Phase I clinical trial of combination imatinib and ipilimumab in patients with advanced malignancies

Clinical and Biomarker Analysis of a Phase I/II Study of PDR001 Plus Imatinib for Advanced Treatment-Refractory Gastrointestinal Stromal Tumors

PURPOSE

In this phase Ib/II study, we aimed to evaluate the safety and efficacy of PDR001, an anti-PD1 antibody, in combination with imatinib in patients with treatment-refractory gastrointestinal stromal tumor (GIST).

PATIENTS AND METHODS

Patients with advanced GIST whose disease had progressed on imatinib, sunitinib, and regorafenib were enrolled. In phase Ib, the standard 3 + 3 dose escalation scheme was applied. Intravenous administration of PDR001 at 400 mg for every 4 weeks plus imatinib (300 and 400 mg daily for dose levels I and II, respectively) was given. The primary outcome for phase II was the disease control rate at 12 weeks. Exploratory biomarker analysis was performed based on PDL1 IHC, next-generation sequencing, and multiplexed IHC.

RESULTS

No dose-limiting toxicity was observed in the phase Ib part (n = 10), and dose level II was selected as the recommended phase II dose. In the phase II part (n = 29), there was no objective response, and the disease control rate at 12 weeks was 37.9%, not meeting the primary efficacy endpoint. For patients in phase Ib-dose level II and phase II (n = 36), the median progression-free survival (PFS) and overall survival were 2.3 and 9.5 months, respectively. The most common grade 3 to 4 adverse event was anemia. Exploratory biomarker analysis indicated that a higher CD8+ T-cell density was associated with a favorable PFS but to a limited degree. Tumor mutational burden and PDL1 were not associated with better PFS.

CONCLUSIONS

In patients with treatment-refractory GIST, PDR001 in combination with imatinib was generally tolerable, but it was not effective.

Novel biomolecules in targeted cancer therapy: a new approach towards precision medicine

Cancer is a major threat to human life around the globe, and the discovery of novel biomolecules continue to be an urgent therapeutic need that is still unmet. Precision medicine relies on targeted therapeutic strategies. Researchers are better equipped to develop therapies that target proteins as they understand more about the genetic alterations and molecules that cause progression of cancer. There has been a recent diversification of the sorts of targets exploited in treatment. Therapeutic antibody and biotechnology advancements enabled curative treatments to reach previously inaccessible sites. New treatment strategies have been initiated for several undruggable targets. The application of tailored therapy has been proven to have efficient results in controlling cancer progression. Novel biomolecules like SMDCs, ADCs, mABs, and PROTACS has gained vast attention in the recent years. Several studies have shown that using these novel technology helps in reducing the drug dosage as well as to overcome drug resistance in different cancer types. Therefore, it is crucial to fully untangle the mechanism and collect evidence to understand the significance of these novel drug targets and strategies. This review article will be discussing the importance and role of these novel biomolecules in targeted cancer therapies.

Biomarkers for immune checkpoint inhibition in sarcomas - are we close to clinical implementation?

Sarcomas are a group of diverse and complex cancers of mesenchymal origin that remains poorly understood. Recent developments in cancer immunotherapy have demonstrated a potential for better outcomes with immune checkpoint inhibition in some sarcomas compared to conventional chemotherapy. Immune checkpoint inhibitors (ICIs) are key agents in cancer immunotherapy, demonstrating improved outcomes in many tumor types. However, most patients with sarcoma do not benefit from treatment, highlighting the need for identification and development of predictive biomarkers for response to ICIs. In this review, we first discuss United States (US) Food and Drug Administration (FDA)-approved and European Medicines Agency (EMA)-approved biomarkers, as well as the limitations of their use in sarcomas. We then review eight potential predictive biomarkers and rationalize their utility in sarcomas. These include gene expression signatures (GES), circulating neutrophil-to-lymphocyte ratio (NLR), indoleamine 2,3-dioxygenase (IDO), lymphocyte activation gene 3 (LAG-3), T cell immunoglobin and mucin domain-containing protein 3 (TIM-3), TP53 mutation status, B cells, and tertiary lymphoid structures (TLS). Finally, we discuss the potential for TLS as both a predictive and prognostic biomarker for ICI response in sarcomas to be implemented in the clinic.

Drug Repurposing to Circumvent Immune Checkpoint Inhibitor Resistance in Cancer Immunotherapy

Immune checkpoint inhibitors (ICI) have achieved unprecedented clinical success in cancer treatment. However, drug resistance to ICI therapy is a major hurdle that prevents cancer patients from responding to the treatment or having durable disease control. Drug repurposing refers to the application of clinically approved drugs, with characterized pharmacological properties and known adverse effect profiles, to new indications. It has also emerged as a promising strategy to overcome drug resistance. In this review, we summarized the latest research about drug repurposing to overcome ICI resistance. Repurposed drugs work by either exerting immunostimulatory activities or abolishing the immunosuppressive tumor microenvironment (TME). Compared to the de novo drug design strategy, they provide novel and affordable treatment options to enhance cancer immunotherapy that can be readily evaluated in the clinic. Biomarkers are exploited to identify the right patient population to benefit from the repurposed drugs and drug combinations. Phenotypic screening of chemical libraries has been conducted to search for T-cell-modifying drugs. Genomics and integrated bioinformatics analysis, artificial intelligence, machine and deep learning approaches are employed to identify novel modulators of the immunosuppressive TME.

Advances in immunology and immunotherapy for mesenchymal gastrointestinal cancers

Mesenchymal gastrointestinal cancers are represented by the gastrointestinal stromal tumors (GISTs) which occur throughout the whole gastrointestinal tract, and affect human health and economy globally. Curative surgical resections and tyrosine kinase inhibitors (TKIs) are the main managements for localized GISTs and recurrent/metastatic GISTs, respectively. Despite multi-lines of TKIs treatments prolonged the survival time of recurrent/metastatic GISTs by delaying the relapse and metastasis of the tumor, drug resistance developed quickly and inevitably, and became the huge obstacle for stopping disease progression. Immunotherapy, which is typically represented by immune checkpoint inhibitors (ICIs), has achieved great success in several solid tumors by reactivating the host immune system, and been proposed as an alternative choice for GIST treatment. Substantial efforts have been devoted to the research of immunology and immunotherapy for GIST, and great achievements have been made. Generally, the intratumoral immune cell level and the immune-related gene expressions are influenced by metastasis status, anatomical locations, driver gene mutations of the tumor, and modulated by imatinib therapy. Systemic inflammatory biomarkers are regarded as prognostic indicators of GIST and closely associated with its clinicopathological features. The efficacy of immunotherapy strategies for GIST has been widely explored in pre-clinical cell and mouse models and clinical experiments in human, and some patients did benefit from ICIs. This review comprehensively summarizes the up-to-date advancements of immunology, immunotherapy and research models for GIST, and provides new insights and perspectives for future studies.

