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.

Lymphocyte activation gene-3 (LAG-3, CD223) in plasmacytoid dendritic cells (pDCs): a molecular target for the restoration of active antitumor immunity

We have recently reported that lymphocyte activation gene-3 (LAG-3,CD223) mediates the alternative, IFNα-deficient activation of plasmacytoid dendritic cells (pDCs) at tumor sites. Our findings define a novel tumor-driven strategy that promotes immunosuppression by pDCs, and we have provided more detailed information regarding the immunomodulatory role of of LAG-3. The translational relevance of our results for the treatment of tumors and autoimmune diseases is discussed herein.

Dose-finding/phase II trial: bevacizumab, immunotherapy, and chemotherapy (BIC) in metastatic renal cell cancer (mRCC). Antitumor effects and variations of circulating T regulatory cells (Treg)

The aim of this study was to explore the efficacy and toxicities of a combined regimen of bevacizumab plus immunotherapy and chemotherapy (BIC) and the circulating T regulatory cells (Treg) in metastatic renal cell cancer (mRCC). Nephrectomized mRCC patients were enrolled into a multicenter single-arm dose-finding study with five escalated dose levels of chemotherapy with intravenous gemcitabine and 5-fluorouracil associated with fixed intravenous doses of bevacizumab, subcutaneous low doses of interleukin-2, and interferon-α-2a. An expanded cohort (phase II study) was treated at the recommended dose for additional safety and efficacy information according to minimax Simon two-stage design. Blood samples for Treg were collected and evaluated by fluorescence-activated cell sorting (FACS) analysis on cycle 1. Fifty-one patients were entered to receive one of five dose levels. Median age was 58 years (male 67 %, pretreated 49 %): 15 patients were low risk according to Memorial Sloan-Kettering Cancer Center (MSKCC) criteria, while 27 and nine were respectively intermediate- and high-risk patients. More frequent grade 3 and 4 toxicities included nonfebrile neutropenia, thrombocytopenia, and fever. Among patients evaluable for response (49), 29.5 % had partial response and 37 % stable disease. Overall median time to progression and median overall survival were 8.8 and 22.67 months, respectively. We observed a rapid increase in the percentage of Treg after immunotherapy and a reduction after bevacizumab only in patient who obtained a partial response or stable disease. The BIC was feasible, well tolerated, and shown interesting activity. Further studies are needed to explore if Treg could have a role in clinical response in mRCC treated with bevacizumab.

Immune cells in the melanoma microenvironment hold information for prediction of the risk of recurrence and response to treatment

Melanoma is an immunogenic tumor and immunotherapy treatment has established an increase in disease-free and overall survival in melanoma patients. However, a complex network of immunosuppressive mechanisms has been demonstrated to occur at the tumor site and in locoregional immune districts, such as sentinel lymph nodes (SLNs). The interplay between tumor cells and the local microenvironment leads to a tumor-driven shaping of the immune response that results in a heterogeneous cellular and molecular composition of tumor infiltrating lymphocytes (TILs). Several studies have reported the potential prognostic value of TILs infiltrating primary tumors and the association of 'immune signature' in SLNs and in melanoma metastases with prognosis and responsiveness to immunotherapeutic approaches. However, a systematic and deeper characterization of the local immunological status of TILs and SLNs is still required to refine melanoma stage classification.

Transcriptional profiling of melanoma sentinel nodes identify patients with poor outcome and reveal an association of CD30(+) T lymphocytes with progression

