The role of the CTLA4 blockade in the treatment of malignant melanoma

Monoclonal Antibodies: What the Diagnostic Neuroradiologist Needs to Know

Monoclonal antibodies have become increasingly popular as novel therapeutics against a variety of diseases due to their specificity, affinity, and serum stability. Due to the nearly infinite repertoire of monoclonal antibodies, their therapeutic use is rapidly expanding, revolutionizing disease course and management, and what is now considered experimental therapy may soon become approved practice. Therefore, it is important for radiologists, neuroradiologists, and neurologists to be aware of these drugs and their possible different imaging-related manifestations, including expected and adverse effects of these novel drugs. Herein, we review the most commonly used monoclonal antibody-targeted therapeutic agents, their mechanism of action, clinical applications, and major adverse events with a focus on neurologic and neurographic effects and discuss differential considerations, to assist in the diagnosis of these conditions.

Targeting post-translational modifications of Foxp3: a new paradigm for regulatory T cell-specific therapy

A healthy immune system is pivotal for the hosts to resist external pathogens and maintain homeostasis; however, the immunosuppressive tumor microenvironment (TME) damages the anti-tumor immunity and promotes tumor progression, invasion, and metastasis. Recently, many studies have found that Foxp3+ regulatory T (Treg) cells are the major immunosuppressive cells that facilitate the formation of TME by promoting the development of various tumor-associated cells and suppressing the activity of effector immune cells. Considering the role of Tregs in tumor progression, it is pivotal to identify new therapeutic drugs to target and deplete Tregs in tumors. Although several studies have developed strategies for targeted deletion of Treg to reduce the TME and support the accumulation of effector T cells in tumors, Treg-targeted therapy systematically affects the Treg population and may lead to the progression of autoimmune diseases. It has been understood that, nevertheless, in disease conditions, Foxp3 undergoes several definite post-translational modifications (PTMs), including acetylation, glycosylation, phosphorylation, ubiquitylation, and methylation. These PTMs not only elevate or mitigate the transcriptional activity of Foxp3 but also affect the stability and immunosuppressive function of Tregs. Various studies have shown that pharmacological targeting of enzymes involved in PTMs can significantly influence the PTMs of Foxp3; thus, it may influence the progression of cancers and/or autoimmune diseases. Overall, this review will help researchers to understand the advances in the immune-suppressive mechanisms of Tregs, the post-translational regulations of Foxp3, and the potential therapeutic targets and strategies to target the Tregs in TME to improve anti-tumor immunity.

Bibliometric analysis of rheumatic immune related adverse events associated with immune checkpoint inhibitors

Background

Immune checkpoint inhibitors (ICIs) has emerged as a popular cancer treatment approach. However, non-specific activation of T cells by ICIs can lead to immune-related adverse events (irAEs), including specific rheumatic manifestations. The study aimed to explore the current trend of ICIs associated rheumatic irAEs and summarize the knowledge structure through bibliometric methods.

Methods

The Web of Science Core Collection database (WoSCC) was selected for retrieving literature on ICIs associated rheumatic irAEs. To evaluate contributions from different countries/regions, institutions, journals, and authors, bibliometric analysis software, including VOSviewer and CiteSpace, as well as bibliometric online platforms, were utilized to construct and visualize bibliometric networks. Through the systematic review of this knowledge domain, future research directions were determined.

Results

In This study, a total of 803 publications on ICIs-associated rheumatic irAEs were included for analysis. The distribution of these publications revealed two distinct growth phases: a stable phase between 2007 to 2015 followed by rapid growth from 2016 to 2020. The United States emerged as the top contributor in terms of publications, citations, and h-index, with the majority of leading institutions and funding agencies located there. Apart from government funding, pharmaceutical companies such as Bristol Myers Squibb and Merck Company also play a significant role in drug development and research. Analysis of keywords and citation bursts indicated that the initial burst was related to "monoclonal antibody," "anti-CLTA4 antibody," and "melanoma". This was followed by a rise in interest related to "sarcoidosis," "safety," "inflammatory arthritis," and "preexisting autoimmune."

