Allovectin-7 therapy in metastatic melanoma

Background: Patients with metastatic melanoma are immunosuppressed by the growing tumor. Allovectin-7 therapy is a form of active immunotherapy that aims at immunization of the host with substances designed to elicit an immune reaction that will eliminate or slow down the growth and spread of the cancer. Objective: to describe the rationale for immunotherapy with Allovectin-7 and assess its safety profile and efficacy based on the results of completed melanoma clinical trials. Methods: we reviewed both the published medical literature and the results of trials pending publication. Results/conclusion: Allovectin-7 is a safe and active immunotherapeutic agent. It induces local and systemic durable responses in patients with metastatic melanoma.     

肿瘤免疫治疗:回顾与展望

随着肿瘤免疫学的迅速发展, 免疫治疗逐渐引起肿瘤治疗领域专家的重视, 相关研究为晚期肿瘤患者提供了新的治疗机会。以程序性死亡受体1及其配体、细胞毒性T淋巴细胞相关抗原4为代表的免疫检查点抑制剂是目前晚期肿瘤临床治疗的研究热点, 已有多种免疫检查点抑制剂获得美国食品药品监督管理局批准用于晚期肿瘤免疫治疗, 其不仅安全性高, 且在晚期黑色素瘤、非小细胞肺癌、肾癌、尿路上皮癌、非霍奇金淋巴瘤中展现出令人振奋的治疗效果, 有效延长了患者生存期。嵌合抗原受体T细胞疗法也是目前免疫治疗领域的明星产品之一, 对急性白血病、非霍奇金淋巴瘤等血液系统恶性肿瘤展现出强大持久的治疗效果, 以Simpuleucel-T为代表的肿瘤疫苗曾一度成为肿瘤免疫治疗里程碑式的成功范例。肿瘤免疫治疗已取得了突破性进展, 研究前景不可估量。     

Ipilimumab in the treatment of melanoma

INTRODUCTION: Recent advances in the understanding of the complex cellular mechanisms regulating cancer immunity have led to new strategies in the development of cancer immunotherapy. Targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4), a key negative regulator of immune activity, with the monoclonal antibody ipilimumab has shown promising clinical benefit in patients with advanced or metastatic melanoma. AREAS COVERED: This review illustrates the pharmacology of ipilimumab and highlights the clinical evidence regarding its efficacy and safety in patients with advanced or metastatic melanoma. The unique clinical response pattern and class-specific immune-related toxicity profile associated with this biologic agent are also characterized. A literature search using PubMed database was undertaken using search words ipilimumab, anti-cytotoxic T-lymphocyte-associated antigen 4, melanoma and tumor immunity barrier. EXPERT OPINION: Ipilimumab, approved by the FDA for patients with advanced or metastatic melanoma based on the overall survival benefit when compared with a peptide vaccine, is a major breakthrough in the treatment of melanoma. While clinicians are embracing this innovative biologic agent, special attentions in patient selection, class-specific immune-related toxicities and their management as well as treatment response evaluation are needed.     

Prospects for immunotherapy as a novel therapeutic strategy against hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly aggressive malignant disease, with a poor clinical prognosis. Many standard therapies are often considered for HCC treatment today; however, these conventional therapies often fail to achieve sufficiently effective clinical results. Today, HCC therapy is set to undergo a major revolution, owing to rapid developments in cancer immunotherapy, particularly immune checkpoint inhibitor therapy. Cancer immunotherapy is a novel and promising treatment strategy that differs significantly from conventional therapies in its approach to achieve antitumor effects. In fact, many cancer immunotherapies have been tested worldwide and shown to be effective against various types of cancer; HCC is no exception to this trend. For example, we identified a specific cancer antigen called glypican-3 (GPC3) and performed clinical trials of GPC3-targeted peptide vaccine immunotherapy in patients with HCC. Here, we present an overview of the immune mechanisms for development and progression of HCC, our GPC3-based immunotherapy, and immune checkpoint inhibitor therapy against HCC. Finally, we discuss the future prospects of cancer immunotherapy against HCC. We believe that this review and discussion of cancer immunotherapy against HCC could stimulate more interest in this promising strategy for cancer therapy and help in its further development.     

