Extension of overall survival beyond objective responses in patients with metastatic renal cell carcinoma treated with high-dose interleukin-2

IL-2 based cancer immunotherapies: an evolving paradigm

Discovered over 4 decades ago in the supernatants of activated T cells, interleukin-2 (IL-2) is a potent pleiotropic cytokine involved in the regulation of immune responses. It is required for effector T cell expansion and differentiation as well as for peripheral tolerance induced by regulatory T cells. High-dose IL-2 treatment was the first FDA-approved immunotherapy for renal cell carcinoma and melanoma, achieving single agent complete and durable responses, albeit only in a small proportion of patients. The therapeutic potential of wild type IL-2 is clinically limited by its short half-life and severe vascular toxicity. Moreover, the activation of regulatory T cells and the terminal differentiation of effector T cells on IL-2 pose additional restrictions. To overcome the toxicity of IL-2 in order to realize its full potential for patients, several novel engineering strategies are being developed and IL-2 based immunotherapy for cancer has emerged as a burgeoning field of clinical and experimental research. In addition, combination of IL-2 with PD-1/L1 pathway blockade shows vastly improved anti-tumor efficacy over either monotherapy in preclinical tumor models. In this review we discuss the biological characteristics of IL-2 and its receptors, as well as its efficacy and treatment limiting toxicities in cancer patients. We also explore the efforts aimed at developing novel and safer IL-2 therapies to harness the full therapeutic potential of this cytokine.

Acute and Chronic Cardiopulmonary Effects of High Dose Interleukin-2 Therapy: An Observational Magnetic Resonance Imaging Study

High dose interleukin-2 (IL-2) is known to be associated with cardiopulmonary toxicity. The goal of this study was to evaluate the effects of high dose IL-2 therapy on cardiopulmonary structure and function. Combined cardiopulmonary magnetic resonance imaging (MRI) was performed in 7 patients in the acute period following IL-2 therapy and repeated in 4 patients in the chronic period. Comparison was made to 10 healthy volunteers. IL-2 therapy was associated with myocardial and pulmonary capillary leak, tissue oedema and cardiomyocyte injury, which resulted in acute significant left ventricular (LV) dilatation, a reduction in LV ejection fraction (EF), an increase in LV mass and a prolongation of QT interval. The acute effects occurred irrespective of symptoms. In the chronic period many of the effects resolved, but LV hypertrophy ensued, driven by focal replacement and diffuse interstitial myocardial fibrosis and increased cardiomyocyte mass. In conclusion, IL-2 therapy is ubiquitously associated with acute cardiopulmonary inflammation, irrespective of symptoms, which leads to acute LV dilatation and dysfunction, increased LV mass and QT interval prolongation. Most of these effects are reversible but IL-2 therapy is associated with chronic LV hypertrophy, driven by interstitial myocardial fibrosis and increased cardiomyocyte mass. The findings have important implications for the monitoring and long term impact of newer immunotherapies. Future studies are needed to improve risk stratification and develop cardiopulmonary-protective strategies.

Interleukin-2 therapy of cancer-clinical perspectives

Interleukin (IL)-2 is a pleiotropic cytokine that displays opposing activities on immune system acting either in favor of or against cancer progression. Advanced/metastatic melanoma and renal cell carcinoma (RCC) are the two types of cancers that included most studies implemented for assessing the role of high-dose IL-2 therapy. The use of high-dose IL-2 therapy can, however, increase the rate of toxicities and interferes with the activity of endothelial cells (ECs) and effector T cells in tumor microenvironment (TME). This implies the need for adjusting strategies related to the cytokine therapy, such as suppressing signals that are interfering with the activity of this cytokine or the use of engineered IL-2 variants. The focus of this review is to discuss about pros and cons related to the IL-2 therapy and propose strategies to increase the efficacy of therapy. The outcomes of this literature will call for application of variants of IL-2 engineered to represent higher half-life and efficacy, and are more safe in the area of cancer immunotherapy.

