Immune therapy for kidney cancer: a second dawn?

Von Hippel–Lindau disease: insights into oxygen sensing, protein degradation, and cancer

Germline loss-of-function mutations of the VHL tumor suppressor gene cause von Hippel–Lindau disease, which is associated with an increased risk of hemangioblastomas, clear cell renal cell carcinomas (ccRCCs), and paragangliomas. This Review describes mechanisms involving the VHL gene product in oxygen sensing, protein degradation, and tumor development and current therapeutic strategies targeting these mechanisms. The VHL gene product is the substrate recognition subunit of a ubiquitin ligase that targets the α subunit of the heterodimeric hypoxia-inducible factor (HIF) transcription factor for proteasomal degradation when oxygen is present. This oxygen dependence stems from the requirement that HIFα be prolyl-hydroxylated on one (or both) of two conserved prolyl residues by members of the EglN (also called PHD) prolyl hydroxylase family. Deregulation of HIF, and particularly HIF2, drives the growth of VHL-defective ccRCCs. Drugs that inhibit the HIF-responsive gene product VEGF are now mainstays of ccRCC treatment. An allosteric HIF2 inhibitor was recently approved for the treatment of ccRCCs arising in the setting of VHL disease and has advanced to phase III testing for sporadic ccRCCs based on promising phase I/II data. Orally available EglN inhibitors are being tested for the treatment of anemia and ischemia. Five of these agents have been approved for the treatment of anemia in the setting of chronic kidney disease in various countries around the world.

Role of the Immune System Elements in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a relatively rare disease, but, today, its incidence tends to increase. The severe course of the disease and poor patient survival rate make PAH a major diagnostic and therapeutic challenge. For this reason, a thorough understanding of the pathogenesis of the disease is essential to facilitate the development of more effective therapeutic targets. Research shows that the development of PAH is characterized by a number of abnormalities within the immune system that greatly affect the progression of the disease. In this review, we present key data on the regulated function of immune cells, released cytokines and immunoregulatory molecules in the development of PAH, to help improve diagnosis and targeted immunotherapy.

PD-1 Expression and its Correlation With Prognosis in Clear Cell Renal Cell Carcinoma

BACKGROUND/AIM

Programmed death ligand-1 (PD-L1) and programmed death protein 1 (PD-1) expression levels in many tumors and their correlation with prognosis have been actively studied. However, studies on PD-1 expression and its prognostic value in clear cell renal cell carcinoma (ccRCC) are limited and controversial. In this study, we describe the expression of PD-1 and its prognostic significance and association with clinical features in patients with ccRCC.

MATERIALS AND METHODS

We obtained clinicopathological data from 166 patients with ccRCC who were treated at Gyeongsang National University Hospital, Jinju, Korea between January 2000 and December 2009. Tissue microarray blocks were made using representative paraffin blocks of ccRCC specimens. Two pathologists analyzed PD-L1 and PD-1 expression in both tumor and inflammatory cells.

RESULTS

PD-1 expression in tumor-infiltrating inflammatory cells was significantly correlated with unfavorable disease-free survival (DFS) (p<0.001) and disease-specific survival (DSS) (p=0.002) in the univariate analysis. A statistically significant correlation between PD-1 expression and unfavorable DFS (p=0.025) was observed in the multivariate analysis.

CONCLUSION

PD-1 expression in tumor-infiltrating inflammatory cells serves as an independent prognostic factor for unfavorable DSS in patients with ccRCC.

Survival prognoses of Heng intermediate-risk patients with metastatic renal cell carcinoma treated with immunotherapy or targeted therapy: A real-world, single-center retrospective study

Purpose

This study aimed to compare progression-free survival (PFS), overall survival (OS), and cancer-specific survival (CSS) in Heng intermediate-risk patients with metastatic renal cell carcinoma (mRCC) treated with first-line immunotherapy (IT) or targeted therapy (TT).

Materials and Methods

From 2000 to 2017, a total of 186 intermediate-risk mRCC patients treated with first-line IT (n=64, 34.4%) or TT (n=122, 65.6%) were retrospectively evaluated for PFS, OS, and CSS using the Kaplan–Meier method with log-rank test and Cox proportional hazards models for their risk factors with a p-value for significance of <0.05.

Results

During a median 5.08-month of systemic treatment and 92.22 months of follow-up, the median PFS, OS, and CSS were 5.16, 18.44, and 19.04 months, respectively. The comparison of baseline characteristics between the two groups showed a significantly higher rate of T3–4 stages, a lower rate of high nuclear grades, shorter follow-up, longer treatment durations, lesser rates of cytoreductive nephrectomy, a lower objective response rate, and no cases of complete response in the TT group compared with the IT group (p<0.05). The survival comparisons between the two groups showed that PFS was significantly different, whereas OS and CSS were not significantly different. The multivariate analyses showed that synchronous metastatic type(hazard ratio [HR], 2.285), IT (HR, 1.746), and treatment-free interval <1 year (HR, 1.926) were significant factors for PFS, whereas none of the risk factors were significant for OS or CSS.

