Successes, failures and new perspectives of idiotypic vaccination for B-cell non-Hodgkin lymphomas

Recent progress in GM-CSF-based cancer immunotherapy

Cancer immunotherapy is a growing field. GM-CSF, a potent cytokine promoting the differentiation of myeloid cells, can also be used as an immunostimulatory adjuvant to elicit antitumor immunity. Additionally, GM-CSF is essential for the differentiation of dendritic cells, which are responsible for processing and presenting tumor antigens for the priming of antitumor cytotoxic T lymphocytes. Some strategies have been developed for GM-CSF-based cancer immunotherapy in clinical practice: GM-CSF monotherapy, GM-CSF-secreting cancer cell vaccines, GM-CSF-fused tumor-associated antigen protein-based vaccines, GM-CSF-based DNA vaccines and GM-CSF combination therapy. GM-CSF also contributes to the regulation of immunosuppression in the tumor microenvironment. This review provides recommendations regarding GM-CSF-based cancer immunotherapy.

The role of novel immunotherapies in non-Hodgkin lymphoma

Immunotherapy is an evolving modality in the treatment of non-Hodgkin lymphoma. Vaccinations with patient-specific tumor-derived antigens have been developed to strengthen immune response to tumor. The success of rituximab, a monoclonal antibody for CD20 on malignant B-cells, fueled further immunotherapy research. The power of the immune system to fight hematologic malignancies is seen in allogeneic stem cell transplant, where donor T cells attack residual malignant cells in the recipient. Now, three innovative therapeutic immunotherapy classes (I) adoptive cellular therapy; (II) immune-checkpoint inhibitors; and (III) novel antibody therapies show promising results in non-Hodgkin lymphoma. Genetically engineered T cells, CAR T cells, obtained remissions in lymphomas refractory to conventional chemotherapy. Immune-checkpoint inhibitors, such as nivolumab and pembrolizumab revolutionized the treatment of many solid tumors, and unprecedented results are now reported in relapsed/refractory lymphoma. Building on the success of rituximab, additional therapeutic monoclonal antibodies were developed for lymphoma treatment. Antibodies have recently been further engineered with multiple binding sites to directly engage both tumor and T cells. There are exciting early clinical trial results for the first bispecific T-cell engager (BiTE), blinatumomab, as well as promising ongoing studies for dual antibody molecules, Dual-Affinity Re-Targeting (DART) proteins. This review highlights these three immunotherapy classes for relapsed/refractory non-Hodgkin lymphomas and discusses the mechanism of action, clinical efficacy, and toxicities of each.

Vaccination strategies in lymphoproliferative disorders: Failures and successes

Anti-tumor vaccines in lymphoproliferative disorders hold out the prospect of effective tumor therapies with minimal side effects. The addition of immunotherapy to old and new chemotherapy regimens has improved both response rates and disease-free survival, leading in many cases to an extended overall survival. Ideally, an antigen that is used for vaccination would be specifically expressed in the tumor; it must have an important, causal part in the multifactorial process that leads to cancer, and it must be expressed stably even after it is attacked by the immune system. Immunotherapies, which aim to activate the immune system to kill cancer cells, include strategies to increase the frequency or potency of antitumor T cells, to overcome suppressive factors in the tumor microenvironment, and to reduce T-cell suppression systemically. In this review, we focus on the results of clinical trials of vaccination in lymphoma, and discuss potential strategies to enhance the efficacy of immunotherapy in the future.

Haematological malignancies: at the forefront of immunotherapeutic innovation

The recent successes of cancer immunotherapies have stimulated interest in the potential widespread application of these approaches; haematological malignancies have provided both initial proofs of concept and an informative testing ground for various immune-based therapeutics. The immune-cell origin of many of the blood malignancies provides a unique opportunity both to understand the mechanisms of cancer immune responsiveness and immune evasion, and to exploit these mechanisms for therapeutic purposes.

Immune checkpoint inhibition in lymphoid disease

It has long been understood that the immune system has intrinsic anti-tumour activity in humans, and that a key mechanism of tumour progression is the ability of a tumour to escape this immune surveillance. A number of attempts have been made to harness this anti-tumour immunity in both solid tumour oncology and haematological malignancies with variable success. Examples include the use of allogeneic stem cell transplantation and donor lymphocyte infusion in haematological cancer and vaccine studies in solid tumours. Enhanced signalling of the Programmed cell death-1 (PDCD1, PD-1)/cytotoxic T-lymphocyte-associated protein 4 (CTLA4) 'immune checkpoint' pathway has emerged recently as a critical mechanism by which tumours can escape the natural anti-tumour immune response. As such, novel therapies have been developed to help enhance this natural immunity by switching off the PDCD1/CTLA4 immune checkpoint pathway. The following review will discuss the pathobiology of these pathways and the exciting new data now available in lymphoid malignancies.