The immunomodulatory effects of bevacizumab on systemic immunity in patients with metastatic melanoma

EDIL3 as an Angiogenic Target of Immune Exclusion Following Checkpoint Blockade

Immune checkpoint blockade (ICB) has become the standard of care for several solid tumors. Multiple combinatorial approaches have been studied to improve therapeutic efficacy. The combination of antiangiogenic agents and ICB has demonstrated efficacy in several cancers. To improve the mechanistic understanding of synergies with these treatment modalities, we performed screens of sera from long-term responding patients treated with ipilimumab and bevacizumab. We discovered a high-titer antibody response against EGF-like repeats and discoidin I-like domains protein 3 (EDIL3) that correlated with favorable clinical outcomes. EDIL3 is an extracellular protein, previously identified as a marker of poor prognosis in various malignancies. Our Tumor Immune Dysfunction and Exclusion analysis predicted that EDIL3 was associated with immune exclusion signatures for cytotoxic immune cell infiltration and nonresponse to ICB. Cancer-associated fibroblasts (CAF) were predicted as the source of EDIL3 in immune exclusion-related cells. Furthermore, The Cancer Genome Atlas Skin Cutaneous Melanoma (TCGA-SKCM) and CheckMate 064 data analyses correlated high levels of EDIL3 with increased pan-fibroblast TGFβ response, enrichment of angiogenic signatures, and induction of epithelial-to-mesenchymal transition. Our in vitro studies validated EDIL3 overexpression and TGFβ regulation in patient-derived CAFs. In pretreatment serum samples from patients, circulating levels of EDIL3 were associated with circulating levels of VEGF, and like VEGF, EDIL3 increased the angiogenic abilities of patient-derived tumor endothelial cells (TEC). Mechanistically, three-dimensional microfluidic cultures and two-dimensional transmigration assays with TEC endorsed EDIL3-mediated disruption of the lymphocyte function-associated antigen-1 (LFA-1)-ICAM-1 interaction as a possible means of T-cell exclusion. We propose EDIL3 as a potential target for improving the transendothelial migration of immune cells and efficacy of ICB therapy.

Safety and Activity of PolyPEPI1018 Combined with Maintenance Therapy in Metastatic Colorectal Cancer: an Open-Label, Multicenter, Phase Ib Study

PURPOSE

Although chemotherapy is standard of care for metastatic colorectal cancer (mCRC), immunotherapy has no role in microsatellite stable (MSS) mCRC, a "cold" tumor. PolyPEPI1018 is an off-the-shelf, multi-peptide vaccine derived from 7 tumor-associated antigens (TAA) frequently expressed in mCRC. This study assessed PolyPEPI1018 combined with first-line maintenance therapy in patients with MSS mCRC.

PATIENTS AND METHODS

Eleven patients with MSS mCRC received PolyPEPI1018 and Montanide ISA51VG adjuvant subcutaneously, combined with fluoropyrimidine/biologic following first-line induction with chemotherapy and a biologic (NCT03391232). In Part A of the study, 5 patients received a single dose; in Part B, 6 patients received up to three doses of PolyPEPI1018 every 12 weeks. The primary objective was safety; secondary objectives were preliminary efficacy, immunogenicity at peripheral and tumor level, and immune correlates.

RESULTS

PolyPEPI1018 vaccination was safe and well tolerated. No vaccine-related serious adverse event occurred. Eighty percent of patients had CD8+ T-cell responses against ≥3 TAAs. Increased density of tumor-infiltrating lymphocytes were detected post-treatment for 3 of 4 patients' liver biopsies, combined with increased expression of immune-related gene signatures. Three patients had objective response according to RECISTv1.1, and 2 patients qualified for curative surgery. Longer median progression-free survival for patients receiving multiple doses compared with a single dose (12.5 vs. 4.6 months; P = 0.017) suggested a dose-efficacy correlation. The host HLA genotype predicted multi-antigen-specific T-cell responses (P = 0.01) indicative of clinical outcome.

CONCLUSIONS

PolyPEPI1018 added to maintenance chemotherapy for patients with unresectable, MSS mCRC was safe and associated with specific immune responses and antitumor activity warranting further confirmation in a randomized, controlled setting.

Advances in Immunotherapy for Adult Glioblastoma

Simple Summary

Therapy failure and disease recurrence are hallmarks of glioblastoma (GBM), the most common and lethal tumor in adults that originates in the brain. Despite aggressive standards of care, tumor recurrence is inevitable with no standardized second-line therapy. Recent clinical studies evaluating therapies that augment the anti-tumor immune response (i.e., immunotherapies) have yielded promising results in subsets of GBM patients. Here, we summarize clinical studies in the past decade that evaluate vaccines, immune checkpoint inhibitors and chimeric antigen receptor (CAR) T cells for treatment of GBM. Although immunotherapies have yet to return widespread efficacy for the majority of GBM patients, critical insights from completed and ongoing clinical trials are informing development of the next generation of therapies, with the goal to alleviate disease burden and extend patient survival.