Exploring the Dynamic Crosstalk between the Immune System and Genetics in Gastrointestinal Stromal Tumors

Gastrointestinal Stromal Tumors (GISTs) represent a paradigmatic model of oncogene addiction. Despite the well-known impact of the mutational status on clinical outcomes, we need to expand our knowledge to other factors that influence behavior heterogeneity in GIST patients. A growing body of studies has revealed that the tumor microenvironment (TME), mostly populated by tumor-associated macrophages (TAMs) and lymphocytes (TILs), and stromal differentiation (SD) have a significant impact on prognosis and response to treatment. Interestingly, even though the current knowledge of the role of immune response in this setting is still limited, recent pre-clinical and clinical data have highlighted the relevance of the TME in GISTs, with possible implications for clinical practice in the near future. Moreover, the expression of immune checkpoints, such as PD-L1, PD-1, and CTLA-4, and their relationship to the clinical phenotype in GIST are emerging as potential prognostic biomarkers. Looking forward, these variables related to the underlying tumoral microenvironment in GIST, though limited to still-ongoing trials, might lead to the potential use of immunotherapy, alone or in combination with targeted therapy, in advanced TKI-refractory GISTs. This review aims to deepen understanding of the potential link between mutational status and the immune microenvironment in GIST.

Targeting the tumor stroma for cancer therapy

Tumors are comprised of both cancer cells and surrounding stromal components. As an essential part of the tumor microenvironment, the tumor stroma is highly dynamic, heterogeneous and commonly tumor-type specific, and it mainly includes noncellular compositions such as the extracellular matrix and the unique cancer-associated vascular system as well as a wide variety of cellular components including activated cancer-associated fibroblasts, mesenchymal stromal cells, pericytes. All these elements operate with each other in a coordinated fashion and collectively promote cancer initiation, progression, metastasis and therapeutic resistance. Over the past few decades, numerous studies have been conducted to study the interaction and crosstalk between stromal components and neoplastic cells. Meanwhile, we have also witnessed an exponential increase in the investigation and recognition of the critical roles of tumor stroma in solid tumors. A series of clinical trials targeting the tumor stroma have been launched continually. In this review, we introduce and discuss current advances in the understanding of various stromal elements and their roles in cancers. We also elaborate on potential novel approaches for tumor-stroma-based therapeutic targeting, with the aim to promote the leap from bench to bedside.

Latest Advances in the Management of Pediatric Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumor is the most common mesenchymal neoplasm of the gastrointestinal tract, usually found in elderly adults. It is infrequent among pediatric patients and usually differs biologically from adult-type diseases presenting mutations of KIT and PDGFR genes. In this population, more frequent is the wild-type GIST possessing SDH, TRK, RAS, NF1 mutations, among others. Both tumor types require individualized treatment with kinase inhibitors that are still being tested in the pediatric population due to the different neoplasm biology. We review the latest updates to the management of pediatric gastrointestinal tumors with a particular focus on the advances in molecular biology of the disease that enables the definition of possible resistance. Emerging treatment with kinase inhibitors that could serve as targeted therapy is discussed, especially with multikinase inhibitors of higher generation, the effectiveness of which has already been confirmed in the adult population.

Prognostic value of receptor tyrosine kinases in malignant melanoma patients: A systematic review and meta-analysis of immunohistochemistry

Background

Substantial evidence suggests that receptor tyrosine kinases (RTKs) are overexpressed in tumors; however, few studies have focused on the prognostic value of RTKs in melanoma.

Objectives

The objective of this study is to evaluate the association between overexpression of RTKs and survival in melanoma patients based on immunohistochemistry (IHC) analysis.

Methods

Our review is registered on PROSPERO (http://www.crd.york.ac.uk/PROSPERO), registration number CRD42021261460. Seven databases were searched, and data were extracted. We used IHC to measure the association between overexpression of RTKs and overall survival (OS), disease-free survival (DFS), progression-free survival (PFS), and clinicopathology in melanoma patients. Pooled analysis was conducted to assess the differences between Hazard Ratios along with 95% confidence intervals.

Results

Of 5,508 publications examined following the database search, 23 publications were included in this study, which included data from a total of 2,072 patients. Vascular endothelial growth factor receptor 2 (VEGF-R2) overexpression was associated with worse OS and DFS in melanoma. Furthermore, there was an association between OS and the expression of several RTKs, including epidermal growth factor receptor (EGFR), mesenchymal-epithelial transition factor (MET), vascular endothelial growth factor receptor 1 (VEGF-R1), and insulin-like growth factor 1 receptor (IGF-1R). There were no significant correlations between EGFR overexpression and worse DFS or PFS. EGFR overexpression was associated with worse OS cutaneous and nasal melanoma, but not uveal melanoma. However, MET overexpression was related to worse OS in both cutaneous and uveal melanoma. Furthermore, EGFR overexpression was associated with a worse OS in Europe compared to other geographic areas. Moreover, EGFR and MET overexpression showed significant prognostic value in patients with the cut-off “≥10% staining”.

Conclusions

Our findings build concrete evidence that overexpression of RTKs is associated with poor prognosis and clinicopathology in melanoma, highlighting RTK expression has the potential to inform individualized combination therapies and accurate prognostic evaluation.

Integrated Antitumor Activities of Cellular Immunotherapy with CIK Lymphocytes and Interferons against KIT/PDGFRA Wild Type GIST

Gastrointestinal stromal tumors (GISTs) are rare, mesenchymal tumors of the gastrointestinal tract, characterized by either KIT or PDGFRA mutation in about 85% of cases. KIT/PDGFRA wild type gastrointestinal stromal tumors (wtGIST) account for the remaining 15% of GIST and represent an unmet medical need: their prevalence and potential medical vulnerabilities are not completely defined, and effective therapeutic strategies are still lacking. In this study we set a patient-derived preclinical model of wtGIST to investigate their phenotypic features, along with their susceptibility to cellular immunotherapy with cytokine-induced killer lymphocytes (CIK) and interferons (IFN). We generated 11 wtGIST primary cell lines (wtGISTc). The main CIK ligands (MIC A/B; ULBPs), along with PD-L1/2, were expressed by wtGISTc and the expression of HLA-I molecules was preserved. Patient-derived CIK were capable of intense killing in vitro against wtGISTc resistant to both imatinib and sunitinib. We found that CIK produce a high level of granzyme B, IFNα and IFNγ. CIK-conditioned supernatant was responsible for part of the observed tumoricidal effect, along with positive bystander modulatory activities enhancing the expression of PD-L1/2 and HLA-I molecules. IFNα, but not In, had direct antitumor effects on 50% (4/8) of TKI-resistant wtGISTc, positively correlated with the tumor expression of IFN receptors. wtGIST cells that survived IFNα were still sensitive to CIK immunotherapy. Our data support the exploration of CIK immunotherapy in clinical studies for TKI-resistant wtGIST, proposing reevaluation for IFNα within this challenging setting.