The immunological era in melanoma treatment: new challenges for heat shock protein-based vaccine in the advanced disease

INTRODUCTION: Tumor-derived heat shock protein (HSP)-peptide complexes (HSPPCs) induced immunity against malignancies in preclinical trials, working across tumor types and bypassing the need to identify single immunogenic peptides. These results paved the way for the use of human gp96 obtained from autologous tumor samples as an anti-cancer vaccine. AREAS COVERED: Autologous tumor-derived HSP gp96 peptide complex (HSPPC-96) vaccine is emerging as a tumor- and patient-specific cancer vaccine, with confirmed activity in several malignancies. It has been tested in Phase III clinical trials in advanced melanoma and kidney cancer with evidence for efficacy in patients with earlier stage disease. HSPPC-96-based vaccine demonstrated an excellent safety profile, thus emerging as a novel therapeutic approach with a suggestive role in cancer therapy. This review summarizes work on the use of HSPPC-96 as an autologous anti-tumor vaccine in advanced melanoma. Data were retrieved by PubMed and Medline research and using the authors' personal experience. EXPERT OPINION: Further investigations are needed to understand the biological basis of immune functions in order to improve the clinical outcome of HSP-based cancer therapy. In the near future, the combination of HSP-based vaccines with other biological compounds might represent a successful strategy in the therapy of advanced melanoma.     

肺癌免疫治疗现状分析

肺癌发病率和死亡率已居各种癌症之首位．需要探索新的治疗模式,免疫治疗以其低毒,高特异性等优点有望成为肺癌治疗的重要辅助治疗方式。本文综述了肺癌的过继免疫治疗、单克隆抗体疗法、基因治疗、肿瘤疫苗、细胞因子治疗、生物反应调节剂六个方面现状及最新进展。     

The immunological era in melanoma treatment: new challenges for heat shock protein-based vaccine in the advanced disease

Introduction: Tumor-derived heat shock protein (HSP)–peptide complexes (HSPPCs) induced immunity against malignancies in preclinical trials, working across tumor types and bypassing the need to identify single immunogenic peptides. These results paved the way for the use of human gp96 obtained from autologous tumor samples as an anti-cancer vaccine.

Areas covered: Autologous tumor-derived HSP gp96 peptide complex (HSPPC-96) vaccine is emerging as a tumor- and patient-specific cancer vaccine, with confirmed activity in several malignancies. It has been tested in Phase III clinical trials in advanced melanoma and kidney cancer with evidence for efficacy in patients with earlier stage disease. HSPPC-96-based vaccine demonstrated an excellent safety profile, thus emerging as a novel therapeutic approach with a suggestive role in cancer therapy. This review summarizes work on the use of HSPPC-96 as an autologous anti-tumor vaccine in advanced melanoma. Data were retrieved by PubMed and Medline research and using the authors' personal experience.

Expert opinion: Further investigations are needed to understand the biological basis of immune functions in order to improve the clinical outcome of HSP-based cancer therapy. In the near future, the combination of HSP-based vaccines with other biological compounds might represent a successful strategy in the therapy of advanced melanoma.     

The Epitope Integration Site for Vaccine Antigens Determines Virus Control While Maintaining Efficacy in an Engineered Cancer Vaccine

Picornaviruses have been developed as potential therapies for gene delivery and vaccination. One drawback to their use is the potential for recombination and viral persistence. Therefore, the engineering strategies used must take into account the possibility for virus escape. We have developed Theiler''s murine encephalomyelitis virus (TMEV) as a potential vaccine vector for use in immunotherapy. This study shows that insertion of a vaccine epitope at a unique site within the TMEV leader protein can dramatically increase the type I interferon (IFN) response to infection and promote rapid viral clearance. This live virus vaccine maintains its ability to drive antigen-specific CD8⁺ T-cell responses to a model antigen as well as to the weakly immunogenic tumor antigen Her2/neu. Furthermore, the epitope integration site does not affect the efficacy of this vaccine as cancer immunotherapy for treating models of melanoma and breast cancer as demonstrated by delayed tumor outgrowth and increased survival in animals implanted with these tumors. These findings show that an attenuated virus retaining limited ability to replicate nonetheless can effectively mobilize CD8⁺ cellular immunity and will be important for the design of picornavirus vectors used as immunotherapy in clinical settings.     