Abstract

Despite aggressive multimodal therapy, glioblastoma (GBM) remains the most common malignant primary brain tumor in adults. With the advent of therapies that revitalize the anti-tumor immune response, several immunotherapeutic modalities have been developed for treatment of GBM. In this review, we summarize recent clinical and preclinical efforts to evaluate vaccination strategies, immune checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR) T cells. Although these modalities have shown long-term tumor regression in subsets of treated patients, the underlying biology that may predict efficacy and inform therapy development is being actively investigated. Common to all therapeutic modalities are fundamental mechanisms of therapy evasion by tumor cells, including immense intratumoral heterogeneity, suppression of the tumor immune microenvironment and low mutational burden. These insights have led efforts to design rational combinatorial therapies that can reignite the anti-tumor immune response, effectively and specifically target tumor cells and reliably decrease tumor burden for GBM patients.

Immunotherapy in oncogene addicted non-small cell lung cancer

The use of immune checkpoint inhibitors (ICIs) targeting the programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) has led to notable changes in treatment strategies for patients with advanced non-small cell lung cancer (NSCLC) and now forms a part of standard of care treatment in patients with advanced disease. However, most patients do not respond to ICI monotherapy, which may be explained by significant variations in efficacy according to different immune and molecular profiles in tumours. Improved response rates have been observed in smokers and are associated with tumors that have high mutation loads, with a higher tendency to form neoantigens. This premise itself defies the eventual significance of ICIs for oncogene-driven NSCLC, which in general are more common in never smokers and potentially have reduced capacity for neoantigen formation. Furthermore, pivotal trials investigating ICIs in advanced NSCLC have usually excluded patients with oncogenic drivers, hence the outcome of these agents in this population is poorly characterized. In this article, we aim to review the most current evidence, encompassing clinical and preclinical data focused on a wide range of oncogene-addicted NSCLCs.

Combination of molecularly targeted therapies and immune checkpoint inhibitors in the new era of unresectable hepatocellular carcinoma treatment

Multikinase inhibitors (MKIs) have been the only first-line treatment for advanced hepatocellular carcinoma (HCC) for more than a decade, until the approval of immune checkpoint inhibitors (ICIs). Moreover, the combination regimen of atezolizumab (anti-programmed cell death protein ligand 1 antibody) plus bevacizumab (anti-vascular endothelial growth factor monoclonal antibody) has recently been demonstrated to have superior efficacy when compared with sorafenib monotherapy. The remarkable efficacy has made this combination therapy the new standard treatment for advanced HCC. In addition to MKIs, many other molecularly targeted therapies are under investigation, some of which have shown promising results. Therefore, in the era of immuno-oncology, there is a significant rationale for testing the combinations of molecularly targeted therapies and ICIs. Indeed, numerous preclinical and clinical studies have shown the synergic antitumor efficacy of such combinations. In this review, we aim to summarize the current knowledge on the combination of molecularly targeted therapies and immune checkpoint therapies for HCC from both preclinical and clinical perspectives.

Trial Watch: Tumor-targeting monoclonal antibodies in cancer therapy

In 1997, for the first time in history, a monoclonal antibody (mAb), i.e., the chimeric anti-CD20 molecule rituximab, was approved by the US Food and Drug Administration for use in cancer patients. Since then, the panel of mAbs that are approved by international regulatory agencies for the treatment of hematopoietic and solid malignancies has not stopped to expand, nowadays encompassing a stunning amount of 15 distinct molecules. This therapeutic armamentarium includes mAbs that target tumor-associated antigens, as well as molecules that interfere with tumor-stroma interactions or exert direct immunostimulatory effects. These three classes of mAbs exert antineoplastic activity via distinct mechanisms, which may or may not involve immune effectors other than the mAbs themselves. In previous issues of OncoImmunology, we provided a brief scientific background to the use of mAbs, all types confounded, in cancer therapy, and discussed the results of recent clinical trials investigating the safety and efficacy of this approach. Here, we focus on mAbs that primarily target malignant cells or their interactions with stromal components, as opposed to mAbs that mediate antineoplastic effects by activating the immune system. In particular, we discuss relevant clinical findings that have been published during the last 13 months as well as clinical trials that have been launched in the same period to investigate the therapeutic profile of hitherto investigational tumor-targeting mAbs.