Conclusions

TT significantly prolonged PFS compared with IT, whereas long-term survival was not significantly different in intermediate-risk mRCC patients.

Role of PDL1 as a prognostic marker in renal cell carcinoma: a prospective observational study in eastern India

Background:

Renal cell carcinoma (RCC) is one of the most common genitourinary malignancies. Programmed death ligand-1 (PDL1) is an immune checkpoint inhibitor, instrumental in ‘T cell escape’ of malignant cells. PDL1 has been shown to be associated with poor prognosis in multiple small studies. In this study, we want to study the role of PDL1 as a prognostic marker in RCC in an Indian population.

Methods:

A total of 30 patients who underwent radical or partial nephrectomy, with histopathological findings of RCC, were included in the study. PDL1 expression was studied in tumour tissue with immunohistochemistry. Patients were followed up for a period of 2 years for disease recurrence and cancer-specific mortality.

Results:

Expression of PDL1 was seen to be associated with higher grade and stage at presentation. PDL1 expression was also associated with statistically significant increased incidence of disease recurrence. Although cancer-specific mortality was higher in patients with positive PDL1 expression, it was seen to be statistically insignificant.

Conclusions:

PDL1 is a novel prognostic marker for RCC and is associated with poor prognosis. More studies with larger patient pool and multicentric studies will establish the role of PDL1 with certainty. This can be the torchbearer for the future management of RCC.

Prognostic value of PD-1 and PD-L1 expression in patients with metastatic clear cell renal cell carcinoma

OBJECTIVE

In renal cell carcinoma (RCC), several prognostic biomarkers have been identified and are under investigation. Several reports have shown that the expression of programmed death 1 (PD-1) and its ligand PD-L1 is associated with poor outcome for patients with RCC. The present study is aimed at evaluating the expression of PD-1 and PD-L1 and to investigate their clinical and prognostic significance in patients with clear cell RCC (CCRCC) having received molecular targeted therapies. In addition, we also evaluated the relationship between the expression of PD-1 and PD-L1 and intratumoral tumor infiltrating lymphocytes (TILs).

METHODS

A total of 33 patients with metastatic CCRCC who underwent surgery and received molecular targeted therapies from March 2008 to April 2016 were retrospectively reviewed and analyzed. Tissue specimens from the patients were analyzed for PD-1 and PD-L1 expression by immunohistochemistry.

RESULTS

The median patient age was 64 years old (range=53-78). The majority of patients were male (81.8%). All Memorial Sloan Kettering Cancer Center risk groups were represented among the patients with 39.4% with favorable-, 51.5% with intermediate- and 9.1% with poor-risk. The expression of PD-1 and PD-L1 was observed in 16 (48.5%) and 9 (27.3%) patients, respectively. The expression of PD-1 and PD-L1 was associated with a larger primary renal tumor size, higher nuclear grade and sarcomatoid feature. Kaplan-Meier analysis revealed that no significant difference in progression free survival of first line molecular targeted therapy was found for PD-1 (P=0.2396) and PD-L1 (P=0.5919) expression. However, PD-1 expression has a significant worse impact on overall survival (OS) (P=0.0385), while for PD-L1 expression only a trend is seen for OS (P=0.1542). The patients with PD-1 and PD-L1 expression showed higher infiltration of CD4 (P<0.0001 and P<0.0001, respectively), CD8 (P=0.0328 and P=0.0044, respectively) and FOXP3 (P<0.0001 and P=0.0033, respectively) positive TILs.

CONCLUSION

PD-1 and PD-L1 expression is significantly associated with adverse clinicopathological features in CCRCC. Furthermore, PD-1 expression could be one of the biomarkers suggesting poor outcome in patients with metastatic CCRCC receiving molecular targeted therapies.

Expression and Functional Characterization of the BNIP3 Protein in Renal Cell Carcinomas

BNIP3 (Bcl-2/adenovirus E1B 19-kDa interacting protein 3) is a BH3-only protein that regulates apoptosis and autophagy. BNIP3 plays also an important role in hypoxia-induced cell response and is regulated by HIF1. Here, we studied a possible association of BNIP3 expression and the prognosis of patients with renal cell carcinomas (RCCs) and examined the functional relevance of BNIP3 in the regulation of cell survival and apoptosis of renal carcinoma cells. BNIP3 expression was determined by immunohistochemistry in RCC tumor tissue samples of 569 patients using a tissue microarray. Functional characterization of BNIP3 in renal carcinoma cells indicates prosurvival effects. In human RCC tumor samples, high cytoplasmic BNIP3 expression was associated with high-grade RCCs and regional lymph node metastasis. BNIP3 expression correlated negatively with disease-specific survival. Multivariate Cox regression analysis retained BNIP3 expression as an independent prognostic factor in patients without distant metastasis. Together, our studies imply that BNIP3 regulates cell survival in RCCs and its expression is an independent prognostic marker in patients with localized RCCs.