Oncogenic KIT Induces Replication Stress and Confers Cell Cycle Checkpoint Vulnerability in Melanoma

Acral and mucosal melanomas arise from sun-protected sites, disproportionately impact darker-skinned individuals, and exact higher mortality than common types of cutaneous melanoma. Genetically, acral and mucosal melanomas harbor more alterations of KIT than typical cutaneous melanomas. Because KIT-mutated melanomas remain largely treatment resistant, we set out to create a faithful murine KIT-driven allograft model to define newer therapeutic strategies. Using the prevalent human KITK642E activating mutation, the murine mKITK641E cellular avatars show features of transformation in vitro and tumorigenicity in immunocompetent C57BL/6J mice. mKITK641E cells proliferate more rapidly, exhibit greater chromosomal aberrations, and sustain three-dimensional spheroid expansion and aggressive tumor growth in C57BL/6J mice compared with their vector-controlled cells. We further verified the functional dependence of these cells on KITK641E with both genetic and pharmacologic suppression. Using these cells, we performed a screen of 199 kinase inhibitors and identified a selective vulnerability to Chk1/ATR inhibition in the KITK641E-activated cells. Mechanistically, we subsequently showed that KITK641E induces a significantly increased level of replication stress compared with murine vector‒controlled cells. These results showcase an allograft model of human KIT-driven melanomas, which uncovered an unappreciated role for replication stress in KIT melanomagenesis and implicated a possible therapeutic strategy with Chk1/ATR inhibitors.

Gastrointestinal Stromal Tumor

Over the past 20 years, gastrointestinal stromal tumor (GIST) has evolved into an increasingly complex clinical entity with ever more challenges. While surgical resection is the gold standard, advancements in genetic testing, therapeutic options, immunotherapy, and management of metastatic disease necessitate a comprehensive, multimodal approach for these tumors. This chapter highlights the importance of genomic testing of GIST, the use of neoadjuvant and adjuvant therapy for localized disease, surgical principles for GIST, as well as current and new approaches for addressing metastatic disease.

Imatinib Mesylate Exerted Antitumor Effect by Promoting Infiltration of Effector T Cells in Tumor

Imatinib mesylate is a potent tyrosine kinase inhibitor that may induce immunological effects, such as inhibition of immune suppressive cells; but, how it modulates the immune system remains to be completely elucidated. In this study, we showed that cell proliferation of CT26 colon cancer and Lewis lung carcinoma (3LL) lung cancer cells was not inhibited by imatinib in vitro, although its administration significantly suppressed the growth of CT26, but not 3LL, subcutaneous tumors, and prolonged survival in CT26 tumor-bearing mice. Further, we examined the expression of immune cell-related molecules in the tumors to elucidate the differences in imatinib-mediated antitumor effects between CT26 and 3LL tumors. The nCounter assay showed that the expression of CD8 and CD8⁺ T cell-recruiting chemokine genes was significantly elevated in imatinib-treated CT26 tumors than that in control tumors; however, the gene expression remained unchanged in imatinib-treated or control 3LL tumors. Furthermore, frequency of interferon-γ⁺ (IFN-γ⁺) CD8⁺ T cells was increased in imatinib-treated CT26 tumors than control tumors, indicating induction of antitumor immunity by imatinib. The analysis indicates that imatinib promotes infiltration of effector T cells in tumors by upregulating expression of cytokines that recruit CD8⁺ T cells in the tumor microenvironment, which may lead to a strong antitumor effect.

Immunotherapies for Pediatric Solid Tumors: A Targeted Update

There are encouraging signs in our collective progress to leverage the immune system to treat pediatric cancers. Here, we summarize interim successes in cancer immunotherapy and opportunities to translate from the adult world to pediatrics, and highlight challenges that could benefit from additional development, focusing on solid tumors. Just a decade ago, other than antibodies targeting disialoganglioside (GD2) in neuroblastoma, pediatric cancer immunotherapy was mostly relegated to obscure preclinical studies in a few academic labs. Today there are numerous clinical trials of a variety of antibody, cellular, gene, and viral therapies and vaccines designed to either promote antitumor immunity or specifically attack validated immunotherapy targets. Understanding those targets and their pediatric relevance is paramount. While much work is underway to evaluate the utility of numerous immunologic targets, the lack of regulatory approvals is emblematic of the challenges that remain. Herein we focus our review on the most promising targeted immunotherapies in clinical trials for children.

Clinical and Prognostic Significance of Tumor-Infiltrating CD8+ T Cells and PD-L1 Expression in Primary Gastrointestinal Stromal Tumors

Purpose

Immunotherapy for gastrointestinal stromal tumors (GISTs) remains a clinical challenge. The present study aimed to explore the clinical and prognostic significance of immune cell infiltration and PD-L1 expression in GISTs.

Methods

A total of 507 clinical tissue specimens of primary GISTs were collected for immunohistochemical analysis of immune cell infiltration and PD-L1 expression. Influencing factors of survival were evaluated by Kaplan–Meier analysis. Univariate and multivariate analyses were performed using the Cox regression model.

Results

There were significant differences in sex, tumor location, size, mitotic index, NIH risk grade, and cell morphology between different gene mutation types of GISTs. Immune cell infiltration in GISTs mainly involved macrophages and T cells. PD-1 was expressed in 48.5% of the tissue specimens, and PD-L1 expression was detected in 46.0% of the samples. PD-L1 expression was negatively correlated with the tumor size and mitotic index but positively correlated with the number of CD8+ T cells. There were significant differences in the number of CD8+ T cells between different gene mutation types. Wild type-mutant GISTs were enriched with CD8+ T cells as compared with KIT- and PDGFRA-mutant GISTs. The number of CD8+ T cells was higher in non-gastric GISTs. PD-L1 and CD8+ T cells were independent predictors for better relapse-free survival of GISTs.

Conclusions

PD-L1 expression is a predictive biomarker for better prognosis of GISTs. Non-gastric GIST patients with wild-type mutations may be the beneficiaries of PD-1/PD-L1 inhibitors.

Melanoma Targeted Therapies beyond BRAF-Mutant Melanoma: Potential Druggable Mutations and Novel Treatment Approaches

Melanomas exhibit the highest rate of somatic mutations among all different types of cancers (with the exception of BCC and SCC). The accumulation of a multimode of mutations in the driver oncogenes are responsible for the proliferative, invasive, and aggressive nature of melanomas. High-resolution and high-throughput technology has led to the identification of distinct mutational signatures and their downstream alterations in several key pathways that contribute to melanomagenesis. This has enabled the development of individualized treatments by targeting specific molecular alterations that are vital for cancer cell survival, which has resulted in improved outcomes in several cancers, including melanomas. To date, BRAF and MEK inhibitors remain the only approved targeted therapy with a high level of evidence in BRAFV600E/K mutant melanomas. The lack of approved precision drugs in melanomas, relative to other cancers, despite harboring one of the highest rates of somatic mutations, advocates for further research to unveil effective therapeutics. In this review, we will discuss potential druggable mutations and the ongoing research of novel individualized treatment approaches targeting non-BRAF mutations in melanomas.