Sequencing Ipilimumab Immunotherapy Before or After Chemotherapy (Nab-Paclitaxel and Bevacizumab) for the Treatment of BRAFwt (BRAF Wild-Type) Metastatic Malignant Melanoma: Results of a Study of Academic and Community Cancer Research United (ACCRU) RU261206I

OBJECTIVES

With the introduction of novel immune therapeutics for the treatment of disseminated malignancies, we sought to evaluate whether deliberate sequencing of immunotherapy before/after conventional cytotoxic chemotherapy would have an impact on clinical outcomes in patients with previously treated metastatic melanoma. We sought to evaluate whether or not ipilimumab immunotherapy administered before or after cytotoxic chemotherapy (nab-paclitaxel+bevacizumab, AB) would impact clinical outcomes.

METHODS

We conducted a randomized phase 2 clinical trial of patients with BRAF wild-type metastatic melanoma (up to 2 prior therapies) who received either: (A) AB followed by ipilimumab therapy at progression; or (B) ipilimumab followed by AB treatment at progression. The primary goal of the study was a comparison of AB versus ipilimumab progression-free survival, with secondary clinical and laboratory endpoints.

RESULTS

This study did not reach full accrual due to concurrent Food and Drug Administration approval of anti-programmed cell death 1 agents. Nevertheless, the available data suggests a cumulative therapeutic advantage to the sequential use of ipilimumab followed by AB. Correlative laboratory data revealed a favorable effect on systemic immune homeostasis in patients receiving AB therapy, of potential interest in further investigations, especially in the context of chemotherapy/immunotherapy combinations.

CONCLUSION

Albeit limited in scope, our data suggest that cytotoxic therapy with nab-paclitaxel and bevacizumab appear to favorably alter systemic parameters of immune function of potential benefit in combination T-cell directed immune checkpoint inhibitor therapy.

Beyond PD-1/PD-L1 Axis Blockade: New Combination Strategies in Metastatic Melanoma Treatment

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Metastatic melanoma treatment has dramatically changed in the last few years, having a breakthrough with the introduction of targeted agents and immunotherapy. PD-1/PD-L1 pathway is one of the physiologic mechanisms of peripheral immune tolerance, but it also represents a mechanism of tumor immune escape. PD-1/PD-L1 inhibitors represent new immune-checkpoint drugs currently used in metastatic melanoma treatment.

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Resistance to PD-1/PD-L1 axis blockade, which is the main cause of therapeutic failure during therapeutic use of these drugs, could be linked to several mechanism of immune escape. In fact, other inhibitory receptor such as CTLA-4, LAG-3, TIM-3 and TIGIT might be co-expressed on T cells, deleting the effect of anti-PD-1/PD-L1; overexpression of the enzyme IDO could cause immunosuppression through the depletion of tryptophan in the tumor microenvironment; defective c ostimulation (through reduced activity of 4-1BB and OX40 receptors) could result in T-cell energy.

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Combination of anti-PD-1/PD-L1 with drugs targeting inhibitory or costimulatory receptors, intracellular pathways, enzymes or neoangiogenesis could be a possible strategy to overcome resistance to single PD-1/PD-L1 blockade. Clinical trials evaluating combination therapies have already showed interesting results, although most of them are still on going.

Baseline Absolute Lymphocyte Count and ECOG Performance Score Are Associated with Survival in Advanced Non-Small Cell Lung Cancer Undergoing PD-1/PD-L1 Blockade

Immune-checkpoint blockade in front-line or second-line treatment improves survival in advanced non-small cell lung cancer (aNSCLC) when compared with chemotherapy alone. However, easily applicable predictive parameters are necessary to guide immune-checkpoint inhibition in clinical practice. In this retrospective bi-centric analysis, we investigated the impact of baseline patient and tumor characteristics on clinical outcome in aNSCLC patients treated with programmed cell death protein 1(PD-1)/programmed cell death ligand 1 (PD-L1) inhibitors. Between May 2015 and January 2018, 142 unselected consecutive NSCLC patients received PD-1/PD-L1 inhibitors during the course of disease. In multivariate analysis, we identified the Eastern Cooperative Oncology Group (ECOG) performance status (ECOG > 1 versus ECOG ≤ 1, HR: 3.23, 95%CI: 1.58-6.60, P = 0.001), baseline absolute lymphocyte count (ALC; high: >0.93 × 109/L versus low: ≤ 0.93 × 109/L, HR: 0.38, 95%CI: 0.23-0.62, P < 0.001), prior or concomitant anti-vascular endothelial growth factor (VEGF) targeting therapy (yes versus no, HR: 2.18, 95%CI: 1.15-4.14, P = 0.017) and TNM stage (IV versus III, HR: 4.18, 95%CI: 1.01-17.36, P = 0.049) as the most relevant parameters for survival. Neither antibiotic exposure (antibiotic-positive versus antibiotic-negative, HR: 0.90, 95%CI: 0.56-1.45, P = 0.675), nor PD-L1 expression on tumor cells (≥1% versus <1%, HR: 0.68, 95%CI: 0.41-1.13, P = 0.140) was associated with survival. Baseline ECOG performance status and ALC were associated with survival in aNSCLC patients treated with PD-1/PD-L1 inhibitors and assessment of these parameters could be suitable in clinical practice.

