Advances in Therapy for Relapsed or Refractory Hodgkin Lymphoma

Advances in Hodgkin's lymphoma pharmacotherapy: a focus on histone deacetylase inhibitors

INTRODUCTION

Classical Hodgkin lymphomas (cHL) usually have excellent cure rates. Yet, for patients with refractory or relapsed cHL, prognosis deteriorates as the disease becomes resistant to subsequent lines of therapies: autologous stem cell transplantation, brentuximab vedotin, and checkpoint inhibitors. Immune escape and drug resistance are hallmarks of Hodgkin Reed Sternberg cell survival, prompting the need for additional therapeutic strategies. Histone modification-based combination is an effective clinical strategy.

AREAS COVERED

In this review, we discuss the different histone deacetylase (HDAC) inhibitor molecules that have been developed and studied in cancer therapy with a focus on cHL. We review their preclinical and clinical activities both as single agents and in combination studies. Literature search was conducted in PubMed, Google Scholar, and ClinicalTrials.gov databases, using search terms 'Hodgkin lymphoma,' 'histone deacetylase inhibitor', and variations on such (e.g. 'HDAC' and individual drug names) in combination using operators 'AND,' 'OR,' and 'NOT' according to Boolean logic.

EXPERT OPINION

HDAC inhibitors alone will not be sufficient for the treatment of R/RcHL, but given their disease control capacity, synergistic interaction with currently approved drugs, and ability to overcome drug resistance, particularly PD-1 inhibitors, we believe that HDACinhibitors will eventually become incorporated into the treatment armamentarium of cHL.

Payload Delivery: Engineering Immune Cells to Disrupt the Tumour Microenvironment

Although chimeric antigen receptor (CAR) T cells have shown impressive clinical success against haematological malignancies such as B cell lymphoma and acute lymphoblastic leukaemia, their efficacy against non-haematological solid malignancies has been largely disappointing. Solid tumours pose many additional challenges for CAR T cells that have severely blunted their potency, including homing to the sites of disease, survival and persistence within the adverse conditions of the tumour microenvironment, and above all, the highly immunosuppressive nature of the tumour milieu. Gene engineering approaches for generating immune cells capable of overcoming these hurdles remain an unmet therapeutic need and ongoing area of research. Recent advances have involved gene constructs for membrane-bound and/or secretable proteins that provide added effector cell function over and above the benefits of classical CAR-mediated cytotoxicity, rendering immune cells not only as direct cytotoxic effectors against tumours, but also as vessels for payload delivery capable of both modulating the tumour microenvironment and orchestrating innate and adaptive anti-tumour immunity. We discuss here the novel concept of engineered immune cells as vessels for payload delivery into the tumour microenvironment, how these cells are better adapted to overcome the challenges faced in a solid tumour, and importantly, the novel gene engineering approaches required to deliver these more complex polycistronic gene constructs.

Promising Immunotherapeutic Modalities for B-Cell Lymphoproliferative Disorders

Over the last few years, treatment principles have been changed towards more targeted therapy for many B-cell lymphoma subtypes and in chronic lymphocytic leukemia (CLL). Immunotherapeutic modalities, namely monoclonal antibodies (mAbs), bispecific antibodies (bsAbs), antibody-drug conjugates (ADCs), and chimeric antigen receptor T (CAR-T) cell therapy, commonly use B-cell-associated antigens (CD19, CD20, CD22, and CD79b) as one of their targets. T-cell engagers (TCEs), a subclass of bsAbs, work on a similar mechanism as CAR-T cell therapy without the need of previous T-cell manipulation. Currently, several anti-CD20xCD3 TCEs have demonstrated promising efficacy across different lymphoma subtypes with slightly better outcomes in the indolent subset. Anti-CD19xCD3 TCEs are being developed as well but only blinatumomab has been evaluated in clinical trials yet. The results are not so impressive as those with anti-CD19 CAR-T cell therapy. Antibody-drug conjugates targeting different B-cell antigens (CD30, CD79b, CD19) seem to be effective in combination with mAbs, standard chemoimmunotherapy, or immune checkpoint inhibitors. Further investigation will show whether immunotherapy alone or in combinatory regimens has potential to replace chemotherapeutic agents from the first line treatment.

[Activity report of the Bone Marrow Transplant Department of the Mohammed VI University Hospital, Marrakech, Morocco, over the period 2012- 2018]

Introduction

hematopoietic stem cell transplantation (HSCT) is part of the cellular immunotherapy arsenal. It is used in the treatment of several malignant and non-malignant hematological conditions as well as other extra-hematological diseases. HSCT has been described since 1950 and introduced in Morocco since the 2000s. GSCH is still little used in our context due to several legal, financial and organizational barriers. The purpose of this study is to report the experience of the Bone Marrow Transplant Department of the Marrakech's Mohammed VI University Hospital with hematopoietic stem cell transplantation, is one of the Hospital Departments in developing countries.

Methods

we carried out a descriptive retrospective study over a period of 6 years.

Results

during the study period, sixty-six HSCT were performed. Multiple myeloma was the main indication for HSCT in our case series (30 patients with autografts). In our case series, mortality rate was around 20%, relapse rate was 23% while complications rate was 38%. Despite the challenges, our results were encouraging during the long follow-up period.

Conclusion

efforts still need to be made to improve therapy results.

