The 20th anniversary of interleukin-2 therapy: bimodal role explaining longstanding random induction of complete clinical responses

Recent Advances in Glioma Cancer Treatment: Conventional and Epigenetic Realms

Glioblastoma (GBM) is the most typical and aggressive form of primary brain tumor in adults, with a poor prognosis. Successful glioma treatment is hampered by ineffective medication distribution across the blood-brain barrier (BBB) and the emergence of drug resistance. Although a few FDA-approved multimodal treatments are available for glioblastoma, most patients still have poor prognoses. Targeting epigenetic variables, immunotherapy, gene therapy, and different vaccine- and peptide-based treatments are some innovative approaches to improve anti-glioma treatment efficacy. Following the identification of lymphatics in the central nervous system, immunotherapy offers a potential method with the potency to permeate the blood-brain barrier. This review will discuss the rationale, tactics, benefits, and drawbacks of current glioma therapy options in clinical and preclinical investigations.

Reassessing Patterns of Response to Immunotherapy with PET: From Morphology to Metabolism

Cancer demands precise evaluation and accurate and timely assessment of response to treatment. Imaging must be performed early during therapy to allow adjustments to the course of treatment. For decades, cross-sectional imaging provided these answers, showing responses to the treatment through changes in tumor size. However, with the emergence of immune checkpoint inhibitors, complex immune response patterns were revealed that have quickly highlighted the limitations of this approach. Patterns of response beyond tumor size have been recognized and include cystic degeneration, necrosis, hemorrhage, and cavitation. Furthermore, new unique patterns of response have surfaced, like pseudoprogression and hyperprogression, while other patterns were shown to be deceptive, such as unconfirmed progressive disease. This evolution led to new therapeutic evaluation criteria adapted specifically for immunotherapy. Moreover, inflammatory adverse effects of the immune checkpoint blockade were identified, many of which were life threatening and requiring prompt intervention. Given complex concepts like tumor microenvironment and novel therapeutic modalities in the era of personalized medicine, increasingly sophisticated imaging techniques are required to address the intricate patterns of behavior of different neoplasms. Fluorine 18-fluorodeoxyglucose PET/CT has rapidly emerged as one such technique that spans both molecular biology and immunology. This imaging technique is potentially capable of identifying and tracking prognostic biomarkers owing to its combined use of anatomic and metabolic imaging, which enables it to characterize biologic processes in vivo. This tailored approach may provide whole-body quantification of the metabolic burden of disease, providing enhanced prediction of treatment response and improved detection of adverse events. ^©RSNA, 2020.

Immunotherapy for glioma: Current management and future application

Gliomas are intrinsic brain tumors that originate from neuroglial progenitor cells. Conventional therapies, including surgery, chemotherapy, and radiotherapy, have achieved limited improvements in the prognosis of glioma patients. Immunotherapy, a revolution in cancer treatment, has become a promising strategy with the ability to penetrate the blood-brain barrier since the pioneering discovery of lymphatics in the central nervous system. Here we detail the current management of gliomas and previous studies assessing different immunotherapies in gliomas, despite the fact that the associated clinical trials have not been completed yet. Moreover, several drugs that have undergone clinical trials are listed as novel strategies for future application; however, these clinical trials have indicated limited efficacy in glioma. Therefore, additional studies are warranted to evaluate novel therapeutic approaches in glioma treatment.

Emerging strategies in cancer therapy combining chemotherapy with immunotherapy

Cancer immunotherapy holds great potential to battle cancer by exerting a durable immunity effect. However, this process might be limited by various constraints existing in the tumor microenvironment (TME), such as the lack of available neoantigen, insufficient T cells from the naive repertoire, or immunosuppressive networks in which immunogenic tissue is protected from immune attacks. Certain chemotherapeutic drugs could elicit immune-potentiating effects by either inducing immunogenicity or relieving tumor-induced immunosuppression. Some also leave tumors directly susceptible to cytotoxic T cell attacks. Mounting evidence accumulated from preclinical and clinical studies suggests that these two treatment modalities might be mutually reinforcing as an effective "chemo-immunotherapy" strategy. Herein, we reviewed the latest advances in cancer immunotherapy and related mechanisms involved in chemotherapeutic-mediated immune activation. The emerging combination strategies and synergistic effects in response to chemo-immunotherapy are highlighted. We also discuss the challenges and critical considerations in its future development.