Combining Immune Checkpoint Inhibitors With Conventional Cancer Therapy

Immune checkpoint inhibitors (ICIs) have recently revolutionized cancer treatment, providing unprecedented clinical benefits. However, primary or acquired therapy resistance can affect up to two-thirds of patients receiving ICIs, underscoring the urgency to elucidate the mechanisms of treatment resistance and to design more effective therapeutic strategies. Conventional cancer treatments, including cytotoxic chemotherapy, radiation therapy, and targeted therapy, have immunomodulatory effects in addition to direct cancer cell-killing activities. Their clinical utilities in combination with ICIs have been explored, aiming to achieve synergetic effects with improved and durable clinical response. Here, we will review the immunomodulatory effects of chemotherapy, targeted therapy, and radiation therapy, in the setting of ICI, and their clinical implications in reshaping modern cancer immunotherapy.

Emerging growth factor receptor antagonists for the treatment of advanced melanoma

INTRODUCTION

Therapy for metastatic melanoma has undergone a rapid transformation over the past 5-10 years. Advances in immunotherapy with checkpoint inhibitors, including both anti-CTLA-4 and anti-PD-1/PD-L1, have led to durable responses in up to 50% of patients. As our understanding of the processes driving the transformation of melanocytes has improved, progress in targeted therapies has also continued. Areas covered: Angiogenesis and the tumor's dependence on an expanded vascular supply has been a target for novel therapies since the 1970's, as this tissue is derived from endothelial cells that are genetically stable in adults. A phase II trial studying combined therapy with bevacizumab (an inhibitor of angiogenesis) and ipilimumab found promising results. Other agents such as sorafenib have not been as successful, failing to extend progression free or overall survival in clinical trials. In this paper other targeted growth factor inhibitors will also be discussed. Expert opinion: Ultimately, melanoma may not be vulnerable solely to chemotherapy or targeted therapy, but may be efficaciously treated with immunotherapy due to its high mutational rate resulting in the expression of numerous neo-antigens. Therapies with combinations of agents including growth factor receptor and either other targeted therapies or immunotherapy may be a promising complimentary approach.

Angiogenesis inhibitors in tackling recurrent glioblastoma

INTRODUCTION

Despite aggressive multimodality treatment of glioblastoma, outcome remains poor and patients mostly die of local recurrences. Besides reoperation and occasionally reirradiation, systemic treatment of recurrent glioblastoma consists of alkylating chemotherapy (lomustine, temozolomide), bevacizumab and combinations thereof. Unfortunately, antiangiogenic agents failed to improve survival either as a monotherapy or in combination treatments. This review provides current insights into tumor-derived escape mechanisms and other areas of treatment failure of antiangiogenic agents in glioblastoma. Areas covered: We summarize the current literature on antiangiogenic agents in the treatment of glioblastoma, with a focus on recurrent disease. A literature search was performed using the terms 'glioblastoma', 'bevacizumab', 'antiangiogenic', 'angiogenesis', 'resistance', 'radiotherapy', 'chemotherapy' and derivations thereof. Expert commentary: New insights in glioma neoangiogenesis, increasing understanding of vascular pathway escape mechanisms, and upcoming immunotherapy approaches might revitalize the therapeutic potential of antiangiogenic agents against glioblastoma, although with a different treatment intention. The combination of antiangiogenic approaches with or without radiotherapy might still hold promise to complement the therapeutic armamentarium of fighting glioblastoma.

Immune-modulating effects of bevacizumab in metastatic non-small-cell lung cancer patients