Peptide-based vaccination for colorectal cancer

Recently, the number of patients with colorectal cancer has been increasing. Although most patients with early colorectal cancer have a good prognosis, in the case of recurrent or metastatic disease, the prognosis is poor and most patients will ultimately die of cancer. Furthermore, the conventional treatment, such as chemotherapy or radiation therapy, occasionally can not be continued due to reasons of toxicity and/or poor response. Therefore, novel therapeutic optional approaches based on immunotherapy are being explored at present. This review describes and sums up the principles and the longstanding problems of peptide vaccine therapy, and demonstrates the results of clinical trials with colorectal cancer peptide vaccine therapy, including the authors' personal appraisal. In conclusion, the future prospects of peptide vaccine therapy are described.     

Dendritic cells transduced with gp100 gene by RGD fiber-mutant adenovirus vectors are highly efficacious in generating anti-B16BL6 melanoma immunity in mice

Dendritic cells (DCs) are the most potent professional antigen-presenting cells for the initiation of antigen-specific immune responses, and antigen-loaded DCs have been regarded as promising vaccines in cancer immunotherapy. We previously demonstrated that RGD fiber-mutant adenovirus vector (AdRGD) could attain highly efficient gene transduction into human and murine DCs. The aim of the present study is to demonstrate the predominance of ex vivo genetic DC manipulation using AdRGD in improving the efficacy of DC-based immunotherapy targeting gp100, a melanoma-associated antigen (MAA). Vaccination with murine bone marrow-derived DCs transduced with AdRGD encoding gp100 (AdRGD-gp100/mBM-DCs) dramatically improved resistance to B16BL6 melanoma challenge and pulmonary metastasis as compared with immunization with conventional Ad-gp100-transduced mBM-DCs. The improvement in antimelanoma effects upon immunization with AdRGD-gp100/mBM-DCs correlated with enhanced cytotoxic activities of natural killer (NK) cells and B16BL6-specific cytotoxic T lymphocytes (CTLs). Furthermore, in vivo depletion analysis demonstrated that CD8(+) CTLs and NK cells were the predominant effector cells responsible for the anti-B16BL6 immunity induced by vaccination with AdRGD-gp100/mBM-DCs, and that helper function of CD4(+) T cells was necessary for sufficiently eliciting effector activity. These findings clearly revealed that highly efficient MAA gene transduction to DCs by AdRGD could greatly improve the efficacy of DC-based immunotherapy against melanoma.     

PD-1/PD-L1 antagonists in gastric cancer: Current studies and perspectives

Immune checkpoints release suppressive signals for T cells, which enable the tumors to escape from immune destruction and provide a new concept that uses the capabilities of the immune system as a therapeutic target for tumors. At present, programmed death receptor 1 (PD-1)/programmed death ligand-1 (PD-L1) has become the most promising therapeutic target. PD-1/PD-L1 blockades exhibit long-lasting antitumor efficacy and safety in patients with various cancers, such as melanoma and non-small-cell lung cancer. Moreover, PD-L1 is highly expressed in the peripheral blood and tumor specimens of patients with cancer, and the expression of PD-L1 is positively correlated with various pathological features and may serve as a predictor of poor prognosis or a diagnostic tool. Clinical trials have verified that PD-1/PD-L1 blockade therapy benefits patients with advanced gastric cancer or gastroesophageal junction cancer. Furthermore, there are many molecules involved in the regulation of PD-1/PD-L1 expression, and the modification of these molecules via drugs and combinations with PD-1/PD-L1 inhibitors may further improve the efficacy of immunotherapy for gastric cancer. In this review, the efficacy, safety, and possible combination treatment options of PD-1/PD-L1 in gastric cancer are reviewed in experimental and clinical settings.     

Immunotherapy of cancer stem cells in solid tumors: initial findings and future prospective

Introduction: Conventional chemotherapies seemed to have reached a therapeutic plateau in the treatment of solid tumors and many metastatic diseases are still incurable. Events of chemo-resistance and relapses appear to be sustained by a subset of putative cancer stem cells (CSCs). New anticancer strategies need to face this new challenge exploring their efficacy against CSCs. Immunotherapy has raised enthusiasms in cancer therapy and its potential against CSCs is an intriguing field of research.