Brentuximab vedotin and bendamustine: an effective salvage therapy for relapsed or refractory Hodgkin lymphoma patients

The prognosis is poor for relapsed or refractory (R/R) classical Hodgkin Lymphoma (cHL) patients. The brentuximab vedotin (Bv) and bendamustine (B) combination has been used as a preferable salvage regimen in R/R cHL patient trials. We retrospectively evaluated response rates, toxicities, and the survival in R/R cHL patients treated with the BvB combination. In a multi-centre real-life study, 61 R/R HL patients received intravenous doses of 1.8 mg/kg Bv on the first day plus 90 mg/m² B on the first and second days of a 21-day cycle as a second-line or beyond-salvage regimen. Patients' median age at BvB initiation was 33 (range: 18-76 years). BvB was given as median third-line treatment for a median of four cycles (range: 2-11). The overall and complete response rates were 82% and 68.9%, respectively. After BvB initiation, the median follow-up was 14 months, and one- and two-year overall survival rates were 85% and 72%, respectively. Grade 3/4 toxicities included neutropenia (24.6%), lymphopenia (40%), thrombocytopenia (13%), anaemia (13%), infusion reactions (8.2%), neuropathy (6.5%), and others. The BvB combination could be given as salvage regimen aiming a bridge to autologous stem cell transplant (ASCT), in patients relapse after ASCT or to transplant-ineligible patients with manageable toxicity profiles.

Childhood Cancer: Occurrence, Treatment and Risk of Second Primary Malignancies

Cancer represents the leading cause of disease-related death and treatment-associated morbidity in children with an increasing trend in recent decades worldwide. Nevertheless, the 5-year survival of childhood cancer patients has been raised impressively to more than 80% during the past decades, primarily attributed to improved diagnostic technologies and multiagent cytotoxic regimens. This strong benefit of more efficient tumor control and prolonged survival is compromised by an increased risk of adverse and fatal late sequelae. Long-term survivors of pediatric tumors are at the utmost risk for non-carcinogenic late effects such as cardiomyopathies, neurotoxicity, or pneumopathies, as well as the development of secondary primary malignancies as the most detrimental consequence of genotoxic chemo- and radiotherapy. Promising approaches to reducing the risk of adverse late effects in childhood cancer survivors include high precision irradiation techniques like proton radiotherapy or non-genotoxic targeted therapies and immune-based treatments. However, to date, these therapies are rarely used to treat pediatric cancer patients and survival rates, as well as incidences of late effects, have changed little over the past two decades in this population. Here we provide an overview of the epidemiology and etiology of childhood cancers, current developments for their treatment, and therapy-related adverse late health consequences with a special focus on second primary malignancies.

Melittin Increases Cisplatin Sensitivity and Kills KM-H2 and L-428 Hodgkin Lymphoma Cells

Hodgkin lymphoma (HL) is neoplasia with high cure rates. However, not all patients can be cured with the current treatment. Chemo-resistance of tumor cells is one factor involved in treatment failure. In addition to its pore-forming activity on lipid bilayer membranes, the toxin melittin from bee venom is an inhibitor of several cancer-related signaling pathways. Moreover, melittin analogs have been shown to inhibit the activity of ATP binding cassette (ABC) transporters which are known to play important roles in the chemo-resistance of tumor cells. Therefore, we tested the toxicity of melittin for HL cell lines KM-H2 and L-428 and whether melittin can increase the chemo-sensitivity of cisplatin-resistant HL cells. We found high toxicity of melittin for KM-H2 and L-428 cells. In co-cultures with normal blood cells, melittin preferentially killed KM-H2 and L-428 cells. In addition, we observed increased cisplatin sensitivity of chemo-resistant L-428 cells after treatment with melittin. ABC transporter activity was not reduced after treatment with melittin. Our data suggest that melittin or melittin analogs might be promising agents for the future development of treatment strategies for HL patients with resistant disease.

Molecular Pathogenesis of Hodgkin Lymphoma: Past, Present, Future

Our understanding of the tumorigenesis of classical Hodgkin lymphoma (cHL) and the formation of Reed–Sternberg cells (RS-cells) has evolved drastically in the last decades. More recently, a better characterization of the signaling pathways and the cellular interactions at play have paved the way for new targeted therapy in the hopes of improving outcomes. However, important gaps in knowledge remain that may hold the key for significant changes of paradigm in this lymphoma. Here, we discuss the past, present, and future of cHL, and review in detail the more recent discoveries pertaining to genetic instability, anti-apoptotic signaling pathways, the tumoral microenvironment, and host-immune system evasion in cHL.

miR-532-3p Inhibits Proliferation and Promotes Apoptosis of Lymphoma Cells by Targeting β-Catenin

Background: Dysregulated expression of miR-532-3p has been observed in several types of cancer and plays a key role in tumor progression and metastasis. In this study, we analyzed the role and molecular mechanism of miR-532-3p in lymphoma progression.

Methods: The expression of miR-532-3p in lymphoma sample tissues was analyzed using the GEO database and in cell lines by quantitative reverse transcription (qRT)-PCR. The functions of miR-532-3p in lymphoma cell proliferation and apoptosis were analyzed by CCK-8 assay and Annexin V-FITC/propidium iodide staining, respectively. In vivo, the tumor weight and volume were measured. The target gene of miR-532-3p was predicted using miRanda software, and then luciferase, qRT-PCR, and western blot assays were performed to verify that β-catenin was the downstream target gene of miR-532-3p.

Results: miR-532-3p was decreased in lymphoma tissues and cell lines. In vitro and in vivo experiments showed that overexpression of miR-532-3p inhibited lymphoma cell proliferation and promoted apoptosis. Mechanistic studies demonstrated that β-catenin was a functional target gene of miR-532-3p. Furthermore, we found that overexpression of β-catenin reversed the tumor-suppression activities caused by overexpression of miR-532-3p in lymphoma proliferation and apoptosis.

Conclusion: This study demonstrates that miR-532-3p functions as a tumor inhibitor in lymphoma progression by targeting β-catenin, suggesting miR-532-3p/β-catenin as a new diagnosis marker or potential therapeutic target in lymphoma.