The mPEBev is an anticancer regimen which combines a chemotherapy doublet, based on cisplatin and oral etoposide (mPE), with bevacizumab (mPEBev), a mAb targeting the vasculo-endothelial growth factor (VEGF). In previous studies, this regimen showed powerful anti-angiogenetic effects and significant antitumor activity in metastatic non-small-cell lung cancer (mNSCLC) patients. We also recorded the best benefit in patients exhibiting low-systemic inflammatory profile at baseline. On these bases, we hypothesized that mPEBev antitumor activity could be partially related to bevacizumab-associated immunological effects. For this reason, we performed an immunological monitoring in 59 out of 120 stage IIIb-IV NSCLC patients enrolled in the BEVA2007 phase II trial, who received fractioned cisplatin (30 mg/sqm days 1-3q21) and oral etoposide (50 mg, days 1-15q21) (mPE doublet) ±bevacizumab. In this group of patients, 12 received the mPE doublet alone and 47 the doublet in combination with bevacizumab (5 mg/kg on the day 3q21; mPEBev regimen). Blood cell counts, serum analysis, multiplex cytokine assay and immunocytofluorimetric analysis, performed on baseline and post-treatment on blood samples from these patients, revealed that bevacizumab addition to the doublet decreased levels of pro-angiogenic (VEGF, Angiostatin-1 and Follistatin) and inflammatory cytokines (interferon (IFN)γ, IL4 and IL17), improved in vivo and in vitro cytotoxic T-lymphocytes (CTL) response and promoted dendritic cell activation. These results suggest that the mPEBev regimen improve the micro-environmental conditions for an efficient antigen-specific CTL response, making it a feasible candidate regimen to be assessed in combination with immune-checkpoint inhibitors in NSCLC patients.

Myeloid-derived suppressor cells contribute to A2B adenosine receptor-induced VEGF production and angiogenesis in a mouse melanoma model

Vascular endothelial growth factor (VEGF) is an angiogenic factor critically involved in tumor progression. Adenosine A2B receptor plays a pivotal role in promoting tumor growth. The aim of this study was to investigate the role of myeloid-derived suppressor cells (MDSCs) in the pro-angiogenic effects of A2B and to determine whether A2B blockade could enhance the effectiveness of anti-VEGF treatment. Mice treated with Bay60-6583, a selective A2B receptor agonist, showed enhanced tumor VEGF-A expression and vessel density. This effect was associated with accelerated tumor growth, which could be reversed with anti-VEGF treatment. Bay60-6583 increased the accumulation of tumor CD11b+Gr1+ cells. Depletion of MDSCs in mice significantly reduced A2B-induced VEGF production. However, A2B receptor stimulation did not directly regulate VEGF expression in isolated tumor myeloid cells. Mechanistically, Bay60-6583-treated melanoma tissues showed increased STAT3 activation. Inhibition of STAT3 significantly decreased the pro-tumor activity of Bay60-6583 and reduced tumor VEGF expression.

Pharmacological blockade of A2B receptor with PSB1115 significantly reduced tumor growth by inhibiting tumor angiogenesis and increasing T cells numbers within the tumor microenvironment. These effects are, at least in part, dependent on impaired tumor accumulation of Gr1+ cells upon A2B receptor blockade. PSB1115 increased the effectiveness of anti-VEGF treatment.

Immune Therapy

Lung cancer has long been considered an unsuitable target for immunotherapy due to its proposed immunoresistant properties. However, recent evidence has shown that anti-tumor immune responses can occur in lung cancer patients, paving the way for lung cancer as a novel target for immunotherapy. In order to take full advantage of the potential of immunotherapy, research is focusing on the presence and function of various immunological cell types in the tumor microenvironment. Immune cells which facilitate or inhibit antitumor responses have been identified and their prognostic value in lung cancer has been established. Knowledge regarding these pro- and anti-tumor immune cells and their mechanisms of action has facilitated the identification of numerous potential immunotherapeutic strategies and opportunities for intervention. A plethora of immunotherapeutic approaches is currently being developed and studied in lung cancer patients and phase 3 clinical trials are ongoing. Many different immunotherapies have shown promising clinical effects in patients with limited and advanced stage lung cancer, however, future years will have to tell whether immunotherapy will earn its place in the standard treatment of lung cancer.

Improved Treatment Efficacy of Antiangiogenic Therapy when Combined with Picornavirus Vaccination in the GL261 Glioma Model

The addition of antiangiogenic therapy to the standard-of-care treatment regimen for recurring glioblastoma has provided some clinical benefits while also delineating numerous caveats, prompting evaluation of the elicited alterations to the tumor microenvironment. Of critical importance, given the steadily increasing incorporation of immunotherapeutic approaches clinically, is an enhanced understanding of the interplay between angiogenic and immune response pathways within tumors. In the present study, the GL261 glioma mouse model was used to determine the effects of antiangiogenic treatment in an immune-competent host. Following weekly systemic administration of aflibercept, an inhibitor of vascular endothelial growth factor, tumor volume was assessed by magnetic resonance imaging and changes to the tumor microenvironment were determined. Treatment with aflibercept resulted in reduced tumor burden and increased survival compared with controls. Additionally, decreased vascular permeability and preservation of the integrity of tight junction proteins were observed. Treated tumors also displayed hallmarks of anti-angiogenic evasion, including marked upregulation of vascular endothelial growth factor expression and increased tumor invasiveness. Aflibercept was then administered in combination with a picornavirus-based antitumor vaccine and tumor progression was evaluated. This combination therapy significantly delayed tumor progression and extended survival beyond that observed for either therapy alone. As such, this work demonstrates the efficacy of combined antiangiogenic and immunotherapy approaches for treating established gliomas and provides a foundation for further evaluation of the effects of antiangiogenic therapy in the context of endogenous or vaccine-induced inflammatory responses.

