Blocking PD-1/PD-L1 in Genitourinary Malignancies: To Immunity and Beyond

Genitourinary malignancies represent a diverse biologic and immunologic landscape. Recently, checkpoint blockade has transformed the treatment paradigms for bladder and kidney cancer. However, continued progress will be essential in bladder and kidney cancer, given response to inhibition of the PD-1/PD-L1 (PD-1/PD-L1) axis remains variable and only a minority of patients respond. In contrast with the clinical trial results in bladder and kidney cancer, studies of anti-PD-1/PD-L1 therapy in prostate cancer have generally been disappointing. Nevertheless, an exciting array of studies is underway that are translating lessons learned from tumor biology into promising clinical trials. Here we highlight important features of the immune tumor microenvironment of bladder, kidney, and prostate cancer and review key completed and ongoing clinical trials of anti-PD-1/PD-L1 therapy in these tumor types.

Immuno-Oncology: Emerging Targets and Combination Therapies

Host immunity recognizes and eliminates most early tumor cells, yet immunological checkpoints, exemplified by CTLA-4, PD-1, and PD-L1, pose a significant obstacle to effective antitumor immune responses. T-lymphocyte co-inhibitory pathways influence intensity, inflammation and duration of antitumor immunity. However, tumors and their immunosuppressive microenvironments exploit them to evade immune destruction. Recent PD-1 checkpoint inhibitors yielded unprecedented efficacies and durable responses across advanced-stage melanoma, showcasing potential to replace conventional radiotherapy regimens. Neverthless, many clinical problems remain in terms of efficacy, patient-to-patient variability, and undesirable outcomes and side effects. In this review, we evaluate recent advances in the immuno-oncology field and discuss ways forward. First, we give an overview of current immunotherapy modalities, involving mainy single agents, including inhibitor monoclonal antibodies (mAbs) targeting T-cell checkpoints of PD-1 and CTLA-4. However, neoantigen recognition alone cannot eliminate tumors effectively in vivo given their inherent complex micro-environment, heterogeneous nature and stemness. Then, based mainly upon CTLA-4 and PD-1 checkpoint inhibitors as a "backbone," we cover a range of emerging ("second-generation") therapies incorporating other immunotherapies or non-immune based strategies in synergistic combination. These include targeted therapies such as tyrosine kinase inhibitors, co-stimulatory mAbs, bifunctional agents, epigenetic modulators (such as inhibitors of histone deacetylases or DNA methyltransferase), vaccines, adoptive-T-cell therapy, nanoparticles, oncolytic viruses, and even synthetic "gene circuits." A number of novel immunotherapy co-targets in pre-clinical development are also introduced. The latter include metabolic components, exosomes and ion channels. We discuss in some detail of the personalization of immunotherapy essential for ultimate maximization of clinical outcomes. Finally, we outline possible future technical and conceptual developments including realistic in vitro and in vivo models and inputs from physics, engineering, and artificial intelligence. We conclude that the breadth and quality of immunotherapeutic approaches and the types of cancers that can be treated will increase significantly in the foreseeable future.

Angiogenic and immunological pathways in metastatic renal cell carcinoma: A counteracting paradigm or two faces of the same medal? The GIANUS Review

In the so-called "antiangiogenic era" of recent years, a number of targeted therapies have been approved for the treatment of metastatic renal cell carcinoma (mRCC). Emerging information about the immunological features of mRCC and the immunomodulating properties of antiangiogenic agents, one of the standard treatments for mRCC, indicates that a more rational design of potentially synergistic combinations should be pursued. Indeed, immunotherapy has undergone a resurgence in clinical practice. In this narrative review, we discuss the immunological features of mRCC and the potential interactions that antiangiogenic agents may also exert on host immunity and tumor immunogenicity, possibly working on both sides of this complex cross-talk. Hence, the recall to Gianus, the ancient two-faced Roman God who was looking both at the future and the past. Treatment strategies will be also critically discussed.

