Targeting the PD-1 pathway: a promising future for the treatment of melanoma

Advanced melanoma presents a significant therapeutic challenge to clinicians. Many therapies for metastatic melanoma are limited by low response rates, severe toxicities, and/or relatively short response duration. Cancer immunotherapies that act as immune-checkpoint inhibitors to block the localized immune suppression mechanisms utilized by tumors are undergoing development and clinical trials. A clinically relevant immune escape mechanism in melanoma is the activation of the programmed cell death-1 (PD-1) receptor on infiltrating T cells. Activating PD-1 triggers an immune checkpoint resulting in inhibition of T cells directed against melanoma antigens and prevents the immune system from combating the melanoma. In Phase I clinical trials, two anti-PD1 therapies, Nivolumab and MK-3475, that block the PD-1 receptor to enable T cell killing have demonstrated objective tumor responses in patients with advanced melanoma. The purpose of this review is to present the available clinical evidence on anti-PD-1 and anti-PD-L1 immunotherapy for the treatment of advanced melanoma. We also discuss limitations associated with anti-PD-1 therapy. The blockade of the PD-1–PD-L1 pathway has shown promising results in clinical trials and has revolutionized melanoma immunotherapy.     

Insights into gene modulation by therapeutic TNF and IFNgamma antibodies: TNF regulates IFNgamma production by T cells and TNF-regulated genes linked to psoriasis transcriptome

Therapeutic antibodies against tumor necrosis factor (TNF) (infliximab) and IFNgamma (fontolizumab) have been developed to treat autoimmune diseases. While the primary targets of these antibodies are clearly defined, the set of inflammatory molecules, which is altered by use of these inhibitors, is poorly understood. We elucidate the target genes of these antibodies in activated human peripheral blood mononuclear cells from healthy volunteers. While genes suppressed by fontolizumab overlap with known IFNgamma-induced genes, majority of genes suppressed by infliximab have previously not been traced to TNF signaling. With this approach we were able to extrapolate new TNF-associated genes to be upregulated in psoriasis vulgaris, an "autoimmune" disease effectively treated with TNF antagonists. These genes represent potential therapeutic targets of TNF antagonists in psoriasis. Furthermore, these data establish an unexpected effect of TNF blockade on IFNgamma synthesis by T cells. Synthesis of IFNgamma, a cytokine of Th1-polarized T cells, is suppressed by 8.1-fold (P<0.01) at the mRNA level, while synthesis of IFNgamma is eliminated in >60% of individual T cells. These data suggest that TNF blockade with infliximab can suppress a major pathway of the adaptive immune response and this observation provides a key rationale for targeting TNF in "Type-1" T-cell-mediated autoimmune diseases.     

Checkpoint‐Inhibitoren in der Immuntherapie: Ein Meilenstein in der Behandlung des malignen Melanoms

It has been known for decades that the immune system is able to detect and destroy tumor cells. In the past, this knowledge – mostly acquired through animal experiments – could not be used to benefit our patients, because immuno‐oncological therapeutic approaches in humans had constantly failed over recent decades. With the exception of adjuvant interferon therapy, none of these approaches had found its way into everyday clinical practice, and only very few patients were able to enjoy long‐term survival associated with good quality of life. With the advent of novel immunological approaches, the meaning of long‐term survival as well as quality of life has been redefined for oncological patients. For the first time, a significant percentage of patients responds to treatment with immune checkpoint inhibitors, showing long‐term remission and even cure. It has already become apparent that immunotherapy will in the future be one of the therapeutic mainstays in the treatment of metastatic melanoma as well as many other tumor types. The present review article presents the most important new treatment modalities, their mechanism of action, clinical data regarding treatment response, and adverse events to be expected.     