Prospects of immune checkpoint modulators in the treatment of glioblastoma

Glioblastoma is the most common primary brain tumour in adults. Prognosis is poor: even with the current gold-standard first-line treatment—maximal safe resection and combination of radiotherapy with temozolomide chemotherapy—the median overall survival time is only approximately 15-17 months, because the tumour recurs in virtually all patients, and no commonly accepted standard treatment for recurrent disease exists. Several targeted agents have failed to improve patient outcomes in glioblastoma. Immunotherapy with immune checkpoint inhibitors such as ipilimumab, nivolumab, and pembrolizumab has provided relevant clinical improvements in other advanced tumours for which conventional therapies have had limited success, making immunotherapy an appealing strategy in glioblastoma. This Review summarizes current knowledge on immune checkpoint modulators and evaluates their potential role in glioblastoma on the basis of preclinical studies and emerging clinical data. Furthermore, we discuss challenges that need to be considered in the clinical development of drugs that target immune checkpoint pathways in glioblastoma, such as specific properties of the immune system in the CNS, issues with radiological response assessment, and potential interactions with established and emerging treatment strategies.

Trial watch - inhibiting PARP enzymes for anticancer therapy

Poly(ADP-ribose) polymerases (PARPs) are a members of family of enzymes that catalyze poly(ADP-ribosyl)ation (PARylation) and/or mono(ADP-ribosyl)ation (MARylation), two post-translational protein modifications involved in crucial cellular processes including (but not limited to) the DNA damage response (DDR). PARP1, the most abundant family member, is a nuclear protein that is activated upon sensing distinct types of DNA damage and contributes to their resolution by PARylating multiple DDR players. Recent evidence suggests that, along with DDR, activated PARP1 mediates a series of prosurvival and proapoptotic processes aimed at preserving genomic stability. Despite this potential oncosuppressive role, upregulation and/or overactivation of PARP1 or other PARP enzymes has been reported in a variety of human neoplasms. Over the last few decades, several pharmacologic inhibitors of PARP1 and PARP2 have been assessed in preclinical and clinical studies showing potent antineoplastic activity, particularly against homologous recombination (HR)-deficient ovarian and breast cancers. In this Trial Watch, we describe the impact of PARP enzymes and PARylation in cancer, discuss the mechanism of cancer cell killing by PARP1 inactivation, and summarize the results of recent clinical studies aimed at evaluating the safety and therapeutic profile of PARP inhibitors in cancer patients.

Evidence of Th2 polarization of the sentinel lymph node (SLN) in melanoma

Melanoma has a propensity for lymphatogenous metastasis. Improved understanding of the sentinel lymph node (SLN) immunological environment may improve outcomes. The immune phenotype of fresh melanoma SLNs (n = 13) were compared to fresh control lymph nodes (n = 13) using flow cytometry. RNA was isolated from CD4⁺ T cells of the SLN and control lymph node and assessed for Th1/Th2 gene expression pathways using qRT-PCR. In addition, VEGF expression was compared between primary melanoma (n = 6) and benign nevi (n = 6) using immunohistochemistry. Melanoma SLNs had fewer CD8⁺ T cells compared to controls (9.2% vs. 19.5%, p = 0.0005). The CD8⁺ T cells within the SLN appeared to have an exhausted phenotype demonstrated by increased PD-1 mRNA expression (2.2% vs. 0.8%, p = 0.004) and a five-fold increase in CTLA-4 mRNA expression. The SLN also contained an increased number of CD14 (22.7% vs. 7.7%, p = 0.009) and CD68 (9.3% vs. 2.7%, p = 0.001) macrophages, and CD20 B cells (31.1% vs. 20.7%, p = 0.008), suggesting chronic inflammation. RT-PCR demonstrated a significant Th2 bias within the SLN. In vitro studies demonstrated a similar Th2 polarization with VEGF treatment of control lymph nodes. The primary melanoma demonstrated strong VEGF expression and an increase in VEGFR1 within the SLN. Melanoma is associated with Th2-mediated “chronic inflammation,” fewer cytotoxic T cells, and an exhausted T cell phenotype within the SLN combined with VEGF overproduction by the primary melanoma. These immunologic changes precede nodal metastasis and suggests consideration of VEGF inhibitors in future immunotherapy studies.