Check point inhibitors a new era in renal cell carcinoma treatment

In the United States, the estimated number of new cases of renal cell carcinoma (RCC) is approximately 65,000 case with about 15,000 deaths in the year of 2018 (Siegel et al. in CA Cancer J Clin 68(1):7, 2018). RCC as an immunogenic malignancy is supported by many theories and facts which include tumor richness of lymphocytes infiltrate, the occurrence of spontaneous tumor regression, and the proved effect of traditional immunotherapy (Finke et al. in J Immunother 11(1):1-11, 1992), all these factors support the potential therapeutic effect of the novel immunotherapeutic agents in RCC. Historically, complete tumor regression in metastatic RCC is achievable in a minority of patients through traditional immunotherapies such as high-dose interleukin-2 (IL-2) (Fyfe et al. in J Clin Oncol 13(3):688, 1995) and interferon-alfa (IFNa) (Negrier et al. in N Engl J Med 338(18):1272, 1998); however due to the significant rate of toxicities and low efficacy; accordingly the targeted therapy with tyrosine kinase inhibitors (TKIs) and vascular endothelial growth factor-antibodies (VEGF) became the standard and prevalent treatment approach for advanced RCC both in front and subsequent lines of therapy (Escudier et al. in Ann Oncol. 25(Suppl 3):iii49-iii56, 2014). A new avenue of immunotherapy utilizing novel strategy to block immune checkpoints has emerged in a new era for RCC treatment (Ascierto et al. in J Transl Med 12:291, 2014). Results from clinical trials are encouraging in both front-line and second-line settings, in a phase III trial (CheckMate 025) nivolumab compared to everolimus improved overall survival in previously treated metastatic RCC who had progressed on prior treatment with targeting agents (Motzer et al. in N Engl J Med 373:1803, 2015). CheckMate 214, a phase III trial, demonstrated superior overall survival and objective response with combined checkpoint inhibitors compared to sunitinib in Treatment-Naïve Advanced RCC among intermediate- and poor-risk group (Motzer et al. in N Engl J Med. 378(14):1277-1290, 2018). In this review, we discuss the systemic Immunotherapy with checkpoint inhibitors that have been approved or are currently being investigated in RCC, clinical experience with these agents, and its future development.

Overview of Current and Future First-Line Systemic Therapy for Metastatic Clear Cell Renal Cell Carcinoma

OPINION STATEMENT

Treatment of metastatic clear cell renal cancer (mccRCC) has seen substantial progress over the last 20 years, with many regulatory approvals since 2006 culminating in a substantial increase to overall survival (OS). Six therapies are currently available for first-line use, with additional treatments currently being tested in this setting, some of which are expected to be approved soon based on new data from the CABOSUN and CheckMate-214 trials. Based on the available evidence, we strongly believe that vascular endothelial growth factor tyrosine kinase inhibitor (VEGF-TKI) therapy over mechanistic target or rapamycin (mTOR; formerly known as mammalian target of rapamycin) inhibitor therapy is the most effective first-line option regardless of risk category assignment. High-dose interleukin-2 (HDIL-2) therapy remains a reasonable treatment option in patients with Eastern Cooperative Oncology Group (ECOG) performance status 0-1 and have minimal comorbid conditions. In the near future, these agents are likely to be surpassed by cabozantinib and by combination immune checkpoint inhibitor therapy with nivolumab and ipilimumab. Independent review has recently confirmed superiority of first-line cabozantinib over sunitinib in a phase 2 trial of 157 patients with intermediate or poor risk mccRCC (progression-free survival [PFS] 8.6 vs 5.3 months, hazard ratio [HR] 0.48, p = 0.0008). In a separate study of 1096 patients treated with either upfront sunitinib or the combination of nivolumab and ipilimumab, those with intermediate and poor risk had significant improvement in both PFS (11.6 vs 8.4 months, HR 0.82, p = 0.0331) and OS (not reached vs 26 months, p < 0.0001). Responses were greater in patients with positive programmed death receptor ligand-1 (PD-L1) tumor staining, and pending regulatory approval may become standard of care in untreated patients with intermediate to poor risk disease with positive PD-L1 status. This likely represents the beginning of additional novel immunotherapy combinations for the first-line treatment of mccRCC.

Efficacy, Safety, and Pharmacokinetics of Axitinib in Nasopharyngeal Carcinoma: A Preclinical and Phase II Correlative Study