Lessons From the Development of the Immune Checkpoint Inhibitors in Oncology

Immunotherapies are becoming increasingly important in the treatment armamentarium of a variety of malignancies. Immune checkpoint inhibitors are the most representative drugs receiving regulatory approval over the past few years. In a recent study published in Clinical Cancer Research, we demonstrated that these agents are being developed faster than other prior anticancer therapies. All checkpoint inhibitors received priority review, being granted with at least one Food and Drug Administration expedited program. Hence, some of them are getting marketing approval after preliminary trials. The model continues to rely on phase I trials, designed with traditional models for dose definition, although a substantial number of patients are treated during the dose expansion cohorts. We demonstrated that efficacy and safety are reasonably predicted from the dose-finding portion of phase I trials with these agents, assuring a low treatment-related mortality for patients throughout the development process. In this article, we further discuss and summarize these findings and update some recent approval information for immune checkpoint inhibitors.

Clinical Response Rates From Interleukin-2 Therapy for Metastatic Melanoma Over 30 Years' Experience: A Meta-Analysis of 3312 Patients

Interleukin-2 (IL-2), initially used in 1986, can induce clinical regression-complete responses (CR) and partial responses (PR) of metastatic malignant melanoma. IL-2 has been used alone or in combination, and in different dosage schedules, as an immunotherapeutic agent for melanoma treatment. This meta-analysis aimed to document and evaluate the spectrum of reported clinical response rates from the combined experience of almost 30 years of IL-2 clinical usage. Clinical trials using IL-2 for metastatic melanoma therapy that reported: dosage, combinations, study details, definitions and clinical CR, PR, and overall response (OR) rates were included. A meta-analysis was conducted using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. In total, 34 studies met inclusion criteria, with 41 separate treatment arms. For all IL-2 treatment modalities collectively, the CR rate was 4.0% [95% confidence interval (CI), 2.8-5.3], PR 12.5% (95% CI, 10.1-15.0), and OR 19.7% (95% CI, 15.9-23.5). CR pre-1994 was 2.7% versus 6.1% post-1994. High and intermediate-IL-2 dosage showed no CR difference, while low-dose IL-2 showed a nonstatistical trend toward an increased CR rate. The highest CR rate resulted from IL-2 combined with vaccine at 5.0%. The meta-analysis showed that IL-2 immunotherapy for advanced metastatic melanoma delivered a CR rate of 4% (range, 0-23%) across nearly 30 years of clinical studies, with gradual improvement over time. The significance is that, contrary to popular belief, the data demonstrated that CR rates were similar for intermediate versus high-IL-2 dosing.

Analysis of Drug Development Paradigms for Immune Checkpoint Inhibitors

Immune checkpoint inhibitors have unique toxicities and response kinetics compared with cytotoxic and gene-targeted anticancer agents. We investigated the impact of innovative/accelerated immunotherapy drug development/approval models on the accuracy of safety and efficacy assessments by searching the FDA website. Initial phase I trials for each agent were reviewed and safety and efficacy data compared with that found in later trials leading to regulatory approvals of the same agents. As of June 2017, the FDA approved six checkpoint inhibitors for a variety of cancer types. All checkpoint inhibitors received a priority review status and access to at least two additional FDA special access programs, more often breakthrough therapy designation and accelerated approval. Median clinical development time (investigational new drug application to approval) was 60.77 months [avelumab had the shortest timeline (52.33 months)]. Response rates during early phase I trials (median = 16%) are higher than for phase I trials of other agents (with the exception of gene-targeted agents tested with a biomarker). Doses approved were usually not identical to doses recommended on phase I trials. Approximately 50% of types of immune-related and 43% of types of clinically relevant toxicities from later trials were identified in early-phase trials. Even so, treatment-related mortality remains exceedingly low in later studies (0.33% of patients). In conclusion, efficacy and safety of immune checkpoint inhibitors appear to be reasonably predicted from the dose-finding portion of phase I trials, indicating that the fast-track development of these agents is safe and justified. Clin Cancer Res; 24(8); 1785-94. ©2017 AACR.