Conclusion

This study summarized the global research trends concerning ICIs associated rheumatic irAEs. The findings can provide valuable insights into the current understanding of rheumatic irAEs, highlight the research trend and developments in the field. Future efforts should focus on developing classification criteria and guidelines, conducting prospective studies, investigating the mechanisms involved, and identifying biomarkers for prediction and monitoring of these events.

[Induction of Uveitis by Immune-Oncologic Therapies, Namely Checkpoint Inhibitors]

BACKGROUND

The recently introduced tumor therapies including immune checkpoint and BRAF/MEK inhibitors (ICI) have substantially contributed to survival and quality of life of the affected patients, but are associated with class-specific, non-toxic immune-related side effects including uveitis. This narrative review focusses to summarize the immune-related adverse event profile associated with the use of ICI.

METHODS

A literature search in PubMed, the publication database of the National Institute of Health in the USA (https://www.ncbi.nlm.nih.gov/pubmed) used the search terms "uveitis" AND "drug-induced" AND/OR "immune checkpoint inhibitor". All articles published in the last five years and the for the purpose of this review relevant cross references were evaluated.

RESULTS

A class-specific phenomenon of ICI and BRAF/MEK inhibitors is their capability to induce systemic and ocular autoimmunity. Ocular side effects are observed in up to 3% of patients and should be differentiated from toxic side effects, since this is not dose-dependent. Melanoma as underlying disease and Pembrolizumab as ICI significantly increase the risk. If timely recognized, systemic treatment with corticosteroids allows to preserve vision without cessation of the tumor treatment in more than 90% of these potentially life-threatening instances.

CONCLUSION

Given their impact onto the survival of cancer and namely melanoma patients, ICI and BRAF/MEK inhibitors are increasingly used alone and in combination, which enhances their inherent risk of developing drug-induced ocular autoimmunity. Favorable functional outcomes are closely linked to early recognition and aggressive treatment of these complications considering the fact that these immune-related adverse events affect multiple organ systems and have an untreated lethality of up to 3%.

Leprosy as a model to understand cancer immunosurveillance and T cell anergy

Leprosy is a disease caused by Mycobacterium leprae that presents on a spectrum of both clinical manifestations and T cell response. On one end of this spectrum, tuberculoid leprosy is a well-controlled disease, characterized by a cell-mediated immunity and immunosurveillance. On the opposite end of the spectrum, lepromatous leprosy is characterized by M. leprae proliferation and T cell anergy. Similar to progressive tumor cells, M. leprae escapes immunosurveillance in more severe forms of leprosy. The mechanisms by which M. leprae is able to evade the host immune response involve many, including the alterations of lipid droplets, microRNA, and Schwann cells, and involve the regulation of immune regulators, such as the negative checkpoint regulators CTLA-4, programmed death 1, and V-domain Ig suppressor of T cell activation-important targets in today's cancer immunotherapies. The means by which tumor cells become able to escape immunosurveillance through negative checkpoint regulators are evidenced by the successes of treatments, such as nivolumab and ipilimumab. Many parallels can be drawn between the immune responses seen in leprosy and cancer. Therefore, the understanding of how M. leprae encourages immune escape during proliferative disease states has potential to add to our understanding of cancer immunotherapy.