Sentinel lymph nodes set the stance of the immune system to a localized tumor and are often the first site to be colonized by neoplastic cells that metastasize. To investigate how the presence of neoplastic cells in sentinel lymph nodes may trigger pathways associated with metastatic progression, we analyzed the transcriptional profiles of archival sentinel node biopsy specimens obtained from melanoma patients. Biopsies from positive nodes were selected for comparable tumor infiltration, presence or absence of further regional node metastases, and relapse at 5-year follow-up. Unsupervised analysis of gene expression profiles revealed immune response to be a major gene ontogeny represented. Among genes upregulated in patients with progressing disease, the TNF receptor family member CD30/TNFRSF8 was confirmed in biopsy specimens from an independent group of patients. Immunohistochemical analysis revealed higher numbers of CD30(+) lymphocytes in nodes from progressing patients compared with nonprogressing patients. Phenotypic profiling demonstrated that CD30(+) lymphocytes comprised a broad population of suppressive or exhausted immune cells, such as CD4(+)Foxp3(+) or PD1(+) subpopulations and CD4(-)CD8(-) T cells. CD30(+) T lymphocytes were increased in peripheral blood lymphocytes of melanoma patients at advanced disease stages. Our findings reinforce the concept that sentinel nodes act as pivotal sites for determining progression patterns, revealing that the presence of CD30(+) lymphocytes at those sites associate positively with melanoma progression.

Immune response markers in sentinel nodes may predict melanoma progression

We recently reported that variable expression of immune-response genes distinguishes tumor positive sentinel nodes in melanoma patients with malignant progression from those with non-progressing disease. Our results depict sentinel nodes as sites in which immune functions are associated with metastatic disease and identify CD30 as a host immune-related cancer prognostic marker and potential therapeutic target.

Risk assessment of venous thrombosis in families with known hereditary thrombophilia: the MARseilles-NImes prediction model

BACKGROUND

Although predicting the risk of venous thrombosis (VT) in an individual from a family with inherited thrombophilia is of major importance, it is often not feasible.

OBJECTIVES

To develop a simple risk assessment model that improves prediction of the risk of VT for individuals of families with inherited thrombophilia.

PATIENTS/METHODS

1201 relatives from 430 families with inherited thrombophilia (deficiencies of antithrombin, protein C or protein S, and the factor V Leiden and F2 20210A mutations) were recruited at the referral center for thrombophilia in Marseilles, France, from 1986 to 2008. One hundred and twenty-two individuals had a personal history of VT. Sixteen preselected clinical and laboratory variables were used to derive the VT risk score.

RESULTS

The scores based on the 16 variables and on the five most strongly associated variables performed similarly (areas under receiver operating characteristic curves of 0.85 and 0.83, respectively). For the five-variable score, named the MARNI score, derived from family history score of VT, von Willebrand factor antigen levels, age, severity of thrombophilia, and FGG rs2066865, the risk of VT ranged from 0.2% for individuals with a score of 0 (n = 186) to > 70% for individuals with a score of ≥ 7 (n = 27). The model was validated with an internal bootstrap method.

CONCLUSIONS

With the use of a simple scoring system, assessment of the risk of VT in subjects from families with inherited thrombophilia can be greatly improved. External validation is now needed to replicate these findings.

Risk assessment of venous thrombosis in families with known hereditary thrombophilia: the MARseilles-NImes prediction model

BACKGROUND

Although predicting the risk of venous thrombosis (VT) in an individual from a family with inherited thrombophilia is of major importance, it is often not feasible.

OBJECTIVES

To develop a simple risk assessment model that improves prediction of the risk of VT for individuals of families with inherited thrombophilia.

PATIENTS/METHODS

1201 relatives from 430 families with inherited thrombophilia (deficiencies of antithrombin, protein C or protein S, and the factor V Leiden and F2 20210A mutations) were recruited at the referral center for thrombophilia in Marseilles, France, from 1986 to 2008. One hundred and twenty-two individuals had a personal history of VT. Sixteen preselected clinical and laboratory variables were used to derive the VT risk score.

RESULTS

The scores based on the 16 variables and on the five most strongly associated variables performed similarly (areas under receiver operating characteristic curves of 0.85 and 0.83, respectively). For the five-variable score, named the MARNI score, derived from family history score of VT, von Willebrand factor antigen levels, age, severity of thrombophilia, and FGG rs2066865, the risk of VT ranged from 0.2% for individuals with a score of 0 (n = 186) to > 70% for individuals with a score of ≥ 7 (n = 27). The model was validated with an internal bootstrap method.