Molecular Pathogenesis of Gastrointestinal Stromal Tumor: A Paradigm for Personalized Medicine

Over the past three to four decades, the molecular pathogenesis of gastrointestinal stromal tumors (GISTs) has been elucidated in great detail. In this review, we discuss the biological genesis of GISTs, identification of the various primary activating driver mutations (focusing on KIT and PDGFRA), oncogene addiction and targeted therapies with imatinib and other tyrosine kinase inhibitors, and the subsequent characterization of the various mechanisms of drug resistance. We illustrate how GIST has become a quintessential paradigm for personalized medicine. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease, Volume 17 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Treatment-Related Serious Adverse Events of Immune Checkpoint Inhibitors in Clinical Trials: A Systematic Review

Background

Immune Checkpoint Inhibitors (ICI) have been progressively used in cancer treatment and produced unique toxicity profiles. This systematic review aims to comprehend the patterns and occurrence of treatment-related adverse events (trAEs) based on ICI.

Methods

PICOS/PRISMA methods were used to identify published English-language on PubMed, Web of Science, and Scopus from 2015 to 2020. Published clinical trials on ICI monotherapy, combined ICIs, and ICI plus other treatment with tabulated data on grade≥3 trAEs were included. Odds ratio (OR), χ² tests were used to analyze for effect size and associations.

Results

This review included 145 clinical trials involving 21786 patients. Grade 3-5 trAEs were more common with ICI when they were plused with other treatments compared with ICI monotherapy(54.3% versus 17.7%, 46.1%, p<0.05). Grade 3-5 trAEs were also more common with CTLA-4 mAbs compared with anti-PD-1 and anti-PD-L1 (34.2% versus 15.1%, 13.6%, p<0.05). Hyperthyroidism (OR 3.8, 95%CI 1.7–8.6), nausea (OR 3.7, 95%CI 2.5–5.3), diarrhea (OR 2.7, 95%CI 2.2–3.2), colitis (OR 3.4, 95%CI 2.7–4.3), ALT increase (OR 4.9, 95%CI 3.9–6.1), AST increase (OR 3.8, 95%CI 3.0–4.9), pruritus (OR 2.4, 95%CI 1.5–3.9), rash (OR 2.8, 95%CI 2.1–3.8), fatigue (OR 2.8, 95%CI 2.2–3.7), decreased appetite (OR 2.4, 95%CI 1.5–3.8), and hypophysitis (OR 2.0, 95%CI 1.2–3.3) were more frequent with combined ICIs. Diarrhea (OR 8.1, 95%CI 6.4–10.3), colitis (OR 12.2, 95%CI 8.7–17.1), ALT increase (OR 5.1, 95%CI 3.5–7.4), AST increase (OR 4.2, 95%CI 2.8–6.3), pruritus (OR 4.1, 95%CI 2.0–8.4), rash (OR 4.4, 95%CI 2.9–6.8), hypophysitis (OR 12.1, 95%CI 6.3–23.4) were more common with CTLA-4 mAbs; whereas pneumonitis (OR 4.7, 95% CI 2.1–10.3) were more frequent with PD-1 mAbs.

Conclusions

Different immune checkpoint inhibitors are associated with different treatment-related adverse events profiles. A comprehensive data in this systematic review will provide comprehensive information for clinicians.

Reversing Imatinib's Immunosuppressive Effects by Modulating Type I IFN Signaling

Signal pathway inhibition is a well-validated approach for treating cancers driven by activated kinases such as KIT. However, kinase inhibitors may make tumor cells less responsive to tumor immune surveillance and less sensitive to immunotherapies. In this issue, Liu and colleagues report that, in a mouse model, inhibition of oncogenic KIT in gastrointestinal stromal tumors reduces type I interferon (IFN) production and signaling, and the effectiveness of the immune system in controlling tumor growth. They were able to partially overcome the immunosuppressive effects of KIT inhibition using agonists of the type I IFN response, pointing the way toward intelligently combining kinase inhibitors and immune modulators for therapy.See article by Liu et al., p. 542.

RTK Inhibitors in Melanoma: From Bench to Bedside

MAPK (mitogen activated protein kinase) and PI3K/AKT (Phosphatidylinositol-3-Kinase and Protein Kinase B) pathways play a key role in melanoma progression and metastasis that are regulated by receptor tyrosine kinases (RTKs). Although RTKs are mutated in a small percentage of melanomas, several receptors were found up regulated/altered in various stages of melanoma initiation, progression, or metastasis. Targeting RTKs remains a significant challenge in melanoma, due to their variable expression across different melanoma stages of progression and among melanoma subtypes that consequently affect response to treatment and disease progression. In this review, we discuss in details the activation mechanism of several key RTKs: type III: c-KIT (mast/stem cell growth factor receptor); type I: EGFR (Epidermal growth factor receptor); type VIII: HGFR (hepatocyte growth factor receptor); type V: VEGFR (Vascular endothelial growth factor), structure variants, the function of their structural domains, and their alteration and its association with melanoma initiation and progression. Furthermore, several RTK inhibitors targeting the same receptor were tested alone or in combination with other therapies, yielding variable responses among different melanoma groups. Here, we classified RTK inhibitors by families and summarized all tested drugs in melanoma indicating the rationale behind the use of these drugs in each melanoma subgroups from preclinical studies to clinical trials with a specific focus on their purpose of treatment, resulted effect, and outcomes.

Thinking Small: Small Molecules as Potential Synergistic Adjuncts to Checkpoint Inhibition in Melanoma

Metastatic melanoma remains the deadliest form of skin cancer. Immune checkpoint inhibition (ICI) immunotherapy has defined a new age in melanoma treatment, but responses remain inconsistent and some patients develop treatment resistance. The myriad of newly developed small molecular (SM) inhibitors of specific effector targets now affords a plethora of opportunities to increase therapeutic responses, even in resistant melanoma. In this review, we will discuss the multitude of SM classes currently under investigation, current and prospective clinical combinations of ICI and SM therapies, and their potential for synergism in melanoma eradication based on established mechanisms of immunotherapy resistance.

Gastrointestinal Stromal Tumors (GISTs): Novel Therapeutic Strategies with Immunotherapy and Small Molecules

Gastrointestinal stromal tumors (GISTs) are the most common types of malignant mesenchymal tumors in the gastrointestinal tract, with an estimated incidence of 1.5/100.000 per year and 1–2% of gastrointestinal neoplasms. About 75–80% of patients have mutations in the KIT gene in exons 9, 11, 13, 14, 17, and 5–10% of patients have mutations in the platelet-derived growth factor receptor a (PDGFRA) gene in exons 12, 14, 18. Moreover, 10–15% of patients have no mutations and are classified as wild type GIST. The treatment for metastatic or unresectable GISTs includes imatinib, sunitinib, and regorafenib. So far, GIST therapies have raised great expectations and offered patients a better quality of life, but increased pharmacological resistance to tyrosine kinase inhibitors is often observed. New treatment options have emerged, with ripretinib, avapritinib, and cabozantinib getting approvals for these tumors. Nowadays, immune checkpoint inhibitors form a new landscape in cancer therapeutics and have already shown remarkable responses in various tumors. Studies in melanoma, non-small-cell lung cancer, and renal cell carcinoma are very encouraging as these inhibitors have increased survival rates. The purpose of this review is to present alternative approaches for the treatment of the GIST patients, such as combinations of immunotherapy and novel inhibitors with traditional therapies (tyrosine kinase inhibitors).