Induction of eEF2-specific antitumor CTL responses in vivo by vaccination with eEF2-derived 9mer-peptides

Eukaryotic elongation factor 2 (eEF2) is an essential factor for protein synthesis. Previous studies have shown that the eEF2 gene was overexpressed and plays an oncogenic role in various types of cancers and that eEF2 gene product elicited both humoral immune responses to produce eEF2-specific IgG autoantibody in cancer-bearing individuals and cellular immune responses to induce eEF2 peptide-specific cytotoxic T lymphocytes (CTLs) in vitro. The purpose of the present study was to induce eEF2-specific, antitumor CTL responses in vivo by vaccination with MHC class I-binding eEF2-derived peptide. First, two mouse MHC class I-restricted eEF2‑derived, 9-mer peptides, EF17 (17-25 aa, ANIRNMSVI) and EF180 (180-188 aa, RIVENVNVI) were identified as eEF2-specific CTL peptides, and mice were vaccinated intradermally eight times with either EF17 or EF180 peptide emulsified with Montanide ISA51 adjuvant. Cytotoxicity assay showed that eEF2-specific CTLs were induced in both EF17‑and EF180‑vaccinated mice, and histological study showed no detectable damage in the organs of these mice. Next, to examine in vivo antitumor effects of eEF2 peptide vaccination in a therapeutic model, mice were vaccinated four times with one each of the two eEF2 peptides at weekly intervals after implantation of eEF2-expressing leukemia cells. The vaccination with eEF2 peptides induced eEF2-specific CTLs and suppressed tumor growth, and disease-free survival was significantly longer in EF180-vaccinated mice compared to control mice. The survival was associated with the robustness of eEF2-specific CTL induction. These results indicate that vaccination with MHC class I-binding eEF2 peptide induced eEF2-targeting, antitumor CTL responses in vivo without damage to normal organs, which provided us a rationale for eEF2 peptide-based cancer immunotherapy.

Ipilimumab pharmacotherapy in patients with metastatic melanoma

Immune augmentation with ipilimumab, an anti-CTLA-4 monoclonal antibody, has joined the ranks of approved immunologic agents for the treatment of metastatic melanoma. Phase III studies of ipilimumab in metastatic melanoma have demonstrated an overall survival advantage as compared to other approved and investigational therapies. However, the adverse effects associated with this medication are unique and often require management with steroids or other immunosuppressants. In addition, the time to response differs with ipilimumab as compared to traditional chemotherapy, and alternative means of assessment of response have been proposed. In this review, we will summarize the basic science of this treatment, its preclinical evaluation, and the clinical trials leading to its approval. We will also discuss the details regarding its use, assessment of response to this drug and other immune-related therapies, and further directions for investigation.

Enhancement of anti-tumor immunity through local modulation of CTLA-4 and GITR by dendritic cells

Cancer vaccines have now demonstrated clinical efficacy, but immune modulatory mechanisms that prevent autoimmunity limit their effectiveness. Systemic administration of mAbs targeting the immune modulatory receptors CTLA-4 and glucocorticoid-induced TNFR-related protein (GITR) on Treg and effector T cells augments anti-tumor immunity both experimentally and clinically, but can induce life-threatening autoimmunity. We hypothesized that local delivery of anti-CTLA-4 and anti-GITR mAbs to the sites where T cells and tumor antigen-loaded DC vaccines interact would enhance the induction of anti-tumor immunity while avoiding autoimmunity. To achieve this goal, DCs transfected with mRNA encoding the H and L chains of anti-mouse CTLA-4 and GITR mAbs were co-administered with tumor antigen mRNA-transfected DCs. We observed enhanced induction of anti-tumor immunity and significantly improved survival in melanoma-bearing mice, without signs of autoimmunity. Using in vitro assays with human DCs, we demonstrated that DCs transfected with mRNA encoding a humanized anti-CTLA-4 mAb and mRNA encoding a soluble human GITR-L fusion protein enhance the induction of anti-tumor CTLs in response to DCs transfected with mRNAs encoding either melanoma or breast cancer antigens. Based on these results, this approach of using local delivery of immune modulators to enhance vaccine-induced immunity is currently being evaluated in a phase I clinical cancer immunotherapy trial.