Intralesional interleukin‐2: A novel option to maximize response to systemic immune checkpoint therapy in loco‐regional metastatic melanoma

The management of metastatic melanoma has been transformed by the development of immune checkpoint inhibitors. However, disease control in patients with extensive locoregional metastases remains a significant challenge. In this context, intralesional interleukin 2 (IL‐2) presents a useful therapeutic option to maximize intratumoural drug concentration and minimize systemic toxicity. The utility of combined intralesional IL‐2 and systemic immune checkpoint therapy, particularly in loco‐regional disease, is unknown. We report the clinical and cellular effects of combined anti‐programmed death‐1 blockade and intralesional IL‐2 therapy in two patients with loco‐regional metastatic melanoma. Combined intralesional and systemic therapy induced a lasting resolution of the injected skin tumors; maintained for up to 2 years. This impressive response was associated with increased PD‐L1 expression and CD8 T cell infiltration. To our knowledge, this is the first report that raises the possibility of a synergistic effect between intralesional IL‐2 and systemic checkpoint inhibition. The lasting remission of injected metastases may be in part due to an altered tumor microenvironment; characterized by increased PD‐L1 expression and increased CD8 T cell infiltration. If this interesting and novel preliminary observation is confirmed in larger studies, combined local and systemic immunotherapy could highlight a novel treatment strategy for extensive loco‐regional disease.     

免疫检查点在感染性疾病中的研究进展

免疫检查点是一类T细胞表达的抑制性受体,其表达过高可致T细胞耗竭,效应免疫反应减弱,在病原体免疫逃逸过程中发挥重要作用。免疫检查点抑制剂有助于恢复T细胞的效应功能,因此已广泛应用于肿瘤等疾病的靶向治疗,在感染性疾病治疗中的价值尚在探讨阶段。本文将从免疫检查点的类型、作用机制、其在感染性疾病中的研究及临床应用等方面进行系统综述。     

Management of side effects of immune checkpoint blockade by anti‐CTLA‐4 and anti‐PD‐1 antibodies in metastatic melanoma

CTLA‐4 and PD‐1 are potential targets for tumor‐induced downregulation of lymphocytic immune responses. Immune checkpoint‐modifying monoclonal antibodies oppose these effects, inducing T cell‐mediated immune responses to various tumors including melanoma. Both anti‐CTLA‐4 and anti‐PD‐1 antibodies modify the interaction between tumor, antigen‐presenting cells, and T lymphocytes. With respect to overall survival, clinical studies have shown a major benefit for the anti‐CTLA‐4 antibody ipilimumab as well as the two anti‐PD‐1 antibodies nivolumab and pembrolizumab. Following approval of ipilimumab in 2011, the latter two achieved market authorization in the summer of 2015. Immune responses thus induced and enhanced inevitably entail autoimmune phenomena, affecting various organs to varying degrees. Knowledge of these side effects is crucial with regard to prevention and management by treating physicians. Typically occurring early on and presenting with pronounced and persistent diarrhea, colitis represents a major and severe side effect. Other immune‐mediated disorders include dermatitis, hypophysitis, thyroiditis, hepatitis, iridocyclitis as well as other less common autoimmune phenomena. Early recognition and initiation of treatment can reduce risks and sequelae for patients. This review describes the mechanisms of action of immune checkpoint blockade as well as its clinical effects in metastatic melanoma, with a detailed focus on the spectrum of adverse events and their therapeutic management.     

CCR4 is expressed on infiltrating cells in lesional skin of early mycosis fungoides and atopic dermatitis

CCR4 is expressed on tumor cells of mycosis fungoides (MF) and Sézary syndrome (SS). In MF, most infiltrating cells in patches and plaques express CXCR3, while tumor cells express CCR4 in advanced stages. Poteligeo Test IHC (CCR4 staining kit) is a newly developed staining kit that can examine the presence of CCR4 expressed on tumor cells of adult T‐cell leukemia/lymphoma, peripheral T‐cell lymphoma and cutaneous T‐cell lymphoma before treatment of anti‐CCR4 antibody using paraffin‐embedded samples. In this study, we analyzed CCR4 expression in lesional skin of MF, SS, atopic dermatitis (AD) and psoriasis with this new kit. CCR4 was expressed on infiltrating cells in lesional skin of patch, plaque, tumor MF and SS, and the number of positive cells increased as the disease progressed. Immunohistochemistry with frozen sections also showed some positive cells scattered in the dermis, although the quality was not high enough to quantify positive cells. There were significant positive correlations between CCR4⁺ cells and serum lactate dehydrogenase levels. Interestingly, CCR4⁺ cells were also detected in AD skin, whose number was larger than that in psoriatic skin. Previous studies showed only scattered CCR4⁺ cells in skin samples by standard immunohistochemical staining. The new, sensitive CCR4 staining kit has revealed that CCR4 is expressed on infiltrating cells in lesional skin of early MF and AD as well as advanced MF and SS. These cells can be therapeutic targets for patients who are resistant to standard treatments.     