Unleashing the power of immunotherapy and targeted therapy combinations: Advancing cancer care or discovering unknown toxicities?

Objective

The purpose of this review was to summarize the triumphs and pitfalls of tyrosine kinase inhibitor (TKI) and immune checkpoint inhibitor (ICI) combinations. Data sources: A literature review of PubMed was conducted and studies were included if they were classified as a clinical trial and assessed TKI and ICI combinations for solid tumor malignancies. Dates of literature search included January 1, 1988 through September 22, 2019. Data summary: In the past decade, TKI and ICI monotherapy strategies have changed the management of many advanced solid tumors through their unique mechanisms of action. Preclinical data suggests that TKIs may be able to sensitize tumors to ICI therapy via direct and indirect pathways; however, optimal mechanisms to support various TKI and ICI combinations have yet to be determined. The FDA recently approved TKI and ICI combinations for renal cell carcinoma, endometrial carcinoma, and melanoma. Several other tumor types currently have TKI and immunotherapy combinations under investigation with mixed results. Dual therapy with TKIs and immunotherapy have the potential to be synergistic and improve patient outcomes; however, careful consideration will need to be taken in regard to what TKI and immunotherapy are combined.

Conclusions

Future research will be needed to determine appropriate sequencing of TKIs and ICIs after progression on combination therapy. Continued research is necessary to determine optimal dual TKI and immunotherapy options.

New drugs in gastrointestinal stromal tumors

PURPOSE OF REVIEW

Tyrosine kinase inhibitors (TKIs) are the backbone for advanced gastrointestinal stromal tumor (GIST) treatment. The increasing knowledge concerning the structure and the changing conformational status because of some mutations in KIT and PDGFRα, allowed the development of new efficient compounds, with the main goal to overcome resistance in GIST. This review summarizes the latest developments in the treatment of GIST patients.

RECENT FINDINGS

Amongst the several TKIs currently being studied in GIST, ripretinib, avapritinib and crenolanib had shown promising potent activity in preclinical studies and clinical trials. Ripretinib is a type II inhibitor that exerts its main action in the switch pocket of the activation loop, by mimicking the inhibition exerted by the regulatory region in this domain. Ripretinib is considered the new standard in the fourth line in advanced GIST. Avapritinib is a type I inhibitor synthesized to exerts its activity in the active conformation of the activation loop of KIT and PDFGRα. The relevant activity reported with avapritinib in patients carrying the D842 v mutation represents, for first time, an active therapeutic option in this resistant mutant. Crenolanib is a type I selective inhibitor of PDGFRα-resistant mutants, mainly D842 V, which is currently under clinical trial.

SUMMARY

New potent TKIs are being approved, adding value to the already three registered drugs. Other agents, such as MEK inhibitors, immunotherapy and TRK-targeted therapy are potential new options in specific subsets of GIST patients.

Tumor microenvironment as a therapeutic target in cancer

Tumor microenvironment denotes the non-cancerous cells and components presented in the tumor, including molecules produced and released by them. The constant interactions between tumor cells and the tumor microenvironment play decisive roles in tumor initiation, progression, metastasis, and response to therapies. The tumor microenvironment as a therapeutic target in cancer has attracted great research and clinical interest. Here we summarize the current progress in targeting the tumor microenvironment in both drug development and clinical trials; highlight challenges in targeting the tumor microenvironment to achieve therapeutic efficacy; explore new technologies and approaches to better decipher the tumor microenvironment; and discuss strategies to intervene in the pro-tumor microenvironment and maximize therapeutic benefits.

Tumor genotype, location, and malignant potential shape the immunogenicity of primary untreated gastrointestinal stromal tumors

Intratumoral immune infiltrate was recently reported in gastrointestinal stromal tumors (GISTs). However, the tumor-intrinsic factors that dictate GIST immunogenicity are still largely undefined. To shed light on this issue, a large cohort (82 samples) of primary untreated GISTs, representative of major clinicopathological variables, was investigated by an integrated immunohistochemical, transcriptomic, and computational approach. Our results indicate that tumor genotype, location, and malignant potential concur to shape the immunogenicity of primary naive GISTs. Immune infiltration was greater in overt GISTs compared with that in lesions with limited malignant potential (miniGISTs), in KIT/PDGFRA-mutated tumors compared with that in KIT/PDGFRA WT tumors, and in PDGFRA-mutated compared with KIT-mutated GISTs. Within the KIT-mutated subset, a higher degree of immune colonization was detected in the intestine. Immune hot tumors showed expression patterns compatible with a potentially proficient but curbed antigen-specific immunity, hinting at sensitivity to immunomodulatory treatments. Poorly infiltrated GISTs, primarily KIT/PDGFRA WT intestinal tumors, showed activation of Hedgehog and WNT/β-catenin immune excluding pathways. This finding discloses a potential therapeutic vulnerability, as the targeting of these pathways might prove effective by both inhibiting pro-oncogenic signals and fostering antitumor immune responses. Finally, an intriguing anticorrelation between immune infiltration and ANO1/DOG1 expression was observed, suggesting an immunomodulatory activity for anoctamin-1.

Will Next-Generation Immunotherapy Overcome the Intrinsic Diversity and Low Immunogenicity of Sarcomas to Improve Clinical Benefit?

Sarcomas are a rare type of a heterogeneous group of tumours arising from mesenchymal cells that form connective tissues. Surgery is the most common treatment for these tumours, but additional neoadjuvant or adjuvant chemotherapy or radiation therapies may be necessary. Unfortunately, a significant proportion of patients treated with conventional therapies will develop metastatic disease that is resistant to therapies. Currently, there is an urgent need to develop more effective and durable therapies for the treatment of sarcomas. In recent years immunotherapies have revolutionised the treatment of a variety of cancers by restoring patient anti-tumour immune responses or through the adoptive infusion of immune effectors able to kill and eliminate malignant cells. The clinicopathologic and genetic heterogeneity of sarcomas, together with the generally low burden of somatic mutations potentially generating neoantigens, are currently limited to broad application of immunotherapy for patients with sarcomas. Nevertheless, a better understanding of the microenvironmental factors hampering the efficacy of immunotherapy and the identification of new and suitable therapeutic targets may help to overcome current limitations. Moreover, the recent advances in the development of immunotherapies based on the direct exploitation or targeting of T cells and/or NK cells may offer new opportunities to improve the treatment of sarcomas, particularly those showing recurrence or resistance to standard of care treatments.