Cancer immunotherapy

Cancer immunotherapy consists of approaches that modify the host immune system, and/or the utilization of components of the immune system, as cancer treatment. During the past 25 years, 17 immunologic products have received regulatory approval based on anticancer activity as single agents and/or in combination with chemotherapy. These include the nonspecific immune stimulants BCG and levamisole; the cytokines interferon-α and interleukin-2; the monoclonal antibodies rituximab, ofatumumab, alemtuzumab, trastuzumab, bevacizumab, cetuximab, and panitumumab; the radiolabeled antibodies Y-90 ibritumomab tiuxetan and I-131 tositumomab; the immunotoxins denileukin diftitox and gemtuzumab ozogamicin; nonmyeloablative allogeneic transplants with donor lymphocyte infusions; and the anti-prostate cancer cell-based therapy sipuleucel-T. All but two of these products are still regularly used to treat various B- and T-cell malignancies, and numerous solid tumors, including breast, lung, colorectal, prostate, melanoma, kidney, glioblastoma, bladder, and head and neck. Positive randomized trials have recently been reported for idiotype vaccines in lymphoma and a peptide vaccine in melanoma. The anti-CTLA-4 monoclonal antibody ipilumumab, which blocks regulatory T-cells, is expected to receive regulatory approval in the near future, based on a randomized trial in melanoma. As the fourth modality of cancer treatment, biotherapy/immunotherapy is an increasingly important component of the anticancer armamentarium.

Ipilimumab: a novel treatment for metastatic melanoma

OBJECTIVE

To review the mechanism of action, pharmacokinetics, efficacy, safety, drug interactions, dosing, and economic considerations of ipilimumab.

DATA SOURCES

A literature search using MEDLINE (1966-November 2010) was performed using the terms ipilimumab, metastatic melanoma, MDX-010, and MDX-101. Additional data were obtained from meeting abstracts, bibliographies, and media releases.

STUDY SELECTION AND DATA EXTRACTION

English-language articles identified from the data sources were reviewed. Selected studies evaluated the pharmacology, pharmacokinetics, efficacy, and safety of ipilimumab for the treatment of metastatic melanoma.

DATA SYNTHESIS

The incidence of melanoma in the US is increasing faster than any other type of cancer in men and more than any other type of cancer, except lung cancer, in women. For patients with metastatic melanoma, systemic therapies are limited by low response rates, short durations of response, and a 5-year survival rate <10%. Ipilimumab, a novel CTLA-4 inhibitor, is under investigation for the treatment of metastatic melanoma. Results of a randomized, controlled Phase 3 trial showed a first-ever overall survival benefit for patients with previously treated metastatic melanoma who received ipilimumab compared with the controls. The majority of adverse events reported with ipilimumab administration are considered to be low-grade immune-related events involving the skin and intestine and can be managed medically. Nonetheless, 10-17% of patients have immune-related adverse events of grade 3 or higher severity, with 2-3% of these events resulting in death.

CONCLUSIONS

Ipilimumab is a novel CTLA-4 inhibitor that has been evaluated for the treatment of metastatic melanoma. On March 25, 2011, the Food and Drug Administration approved ipilimumab, making it the first agent indicated for unresectable or metastatic melanoma in more than a decade.

ICOStomizing immunotherapies with T(H)17

New insights on the role of costimulatory molecules in T helper cell function have yielded exciting alternatives to the development of therapeutic strategies that target T cell costimulatory pathways. Inducible costimulatory molecule (ICOS) signaling is now shown by Paulos and colleagues to support expansion of human T helper 17 (T(H)17) cells that could exert antitumor activity. Here we discuss (i) how these findings aid in our understanding of mechanisms that govern T(H)17 cell functions and (ii) the potential application of these new insights to the development of immunotherapies.