CONCLUSIONS

With the use of a simple scoring system, assessment of the risk of VT in subjects from families with inherited thrombophilia can be greatly improved. External validation is now needed to replicate these findings.

Alternative activation of human plasmacytoid DCs in vitro and in melanoma lesions: involvement of LAG-3

Plasmacytoid dendritic cells (pDCs) at tumor sites are often tolerogenic. Although pDCs initiate innate and adaptive immunity upon Toll-like receptor (TLR) triggering by pathogens, TLR-independent signals may be responsible for pDC activation and immune suppression in the tumor inflammatory environment. To identify molecules that are potentially involved in alternative pDC activation, we explored the expression and function of lymphocyte activation gene 3 (LAG-3) in human pDCs. In this report, we showed the expression of LAG-3 on the cell surface of a subset of circulating human pDCs. LAG-3+ pDCs exhibited a partially mature phenotype and were enriched at tumor sites in samples from melanoma patients. We found that LAG-3 interacted with major histocompatibility complex class II (MHC-II) to induce TLR-independent activation of pDCs with limited IFNα and enhanced IL-6 production. This in vitro cytokine profile of LAG-3-activated pDCs paralleled that of tumor-associated pDCs analyzed ex vivo. By confocal microscopy, LAG-3+ pDCs detected in melanoma-invaded lymph nodes (LNs) stained positive for IL-6 and preferentially localized near melanoma cells. These results suggest that LAG-3-mediated activation of pDCs takes place in vivo at tumor sites, and it is in part responsible for directing an immune-suppressive environment.

[ICU patients and days of intensive care: A mathematical model optimizing the consequences of ICU unit function, intensive care and continual monitoring on incurred supplementary costs]

INTRODUCTION

"Critical Care Units" are intended to admit patients with multiple organ failure. The severity of patients admitted is variable. The aim of the study was to estimate the number of days that an optimum care organization could release, and therefore the additional admissions that would have been allowed. Estimates of earnings related to the various supplements were carried out jointly.

METHODS

Reporting days associated or not with a resuscitation care during the year 2011 in an ICU of a university hospital (16 beds), optimized patient flow simulation, and computation of medical act inducing financial supplements.

RESULTS

Six hundred and fifty-seven patients (SAPS II from 0 to 110, 41% ventilated more than 48hours, mortality=26%) were admitted representing 5095days (occupancy rate=87%). Two hundred and twenty-two patients (34%) did not trigger supplement for resuscitation care for 415days in the unit. Four hundred and thirty-five patients have triggered this supplement representing 4680days, including 3035days with resuscitation care and 1645 (35% of days valued resuscitation, 32% of total days) without any. The entire year 2011 has generated earnings of 3,980,192€. Optimization of management would have allowed the admission of additional 235 to 295 patients and potential additional earnings from 524,735€ to 1,063,804€, depending on the occupancy rate chosen (80% or real 2011s) and the severity of discharged patients.

CONCLUSION

Optimization of the patients flow between "Critical Care", Intensive Care and Continuous Monitoring Units would increase the number of patients admitted in "Critical Care" Units without any financial loss related to supplements.

Structured myeloid cells and anti-angiogenic therapy in alveolar soft part sarcoma