Emerging role of metabolic reprogramming in tumor immune evasion and immunotherapy

Mounting evidence has revealed that the therapeutic efficacy of immunotherapies is restricted to a small portion of cancer patients. A deeper understanding of how metabolic reprogramming in the tumor microenvironment (TME) regulates immunity remains a major challenge to tumor eradication. It has been suggested that metabolic reprogramming in the TME may affect metabolism in immune cells and subsequently suppress immune function. Tumor cells compete with infiltrating immune cells for nutrients and metabolites. Notably, the immunosuppressive TME is characterized by catabolic and anabolic processes that are critical for immune cell function, and elevated inhibitory signals may favor cancer immune evasion. The major energy sources that supply different immune cell subtypes also undergo reprogramming. We herein summarize the metabolic remodeling in tumor cells and different immune cell subtypes and the latest advances underlying the use of metabolic checkpoints in antitumor immunotherapies. In this context, targeting both tumor and immune cell metabolic reprogramming may enhance therapeutic efficacy.

Therapeutic Development of Immune Checkpoint Inhibitors

Immune checkpoint blockade (ICB) has been proven to be an effective strategy for enhancing the effector activity of anti-tumor T cells, and checkpoint blockers targeting CTLA-4, PD-1, and PD-L1 have displayed strong and durable clinical responses in certain cancer patients. The new hope brought by ICB therapy has led to the boost in therapeutic development of ICBs in recent years. Nonetheless, the therapeutic efficacy of ICBs varies substantially among cancer types and patients, and only a proportion of cancer patients could benefit from ICBs. The emerging targets and molecules for enhancing anticancer immunity may bring additional therapeutic opportunities for cancer patients. The current challenges in the ICB therapy have been discussed, aimed to provide further strategies for maximizing the efficacy of ICB therapy.

Current Advances in the Treatment of BRAF-Mutant Melanoma

Melanoma is the most lethal form of skin cancer. Melanoma is usually curable with surgery if detected early, however, treatment options for patients with metastatic melanoma are limited and the five-year survival rate for metastatic melanoma had been 15-20% before the advent of immunotherapy. Treatment with immune checkpoint inhibitors has increased long-term survival outcomes in patients with advanced melanoma to as high as 50% although individual response can vary greatly. A mutation within the MAPK pathway leads to uncontrollable growth and ultimately develops into cancer. The most common driver mutation that leads to this characteristic overactivation in the MAPK pathway is the B-RAF mutation. Current combinations of BRAF and MEK inhibitors that have demonstrated improved patient outcomes include dabrafenib with trametinib, vemurafenib with cobimetinib or encorafenib with binimetinib. Treatment with BRAF and MEK inhibitors has met challenges as patient responses began to drop due to the development of resistance to these inhibitors which paved the way for development of immunotherapies and other small molecule inhibitor approaches to address this. Resistance to these inhibitors continues to push the need to expand our understanding of novel mechanisms of resistance associated with treatment therapies. This review focuses on the current landscape of how resistance occurs with the chronic use of BRAF and MEK inhibitors in BRAF-mutant melanoma and progress made in the fields of immunotherapies and other small molecules when used alone or in combination with BRAF and MEK inhibitors to delay or circumvent the onset of resistance for patients with stage III/IV BRAF mutant melanoma.

[Wild-type gastroinestinal stromal tumors]

Gastrointestinal stromal tumors (GIST) are the most common non-epithelial tumors of the gastrointestinal tract. Wild-type GISTs (WT-GIST) consist of a rare heterogeneous group characterized by the lack of activating mutations in the tyrosine kinase receptor (Kit) and/or platelet derived growth factor receptor A (PDGFRA). However, WT-GIST is characterized by other genomic alterations, including dehydrogenase succinate (SDH) deficiency or mutations in the Ras pathway. Recent studies have reported many mutations in others genes that may be incriminated in the development of WT-GISTs. Moreover, WT-GIST is frequently associated with hereditary cancer syndromes such as the Carney Triad and Type 1 Neurofibromatosis (NF1). WT-GIST affects usually young and pediatric patients. Most WT-GIST subtypes are insensitive to imatinib; therefore, their therapeutic management is somewhat different from usual GISTs. This review resumes the molecular and therapeutic features of this rare entity.

Comprehensive review into the challenges of gastrointestinal tumors in the Gulf and Levant countries

Although gastrointestinal stromal tumors (GISTs) are rare, with an incidence of 1/100000 per year, they are the most common sarcomas in the peritoneal cavity. Despite considerable progress in the diagnosis and treatment of GIST, about half of all patients are estimated to experience recurrence. With only two drugs, sunitinib and regorafenib, approved by the Food and Drug Administration, selecting treatment options after imatinib failure and coordinating multidisciplinary care remain challenging. In addition, physicians across the Middle East face some additional and unique challenges such as lack of published local data from clinical trials, national disease registries and regional scientific research, limited access to treatment, lack of standardization of care, and limited access to mutational analysis. Although global guidelines set a framework for the management of GIST, there are no standard local guidelines to guide clinical practice in a resource-limited environment. Therefore, a group of 11 experienced medical oncologists from across the Gulf and Levant region, part of the Rare Tumors Gastrointestinal Group, met over a period of one year to conduct a narrative review of the management of GIST and to describe regional challenges and gaps in patient management as an essential step to proposing local clinical practice recommendations.

Durable tumor regression in highly refractory metastatic KIT/PDGFRA wild-type GIST following treatment with nivolumab

Gastrointestinal stromal tumor (GIST) is a devastating disease, especially in the setting of metastasis. The natural progression of GIST has been significantly altered by the development of small molecule tyrosine kinase inhibitors (TKIs), including imatinib, sunitinib, and regorafenib, all of which are FDA approved. However, TKIs are not always well-tolerated, and the refractory disease continues to be a problem. For these reasons, alternative treatments are needed. In this report, we discuss a patient with metastatic wild-type (WT) GIST refractory to multiple TKIs, but with a durable clinical response to the anti-programmed cell death protein 1 (PD-1) antibody, nivolumab. This report suggests that continued research evaluating checkpoint inhibitors in GIST is warranted.

Diarylamides in anticancer drug discovery: A review of pre-clinical and clinical investigations

Several diarylamide compounds have been highlighted as potential anticancer agents. Among them, imatinib, dasatinib, and nilotinib have been marketed for treatment of chronic myeloid leukemia (CML). CML is a cancer type that originates in specific cells in bone marrow and is considered as life-threating disease. Imatinib is the first generation of tyrosine kinase inhibitor (TKI) to be approved for treatment of CML. Second generation drugs, dasatinib and nilotinib, were introduced for patients that are resistant or intolerant to imatinib therapy. Second generation drugs induce faster responses with fewer side effects when compared to imatinib. In this literature review, we reviewed recent advances of diarylamide anticancer agents, including first and second generation drugs treating CML and their other uses, in addition to other compounds that are still in preclinical phases. This review focuses on the reports published in the literature from 2010 to 2019.