Targeting cytotoxic T-lymphocyte antigen 4 in immunotherapies for melanoma and other cancers

The immune system can simultaneously protect against tumor growth and sculpt resistant tumor strains. By a variety of mechanisms, anti-cytotoxic T-lymphocyte antigen (CTLA)-4 therapy may shift such opposing forces towards tumor elimination. In recent clinical trials, anti-CTLA-4 therapy induces durable responses that correlate with markers of immune activity, such as antigen-specific CD4+ or CD8+ cytokine release, antitumor antibody formation or cellular phenotype differentiation. However, some patients exhibit atypical responses to anti-CTLA-4 therapy, demonstrating transient/delayed responses or heterogeneity by lesion site. Such atypical responses may offer insight into the mechanism of anti-CTLA-4 therapy. The immunogram – a newly described graphical synthesis of treatment data and immune correlates in individual patients – may help us to confirm, reject or formulate new hypotheses regarding the mechanism of anti-CTLA-4 activity.

Safety and immunotoxicity assessment of immunomodulatory monoclonal antibodies

Most therapeutic monoclonal antibodies (mAbs) licensed for human use or in clinical development are indicated for treatment of patients with cancer and inflammatory/autoimmune disease and as such, are designed to directly interact with the immune system. A major hurdle for the development and early clinical investigation of many of these immunomodulatory mAbs is their inherent risk for adverse immune-mediated drug reactions in humans such as infusion reactions, cytokine storms, immunosuppression and autoimmunity. A thorough understanding of the immunopharmacology of a mAb in humans and animals is required to both anticipate the clinical risk of adverse immunotoxicological events and to select a safe starting dose for first-in-human (FIH) clinical studies. This review summarizes the most common adverse immunotoxicological events occurring in humans with immunomodulatory mAbs and outlines non-clinical strategies to define their immunopharmacology and assess their immunotoxic potential, as well as reduce the risk of immunotoxicity through rational mAb design. Tests to assess the relative risk of mAb candidates for cytokine release syndrome, innate immune system (dendritic cell) activation and immunogenicity in humans are also described. The importance of selecting a relevant and sensitive toxicity species for human safety assessment in which the immunopharmacology of the mAb is similar to that expected in humans is highlighted, as is the importance of understanding the limitations of the species selected for human safety assessment and supplementation of in vivo safety assessment with appropriate in vitro human assays. A tiered approach to assess effects on immune status, immune function and risk of infection and cancer, governed by the mechanism of action and structural features of the mAb, is described. Finally, the use of immunopharmacology and immunotoxicity data in determining a minimum anticipated biologic effect Level (MABEL) and in the selection of safe human starting dose is discussed.

A phase II multicenter study of ipilimumab with or without dacarbazine in chemotherapy-naïve patients with advanced melanoma

OBJECTIVE

Ipilimumab is a fully human, anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4) monoclonal antibody that has demonstrated antitumor activity in advanced melanoma. We evaluated the safety and efficacy of ipilimumab alone and in combination with dacarbazine (DTIC) in patients with unresectable, metastatic melanoma.

METHODS

Chemotherapy-naïve patients were randomized in this multicenter, phase II study to receive ipilimumab at 3 mg/kg every 4 weeks for four doses either alone or with up to six 5-day courses of DTIC at 250 mg/m(2)/day. The primary efficacy endpoint was objective response rate.

RESULTS

Seventy-two patients were treated per-protocol (ipilimumab plus DTIC, n = 35; ipilimumab, n = 37). The objective response rate was 14.3% (95% CI, 4.8-30.3) with ipilimumab plus DTIC and was 5.4% (95% CI, 0.7-18.2) with ipilimumab alone. At a median follow-up of 20.9 and 16.4 months for ipilimumab plus DTIC (n = 32) and ipilimumab alone (n = 32), respectively, median overall survival was 14.3 months (95% CI, 10.2-18.8) and 11.4 months (95% CI, 6.1-15.6); 12-month, 24-month, and 36-month survival rates were 62%, 24% and 20% for the ipilimumab plus DTIC group and were 45%, 21% and 9% for the ipilimumab alone group, respectively. Immune-related adverse events were, in general, medically manageable and occurred in 65.7% of patients in the combination group versus 53.8% in the monotherapy group, with 17.1% and 7.7% ≥grade 3, respectively.