Alveolar soft part sarcoma (ASPS) is a rare soft tissue sarcoma and the clinical management of patients with unresectable, metastatic disease is still challenging. ASPS expresses an array of potentially therapeutically targetable, angiogenesis-related molecules and, importantly, it has a distinctive angiogenic phenotype marked by a peculiar tumor-associated vasculature. Several studies, conducted in transgenic mouse models and in a large variety of human tumors of different histotype, clearly proved the substantial contribution of tumor-infiltrating myeloid cells, such as myeloid derived suppressor cells, monocytes and macrophages, in the formation and maintenance of abnormal blood vessels in tumors. By immunohistochemistry we thus explored the presence and the distribution of cells expressing myeloid markers in the inflammatory infiltrate of surgical treated metastatic ASPS. Indeed, we found that myeloid cells expressing CD14 and CD163 markers constitute the prominent cells in the inflammatory infiltrate of ASPS. These macrophage-like cells form a network surrounding the endothelial cells, or, interspersed in the tumor nest, they keep deep contact with tumor cells. In this commentary, we discussed our findings in relation to the recently published paper by Kummar and colleagues reporting the clinical and molecular results of a phase II clinical trial in patients with unresectable, metastatic ASPS treated with the anti-angiogenic drug cediranib, targeting the VEGFR-1,-2,-3 tyrosine kinases.

Limited induction of tumor cross-reactive T cells without a measurable clinical benefit in early melanoma patients vaccinated with human leukocyte antigen class I-modified peptides

PURPOSE

The progressive immune dysfunctions that occur in patients with advanced melanoma make them unlikely to efficiently respond to cancer vaccines. A multicenter randomized phase II trial was conducted to test whether immunization with modified HLA class I tumor peptides in the context of adjuvant therapy results in better immunologic responses and improved clinical outcomes in patients with early melanoma (stages IIB/C-III).

EXPERIMENTAL DESIGN

Forty-three patients were enrolled to undergo vaccination (n = 22) or observation (n = 21). The vaccine included four HLA-A*0201-restricted modified peptides (Melan-A/MART-1([27L]), gp100([210M]), NY-ESO-1([165V]), and Survivin([97M])) emulsified in Montanide ISA51 and injected subcutaneously in combination with cyclophosphamide (300 mg/m(2)) and low-dose IL-2 (3 × 10(6) IU). The immune responses were monitored using ex vivo IFN-γ-ELISpot, HLA/multimer staining, and in vitro short-term peptide sensitization assays.

RESULTS

Vaccination induced a rapid and persistent increase in specific effector memory CD8(+) T cells in 75% of the patients. However, this immunization was not associated with any significant increase in disease-free or overall survival as compared with the observation group. An extensive immunologic analysis revealed a significantly reduced cross-recognition of the corresponding native peptides and, most importantly, a limited ability to react to melanoma cells.

CONCLUSIONS

Adjuvant setting is an appealing approach for testing cancer vaccines because specific CD8(+) T cells can be efficiently induced in most vaccinated patients. However, the marginal antitumor activity of the T cells induced by modified peptides in this study largely accounts for the observed lack of benefit of vaccination. These findings suggest reconsidering this immunization strategy, particularly in early disease.

Frequency of circulating Tregs with demethylated FOXP3 intron 1 in melanoma patients receiving tumor vaccines and potentially Treg-depleting agents

PURPOSE

Regulatory T cells (Tregs) are thought to inhibit antitumor immune responses, and their depletion could therefore have a synergistic effect with therapeutic cancer vaccines. We investigated the impact of three medications on blood Treg frequency in vaccinated cancer patients.

EXPERIMENTAL DESIGN

To date, the most specific marker for human Tregs is demethylation in the DNA that encodes the transcription factor FOXP3. Thus, we used a FOXP3 methylation-specific quantitative PCR assay (MS-qPCR) to measure Treg frequencies in the peripheral blood mononuclear cells (PBMCs) of melanoma patients. The patients participated in three clinical trials that combined tumor vaccines with potential Treg-depleting agents: low-dose cyclophosphamide, anti-CD25 monoclonal antibody daclizumab, and the IL-2/diphtheria toxin fusion protein denileukin diftitox.

RESULTS

In the nine control patients, blood Treg frequencies varied over time; there was a 46% reduction in one patient. In treated patients, a more than 2-fold decrease in Tregs was observed in one out of 11 patients receiving cyclophosphamide and in four out of 13 receiving daclizumab, but there was no such Treg decrease in any of the six patients who received denileukin diftitox. As a positive control, a more than 2-fold increase in blood Tregs was detected in four out of nine patients who were treated with interleukin-2.