BH3‐only proteins – possible proapoptotic triggers for melanoma therapy

Despite recent developments for new targeted therapies in melanoma, as BRAF inhibitors and immune‐stimulating antibodies, tumor relapse frequently follows within less than a year. Therapy resistance is explained by defects in proapoptotic signalling. Thus, efficient induction of apoptosis in tumor cells appears as predominant therapeutic goal. In apoptosis control of melanoma, the balance between pro‐ and antiapoptotic Bcl‐2 proteins plays a decisive role. In particular, members of the subfamily of BH3‐only proteins function as proapoptotic triggers, and mimetics of these proteins are already in clinical trials in other cancers. Recent experimental work has revealed that the effects of different treatments in melanoma are related to the activation of BH3‐only proteins, and also the proapoptotic effects of BRAF inhibitors are prevented by knockdown of the BH3‐only protein Bim. Thus, melanoma therapy might be critically improved by the combination of survival pathway antagonists as BRAF inhibitors with BH3 mimetics.     

Role of chemokines in melanoma progression

Metastasis is the main cause of death from melanoma. Chemokines are low molecular weight chemotactic cytokines that facilitate cellular migration. Thus, cells that express receptors for a given chemokine are attracted to the site of its production. As certain chemokines are found in abundance in organs that are common targets of metastasis and receptors for these chemokines are expressed by tumor cells, it was hypothesized that chemokine gradients might selectively facilitate metastasis to these organs. A later finding that these chemokines were produced by tumor cells, with evidence of autocrine effects, obliged the modification of that hypothesis. Many chemokines are also known to have opposing effects according to the type of cell they are acting on (tumor, inflammatory/immune, or endothelial cells), their functional status, or interactions with other molecules. The expression of chemokines and their receptors by melanoma cells enhances tumor progression by altering their microenvironment, stimulating angiogenesis, and inhibiting the immune response.     

Successful treatment of mogamulizumab‐resistant mycosis fungoides with mogamulizumab plus etoposide combined therapy: Investigation of the immunomodulatory effects of etoposide on the tumor microenvironment

Mogamulizumab shows cytotoxicity against CCR4+ lymphoma cells by antibody‐dependent cell‐mediated cytotoxicity (ADCC) in advanced cutaneous T‐cell lymphoma (CTCL) patients. Although mogamulizumab is used as one of the anchor drugs for the treatment of advanced CTCL, its efficacy is unsatisfactory, especially in mycosis fungoides (MF). Therefore, additional drugs to enhance the antitumor effects of mogamulizumab are needed to further optimize its use for the treatment of MF. In this report, two cases of mogamulizumab‐resistant MF successfully treated with additional administration of etoposide are presented. Moreover, the possible mechanisms of mogamulizumab‐etoposide combined therapy for the treatment of MF were investigated based on the modulation of chemokine profiles in vivo using an EL‐4 mouse T‐cell lymphoma model. Intraperitoneal administration of etoposide significantly increased the mRNA expressions of CCL17, CXCL5, and CXCL10, suggesting that CCR4+ CTCL cells gather around the tumor‐associated macrophagess. Furthermore, the immunomodulatory effects of etoposide on the mRNA expressions of these chemokines were validated using monocyte‐derived M2 macrophages in vitro. Since mogamulizumab shows cytotoxicity against CCR4+ lymphoma cells by ADCC that depends on the contact between the lymphoma cells and the effector cells, these chemokines could enhance the therapeutic effect of mogamulizumab.     

Impfstrategien zur Behandlung des Melanoms

Malignant melanoma is a highly aggressive although immunogenic tumor which can be recognized and destroyed by the immune system. Therefore, immunotherapy has been represented an essential part of the therapeutic arsenal for decades. Besides non-specific immunotherapeutic approaches (whole tumor cell vaccine, cytokine therapy, toll-like receptor agonists), targeted immunotherapy has been made possible by the identification of tumor-associated antigens. Despite undisputable successes, the ultimate breakthrough has not yet been achieved. This overview deals with the fundamental aspects of antigen-specific immunotherapy and highlights future strategies to improve its clinical efficacy.     