CONCLUSION

Ipilimumab therapy resulted in clinically meaningful responses in advanced melanoma patients, and the results support further investigations of ipilimumab in combination with DTIC.

Novel tools for modulating immune responses in the host-polysaccharides from the capsule of commensal bacteria

The intestinal microflora of mammals includes organisms with many unique molecules that enable them to modulate their immediate environment and thus to survive and reside successfully in the gut. Little is known about how individual molecules from these microbes affect the host's health and development, but the microbiome is considered a crucial factor in intestinal homeostasis. The literature highlights numerous ways in which the microflora stimulates the mammalian host's immune system, starting with its development and continuing to the initiation and resolution of inflammation. The influence of the microflora on the host's immune system is mediated principally by interactions with various antigen-presenting cells of the gut; these interactions result in substantial modulation of both the innate and the adaptive arms of the immune system. Certain polysaccharide antigens from the capsules of some commensal bacteria represent a functional class of molecules that exert profound immunomodulatory effects. Because of their unique structural features, including a zwitterionic charge motif, these polysaccharides can participate to a significant extent in the orchestration of host immune homeostasis. These molecules can be used to elucidate the basic biology of the mammalian intestine and have the potential for use in novel therapeutic regimens for various systemic or intestinal pathological conditions.

Immunotherapy of distant metastatic disease

Immunotherapy of metastatic melanoma consists of various approaches leading to specific or non-specific immunomodulation. The use of FDA-approved interleukin (IL)-2 alone, in combination with interferon alpha, and/or with various chemotherapeutic agents (biochemotherapy) is associated with significant toxicity and poor efficacy that does not improve overall survival of 96% of patients. Many studies with allogeneic and autologous vaccines have demonstrated no clinical benefit, and some randomised trials even showed a detrimental effect in the vaccine arm. The ongoing effort to develop melanoma vaccines based on dendritic cells and peptides is driven by advances in understanding antigen presentation and processing, and by new techniques of vaccine preparation, stabilisation and delivery. Several agents that have shown promising activity in metastatic melanoma including IL-21 and monoclonal antibodies targeting cytotoxic T lymphocyte-associated antigen 4 (anti-CTLA-4) or CD137 are discussed. Recent advances of intratumour gene transfer technologies and adoptive immunotherapy, which represents a promising although technically challenging direction, are also discussed.

Dendritic cells engineered to secrete anti-GITR antibodies are effective adjuvants to dendritic cell-based immunotherapy

A number of monoclonal antibodies (mAbs) have been studied for their ability to enhance immune responses. Although these antibodies are effective in pre-clinical and clinical studies, they are costly and have occasionally been associated with adverse effects such as autoimmunity and cytokine storm. Numerous studies have shown that treatment of mice with an agonistic mAb, clone DTA-1, targeting murine glucocorticoid-induced tumor necrosis factor receptor (GITR) results in enhanced immune responses in tumor-bearing animals. Herein, we evaluate the novel approach of transfecting dendritic cell (DC) with mRNA encoding the heavy and light chain of the anti-GITR mAb. We show the induction of significantly enhanced tumor immunity by vaccinating with a combination of anti-GITR-secreting DC and tumor antigen-presenting DC. This enhancement is comparable to that seen with systemically delivered mAb along with the antigen-presenting DC. Importantly, when anti-GITR was delivered using RNA-transfected DC, we observed no evidence of autoimmune hypopigmentation in any tumor-free mice. We also show enhanced induction of cytotoxic T-lymphocyte responses, which is only observed when the antigen-presenting and antibody-secreting DC are co-injected at the same site. To illustrate the broad utility of this strategy, we show that DC transfected with mRNA encoding GITR-ligand/Fc fusion protein is also an effective tumor vaccine adjuvant.