Areas covered: In this work we reviewed the immunotherapy approaches directed against CSCs in solid tumors. We schematically divided adaptive immunotherapy strategies, mainly based on dendritic cell-vaccination, and strategies exploiting MHC-unrestricted effectors like natural killer cells, γδ T lymphocytes and cytokine-induced killer cells. Findings, strength and limitations of these models are discussed and compared highlighting their potential clinical relevance.

Expert opinion: The important biologic role and clinical relevance of CSCs introduced a ‘noble target’ for immunotherapy and cancer treatments in general. Initial evidences suggest that CSCs may be susceptible to various types of immunotherapy attacks, overcoming their chemo-resistance. Investigation of important safety issues, based on shared features with ‘normal’ stem cells, along with intriguing synergisms with modulatory agents are open challenges for the next future and effective clinical translation.     

Non-BRAF-targeted therapy,immunotherapy, and combination therapy for melanoma

Introduction: Melanoma is an aggressive disease characterized by a complex etiology. The discovery of key driving mutations (primarily BRAF mutations) led to the development of specific molecular inhibitors providing clinical benefit.

Areas covered: Although BRAF-specific drugs have perhaps yielded the best results in melanoma-targeted therapy, there still remain several limitations, mostly due to the emergence of resistance and the lack of efficacy in patients without BRAF mutation. Novel drugs are currently being tested in clinical trials and showed encouraging results. Such drugs can specifically target molecular pathways aberrantly activated or repressed during melanoma development (targeted therapy) or act in a way to enhance the host immune system to fight cancer (immunotherapy). Here we provide a detailed overview of the current clinical strategies, which lay beyond BRAF-targeted therapy, spanning from molecular-targeted therapy to immunotherapy and to combination therapy.

Expert opinion: Major advances in our understanding of the mechanisms behind melanoma development have led to the implementation of novel therapeutic drugs. Unfortunately, tools allowing prediction of responsiveness to a given treatment are not available yet. The increasing availability of high-throughput technologies will allow the elucidation of molecular mechanisms underlying responsiveness to cancer therapy and unveil an increased number of potential therapeutic targets.     

Cytotoxic T lymphocyte antigen-4 and immune checkpoint blockade

The relationship between cancer and the immune system is complex and provides unique therapeutic opportunities. Cytotoxic T lymphocyte antigen-4 (CTLA-4) is a regulatory molecule that suppresses T cell effector function following initial activation by costimulatory signals. Fully human monoclonal antibodies targeting CTLA-4 have been shown to increase T cell function and antitumor responses in patients with advanced metastatic melanoma. Responses observed with such immune checkpoint therapy can follow a different pattern from that seen with cytotoxic chemotherapy or targeted therapy and may continue after therapy is discontinued. In addition, the toxicities that are associated with anti–CTLA-4 therapy may differ from those of conventional therapies and consist of inflammatory events in parts of the body that do not contain cancerous cells. Early recognition of these inflammatory events and intervention is important, and the identification of predictive biomarkers continues to be an unfulfilled need in the field of immunotherapy. Combinatorial approaches with targeted therapies, radiation therapy, chemotherapy, or other immune checkpoint agonists/antagonists have the potential to increase the efficacy of CTLA-4 blockade.     

New survival curve model for comparison of adjuvant therapy of malignant diseases

Two mathematical models were presented to approximate the various survival curves for malignant diseases. The models individualized several segments in the survival curve. Also, the hazard function of the curve and the confidence intervals of the curve could be calculated. First, we studied the survival-after-relapse curve for adjuvant therapy of malignant melanoma. The curve for chemoimmunotherapy had three segments and the curve for immunotherapy, two segments. The immunotherapy showed its effect in the early period of treatment. Second, the disease-free survival curves for adjuvant therapies of breast cancer were compared; Oncofrance trial: a combination of AVCF was superior to a combination of CMF in all the periods of the therapy; Lacour's trial: Poly A-Poly U was more effective than the control in the middle and late period; Bonadonna's trial: CMF was superior to the control in the early period. Third, the survival curves for adjuvant therapy of stomach cancer; immunotherapy versus non-immunotherapy were analysed. Comparison of the confidence intervals of each curve clarified that no significant difference could be found between them. Thus, these analyses showed the effectiveness of the compared adjuvant treatments.     