Atopic dermatitis – Perspectives and unmet medical needs

Atopic dermatitis (AD) is a chronic inflammatory skin disease for which many new insights have been gained in recent years through a better understanding of pathophysiology, concomitant diseases and therapeutics in particular. In this review, new and practice-relevant results from current research are presented. Many studies have been performed on the diagnosis of AD and on different subtypes, yet no diagnostic biomarker or clinical predictor of treatment response has been established. For topical treatment, some agents such as Janus kinase (JAK) inhibitors are in advanced stages of clinical trials or already approved in some countries, which will be available in Europe for the treatment of certain eczema subtypes in the foreseeable future. Current systemic therapies in Europe include two antibodies for inhibition of the interleukin (IL)-4/13 signaling cascades and three oral JAK inhibitors with somewhat different efficacy and safety profiles. Among the antibody therapies for AD already advanced in development, promising new targets include blockade of IL-31, of neurokinin-1 receptor on sensory neurons, and inhibition of the OX40/OX40L axis for cutaneous dendritic cell and T lymphocyte interaction. Primary prevention and modulation of sequential disease progression as well as effects on concomitant diseases by early therapeutic intervention will be important questions in future research on AD.     

恶性黑素瘤免疫检查点抑制疗法研究进展

【摘要】 免疫检查点抑制剂在过去几年中已成为许多恶性黑素瘤患者的重要治疗选择，其旨在恢复并促进效应T细胞特异性识别和杀伤肿瘤细胞的功能，系统性增强全身的抗肿瘤免疫反应，对于手术切除后具有高复发风险或处于疾病晚期（不可切除或存在转移）的患者都是较好的治疗选择。目前免疫检查点抑制的主要目标是程序性死亡受体 1与细胞毒性T淋巴细胞相关抗原4，它们分别是中枢和外周免疫耐受的两个关键受体。本文主要讨论不同免疫检查点抑制剂的临床效应、可能存在的药物反应性预测标志物与相关不良反应。     

Tumor-derived CCL20 affects B16 melanoma growth in mice

BackgroundChemokine ligand-20 (CCL20) expressed in the epidermis is a potent impetus for the recruitment of CC-chemokine receptor 6 (CCR6)-expressing subsets of DCs, B-cells and memory T-cells into the skin. CCL20 and CCR6+ immune cells have been detected in chronic inflammatory skin diseases and several malignancies, including melanoma. Yet, the functional contribution of the CCR6/CCL20 axis for melanoma progression remains controversial.ObjectiveThe functional contribution of CCR6-expressing immune cell subsets and local CCL20 in the tumor microenvironment for the immune control of melanoma was studied.MethodsHomeostatic and inducible CCL20 secretion of murine (B16, Ret) and human (A375, C32) melanoma cells was analyzed by ELISA. To assess the functional relevance of CCR6/CCL20 interactions on local tumor progression, prestimulated or retrovirally transduced B16/F1 melanoma cells overexpressing CCL20 (B16-CCL20) were injected subcutaneously into C57BL/6 Wt mice and congenic CCR6-deficient (CCR6^−/−) mice. Infiltrating leucocytes were examined by flow cytometry in tumors and draining lymph nodes (DLNs).ResultsMelanoma cell lines up-regulate CCL20 secretion upon stimulation with pro-inflammatory cytokines in vitro. While only moderate changes in phenotype and composition of leucocytes were detected in advanced tumors and DLNs, mice injected with CCR6+ B16-CCL20 cells developed smaller tumors compared to B16-Control injected littermates, with CCR6-/- mice displaying the most pronounced reduction in tumor growth and incidence.ConclusionOur results suggest that CCR6/CCL20 interactions and individual independent effects of CCL20 and CCR6 in the microenvironment may be essential for melanoma progression and suggest a decisive role of this chemokine axis for melanoma pathogenesis beyond chemoattraction.     