CONCLUSIONS

We used a MS-qPCR method that detects Tregs but not other activated T lymphocytes; however, none of the Treg-depleting strategies that we tested led, in the majority of patients, to a conservative 50% reduction in blood Tregs.

Clinical predictors of dual aspirin and clopidogrel poor responsiveness in stable cardiovascular patients from the ADRIE study

BACKGROUND

Poor response to both aspirin and clopidogrel (dual poor responsiveness [DPR]) is a major risk factor for recurrent ischemic events.

OBJECTIVES

The aim of this study was to identify factors associated with DPR, defined with specific tests, and derive a predictive clinical score.

METHODS

We studied 771 consecutive stable cardiovascular patients treated with aspirin (n = 223), clopidogrel (n = 111), or both drugs (n = 37). Aspirin responsiveness was evaluated by serum thromboxane (Tx)B₂ assay, and clopidogrel responsiveness by calculating the platelet reactivity index (PRI) on the basis of the phosphorylation status of the vasodilator phosphoprotein. The analysis was focused on patients treated with both drugs, and on independent predictors of DPR.

RESULTS

Among patients on dual therapy, there was no relevant correlation between TxB₂ levels and PRI values (r = 0.11). Sixty-seven patients (15.4%) had DPR. Diabetes [odds ratio (OR) 1.89, 95% confidence interval (CI) 1.06-3.39], high body weight (> 86 kg vs. < 77 kg, OR 4.74, 95% CI 2.49-9.73), low aspirin dose (75-81 mg vs. ≥ 160 mg, OR 0.12, 95% CI 0.09-0.93) and high C-reactive protein (CRP) level (> 1.6 mg L⁻¹ vs. < 0.6 mg L⁻¹, OR 3.66, 95% CI 1.74-8.72) were independently associated with DPR, via increased TxB(2) levels, increased PRI, or both. These associations with TxB₂ and PRI were reproduced across the whole population. With use of a factor-weighed score (c-index = 0.74), the predicted prevalence of DPR was 57% in the highest strata of the score as compared with < 4% for the lowest strata.

CONCLUSIONS

Diabetes, body weight, the aspirin dose and CRP levels are readily available independent predictors of DPR, and some are potential targets for reducing its prevalence.

Prothrombin G20210A carriers the genetic mutation and a history of venous thrombosis contributes to thrombin generation independently of factor II plasma levels

SUMMARY BACKGROUND

The prothrombin (PT) G20210A gene mutation is a common risk factor for venous thrombosis (VT), which is mainly mediated through an increase in factor II (FII) plasma levels. High FII plasma levels may act through an increase in endogenous thrombin potential (ETP) a key step in hemostasis and thrombosis. While FII may be the main contributor to ETP in PT G20210A carriers, the knowledge of other environmental or genetic factors influencing ETP may help to better identify those at risk of VT.

AIMS

ETP was determined in 472 non-carriers of PT G20210A (PT-) and in 325 unrelated carriers of PT G20210A (PT+) with (symptomatic n = 158) or without (asymptomatic, n = 167) a history of VT. All PT+ were heterozygous and free of other thrombophilic defects.

RESULTS

ETP was higher in asymptomatic PT+ than in PT- (2038 +/- 371 vs. 1616 +/- 267 nmol L(-1) min; P < 0.0001). ETP was significantly higher in symptomatic PT+ than in controls PT+ (2129 +/- 430 vs. 2038 +/- 371 nmol L(-1) min; P = 0.01). Multivariate analyses evidenced the importance of FII and fibrinogen plasma levels in determining ETP.

DISCUSSION

After taking these variables into account, a personal history of VT remained associated with ETP in PT+ carriers. Moreover, PTG20210A still contributes to ETP after consideration of FII levels.

CONCLUSION

In conclusion, the increase in ETP observed in carriers is not entirely explained by higher FII or fibrinogen plasma levels but also by the history of VT.