Immune monitoring of cancer patients undergoing experimental immunotherapy

Advancements in the understanding of cellular immunity within the last decade, along with the characterization of tumor antigens, have led to immunotherapeutic approaches for cancer therapy. This mode of treatment is expected to provide more tumor-specific activity, thereby being less toxic to normal cells than standard modalities. Clinical trials are underway throughout the world to determine whether immunotherapy is a practical and viable alternative to conventional cancer therapies. Unlike radiotherapy and chemotherapy, wherein tumor regression is the standard for determining efficacy of the regimens, immunotherapy has to be evaluated by the examination of several immunological parameters within patients. The purpose of this article is to review the methods currently utilized to evaluate the induction, maintenance, and duration of antitumor immune reactivity in cancer patients undergoing immunotherapy.     

Promising immunotherapies for esophageal cancer

Introduction: Esophageal cancer (EC) is the eighth most common cancer in the world, and the prognosis of EC is still poor. Although immunotherapy has been developed in melanoma and lung cancer, it is also expected to show efficacy in EC. Currently, several clinical trials are ongoing to evaluate the safety and efficacy of immunotherapies, immune checkpoint inhibitors, adoptive T cell transfer, and therapeutic cancer vaccines in EC.

Areas covered: This review provides an overview and the status of immunotherapy in EC. Clinical significance of molecules related immune checkpoints, especially PD-1 and PD-L1 is presented and the designs, results and future directions of clinical trials using immunotherapy in EC are provided.

Expert opinion: To bring immunotherapy to the forefront of treatment for EC, it is necessary to select patients who can obtain a high efficacy of immunotherapy and to also elucidate the correct timing for administration. Moreover, combination therapies of immunotherapy with existing chemotherapy or radiation or other immunotherapy with different mechanisms of action must be evaluated to achieve excellent outcomes in patients with EC.     

Synergy of molecular targeted approaches and immunotherapy in melanoma: preclinical basis and clinical perspectives

Introduction: Targeted therapy and immunotherapies are the novel pharmacologic treatment strategies for metastatic melanoma. BRAF and MEK inhibitors effectively block the hyperactivation of the MAPK pathway in BRAF mutant melanomas and also have several other effects on melanoma cells and on the immune response. The aim of this work is to discuss the rationale, evidence and perspectives of approaches combining target and immunotherapy against melanoma.

Areas covered: We first review the effects of BRAF and MEK inhibitors on melanoma cells and on the different components of the immune system. Afterwards, we summarize the results of the preclinical and clinical studies that have combined targeted therapy and immunotherapy for the treatment of melanoma.

Expert opinion: Clinical applications of immunotherapy strategies have recently changed the therapeutic mainstay for metastatic melanoma. Biologic and initial preclinical data support their integration with innovative molecular targeted therapies, opening enormous perspectives for researchers in the effort of finding a definitive cure. Main open challenges are the definition of reliable research models, assessment of effective schedules, safety issues and designing of personalized approaches.     

Prophylactic immunization with Bubble liposomes and ultrasound-treated dendritic cells provided a four-fold decrease in the frequency of melanoma lung metastasis

Melanoma has an early tendency to metastasize, and the majority of the resulting deaths are caused by metastatic melanoma. It is therefore important to develop effective therapies for metastasis. Dendritic cell (DC)-based cancer immunotherapy has been proposed as an effective therapeutic strategy for metastasis and recurrence due to prime tumor-specific cytotoxic T lymphocytes. In this therapy, it is important that DCs present peptides derived from tumor-associated antigens on MHC class I molecules. Previously, we developed an innovative approach capable of directly delivering exogenous antigens into the cytosol of DCs using perfluoropropane gas-entrapping liposomes (Bubble liposomes, BLs) and ultrasound. In the present study, we investigated the prevention of melanoma lung metastasis via DC-based immunotherapy. Specifically, antigens were extracted from melanoma cells and used to treat DCs by BL and ultrasound. Delivery into the DCs by this route did not require the endocytic pathway. The delivery efficiency was approximately 74.1%. DCs treated with melanoma-derived antigens were assessed for in vivo efficacy in a mouse model of lung metastasis. Prophylactic immunization with BL/ultrasound-treated DCs provided a four-fold decrease in the frequency of melanoma lung metastases. These in vitro and in vivo results demonstrate that the combination of BLs and ultrasound is a promising method for antigen delivery system into DCs.