Side effect management during immune checkpoint blockade using CTLA‐4 and PD‐1 antibodies for metastatic melanoma – an update

CTLA‐4 and PD‐1 play a key role in tumor‐induced downregulation of lymphocytic immune responses. Immune checkpoint inhibitors have been shown to alter the immune response to various cancer types. Anti‐CTLA‐4 and anti‐PD‐1 antibodies affect the interaction between tumor, antigen‐presenting cells and T lymphocytes. Clinical studies of the anti‐CTLA‐4 antibody ipilimumab and the anti‐PD‐1 antibodies nivolumab and pembrolizumab have provided evidence of their positive effects on overall survival in melanoma patients. Combined treatment using ipilimumab and nivolumab has been shown to achieve five‐year survival rates of 52 %. Such enhancement of the immune response is inevitably associated with adverse events. Knowledge of the spectrum of side effects is essential, both in terms of prevention and management. Adverse events include colitis, dermatitis, hypophysitis, thyroiditis, hepatitis and other, less common autoimmune phenomena. In recent years, considerable progress has been made in the detection and treatment of the aforementioned immune‐related adverse events. However, early diagnosis of rare neurological or cardiac side effects, which may be associated with increased mortality, frequently pose a challenge. The present update highlights our current understanding as well as new insights into the spectrum of side effects associated with checkpoint inhibitors and their management.     

Neoadjuvant immunotherapy with combined ipilimumab and nivolumab in patients with melanoma with primary or in transit disease

The introduction of new therapeutic agents has revolutionized the treatment of metastatic melanoma. The approval of adjuvant anti-programmed death-1 monotherapy with nivolumab or pembrolizumab, and dabrafenib plus trametinib has recently set a new landmark in the treatment of stage III melanoma. Now, clinical trials have shown that immune checkpoint blockade can be performed in a neoadjuvant setting, an approach established as a standard therapeutic approach for other tumour entities such as breast cancer. Recent studies suggest that a pathological response achieved by neoadjuvant immunotherapy is associated with long-term tumour control and that short neoadjuvant application of checkpoint inhibitors may be superior to adjuvant therapy. Most recently, neoadjuvant ipilimumab plus nivolumab in stage III melanoma was reported. With two courses of dose-optimized ipilimumab (1 mg kg⁻¹) combined with nivolumab (3 mg kg⁻¹), pathological responses were observed in 77% of patients, while only 20% of patients experienced grade 3 or 4 adverse events. However, the neoadjuvant trials employing combined immune checkpoint blockade conducted so far have excluded patients with in transit metastases, a common finding in stage III melanoma. Here we report four patients with in transit metastases or an advanced primary tumour who have been treated with neoadjuvant ipilimumab plus nivolumab according to the OpACIN-neo trial scheme (arm B). All patients achieved radiological disease control and a pathological response. None of the patients has relapsed so far. Linked Comment:   Blankenstein and van Akkooi. Br J Dermatol 2020; 183 :421–422 .     

Fibroblast growth factor receptors as therapeutic targets in human melanoma: synergism with BRAF inhibition

Cutaneous melanoma is a tumor with rising incidence and a very poor prognosis at the disseminated stage. Melanomas are characterized by frequent mutations in BRAF and also by overexpression of fibroblast growth factor 2 (FGF2), offering opportunities for therapeutic intervention. We investigated inhibition of FGF signaling and its combination with dacarbazine or BRAF inhibitors as an antitumor strategy in melanoma. The majority of melanoma cell lines displayed overexpression of FGF2 but also FGF5 and FGF18 together with different isoforms of FGF receptors (FGFRs) 1-4. Blockade of FGF signals with dominant-negative receptor constructs (dnFGFR1, 3, or 4) or small-molecule inhibitors (SU5402 and PD166866) reduced melanoma cell proliferation, colony formation, as well as anchorage-independent growth, and increased apoptosis. DnFGFR constructs also significantly inhibited tumor growth in vivo. Combination of FGF inhibitors with dacarbazine showed additive or antagonistic effects, whereas synergistic drug interaction was observed when combining FGFR inhibition with the multikinase/BRAF inhibitor sorafenib or the V600E mutant-specific BRAF inhibitor RG7204. In conclusion, FGFR inhibition has antitumor effects against melanoma cells in vitro and in vivo. Combination with BRAF inhibition offers a potential for synergistic antimelanoma effects and represents a promising therapeutic strategy against advanced melanoma.