CRISPR-Mediated VHL Knockout Generates an Improved Model for Metastatic Renal Cell Carcinoma

Metastatic renal cell carcinoma (mRCC) is nearly incurable and accounts for most of the mortality associated with RCC. Von Hippel Lindau (VHL) is a tumour suppressor that is lost in the majority of clear cell RCC (ccRCC) cases. Its role in regulating hypoxia-inducible factors-1α (HIF-1α) and -2α (HIF-2α) is well-studied. Recent work has demonstrated that VHL knock down induces an epithelial-mesenchymal transition (EMT) phenotype. In this study we showed that a CRISPR/Cas9-mediated knock out of VHL in the RENCA model leads to morphologic and molecular changes indicative of EMT, which in turn drives increased metastasis to the lungs. RENCA cells deficient in HIF-1α failed to undergo EMT changes upon VHL knockout. RNA-seq revealed several HIF-1α-regulated genes that are upregulated in our VHL knockout cells and whose overexpression signifies an aggressive form of ccRCC in the cancer genome atlas (TCGA) database. Independent validation in a new clinical dataset confirms the upregulation of these genes in ccRCC samples compared to adjacent normal tissue. Our findings indicate that loss of VHL could be driving tumour cell dissemination through stabilization of HIF-1α in RCC. A better understanding of the mechanisms involved in this phenomenon can guide the search for more effective treatments to combat mRCC.

Breast cancer gene therapy using an adenovirus encoding human IL-2 under control of mammaglobin promoter/enhancer sequences

Interleukin-2 (IL-2) has been used clinically for the treatment of some malignancies, but the toxicities associated with systemic IL-2 therapy are a major challenge. Here we have determined whether transcriptional targeting of IL-2 to breast cancer (BrCa) using an engineered human mammaglobin promoter/enhancer (MPE2) is a feasible option for reducing IL-2-associated toxicities while still achieving a meaningful antitumor effect. We have constructed nonreplicating adenovirus vectors encoding either a reporter gene (luciferase) or human IL-2 (hIL-2) complementary DNA under control of the MPE2 sequence, the murine cytomegalovirus immediate early (MCMV) promoter or the human telomerase reverse transcriptase (hTERT) promoter. Luciferase and hIL-2 complementary DNAs under the control of the MPE2 sequence in adenovirus vectors were expressed at high levels in BrCa cells and at lower levels in normal cells of human and murine origin. Cancer specificity of the hTERT promoter was found to be similar to that of the MPE2 promoter in cells of human origin, but reduced specificity in murine cells. The MPE2 regulatory sequence demonstrated excellent tissue specificity in a mouse tumor model. Whereas the MCMV promoter-controlled IL-2 vector generated high liver toxicity in mice, the MPE2-controlled IL-2 vector generated little or no liver toxicity. Both IL-2 vectors exerted significant tumor growth delay; however, attempts to further enhance antitumor activity of the IL-2 vectors by combining with the proapoptotic drug procaspase activating compound 1 (PAC1) were unsuccessful.

Truncated Escherichia coli thioredoxin induces proliferation of human blood mononuclear cells and production of reactive oxygen species as well as proinflammatory cytokines

Thioredoxin (Trx) is a redox protein characterized by a Trx fold. A naturally occurring truncated human Trx, Trx 80, which lacks the C-terminal strand-helix of the Trx fold, stimulates proliferation of peripheral blood mononuclear cells (PBMCs). It has not been clear how Trx80 gains this function. This study investigates whether a peptide with substantial sequence difference from Trx80, but retaining an abridged Trx fold can elicit PBMC proliferation. We genetically truncated a carboxy-terminal β-α motif of Escherichia coli Trx to produce a peptide, Trx83, which shares low sequence identity with human Trx80. Addition of reduced-form Trx83 to resting human PBMCs promoted cell proliferation, while oxidized-form Trx83 lacked the function. By contrast, oxidized-form Trx80 exhibited a high activity in promoting PBMC proliferation, indicating the importance of sequence context of an abridged thioredoxin in influencing PBMC proliferation. Trx83 increases cellular reactive oxygen species and proinflammatory cytokines TNF-α and IL-1β, suggesting that Trx83 modulates inflammatory pathways. This notion is supported by the observation that cystine or cysteine abolishes the Trx83 induced PBMC proliferation. The PBMC stimulatory activity of Trx83 may have potential for pharmacological developments.

SIGNIFICANCE OF THE STUDY

Elicitation of primary proliferative responses of PBMCs by a protein is generally difficult. We show that Escherichia coli Trx83 with a truncated Trx fold induces PBMC proliferation, but only in the disulfide-reduced form. In contrast, oxidized-form human Trx80 is a potent stimulator. These results demonstrate that the sequence context of an abridged Trx fold is influential in inducing PBMC proliferation. The stimulatory effect of Trx83 is associated with an increase of inflammatory response. The possibility of eliciting PBMC proliferation and switching this activity on/off by redox control provides a perspective for developing Trx83 as a PBMC stimulatory agent. Copyright © 2016 John Wiley & Sons, Ltd.