Ipilimumab-induced hypophysitis: MR imaging findings

Ipilimumab is a promising new immunotherapeutic antineoplastic agent with clinical activity in the treatment of metastatic melanoma and renal cell carcinoma. With advances in immunotherapy, however, a host of new side effects related to the mechanism of action of these drugs has appeared. At our institution, 3 patients presented with hypophysitis, which was attributed to an autoimmune process based on the documented relationship of the drug to other autoimmune phenomena and significant and rapid improvement with discontinuation of the drug and addition of steroids. We present the imaging findings in 3 patients with presumed ipilimumab-induced hypophysitis.

Regulatory lymphocytes and intestinal inflammation

The immune system is pivotal in mediating the interactions between host and microbiota that shape the intestinal environment. Intestinal homeostasis arises from a highly dynamic balance between host protective immunity and regulatory mechanisms. This regulation is achieved by a number of cell populations acting through a set of shared regulatory pathways. In this review, we summarize the main lymphocyte subsets controlling immune responsiveness in the gut and their mechanisms of control, which involve maintenance of intestinal barrier function and suppression of chronic inflammation. CD4(+)Foxp3(+) T cells play a nonredundant role in the maintenance of intestinal homeostasis through IL-10- and TGF-beta-dependent mechanisms. Their activity is complemented by other T and B lymphocytes. Because breakdown in immune regulatory networks in the intestine leads to chronic inflammatory diseases of the gut, such as inflammatory bowel disease and celiac disease, regulatory lymphocytes are an attractive target for therapies of intestinal inflammation.

T-regulatory cell modulation: the future of cancer immunotherapy?

T-regulatory cells suppress anti-tumour immunity in cancer patients and in murine tumour models. Furthermore, their activity is likely to have an effect on the effectiveness of immunotherapeutic treatments for cancer. Here we describe the current status of developing clinical strategies for modulating Treg activity in cancer patients.

Genetically engineered Newcastle disease virus for malignant melanoma therapy

Despite the advances in cancer therapies in the past century, malignant melanoma continues to present a significant clinical challenge due to lack of chemotherapeutic response. Systemic therapy with immunostimulatory agents such as interferon and interleukin-2 (IL-2) has shown some promise, though each is associated with significant side effects. Over the past 50 years, oncolytic Newcastle disease virus (NDV) has emerged as an alternative candidate for cancer therapy. The establishment of reverse-genetics systems for the virus has allowed us to further manipulate the virus to enhance its oncolytic activity. Introduction of immunomodulatory molecules, especially IL-2, into the NDV genome was shown to enhance the oncolytic potential of the virus in a murine syngeneic colon carcinoma model. We hypothesize that a recombinant NDV expressing IL-2 would be an effective agent for therapy of malignant melanoma. We show that recombinant NDV possesses a strong cytolytic activity against multiple melanoma cell lines, and is effective in clearing established syngeneic melanoma tumors in mice. Moreover, introduction of murine IL-2 into NDV significantly enhanced its activity against syngeneic melanomas, resulting in increased overall animal survival and generation of antitumor immunity. These findings warrant further investigations of IL-2-expressing NDV as an antimelanoma agent in humans.

Anti-tumour effects of exosomes in combination with cyclophosphamide and polyinosinic-polycytidylic acid

We examined the anti-tumour activity of exosomes derived from dendritic cells (DCs) in combination with cyclophosphamide (CTX) and polyinosinic-polycytidylic acid sodium salt (poly I:C). DCs were pulsed with L1210 lymphocytic leukaemia cell antigen and lipopolysaccharide. The exosomes that the DCs secreted were purified. In vitro, the anti-tumour activity of exosomes was assessed by measuring their ability to induce spleen cell proliferation and the extent to which they induced spleen cells to kill L1210 cells. Poly I:C was able to induce DC maturation. DC-derived exosomes stimulated spleen cell proliferation and enhanced the cytotoxic effects of spleen cells in vitro. DC-derived exosomes, in combination with CTX and poly I:C, suppressed L1210 tumour growth in vivo and gave the greatest prolongation of survival time in tumour-bearing DBA2 mice. These findings suggest that this combination of a tumour vaccine, a conventional anti-cancer agent and a promoter of DC maturation might be a useful anti-cancer therapy.