Predictive biomarkers for immune checkpoint blockade and opportunities for combination therapies

Immune checkpoint blockade therapies (ICBs) are a prominent breakthrough in cancer immunotherapy in recent years (named the 2013 “Breakthrough of the Year” by the Science magazine). Thus far, FDA-approved ICBs primarily target immune checkpoints CTLA-4, PD-1, and PD-L1. Notwithstanding their impressive long-term therapeutic benefits, their efficacy is limited to a small subset of cancer patients. In addition, ICBs induce inadvertent immune-related adverse events (irAEs) and can be costly for long-term use. To overcome these limitations, two strategies are actively being pursued: identification of predictive biomarkers for clinical response to ICBs and multi-pronged combination therapies. Biomarkers will allow clinicians to practice a precision medicine approach in ICBs (biomarker-based patient selection) such as treating triple-negative breast cancer patients that exhibit PD-L1 staining of tumor-infiltrating immune cells in ≥1% of the tumor area with nanoparticle albumin-bound (nab)–paclitaxel plus anti-PD-L1 and treating patients of MSI-H or MMR deficient unresectable or metastatic solid tumors with pembrolizumab (anti-PD-1). Importantly, the insights gained from these biomarker studies can guide rational combinatorial strategies such as CDK4/6 inhibitor/fractionated radiotherapy/HDACi in conjunction with ICBs to maximize therapeutic benefits. Further, with the rapid technological advents (e.g., ATCT-Seq), we predict more reliable biomarkers will be identified, which in turn will inspire more promising combination therapies.

Cyclophosphamide, Fluorouracil and subcutaneous Interleukin-2 in the treatment of advanced GIST: A Case Report

A male 68 years hold patient was admitted to surgical ward for hemorrhagic shock. After CT scan detection of 6x5 cm neoformation of first jejunal loop, he was submitted to segmental resection and pathological diagnosis was gastrointestinal stromal tumor. The patient was defined as high-risk according to Takahashi criteria, but refused Imatinib adjuvant therapy. After 15 months of disease-free interval, he developed bilobar liver metastases. After treatment with Imatinib 400 mg he reported G3 hepatotoxicity resolved with temporary suspension, he continue low dose with stable disease. After liver progression, he resumed Imatinib full dose with disease stabilization for 9 months. After liver progression, second line Sunitinib 37,5 mg/day was started for four months with stable disease. After further liver and lymph node mediastinal progression he was treated for four months with Regorafenib with disease stabilization. Patient developed slow but inexorable progression of liver disease with severe abdominal pain resistant to opioid and was treated with authorized compassionate program comprising Cyclophosphamide 300 mg/sqm and Fluorouracil 500 mg/sqm on day 1 intravenously followed by Interleukin-2 4.5 MUI subcutaneously on days 3–6 and 17–20 every four weeks. After three cycles the patients obtained a relevant subjective improvement with partial response on mediastinal lymph node and liver stabilization. A substantial increase on neutrophil, lymphocytes, monocytes, platelets, T regulator cells count, and a decrease on platelets/lymphocytes, CD8/T regulator cells ratio, CD8, NK count and C-reactive protein value were observed after treatment compared to basal value. The toxicity was mild represented by fever G1, flue-like-syndrome G1 during the treatment. After four cycle of chemo-immunotherapy, the patient demonstrated progression of disease and died five months after treatment. Noteworthy is the temporal disease control with significant symptomatic improvement achieved for the first time with this chemo-immunotherapeutic combination in a patient with very advanced pretreated GIST.

KIT as an Oncogenic Driver in Melanoma: An Update on Clinical Development

Metastatic melanoma is a heterogenous disease that has served as a model for the development of both targeted therapy and immunotherapy. KIT-mutated melanoma represents a rare subset, most commonly arising from acral, mucosal, and chronically sun-damaged skin. Additionally, KIT alterations are enriched in the triple wild-type subtype of cutaneous melanoma. Activating alterations of KIT-a transmembrane receptor tyrosine kinase important for cell development, growth, and differentiation-have been shown to be critical to oncogenesis across many tumor subtypes. Following the successes of BRAF-targeted therapy in melanoma and KIT-targeted therapy in gastrointestinal stromal tumors, small-molecule tyrosine kinase inhibitors targeting KIT have been examined in KIT-mutated melanoma. KIT inhibitors that have been investigated in relevant clinical trials in advanced melanoma include imatinib, sunitinib, dasatinib, and nilotinib. In these studies, selected patients with KIT-mutated melanoma were shown to be responsive to therapy with KIT inhibition, especially patients with L576P and K642E mutations. This has led to the incorporation of KIT-targeted therapy in the National Comprehensive Cancer Network guidelines for systemic therapy for metastatic or unresectable melanoma. Current research and development efforts include novel KIT-targeted therapies and testing KIT inhibitors in combination with immunotherapy.

Gastrointestinal stromal tumor - A review of clinical studies

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. With the advent of Imatinib, the treatment of gastrointestinal stromal tumor has been revolutionized as both the progression-free and overall survival rates have increased dramatically. Unfortunately, gastrointestinal stromal tumor patients on Imatinib do eventually fail due to resistance. Even though sunitinib and regorafenib have been shown to be highly effective as second- and third-line treatments, both have limited effects. New treatments are highly warranted for this reason. In this present review, 25 registered pharmacological clinical trials at ClinicalTrials.gov have been reviewed and show promising and encouraging results.

Strategies to Improve Cancer Immune Checkpoint Inhibitors Efficacy, Other Than Abscopal Effect: A Systematic Review

Despite that the impact of immune checkpoint inhibitors on malignancies treatment is unprecedented, a lack of response to these molecules is observed in several cases. Differently from melanoma and non-small cell lung cancer, where the use of immune checkpoint inhibitors results in a high efficacy, the response rate in other tumors, such as gastrointestinal cancers, breast cancer, sarcomas, and part of genitourinary cancers remains low. The first strategy evaluated to improve the response rate to immune checkpoint inhibitors is the use of predictive factors for the response such as PD-L1 expression, tumor mutational burden, and clinical features. In addition to the identification of the patients with a higher expression of immune checkpoint molecules, another approach currently under intensive investigation is the use of therapeutics in a combinatory manner with immune checkpoint inhibitors in order to obtain an enhancement of efficacy through the modification of the tumor immune microenvironment. In addition to the abscopal effect induced by radiotherapy, a lot of studies are evaluating several drugs able to improve the response rate to immune checkpoint inhibitors, including microbiota modifiers, drugs targeting co-inhibitory receptors, anti-angiogenic therapeutics, small molecules, and oncolytic viruses. In view of the rapid and extensive development of this research field, we conducted a systematic review of the literature identifying which of these drugs are closer to achieving validation in the clinical practice.