Purpose: We hypothesized that axitinib is active with an improved safety profile in nasopharyngeal carcinoma (NPC).Experimental Design: We evaluated axitinib in preclinical models of NPC and studied its efficacy in a phase II clinical trial in recurrent or metastatic NPC patients who progressed after at least one line of prior platinum-based chemotherapy. We excluded patients with local recurrence or vascular invasion. Axitinib was started at 5 mg twice daily in continuous 4-week cycles. Primary endpoint was clinical benefit rate (CBR), defined as the percentage of patients achieving complete response, partial response, or stable disease by RECIST criteria for more than 3 months.Results: We recruited 40 patients, who received a median of 3 lines of prior chemotherapy. Axitinib was administered for a mean of 5.6 cycles, with 16 patients (40%) receiving ≥6 cycles. Of 37 patients evaluable for response, CBR was 78.4% (95% CI, 65.6%-91.2%) at 3 months and 43.2% (30.4%-56.1%) at 6 months. Grade 3/4 toxicities were uncommon, including hypertension (8%), diarrhea (5%), weight loss (5%), and pain (5%). All hemorrhagic events were grade 1 (15%) or grade 2 (3%). Elevated diastolic blood pressure during the first 3 months of axitinib treatment was significantly associated with improved overall survival (HR, 0.29; 95% CI, 0.13-0.64, P = 0.0012). Patient-reported fatigue symptom was associated with hypothyroidism (P = 0.039). Axitinib PK parameters (C_max and AUC_(0-t)) were significantly correlated with tumor response, toxicity, and serum thyroid-stimulating hormone changes.Conclusions: Axitinib achieved durable disease control with a favorable safety profile in heavily pretreated NPC patients. Clin Cancer Res; 24(5); 1030-7. ©2018 AACR.

Individualized dosing with axitinib: rationale and practical guidance

Axitinib is a potent, selective, vascular endothelial growth factor receptor inhibitor with demonstrated efficacy as second-line treatment for metastatic renal cell carcinoma. Analyses of axitinib drug exposures have demonstrated high interpatient variability in patients receiving the 5 mg twice-daily (b.i.d.) starting dose. Clinical criteria can be used to assess whether individual patients may benefit further from dose modifications, based on their safety and tolerability data. This review provides practical guidance on the 'flexible dosing' method, to help physicians identify who would benefit from dose escalations, dose reductions or continuation with manageable toxicity at the 5 mg b.i.d. dose. This flexible approach allows patients to achieve the best possible outcomes without compromising safety.

Predictive markers of anti-VEGF and emerging role of angiogenesis inhibitors as immunotherapeutics

The critical role of angiogenesis in promoting tumor growth and metastasis has been well established scientifically, and consequently blocking this pathway as a therapeutic strategy has demonstrated great clinical success for the treatment of cancer. The holy grail however, has been the identification of patients who derive significant survival benefit from this class of agents. Here we attempt to delineate the diverse mechanisms related to anti-VEGF including its role as an anti-vascular, anti-angiogenic or an anti-permeability factor and review the most promising predictive biomarkers interrogated in large clinical trials, that identify patients who may derive significant survival advantage with VEGF inhibition. Lastly, we describe the function of VEGF as an immunomodulator and illustrate the evidence for anti-VEGF in reprogramming the tumor milieu from an immunosuppressive to an immune permissive microenvironment in human cancers, thus elucidating the role of anti-VEGF as an optimal combination partner for immune checkpoint inhibitors.

Emerging immunotherapy in advanced renal cell carcinoma

Immunotherapy has recently catapulted to the forefront of treatments for patients with solid tumors. Given its inherent immunogenic properties, renal cell carcinoma (RCC) has historically responded to immunotherapy and remains primed for further development. Although immunotherapy with high-dose interleukin 2 was a primary treatment for advanced RCC (aRCC), recent discoveries of key molecular and immunological alterations have led to the FDA-approval of nivolumab, an antiprogrammed cell death inhibitor, which has demonstrated an overall survival in patients with previously treated aRCC. However, despite recent therapeutic advances, aRCC remains an incurable disease for most patients. In this review, we assess the current landscape and future developments of immunotherapy in aRCC.

Checkpoint Inhibitors for the Treatment of Renal Cell Carcinoma

OPINION STATEMENT

The advent of checkpoint inhibitors has revolutionized systemic therapy for many malignancies, including renal cell carcinoma (RCC) where multiple PD-1, PD-L1, and CTLA-4 inhibitors have demonstrated responses and improved survival for patients in clinical trials. Durable benefit with manageable toxicity can be achieved with these agents-but unfortunately for only a minority of individuals. Efforts are ongoing to understand mechanisms driving the response and resistance to checkpoint inhibitors in order to personalize therapy and extend benefit to more patients. In particular, combination immunotherapy is an area of active study with multiple ongoing trials in RCC. Novel immunotherapeutic agents are being explored as well. Clinically, there are nuances related to the use of immunotherapy that are important to understand in order to provide optimal care to patients. Potential autoimmune toxicities are important to identify early so they can be best mitigated with immunosuppression, and careful review of imaging with clinical correlation is important to ensure responding patients are not taken off treatment prematurely due to "pseudo-progression." Lastly, although immunotherapy is an important new tool, it exists among other active agents in the treatment of RCC, and further study is needed to understand where it best fits in the treatment paradigm. In this article, we review the most recent data for immune checkpoint inhibitors in metastatic renal cell carcinoma and more broadly discuss the rapidly evolving landscape of immunotherapy in RCC, including combination immunotherapies.

