:9.45 months OS (p<0.001).

CONCLUSION

Ref-HL patients have encouraging survival after HDC auto-SCT and can even be salvaged after auto-SCT failure. Based on prognostic factors, survival prediction is possible. Patients who fail to respond to HDC auto-SCT may benefit from newer treatments strategies and may qualify for enrollment in clinical trials.

Current Status of Novel Agents for the Treatment of B Cell Malignancies: What's Coming Next?

Resistance to death is one of the hallmarks of human B cell malignancies and often contributes to the lack of a lasting response to today's commonly used treatments. Drug discovery approaches designed to activate the death machinery have generated a large number of inhibitors of anti-apoptotic proteins from the B-cell lymphoma/leukemia 2 family and the B-cell receptor (BCR) signaling pathway. Orally administered small-molecule inhibitors of Bcl-2 protein and BCR partners (e.g., Bruton's tyrosine kinase and phosphatidylinositol-3 kinase) have already been included (as monotherapies or combination therapies) in the standard of care for selected B cell malignancies. Agonistic monoclonal antibodies and their derivatives (antibody-drug conjugates, antibody-radioisotope conjugates, bispecific T cell engagers, and chimeric antigen receptor-modified T cells) targeting tumor-associated antigens (TAAs, such as CD19, CD20, CD22, and CD38) are indicated for treatment (as monotherapies or combination therapies) of patients with B cell tumors. However, given that some patients are either refractory to current therapies or relapse after treatment, novel therapeutic strategies are needed. Here, we review current strategies for managing B cell malignancies, with a focus on the ongoing clinical development of more effective, selective drugs targeting these molecules, as well as other TAAs and signaling proteins. The observed impact of metabolic reprogramming on B cell pathophysiology highlights the promise of targeting metabolic checkpoints in the treatment of these disorders.

Promising drugs and treatment options for pediatric and adolescent patients with Hodgkin lymphoma

Currently-available therapies for newly-diagnosed pediatric and adolescent patients with Hodgkin lymphoma result in >95% survival at 5 years. Long-term survivors may suffer from long-term treatment-related side effects, however, so the past 20 years have seen clinical trials for children and adolescents with HL gradually abandon the regimens used in adults in an effort to improve this situation. Narrower-field radiotherapy can reduce long-term toxicity while maintaining good tumor control. Various risk-adapted chemo-radiotherapy strategies have been used. Early assessment of tumor response with interim positron emission tomography and/or measuring metabolic tumor volume has been used both to limit RT in patients with favorable characteristics and to adopt more aggressive therapies in patients with a poor response. Most classical Hodgkin's lymphoma relapses occur within 3 years of initial treatment, while relapses occurring 5 years or more after diagnosis are rare. As the outcome for patients with relapsed/refractory classical Hodgkin lymphoma remains unsatisfactory, new drugs have been proposed for its prevention or treatment. This review summarizes the important advances made in recent years in the management of pediatric and adolescent with classical Hodgkin lymphoma, and the novel targeted treatments for relapsed and refractory classical Hodgkin lymphoma.

Current and Emerging Approaches to Study Microenvironmental Interactions and Drug Activity in Classical Hodgkin Lymphoma

Simple Summary

In classical Hodgkin Lymphoma (cHL), the tumor microenvironment (TME) plays an important role in tumor progression and treatment response, making its evaluation critical for determining prognosis, treatment strategies and predicting an increase in drug toxicity. Therefore, there is a need to utilize more complex systems to study the cHL-TME and its interplay with tumor cells. To evaluate new anticancer drugs and to find the mechanisms of drug resistance, this review summarizes emerging approaches for the analysis of the TME composition and to identify the state of the disease; the in vitro techniques used to determine the mechanisms involved in the building of an immunosuppressive and protective TME; new 3-dimensional (3D) models, the heterospheroids (HS), developed to mimic TME interactions. Here, we describe the present and likely future clinical applications indicated by the results of these studies and propose a classification for the in vitro culture methods used to study TME interactions in cHL.

Abstract

Classic Hodgkin lymphoma is characterized by a few tumor cells surrounded by a protective and immunosuppressive tumor microenvironment (TME) composed by a wide variety of noncancerous cells that are an active part of the disease. Therefore, new techniques to study the cHL-TME and new therapeutic strategies targeting specifically tumor cells, reactivating the antitumor immunity, counteracting the protective effects of the TME, were developed. Here, we describe new methods used to study the cell composition, the phenotype, and the spatial distribution of Hodgkin and Reed–Sternberg (HRS) cells and of noncancerous cells in tumor tissues. Moreover, we propose a classification, with increasing complexity, of the in vitro functional studies used to clarify the interactions leading not only to HRS cell survival, growth and drug resistance, but also to the immunosuppressive tumor education of monocytes, T lymphocytes and fibroblasts. This classification also includes new 3-dimensional (3D) models, obtained by cultivating HRS cells in extracellular matrix scaffolds or in sponge scaffolds, under non-adherent conditions with noncancerous cells to form heterospheroids (HS), implanted in developing chick eggs (ovo model). We report results obtained with these approaches and their applications in clinical setting.

The Emerging Role of CAR T Cell Therapy in Relapsed/Refractory Hodgkin Lymphoma

Treatment for Hodgkin lymphoma (HL) has evolved considerably from the time it was originally described in the 19th century with many patients now being cured with frontline therapy. Despite these advances, upwards of 10% of patients experience progressive disease after initial therapy with an even higher percentage relapsing. Until recently there had been limited therapeutic options for relapsed and/or refractory HL outside of highly intensive chemotherapy with stem cell rescue. Improved understanding of the pathophysiology of HL, coupled with the emergence of more targeted therapeutics, has reshaped how we view the treatment of relapsed/refractory HL and its prognosis. With this, there has been an increased focus on immunotherapies that can reprogram the immune system to better overcome the immunosuppressive milieu found in HL for improved cancer cell killing. In particular, chimeric antigen receptor (CAR) T cells are emerging as a valuable therapeutic tool in this area. Building on the success of antibody-drug conjugates directed against CD30, CAR T cells engineered to recognize the same antigen are now reaching patients. Though still in its infancy, CAR T therapy for relapsed/refractory HL has shown exceptional promise in early-stage clinical trials with the potential for durable responses even in patients who had progressed through multiple lines of prior therapy. Here we will review currently available data on the use of CAR T cells in HL, strategies to optimize their effectiveness, and how this therapy may fit into the treatment paradigm of HL going forward.