Long-term progression-free survival of patients with metastatic melanoma or renal cell carcinoma following high-dose interleukin-2

High-dose interleukin-2 (HD IL-2) was approved in the 1990s after demonstrating durable complete responses (CRs) in some patients with metastatic melanoma (mM) and metastatic renal cell carcinoma (mRCC). Patients who achieve this level of disease control have also demonstrated improved survival compared with patients who progress, but limited data are available describing the long-term course. The aim of this study was to better characterize long-term survival following successful HD IL-2 treatment in patients with no subsequent systemic therapy. Eleven HD IL-2 treatment centers identified patients with survival ≥5 years after HD IL-2, with no subsequent systemic therapy. Survival was evaluated from the date of IL-2 treatment to June 2017. Treatment courses consisted of 2 1-week cycles of HD IL-2. Patients were treated with HD IL-2 alone, or HD IL-2 followed by local therapy to achieve maximal response. 100 patients are reported: 54 patients with mM and 46 patients with mRCC. Progression-free survival (PFS) after HD IL-2 ranges from 5+ years to 30+ years, with a median follow-up of 10+ years. 27 mRCC and 32 mM are alive ≥10 years after IL-2. Thus, a small subset of patients with mM and mRCC achieve long-term PFS (≥5 years) after treatment with HD IL-2 as their only systemic therapy. The ability of HD IL-2 therapy to induce prolonged PFS should be a major consideration in studies of new immunotherapy combinations for mM and mRCC.

Landscape of Immunotherapy in Genitourinary Malignancies

The past decade has witnessed a revolution in the development of immune checkpoint inhibitors for the treatment of multiple tumor types, including genitourinary cancers. Immune checkpoint inhibitors have notably improved the treatment outcomes of patients with metastatic renal cell carcinoma and metastatic urothelial carcinoma. In prostate cancer, the role of immunotherapy with checkpoint inhibitors is not yet established except for microsatellite instability high (MSI-H) tumors. Other immunotherapeutic approaches that have been explored in these malignancies include cytokines, vaccines, and cellular therapy. Ongoing studies are exploring the use of immunotherapy combinations as well as combination with chemotherapy and targeted therapy in these types of tumors. The use of immunotherapy beyond the metastatic setting is an active area of research. Moreover, there is great interest in biomarker development to predict response to immunotherapy and risk of toxicity. This book chapter is a comprehensive review of immunotherapeutic approaches, both approved and investigational, for the treatment of renal cell carcinoma, urothelial carcinoma, and prostate cancer.

The clinical significance of routine risk categorization in metastatic renal cell carcinoma and its impact on treatment decision-making: a systematic review

Aim: To analyze responses to first-line metastatic renal cell carcinoma (mRCC) treatment stratified by risk criteria. Patients & methods: Clinical trials and observational studies of patients aged ≥18 years, published January 2005-May 2019, were identified via Ovid from MEDLINE, EMBASE, the Cochrane Central Trials Register and the Cochrane Database of Systematic Reviews. Data extracted included progression-free survival (PFS), overall survival (OS) and objective response rate (ORR). Results: 47/1269 articles met eligibility criteria. Most studies stratified patients by International Metastatic RCC Database Consortium (n = 19) or Memorial Sloan Kettering Cancer Center (n = 21). PFS, OS and ORR varied according to risk group. Conclusion: Pembrolizumab + axitinib, ipilimumab + nivolumab and avelumab + axitinib were most effective across all risk groups. Favorable-risk patients benefit from sunitinib treatment.

Overall survival by clinical risk category for high dose interleukin-2 (HD IL-2) treated patients with metastatic renal cell cancer (mRCC): data from the PROCLAIMSM registry

BACKGROUND

Prognostic scoring systems are used to estimate the risk of mortality from metastatic renal cell carcinoma (mRCC). Outcomes from different therapies may vary within each risk group. These survival algorithms have been applied to assess outcomes in patients receiving T-cell checkpoint inhibitory immunotherapy and tyrosine kinase inhibitor therapy, but have not been applied extensively to patients receiving high dose interleukin-2 (HD IL-2) immunotherapy.