Targeting Tumor Metabolism: A New Challenge to Improve Immunotherapy

Currently, a marked number of clinical trials on cancer treatment have revealed the success of immunomodulatory therapies based on immune checkpoint inhibitors that activate tumor-specific T cells. However, the therapeutic efficacy of cancer immunotherapies is only restricted to a small fraction of patients. A deeper understanding of key mechanisms generating an immunosuppressive tumor microenvironment (TME) remains a major challenge for more effective antitumor immunity. There is a growing evidence that the TME supports inappropriate metabolic reprogramming that dampens T cell function, and therefore impacts the antitumor immune response and tumor progression. Notably, the immunosuppressive TME is characterized by a lack of crucial carbon sources critical for T cell function and increased inhibitory signals. Here, we summarize the basics of intrinsic and extrinsic metabolic remodeling and metabolic checkpoints underlying the competition between cancer and infiltrating immune cells for nutrients and metabolites. Intriguingly, the upregulation of tumor programmed death-L1 and cytotoxic T lymphocyte-associated antigen 4 alters the metabolic programme of T cells and drives their exhaustion. In this context, targeting both tumor and T cell metabolism can beneficially enhance or temper immunity in an inhospitable microenvironment and markedly improve the success of immunotherapies.

Characteristics and outcomes of patients with advanced sarcoma enrolled in early phase immunotherapy trials

Background

Immunotherapies, specifically those based on immune checkpoint inhibitors, have shown promising activity in multiple tumor types. Other than mifamurtide (MEPACT®) for osteosarcoma approved by European Medicines Agency, there are no approved immunotherapies for sarcomas.

Methods

We analyzed medical records of patients with advanced sarcoma who were referred to Phase 1 clinic at MD Anderson and received an immunotherapy (checkpoint inhibitors, vaccines, or cytokine based therapies). Clinical parameters including demographics, clinical history, toxicity, and response were abstracted.

Results

Among 50 patients enrolled in immunotherapy trials (Bone 10; Soft-tissue 40) we found 14 different subtypes of sarcomas. Royal Marsden Hospital (RMH) prognostic score was <2 (86%). Performance status (PS) was 0–1 in 48 patients (96%); median number of prior therapies was 3 (0–12). Immunotherapy consisted of checkpoint inhibitors (82%: PD1 = 7, PD-L1 = 11, CTLA4 = 22, other = 1) of which 42% were combinations, as well as vaccines (14%), and cytokines (4%). Median overall survival (OS) was 13.4 months (11.2 months: not reached). Median progression free survival (PFS) was 2.4 months (95% CI = 1.9–3.2 months). Best response was partial response (PR) in 2 patients with alveolar soft part sarcoma (ASPS) and stable disease (SD) in 11 patients (3 GIST, 3 liposarcomas (2 DDLS, 1 WDLS), 2 ASPS, 2 leiomyo, 1 osteo). PFS was 34% (23%, at 50%) at 3 months, 16% (8%, 30%) at 6 months, and 6% (2%, 20%) at 1 year. Pseudo-progression followed by stable disease was observed in 2 patients (4%). Grade 3/4 adverse events included rash (10%), fever (6%), fatigue (6%), and nausea/vomiting (6%).

Conclusion

Immunotherapies were well tolerated in advanced sarcoma patients enrolled in trials. All four ASPS patients had clinical benefit with checkpoint inhibitors and this was the only subtype experiencing partial response. Further evaluation of checkpoint inhibitors in ASPS is warranted.

Trial watch: DNA-based vaccines for oncological indications

DNA-based vaccination is a promising approach to cancer immunotherapy. DNA-based vaccines specific for tumor-associated antigens (TAAs) are indeed relatively simple to produce, cost-efficient and well tolerated. However, the clinical efficacy of DNA-based vaccines for cancer therapy is considerably limited by central and peripheral tolerance. During the past decade, considerable efforts have been devoted to the development and characterization of novel DNA-based vaccines that would circumvent this obstacle. In this setting, particular attention has been dedicated to the route of administration, expression of modified TAAs, co-expression of immunostimulatory molecules, and co-delivery of immune checkpoint blockers. Here, we review preclinical and clinical progress on DNA-based vaccines for cancer therapy.

How Signaling Molecules Regulate Tumor Microenvironment: Parallels to Wound Repair

It is now suggested that the inhibition of biological programs that are associated with the tumor microenvironment may be critical to the diagnostics, prevention and treatment of cancer. On the other hand, a suitable wound microenvironment would accelerate tissue repair and prevent extensive scar formation. In the present review paper, we define key signaling molecules (growth factors, cytokines, chemokines, and galectins) involved in the formation of the tumor microenvironment that decrease overall survival and increase drug resistance in cancer suffering patients. Additional attention will also be given to show whether targeted modulation of these regulators promote tissue regeneration and wound management. Whole-genome transcriptome profiling, in vitro and animal experiments revealed that interleukin 6, interleukin 8, chemokine (C-X-C motif) ligand 1, galectin-1, and selected proteins of the extracellular matrix (e.g., fibronectin) do have similar regulation during wound healing and tumor growth. Published data demonstrate remarkable similarities between the tumor and wound microenvironments. Therefore, tailor made manipulation of cancer stroma can have important therapeutic consequences. Moreover, better understanding of cancer cell-stroma interaction can help to improve wound healing by supporting granulation tissue formation and process of reepithelization of extensive and chronic wounds as well as prevention of hypertrophic scars and formation of keloids.

Trial watch: Immune checkpoint blockers for cancer therapy

Immune checkpoint blockers (ICBs) are literally revolutionizing the clinical management of an ever more diversified panel of oncological indications. Although considerable attention persists around the inhibition of cytotoxic T lymphocyte-associated protein 4 (CTLA4) and programmed cell death 1 (PDCD1, best known as PD-1) signaling, several other co-inhibitory T-cell receptors are being evaluated as potential targets for the development of novel ICBs. Moreover, substantial efforts are being devoted to the identification of biomarkers that reliably predict the likelihood of each patient to obtain clinical benefits from ICBs in the absence of severe toxicity. Tailoring the delivery of specific ICBs or combinations thereof to selected patient populations in the context of precision medicine programs constitutes indeed a major objective of the future of ICB-based immunotherapy. Here, we discuss recent preclinical and clinical advances on the development of ICBs for oncological indications.

Clinical Applications of Immunotherapy Combination Methods and New Opportunities for the Future

In the last decade, we have gained a deeper understanding of innate immune system. The mechanism of the continuous guarding of progressive mutations happening in a single cell was discovered and the production and the recognition of tumor associated antigens by the T-cells and elimination of numerous tumors by immune-editing were further understood. The new discoveries on immune mechanisms and its relation with carcinogenesis have led to development of a new class of drugs called immunotherapeutics. T lymphocyte-associated antigen 4, programmed cell death protein 1, and programmed cell death protein ligand 1 are the classes drugs based on immunologic manipulation and are collectively known as the "checkpoint inhibitors." Checkpoint inhibitors have shown remarkable antitumor efficacy in a broad spectrum of malignancies; however, the strongest and most durable immune responses do not last long and the more durable responses only occur in a small subset of patients. One of the solutions which have been put forth to overcome these challenges is combination strategies. Among the dual use of methods, a backbone with either PD-1 or PD-L1 antagonist drugs alongside with certain cytotoxic chemotherapies, radiation, targeted drugs, and novel checkpoint stimulators is the most promising approach and will be on stage in forthcoming years.