The second wave of immune checkpoint inhibitor tsunami: advance, challenges and perspectives

After the first wave of the tsunami of immune checkpoint inhibitors, 2016 was marked by the second wave, revealed by numerous US FDA approvals, publications and abstracts in relation with these drugs in different cancers and settings. First, we reported all new indications of anti-CTLA4, anti-programmed cell death protein 1 and anti-PDL1 approved by the FDA, the positive clinical trials published and the abstracts reported at important scientific meetings during 2016. Then, we highlighted the updates on debatable issues related to checkpoint inhibitors, since the first wave published in a previous issue. We focused on the predictive biomarkers, combination therapies, tumor response patterns and efficacy in particular settings and the side effect management. Finally, the impact of checkpoint inhibitors development on the care management of cancer centers will be discussed.

New treatment options for metastatic renal cell carcinoma

During the last decade, the treatment of advanced or metastatic renal cell carcinoma (RCC) was revolutionised with the advent of antiangiogenic drugs and tyrosine-kinase inhibitors. Several agents targeting the vascular endothelial growth factor (VEGF) pathway (sunitinib, bevacizumab, pazopanib, axitinib) or the mammalian target of rapamycin pathway (temsirolimus, everolimus) were since then progressively approved for first-line or later-line use in the treatment of patients with advanced RCC and became the new standard of care. As a result, the survival of patients with advanced RCC has significantly improved from a median overall survival of approximately 12 months in the cytokines era to more than 26 months with first-line VEGF inhibitors. During the two last years, the treatment of advanced RCC has witnessed a second revolution with the advent of immune checkpoint inhibitors, especially agents targeting the programmed cell death-1 receptor, as well as with the advent of new generation tyrosine-kinase receptor inhibitors. This article will review the new therapeutic options available for the treatment of advanced RCC, as well as the future potential molecular targets that are currently being investigated.

Renal cell carcinoma: molecular characterization and evolving treatment paradigms

PURPOSE OF REVIEW

The treatment landscape of advanced renal cell carcinoma (RCC) continues to shift as both new targeted therapies and immunotherapies show efficacy in treating the disease. Contemporary insights into the molecular characterization of RCC are likely to fuel the development of additional therapies. This review summarizes recent advancements in the biologic characterization of RCC and discusses newly approved therapies and ongoing studies in the treatment of advanced RCC.

RECENT FINDINGS

The Cancer Genome Atlas has now completed comprehensive molecular characterization of clear cell, papillary, and chromophobe RCC, providing insights into the biology of these entities. Two new 'targeted' therapies, cabozantinib and lenvatinib, as well as a novel immune checkpoint inhibitor, the programed death 1 inhibitor nivolumab, have recently been approved for the treatment of metastatic RCC. Although some of these newer therapies are associated with prolongation of survival, there are few long-term responders and the quest for more durable treatment strategies continues.

SUMMARY

The addition of several new agents effective in metastatic RCC has resulted in improvements in overall survival; however, there are few avenues to durable responses or cure. Ongoing studies as well advances in our understanding of the molecular alterations underlying distinct forms of RCC promise further therapeutic advances and have the potential to alter the current treatment paradigm.

Immunotherapeutic strategies for the treatment of renal cell carcinoma: Where will we go?

INTRODUCTION

Historically, renal cell carcinoma (RCC) is considered a chemotherapy-resistant tumor. The cornerstone of systemic therapy included mammalian target of rapamycin (mTOR) inhibitors, endothelial growth factor receptor (VEGFR) and tyrosine kinase inhibitors (TKIs). Currently, a new era is enteres with promising immunotherapeutic treatments, which are becoming commercially available. Areas covered: We provide a comprehensive review using PubMed and ClinicalTrials.gov about the following immunotherapies in RCC: i) vaccine therapy, ii) adoptive T Cell Transfer and CAR T cells, iii) nonspecific immunotherapy - IL-2 (new formulations), iv) Checkpoint inhibitors, v) other checkpoint-molecules. We will also discuss their mechanism of action and toxicity, the importance of developing new patient selection algorithms (immunoprofiling, guidelines updates) and new biomarkers such as PD-1 expression. Expert commentary: Immunotherapy shows promise, and the current tools used in clinical practice, including guidelines, staging-classification and algorithms should be revised and adapted to the new immunotherapeutic drugs. Although immunotherapy in RCC show promising results, more research is needed in parallel to discover biomarkers that enable the prediction of a treatment response and therefore lead to better patient selection.