METHODS

Survival of 810 mRCC patients treated from 2006 to 2017 with high dose IL-2 (aldesleukin) and enrolled in the PROCLAIMSM registry data base was assessed utilizing the International Metastatic RCC Database Consortium (IMDC) risk criteria. Median follow-up is 23.4 months (mo.) (range 0.2-124 mo.). Subgroup evaluations were performed by separating patients by prior or no prior therapy, IL-2 alone, or therapy subsequent to IL-2. Some patients were in two groups. We will focus on the 356 patients who received IL-2 alone, and evaluate outcome by risk factor categories.

RESULTS

Among the 810 patients, 721 were treatment-naïve (89%) and 59% were intermediate risk. Overall, of the 249 patients with favorable risk, the median overall survival (OS) is 63.3 mo. and the 2-year OS is 77.6%. Of 480 patients with intermediate risk, median OS is 42.4 mo., 2-year OS 68.2%, and of 81 patients with poor risk, median OS 14 mo., 2-year OS 40.4%. Among those who received IL-2 alone (356 patients), median OS is 64.5, 57.6, and 14 months for favorable, intermediate and poor risk categories respectively. Two year survival among those treated only with HD IL-2 is 73.4, 63.7 and 39.8%, for favorable, intermediate and poor risk categories respectively.

CONCLUSIONS

Among mRCC patients treated with HD IL-2, all risk groups have median and 2-year survival consistent with recent reports of checkpoint or targeted therapies for mRCC. Favorable and intermediate risk (by IMDC) patients treated with HD IL-2 have longer OS compared with poor risk patients, with most durable OS observed in favorable risk patients. Favorable risk patients treated with HD IL-2 alone have a 2-year OS of 74%. These data continue to support a recommendation for HD IL-2 for patients with mRCC who meet eligibility criteria.

TRIAL REGISTRATION

PROCLAIM, NCT01415167 was registered with ClinicalTrials.gov on August 11, 2011, and initiated for retrospective data collection until 2006, and prospective data collection ongoing since 2011.

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.

Evolving Treatment Paradigm in Metastatic Renal Cell Carcinoma

The treatment paradigm for advanced and metastatic renal cell carcinoma (mRCC) has evolved rapidly since the arrival of targeted therapies and novel immunotherapies. mRCC was previously treated only with cytokines. However, discoveries of mutations affecting the von Hippel-Lindau tumor suppressor gene (leading to increased expression of VEGF and hypoxia inducible factor/HIF-1) and of deregulations in the phosphatidylinositol-3 kinase/AKT/mTOR pathway (resulting in tumor angiogenesis, cell proliferation, and tumor growth) have led to the development of numerous targeted therapies. The U.S. Food and Drug Administration (FDA) has thus approved a total of nine targeted therapies since 2005, including VEGF tyrosine kinase inhibitors (sunitinib, pazopanib, axitinib, sorafenib, and lenvatinib), a monoclonal antibody targeting VEGF (bevacizumab), mTOR inhibitors (temsirolimus and everolimus), and a multityrosine kinase inhibitor (cabozantinib). Furthermore, the development of immune checkpoint inhibitors has again shifted the mRCC therapeutic landscape with the FDA's approval of nivolumab. Herein, we discuss the unprecedented changes in the field of clear cell histology mRCC in both the first-line and salvage settings, and we also discuss future therapies and recommend a treatment paradigm on sequencing of these agents.

Dorsal Muscle Attenuation May Predict Failure to Respond to Interleukin-2 Therapy in Metastatic Renal Cell Carcinoma

RATIONALE AND OBJECTIVES

To explore whether the sarcopenia body type can help predict response to interleukin-2 (IL-2) therapy in metastatic renal cell carcinoma (RCC).