Trial Watch: Proteasomal inhibitors for anticancer therapy

The so-called "ubiquitin-proteasome system" (UPS) is a multicomponent molecular apparatus that catalyzes the covalent attachment of several copies of the small protein ubiquitin to other proteins that are generally (but not always) destined to proteasomal degradation. This enzymatic cascade is crucial for the maintenance of intracellular protein homeostasis (both in physiological conditions and in the course of adaptive stress responses), and regulates a wide array of signaling pathways. In line with this notion, defects in the UPS have been associated with aging as well as with several pathological conditions including cardiac, neurodegenerative, and neoplastic disorders. As transformed cells often experience a constant state of stress (as a result of the hyperactivation of oncogenic signaling pathways and/or adverse microenvironmental conditions), their survival and proliferation are highly dependent on the integrity of the UPS. This rationale has driven an intense wave of preclinical and clinical investigation culminating in 2003 with the approval of the proteasomal inhibitor bortezomib by the US Food and Drug Administration for use in multiple myeloma patients. Another proteasomal inhibitor, carfilzomib, is now licensed by international regulatory agencies for use in multiple myeloma patients, and the approved indications for bortezomib have been extended to mantle cell lymphoma. This said, the clinical activity of bortezomib and carfilzomib is often limited by off-target effects, innate/acquired resistance, and the absence of validated predictive biomarkers. Moreover, the antineoplastic activity of proteasome inhibitors against solid tumors is poor. In this Trial Watch we discuss the contribution of the UPS to oncogenesis and tumor progression and summarize the design and/or results of recent clinical studies evaluating the therapeutic profile of proteasome inhibitors in cancer patients.

Trial watch: Tumor-targeting monoclonal antibodies for oncological indications

An expanding panel of monoclonal antibodies (mAbs) that specifically target malignant cells or intercept trophic factors delivered by the tumor stroma is now available for cancer therapy. These mAbs can exert direct antiproliferative/cytotoxic effects as they inhibit pro-survival signal transduction cascades or activate lethal receptors at the plasma membrane of cancer cells, they can opsonize neoplastic cells to initiate a tumor-targeting immune response, or they can be harnessed to specifically deliver toxins or radionuclides to transformed cells. As an indication of the success of this immunotherapeutic paradigm, international regulatory agencies approve new tumor-targeting mAbs for use in cancer patients every year. Moreover, the list of indications for previously licensed molecules is frequently expanded to other neoplastic disorders as the results of large, randomized clinical trials become available. Here, we discuss recent advances in the preclinical and clinical development of tumor-targeting mAbs for oncological indications.

Immunotherapy for head and neck squamous cell carcinoma

OBJECTIVES

To review the current state of immunotherapy of head and neck squamous cell carcinoma.

MATERIALS AND METHODS

Review of the literature with emphasis on clinical trial data.

RESULTS

Patients with head and neck squamous cell carcinoma (HNSCC) have long been known to be immunosuppressed. This impairment of the immune system is believed, at least in part, to underlie the poor outcomes in this patient population. Modulating the immune system to improve cancer outcomes is an attractive concept in this difficult to treat population.

CONCLUSION

New studies have started to unravel the mechanisms of immunosuppression and new therapies are being developed to exploit this new information.

Classification of current anticancer immunotherapies

During the past decades, anticancer immunotherapy has evolved from a promising therapeutic option to a robust clinical reality. Many immunotherapeutic regimens are now approved by the US Food and Drug Administration and the European Medicines Agency for use in cancer patients, and many others are being investigated as standalone therapeutic interventions or combined with conventional treatments in clinical studies. Immunotherapies may be subdivided into "passive" and "active" based on their ability to engage the host immune system against cancer. Since the anticancer activity of most passive immunotherapeutics (including tumor-targeting monoclonal antibodies) also relies on the host immune system, this classification does not properly reflect the complexity of the drug-host-tumor interaction. Alternatively, anticancer immunotherapeutics can be classified according to their antigen specificity. While some immunotherapies specifically target one (or a few) defined tumor-associated antigen(s), others operate in a relatively non-specific manner and boost natural or therapy-elicited anticancer immune responses of unknown and often broad specificity. Here, we propose a critical, integrated classification of anticancer immunotherapies and discuss the clinical relevance of these approaches.

Trial Watch: Radioimmunotherapy for oncological indications

During the past two decades, it has become increasingly clear that the antineoplastic effects of radiation therapy do not simply reflect the ability of X-, β- and γ-rays to damage transformed cells and directly cause their permanent proliferative arrest or demise, but also involve cancer cell-extrinsic mechanisms. Indeed, among other activities, radiotherapy has been shown to favor the establishment of tumor-specific immune responses that operate systemically, underpinning the so-called 'out-of-field' or 'abscopal' effect. Thus, ionizing rays appear to elicit immunogenic cell death, a functionally peculiar variant of apoptosis associated with the emission of a particularly immunostimulatory combination of damage-associated molecular patterns. In line with this notion, radiation therapy fosters, and thus exacerbates, the antineoplastic effects of various treatment modalities, including surgery, chemotherapy and various immunotherapeutic agents. Here, we summarize recent advances in the use of ionizing rays as a means to induce or potentiate therapeutically relevant anticancer immune responses. In addition, we present clinical trials initiated during the past 12 months to test the actual benefit of radioimmunotherapy in cancer patients.