Challenging the treatment paradigm for advanced renal cell carcinoma: a review of systemic and localized therapies

The current standard of care for the management of advanced renal cell carcinoma (RCC) revolves around systemic therapy with molecularly targeted agents. Over the last decade, a total of seven targeted drugs have been approved but, altogether, only exploit two molecular targets in this disease: the vascular endothelial growth factor (VEGF) axis and the mammalian target of rapamycin (mTOR). Introduction of these agents has markedly improved outcomes compared with those in the cytokine era, yet comparatively little progress has been made since registration of the first targeted therapeutics occurred 10 years ago. In this article, we review efforts to improve on this current treatment paradigm. We discuss novel targets in this disease and corresponding new agents under investigation. The article dedicates particular attention to targeted immunotherapeutics, which are rapidly emerging as a new category of interest in this disease. Last, we review current data supporting the use of surgical interventions to improve outcomes in patients with metastatic disease.

Differential Expression of PD-L1 between Primary and Metastatic Sites in Clear-Cell Renal Cell Carcinoma

PD-L1 expression in primary clear-cell renal cell carcinoma (ccRCC) increases the likelihood of response to anti-PD-1 inhibition, but fails to identify all responders. We hypothesized that PD-L1 levels assessed in randomly selected areas of the primary tumors may not accurately reflect expression levels in metastatic lesions, which are the target of systemic therapy. Therefore, we compared PD-L1 expression in a series of primary ccRCC and their metastases. Tissue blocks from 53 primary ccRCCs and 76 corresponding metastases were retrieved. Areas with predominant and highest nuclear grade were selected. Slides were immunostained with a validated anti-PD-L1 antibody (405.9A11). Membranous expression in tumor cells was quantified using H-score. Expression in tumor-infiltrating mononuclear cells (TIMC) was quantified using a combined score. Discordant tumor cell PD-L1 staining between primary tumors and metastases was observed in 11 of 53 cases (20.8%). Overall, tumor cell PD-L1 levels were not different in primary tumors and metastases (P = 0.51). Tumor cell PD-L1 positivity was associated with higher T stage (P = 0.03) and higher Fuhrman nuclear grade (P < 0.01). Within individual lesions, PD-L1 positivity was heterogeneous and almost exclusively detected in high nuclear grade areas (P < 0.001). No difference was found in PD-L1 levels in TIMCs between primary tumors and metastases (P = 0.82). The heterogeneity of PD-L1 expression in ccRCC suggests that its assessment as a predictive biomarker for PD-1 blockade may require analysis of metastatic lesions. Notably, because PD-L1 expression was mostly detected in high nuclear grade areas, to avoid false-negative results, these areas should be specifically selected for assessment.

A neutral lipid envelope-type nanoparticle composed of a pH-activated and vitamin E-scaffold lipid-like material as a platform for a gene carrier targeting renal cell carcinoma

A renal cell carcinoma (RCC) is one of the refractory tumors, since it readily acquires resistance against chemotherapy. Thus, alternative therapeutic approaches such as obstructing the neovasculature are needed. We previously reported on the development of a plasmid DNA (pDNA)-encapsulating liposomal nanoparticle (LNP) as a hepatic gene delivery system that is applicable to systemic administration. The key molecular component is a SS-cleavable and pH-activated lipid-like material (ssPalm) that mounts dual sensing motifs (ternary amines and disulfide bonding) that are responsive to the intracellular environment. The main purpose of the present study was to expand its application to a tumor-targeting gene delivery system in mice bearing tumors established from a RCC (OS-RC-2). When the modification of the surface of the particle is optimized for the polyethyleneglycol (PEG), stability in the blood circulation is improved, and consequently tumor-selective gene expression can be achieved. Furthermore, gene expression in the tumor was increased slightly when the hydrophobic scaffold of the ssPalm was replaced from the conventionally used myristic acid (ssPalmM) to α-tocopherol succinate (ssPalmE). Moreover, tumor growth was significantly suppressed when the completely CpG-free pDNA encoding the solute form of VEGFR (fms-like tyrosine kinase-1: sFlt-1) was used, especially when it was delivered by the LNP formed with ssPalmE (LNP(ssPalmE)). Thus, the PEG-modified LNP(ssPalmE) is a promising gene carrier for the cancer gene therapy of RCC.

A review of interventional clinical trials in renal cell carcinoma: a status report from the ClinicalTrials.gov WebSite

INTRODUCTION

The treatment of renal cell carcinoma (RCC) has undergone a major shift over the past 10 years and continues to evolve. The objective of this study was to assess the current landscape of clinical trials (CTs) in RCC to identify areas of strength and opportunities for improvement.