MATERIALS AND METHODS

Institutional review board approval was obtained for this Health Insurance Portability and Accountability Act-compliant retrospective cohort study of 75 subjects with metastatic RCC who underwent pretreatment contrast-enhanced computed tomography within 1 year of initiating IL-2 therapy. Cross-sectional area and attenuation of normal-density (31-100 Hounsfield units [HU]) and low-density (0-30 HU) dorsal muscles were obtained at the T11 vertebral level. The primary outcome was partial or complete response to IL-2 using RECIST 1.1 criteria at 6 weeks. A conditional inference tree was used to determine an optimal HU cutoff for predicting outcome. Bonferroni-adjusted multivariate logistic regression was conducted to investigate the independent associations between imaging features and response after controlling for demographics, doses of IL-2, and RCC prognostic scales (eg, Heng and the Memorial Sloan Kettering Cancer Center [MSKCC]).

RESULTS

Most subjects had intermediate prognosis by Heng (65% [49 of 75]) and the MSKCC (63% [47 of 75]) criteria; 7% had complete response and 12% had partial response. Mean attenuation of low-density dorsal muscles was a significant univariate predictor of IL-2 response after Bonferroni correction (P = 0.03). The odds of responding to treatment were 5.8 times higher for subjects with higher-attenuation low-density dorsal muscles (optimal cutoff: 18.1 HU). This persisted in multivariate analysis (P = 0.02). Body mass index (P = 0.67) and the Heng (P = 0.22) and MSKCC (P = 0.08) clinical prognostic scales were not significant predictors of response.

CONCLUSIONS

Mean cross-sectional attenuation of low-density dorsal muscles (ie, sarcopenia) may predict IL-2 response in metastatic RCC. Clinical variables are poor predictors of response.

The Role of High Dose Interleukin-2 in the Era of Targeted Therapy

PURPOSE

We assessed survival outcomes following high dose interleukin-2 in a contemporary cohort of patients during the era of targeted agents.

MATERIALS AND METHODS

We retrospectively reviewed the records of patients with metastatic renal cell carcinoma treated with high dose interleukin-2 between July 2007 and September 2014. Clinicopathological data were abstracted and patient response to therapy was based on RECIST (Response Evaluation Criteria In Solid Tumors), version 1.1 criteria. The Kaplan-Meier method was used to estimate progression-free and overall survival in the entire cohort, the response to high dose interleukin-2 in regard to previous targeted agent therapy and the response to the targeted agent in relation to the response to high dose interleukin-2.

RESULTS

We identified 92 patients, of whom 87 had documentation of a response to high dose interleukin-2. Median overall survival was 34.4 months from the initiation of high dose interleukin-2 therapy in the entire cohort. Patients who received targeted therapy before high dose interleukin-2 had overall survival (median 34.4 and 30.0 months, p = 0.88) and progression-free survival (median 1.5 and 1.7 months, p = 0.8) similar to those in patients who received no prior therapy, respectively. Additionally, patients with a complete or partial response to high dose interleukin-2 had similar outcomes for subsequent targeted agents compared to patients whose best response was stable or progressive disease (median overall survival 30.1 vs 25.4 months, p = 0.4).

CONCLUSIONS

Our data demonstrate that patient responses to high dose interleukin-2 and to targeted agents before and after receiving high dose interleukin-2 are independent. As such, carefully selected patients should be offered high dose interleukin-2 for the possibility of a complete and durable response without the fear of limiting the treatment benefit of targeted agents.

Neutrophil-lymphocyte ratio as a predictive biomarker for response to high dose interleukin-2 in patients with renal cell carcinoma

BACKGROUND

Immunotherapy with high-dose interleukin-2 (HD-IL2) results in long-term survival in some metastatic renal cell carcinoma (mRCC) patients but has significant acute toxicities. Biomarkers predicting response to therapy are needed to better select patients most likely to benefit. NLR (absolute neutrophil count (ANC)/absolute lymphocyte count (ALC)) is a prognostic and predicative biomarker in various malignancies. The goal was to determine whether NLR can predict response to HD-IL2 in this setting.