Heat shock proteins gp96 as immunogens in cancer patients

Heat shock proteins have been the focus of many experimental studies during the last few years in order to understand their biology and their imunologic features. We conducted pre-clinical experiments showing that gp96 purified from human melanoma lines can represent melanoma antigens and stimulate T cells known to recognize such antigens. Clinical studies of vaccination were then initiated by our group by using heat-shock protein gp96 purified from autologous tumor tissues in patients with melanoma and colorectal carcinoma. The results of these trials in metastatic melanoma patients with measurable disease showed that a melanoma-specific T cell response can be generated or increased in approximately 50% of vaccinated patients. Moreover, signs of clinical responses were obtained consisting of two complete responses and three long-lasting stabilizations. Similar results were obtained in patients with liver metastases of colorectal cancer made disease-free by surgery. In both studies a clear association was found between T cell immune response induced by the vaccine and clinical response both in the trial of melanoma (tumor response) and in that of colorectal cancer patients (disease-free and overall survival at 5 years).

Modified peptides in anti-cancer vaccines: are we eventually improving anti-tumour immunity?

The discovery of tumour antigens recognized by T cells and the features of immune responses directed against them has paved the way to a multitude of clinical studies aimed at boosting anti-tumour T cell immunity as a therapeutic tool for cancer patients. One of the different strategies explored to ameliorate the immunogenicity of tumour antigens in vaccine protocols is represented by the use of optimized peptides or altered peptide ligands, whose amino acid sequence has been modified for improving HLA binding or TCR interaction with respect to native epitopes. However, despite the promising results achieved with preclinical studies, the clinical efficacy of this approach has not yet met the expectations. Although multiple reasons could explain the relative failure of altered peptide ligands as more effective cancer vaccines, the possibility that T cells primed by modified tumour peptides might may be unable to effectively cross-recognize tumour cells has not been sufficiently addressed. Indeed, the introduction of conservative amino acid substitutions may still produce diverse and unpredictable changes in the HLA/peptide interface, with consequent modifications of the TCR repertoire that can interact with the complex. This could lead to the expansion of a broad array of T cells whose TCRs may not necessarily react with equivalent affinity with the original antigenic epitope. Considering the results presently achieved with this vaccine approach, and the emerging availability of alternative strategies for boosting anti-tumour immunity, the use of modified tumour peptides could be reconsidered.

Human plasmacytoid dendritic cells interact with gp96 via CD91 and regulate inflammatory responses

Glucose-regulated stress protein gp96 is known to be involved in the host response to pathogens and to cancer. Our study explored the relationships between gp96 and human blood plasmacytoid dendritic cells (pDC) and proved that gp96 directly targets pDC by a receptor-dependent interaction. Competition studies identified CD91 as a gp96 receptor on pDC, and laser confocal imaging indicated that CD91 triggering was followed by gp96 endocytosis and trafficking into early endosomes and later into the endoplasmic reticulum compartment. Using two alternative Abs, we showed that human blood pDC reproducibly expressed CD91, although different levels of expression were detectable among the analyzed donors. Moreover, CpG-matured pDC displayed CD91 receptor up-regulation that correlated with an increased gp96 binding. Functionally, gp96-pDC interaction activated the NF-kappaB pathway, leading to the nuclear translocation of the NF-kappaB complex. gp96-treated pDC maintained an immature phenotype, while they down-modulated the release of IL-8, suggesting an anti-inflammatory role of this pathway, and they strongly up-regulated the cell surface expression of the gp96 receptor CD91. CpG-matured or gp96-treated pDC, expressing high levels of the gp96 receptor CD91, antagonized the gp96-induced activation of monocyte-derived dendritic cells in terms of cell surface phenotype and cytokine production. Altogether, these results suggest that gp96-pDC interaction might represent an active mechanism controlling the strength of the immune response to free, extracellular available gp96; this mechanism could be particularly relevant in wounds and chronic inflammation.