An adenoviral cancer vaccine co-encoding a tumor associated antigen together with secreted 4-1BBL leads to delayed tumor progression

Previous studies have shown promising results when using an agonistic anti-4-1BB antibody treatment against established tumors. While this is promising, this type of treatment can induce severe side effects. Therefore, we decided to incorporate the membrane form of 4-1BB ligand (4-1BBL) in a replicative deficient adenovirus vaccine expressing the invariant chain (Ii) adjuvant fused to a tumor associated antigen (TAA). The Ii adjuvant increases and prolongs TAA specific CD8+ T cells as previously shown and local expression of 4-1BBL was chosen to avoid the toxicity associated with systemic antibody administration. Furthermore, adenovirus encoded 4-1BBL expression has previously been successfully used to enhance responses toward Plasmodium falciparum and Influenza A antigens. We showed that the incorporation of 4-1BBL in the adenovirus vector led to surface expression of 4-1BBL on antigen presenting cells, but it did not enhance T cell responses in mice towards the Ii linked antigen. In tumor-bearing mice, our vaccine was found to decrease the frequency of TAA specific CD8+ T cells, but this difference did not alter the therapeutic efficacy. In order to reconcile our findings with the previous reports of increased anti-cancer efficacy using systemically delivered 4-1BB agonists, we incorporated a secreted version of 4-1BBL (Fc-4-1BBL) in our vaccine and co-expressed it with the Ii linked to TAA. In tumor bearing mice, this vaccine initially delayed tumor growth and slightly increased survival compared to the vaccine expressing the membrane form of 4-1BBL. Accordingly, secreted 4-1BBL co-encoded with the Ii linked antigen may offer a simplification compared to administration of drug and vaccine separately.

The Immune System and Responses to Cancer: Coordinated Evolution

This review explores the incessant evolutionary interaction and co-development between immune system evolution and somatic evolution, to put it into context with the short, over 60-year, detailed human study of this extraordinary protective system. Over millions of years, the evolutionary development of the immune system in most species has been continuously shaped by environmental interactions between microbes, and aberrant somatic cells, including malignant cells. Not only has evolution occurred in somatic cells to adapt to environmental pressures for survival purposes, but the immune system and its function has been successively shaped by those same evolving somatic cells and microorganisms through continuous adaptive symbiotic processes of progressive simultaneous immunological and somatic change to provide what we observe today. Indeed, the immune system as an environmental influence has also shaped somatic and microbial evolution. Although the immune system is tuned to primarily controlling microbiological challenges for combatting infection, it can also remove damaged and aberrant cells, including cancer cells to induce long-term cures. Our knowledge of how this occurs is just emerging. Here we consider the connections between immunity, infection and cancer, by searching back in time hundreds of millions of years to when multi-cellular organisms first began. We are gradually appreciating that the immune system has evolved into a truly brilliant and efficient protective mechanism, the importance of which we are just beginning to now comprehend. Understanding these aspects will likely lead to more effective cancer and other therapies.

The Immune System and Responses to Cancer: Coordinated Evolution

This review explores the incessant evolutionary interaction and co-development between immune system evolution and somatic evolution, to put it into context with the short, over 60-year, detailed human study of this extraordinary protective system. Over millions of years, the evolutionary development of the immune system in most species has been continuously shaped by environmental interactions between microbes, and aberrant somatic cells, including malignant cells. Not only has evolution occurred in somatic cells to adapt to environmental pressures for survival purposes, but the immune system and its function has been successively shaped by those same evolving somatic cells and microorganisms through continuous adaptive symbiotic processes of progressive simultaneous immunological and somatic change to provide what we observe today. Indeed, the immune system as an environmental influence has also shaped somatic and microbial evolution. Although the immune system is tuned to primarily controlling microbiological challenges for combatting infection, it can also remove damaged and aberrant cells, including cancer cells to induce long-term cures. Our knowledge of how this occurs is just emerging. Here we consider the connections between immunity, infection and cancer, by searching back in time hundreds of millions of years to when multi-cellular organisms first began. We are gradually appreciating that the immune system has evolved into a truly brilliant and efficient protective mechanism, the importance of which we are just beginning to now comprehend. Understanding these aspects will likely lead to more effective cancer and other therapies.