METHODS

Patients with clear cell mRCC treated with HD-IL2 were identified from an institutional database from 2003-2012. Baseline variables for the assessment of IMDC risk criteria, and neutrophil and lymphocyte count, were collected. Best response criteria were based on RECIST 1.0. Wilcoxon rank-sum test was used to evaluate the association of continuous baseline variables with disease control. NLR was stratified by ≤4 or >4. Progression free survival (PFS) and overall survival (OS) were estimated with the Kaplan-Meier method and Cox proportional hazard models assessed associations of NLR with survival.

RESULTS

In 71 eligible patients, median NLR in those with an objective response (n = 14, 20%) was 2.3 vs 3.4 in those without (n = 57, 80%, p = 0.02). NLR ≤4 was associated with improved progression free and overall survival. After adjustment for IMDC risk criteria, NLR remained a significant predictor of OS (ANC/ALC ≤4 vs >4, HR 0.41, 95% CI 1.09-5.46, p = 0.03; ANC/ALC continuous variable per unit change in NLR, HR 1.08, 95% CI 1.01-1.14, p = 0.03).

CONCLUSIONS

In this discovery set, NLR predicts overall survival in patients treated with HD-IL2 in mRCC, and may allow better patient selection in this setting. Data needs validation in an independent cohort.

Conditional survival of metastatic renal cell carcinoma patients treated with high-dose interleukin-2

Conditional survival (CS) is a clinically useful prediction measure which adjusts a patient's prognosis based on their duration of survival since initiation of therapy. CS has been described in numerous malignancies, and recently described in patients with metastatic renal cell carcinoma (mRCC) who received vascular endothelial growth factor tyrosine kinase inhibitor (VEGFTKI) therapy. However, CS has been not reported in the context of mRCC treated with high-dose interleukin-2 therapy (HDIL-2). A total of 176 patients with histologically confirmed metastatic clear cell RCC (mccRCC) treated with HDIL-2 at the University of Utah Huntsman Cancer Institute from 1988-2012 were evaluated. Using the Heng/IMDC model, they were stratified by performance status and prognostic risk groups. Two-year CS was defined as the probability of surviving an additional two years from initiation of HDIL-2 to 18 months after the start of HDIL-2 at three-month intervals. The median overall survival (OS) was 19.9 months. Stratifying patients into favourable (n = 35; 20%), intermediate (n = 110; 63%), and poor (n = 31; 18%) prognostic groups resulted in median OS of 47.5 (HR 0.57, 95% CI 0.35-0.88, p = 0.0106 versus intermediate), 19.6 (HR 0.33, 95% CI 0.10-0.33, p < 0.0001 versus poor), and 8.8 (HR 5.34, 95% CI 3.00-9.62, p < 0.0001 versus favourable) months respectively. Two-year overall CS increased from 43% at therapy initiation to 100% at 18 months. These results have significant ramifications in prognostication. Furthermore, it is important when counseling patients with mccRCC who have completed treatment with HDIL-2 and are in active follow-up.

Immunotherapy of advanced renal cell carcinoma: Current and future therapies

Previously a malignancy with few therapeutic options, metastatic renal cell carcinoma (mRCC) treatment is rapidly evolving. Although cytokine therapies (interferon-a, interleukin-2) have been used less frequently over the past decade, recent approval of an immune checkpoint inhibitor, nivolumab, has led to a resurgence in immune therapy for mRCC. With greater understanding of the complex and dynamic interaction between the tumor and the immune system, numerous new immunotherapies are being studied for mRCC. In this article, we review the mechanism of action, clinical outcomes and toxicity profiles of both clinically approved and selected investigational immunotherapies. Either alone or in combination, these novel agents are encouraging for the future of mRCC therapy.