Systemic inflammation, as measured by the neutrophil/lymphocyte ratio, may have differential prognostic impact before and during treatment with fluorouracil, irinotecan and bevacizumab in metastatic colorectal cancer patients

The inflammatory index neutrophil/lymphocyte ratio (NLR) has an adverse prognostic value in patients with localized colorectal cancer (CRC). We aimed at evaluating its role in metastatic CRC (mCRC) patients treated with standard first-line chemotherapy. Among consecutive CRC patients referred to our Unit, those with metastatic disease eligible for treatment with fluorouracil, irinotecan and bevacizumab (FOLFIRI-Bev) were included in the study. NLR was routinely assessed before each treatment cycle and correlated with outcome together with common clinical, biochemical and histological variables. A sub-analysis focused on patients with stable disease (SD) was also performed to test the net influence of NLR changes independently of tumor shrinkage. At multivariate Cox regression analysis, baseline NLR, taken as continuous variable, was the most powerful prognosticator for survival (HR 1.80, p 0.0019). Surprisingly, among SD patients, the prognostic effect of NLR changes after two cycles of therapy was of opposite sign, and those in whom NLR increased or was maintained had a 67 % reduction in the risk of death as compared with patients with significant NLR decrease: mOS 56 versus 23 months, respectively, p 0.02. In conclusion, we were able to confirm the adverse prognostic value of high baseline NLR for mCRC patients treated with FOLFIRI-Bev. However, FOLFIRI-Bev-induced NLR changes in SD patients seem to differently affect survival. The specific molecular pathways involved in NLR modulation by FOLFIRI-Bev warrant further investigation.

Immunomodulatory effects of sex hormones: requirements for pregnancy and relevance in melanoma

Similarities between the pathologic progression of cancer and the physiologic process of placentation (eg, proliferation, invasion, and local/systemic tolerance) have been recognized for many years. Sex hormones such as human chorionic gonadotropin, estrogens, progesterone, and others contribute to induction of immunologic tolerance at the beginning of gestation. Sex hormones have been shown to play contributory roles in the growth of cancers such as breast cancer, prostrate cancer, endometrial cancer, and ovarian cancer, but their involvement as putative mediators of the immunologic escape of cancer is still being elucidated. Herein, we compare the emerging mechanism by which sex hormones modulate systemic immunity in pregnancy and their potentially similar role in cancer. To do this, we conducted a PubMed search using combinations of the following keywords: "immune regulation," "sex hormones," "pregnancy," "melanoma," and "cancer." We did not limit our search to specific publication dates. Mimicking the maternal immune response to pregnancy, especially in late gestation, might aid in design of better therapies to reconstitute endogenous antitumor immunity and improve survival.

Trial Watch: Peptide vaccines in cancer therapy

Throughout the past 3 decades, along with the recognition that the immune system not only influences oncogenesis and tumor progression, but also determines how established neoplastic lesions respond therapy, renovated enthusiasm has gathered around the possibility of using vaccines as anticancer agents. Such an enthusiasm quickly tempered when it became clear that anticancer vaccines would have to be devised as therapeutic, rather than prophylactic, measures, and that malignant cells often fail to elicit (or actively suppress) innate and adaptive immune responses. Nonetheless, accumulating evidence indicates that a variety of anticancer vaccines, including cell-based, DNA-based, and purified component-based preparations, are capable of circumventing the poorly immunogenic and highly immunosuppressive nature of most tumors and elicit (at least under some circumstances) therapeutically relevant immune responses. Great efforts are currently being devoted to the identification of strategies that may provide anticancer vaccines with the capacity of breaking immunological tolerance and eliciting tumor-associated antigen-specific immunity in a majority of patients. In this sense, promising results have been obtained by combining anticancer vaccines with a relatively varied panels of adjuvants, including multiple immunostimulatory cytokines, Toll-like receptor agonists as well as inhibitors of immune checkpoints. One year ago, in the December issue of OncoImmunology, we discussed the biological mechanisms that underlie the antineoplastic effects of peptide-based vaccines and presented an abundant literature demonstrating the prominent clinical potential of such an approach. Here, we review the latest developments in this exciting area of research, focusing on high-profile studies that have been published during the last 13 mo and clinical trials launched in the same period to evaluate purified peptides or full-length proteins as therapeutic anticancer agents.