Systemic cancer therapy: evolution over the last 60 years

The 1940s marked the beginning of an era of important discoveries that contributed to modern concepts underlying the current practice of cancer chemotherapy, such as the log kill hypothesis reported by Skipper, the Norton-Simon hypothesis, and the Goldie-Coldman hypothesis. The early success of nitrogen mustards and antifolates in the treatment of hematologic malignancies paved the way for drug discovery platforms, which resulted in the generation of more drugs that nonetheless predominantly are genotoxic. The turn of the new millennium marked a new phase in the evolution of cancer chemotherapy. Scientific progress in the preceding 60 years elucidated the important ideas behind tumor microenvironment and 'targeted' therapy that had their inception in the late 19th century. Breakthroughs in molecular biology have paved the way for the development of novel agents that modulate the dysregulated molecular pathways implicated in carcinogenesis. The key approaches and evidence pertinent to the clinical development of these novel agents are presented in this review.

CTLA4 blockade with ipilimumab to treat relapse of malignancy after allogeneic hematopoietic cell transplantation

Relapse of malignancy after allogeneic hematopoietic cell transplantation (allo-HCT) remains a therapeutic challenge. Blockade of the CTLA4 molecule can effectively augment antitumor immunity mediated by autologous effector T cells. We have assessed the safety and preliminary efficacy of a neutralizing, human anti-CTLA4 monoclonal antibody, ipilimumab, in stimulating the graft-versus-malignancy (GVM) effect after allo-HCT. Twenty-nine patients with malignancies that were recurrent or progressive after allo-HCT, received ipilimumab as a single infusion at dose cohorts between 0.1 and 3.0 mg/kg. Dose-limiting toxicity was not encountered, and ipilimumab did not induce graft-versus-host disease (GVHD) or graft rejection. Organ-specific immune adverse events (IAE) were seen in 4 patients (grade 3 arthritis, grade 2 hyperthyroidism, recurrent grade 4 pneumonitis). Three patients with lymphoid malignancy developed objective disease responses following ipilimumab: complete remission (CR) in 2 patients with Hodgkin disease and partial remission (PR) in a patient with refractory mantle cell lymphoma. At the 3.0 mg/kg dose, active serum concentrations of ipilimumab were maintained for more than 30 days after a single infusion. Ipilimumab, as administered in this clinical trial, does not induce or exacerbate clinical GVHD, but may cause organ-specific IAE and regression of malignancy. This study is registered at (http://clinicaltrials.gov) under NCI protocol ID P6082.

Combating immunosuppression in glioma

Despite maximal therapy, malignant gliomas have a very poor prognosis. Patients with glioma express significant immune defects, including CD4 lymphopenia, increased fractions of regulatory T cells in peripheral blood and shifts in cytokine profiles from Th1 to Th2. Recent studies have focused on ways to combat immunosuppression in patients with glioma as well as in animal models for glioma. We concentrate on two specific ways to combat immunosuppression: inhibition of TGF-beta signaling and modulation of regulatory T cells. TGF-beta signaling can be interrupted by antisense oligonucleotide technology, TGF-beta receptor I kinase inhibitors, soluble TGF-beta receptors and antibodies against TGF-beta. Regulatory T cells have been targeted with antibodies against T-cell markers, such as CD25, CTLA-4 and GITR. In addition, vaccination against Foxp3 has been explored. The results of these studies have been encouraging; combating immunosuppression may be one key to improving prognosis in malignant glioma.