MATERIALS AND METHODS

ClinicalTrials.gov was queried using 17 prespecified search criteria. Only open, RCC-dedicated, interventional CTs in adult patients were included. Descriptive statistics and Fisher exact tests were used to compare features of CTs.

RESULTS

The study cohort consisted of 169 trials. Phase II trials were the most common (67, 39.6%) and 52.7% (89) of CTs examined patients with stage IV disease. Only 26.6% (45) were randomized and 64.5% (109) were single-arm. Targeted therapies (TTs) were studied in 47.9% (81) of CTs overall and 71.1% (81 of 114) of the systemic therapy trials. Immunotherapies (ITs) were the next most common systemic therapy accounting for 5.9% (10) of trials. The primary end point of feasibility or biomarker analysis, progression-free survival, or overall survival was noted in 27.8%, 51.5%, and 2.1% of TT CTs (27, 50, 2 trials, respectively) and 42.9%, 35.7%, and 14.3% of IT CTs (6, 5, 2 trials respectively; P = .037). Biomarkers were assessed in 45% (76) of CTs overall and were more frequently examined in TT and IT CTs (53.6% [52/97] and 64.3% [9/14]) than in surgery and other CTs (22.2% [4/18] and 27.5% [11/40]; P = .002). Sponsorship differed according to treatment type (P = .003).

CONCLUSION

Clinical trials in RCC are largely nonrandomized, single-arm, with minimal focus on non-clear-cell RCC. Significant differences were noted in the primary end point, sponsorship, and biomarker assessment between treatment types.

The relevance of testing the efficacy of anti-angiogenesis treatments on cells derived from primary tumors: a new method for the personalized treatment of renal cell carcinoma

Despite the numerous available drugs, the most appropriate treatments for patients affected by common or rare renal cell carcinomas (RCC), like those associated with the Xp11.2 translocation/transcription factor for immunoglobulin heavy-chain enhancer 3 (TFE3) gene fusion (TFE3 RCC), are not clearly defined. We aimed to make a parallel between the sensitivity to targeted therapies on living patients and on cells derived from the initial tumor. Three patients diagnosed with a metastatic RCC (one clear cell RCC [ccRCC], two TFE3 RCC) were treated with anti-angiogenesis drugs. The concentrations of the different drugs giving 50% inhibition of cell proliferation (IC50) were determined with the Thiazolyl Blue Tetrazolium Bromide (MTT) assay on cells from the primary tumors and a reference sensitive RCC cell line (786-O). We considered the cells to be sensitive if the IC50 was lower or equal to that in 786-O cells, and insensitive if the IC50 was higher to that in 786-O cells (IC 50 of 6 ± 1 µM for sunitinib, 10 ± 1 µM for everolimus and 6 ± 1 µM for sorafenib). Based on this standard, the response in patients and in cells was equivalent. The efficacy of anti-angiogenesis therapies was also tested in cells obtained from five patients with non-metastatic ccRCC, and untreated as recommended by clinical practice in order to determine the best treatment in case of progression toward a metastatic grade. In vitro experiments may represent a method for evaluating the best first-line treatment for personalized management of ccRCC during the period following surgery.

PD-1 as a potential target in cancer therapy

Recently, an improved understanding of the molecular mechanisms governing the host response to tumors has led to the identification of checkpoint signaling pathways involved in limiting the anticancer immune response. One of the most critical checkpoint pathways responsible for mediating tumor-induced immune suppression is the programmed death-1 (PD-1) pathway, normally involved in promoting tolerance and preventing tissue damage in settings of chronic inflammation. Many human solid tumors express PD ligand 1 (PD-L1), and this is often associated with a worse prognosis. Tumor-infiltrating lymphocytes from patients with cancer typically express PD-1 and have impaired antitumor functionality. Proof-of-concept has come from several preclinical studies in which blockade of PD-1 or PD-L1 enhanced T-cell function and tumor cell lysis. Three monoclonal antibodies against PD-1, and one against PD-L1, have reported phase 1 data. All four agents have shown encouraging preliminary activity, and those that have been evaluated in larger patient populations appear to have encouraging safety profiles. Additional data are eagerly awaited. This review summarizes emerging clinical data and potential of PD-1 pathway–targeted antibodies in development. If subsequent investigations confirm the initial results, it is conceivable that agents blocking the PD-1/PD-L1 pathway will prove valuable additions to the growing armamentarium of targeted immunotherapeutic agents.

Next-generation immunotherapy agents that target the PD-1 checkpoint pathway are demonstrating antitumor activity and encouraging safety profiles in early clinical trials. Current and future clinical trials will provide new insights, and the evaluation of biomarkers and rational combination therapies is ongoing.