Chemotherapy for Late-Stage Cancer Patients: Meta-Analysis of Complete Response Rates

Complete response (CR) rates reported for cytotoxic chemotherapy for late-stage cancer patients are generally low, with few exceptions, regardless of the solid cancer type or drug regimen. We investigated CR rates reported in the literature for clinical trials using chemotherapy alone, across a wide range of tumour types and chemotherapeutic regimens, to determine an overall CR rate for late-stage cancers. A total of 141 reports were located using the PubMed database. A meta-analysis was performed of reported CR from 68 chemotherapy trials (total 2732 patients) using standard agents across late-stage solid cancers—a binomial model with random effects was adopted. Mean CR rates were compared for different cancer types, and for chemotherapeutic agents with different mechanisms of action, using a logistic regression. Our results showed that the CR rates for chemotherapy treatment of late-stage cancer were generally low at 7.4%, regardless of the cancer type or drug regimen used. We found no evidence that CR rates differed between different chemotherapy drug types, but amongst different cancer types small CR differences were evident, although none exceeded a mean CR rate of 11%. This remarkable concordance of CR rates regardless of cancer or therapy type remains currently unexplained, and motivates further investigation.

Cytokine therapy restores antitumor responses of NK cells rendered anergic in MHC I-deficient tumors

Recent extraordinary advances in cancer immunotherapy rely primarily on marshaling T cell responses. Here we discuss how NK cell responses can be amplified. We find that MHC I-deficient tumors induce anergy of NK cells but that cytokine therapy restores NK cell activity and increases the survival of mice bearing MHC I-deficient tumors.

Long-term survival in advanced melanoma patients using repeated therapies: successive immunomodulation improving the odds?

Background

Patients with advanced metastatic melanoma are often confronted with little prospect of medium- to longer-term survival by any currently available therapeutic means. However, most clinicians are aware of exceptional cases where survival defies the notion of futility. Prolonged survival from immunotherapies, including interleukin-2, vaccines and antibodies to cytotoxic lymphocyte antigen-4, and programmed death-1 receptor inhibitory monoclonal antibody, implies a role for immune system modulation. We aimed to identify cases where exceptional survival from advanced melanoma occurred prior to recent novel therapies to facilitate better understanding of this phenomenon.

Methods

Cases of long-term survival of ≥3 years’ duration (from diagnosis of metastatic disease) were identified from the database of one clinician; these cases were treated before the availability of newer immunotherapies, and they were documented and examined. A literature search for reported outcome measures from published studies using older and recent therapies for advanced melanoma was conducted to enable the comparison of data.

Results

Eighteen cases were identified that identified survival of ≥3 years’ duration from metastatic disease (12 American Joint Committee on Cancer [AJCC] Stage IV cases; six AJCC III cases) diagnosis. These were assessed and reported to detail the clinical course. Standard clinical prognostication methods predicted high risk of early mortality in those patients. No identifiable differences could be detected between these and other patients with similar patterns of disease. At evaluation, 17 patients (94%) had survived ≥5 years, and eleven patients (61%) had survived ≥10 years (range: 3–15 years). The median survival duration with metastatic disease was 11 years; 15 remained alive and three had died. Published studies of melanoma therapies were tabled for comparison.

Conclusion

The fact that 18 cases of exceptional survival in advanced melanoma were identified is remarkable in itself. Even with recent therapies, the factors for improved survival remain enigmatic; however, one apparent common denominator in most cases was the persistent use of repeated therapies to reduce tumor bulk, induce tumor necrosis, and/or cause immunostimulation. These cases are instructive, suggesting manipulation of an established, endogenous, existing immune response. These observations provide practical evidence that the course for any patient with advanced melanoma at the outset should be considered unpredictable, open to immunomanipulation, and thus not uniformly fatal. The findings were compared and interpreted with reported newer immunotherapeutic approaches.

Molecular dissection of the interactions of an antitumor interleukin-2-derived mutein on a phage display-based platform

A mutein with stronger antitumor activity and lower toxicity than wild-type human interleukin-2 (IL-2) has been recently described. The rationale behind its design was to reinforce the immunostimulatory potential through the introduction of four mutations that would selectively disrupt the interaction with the IL-2 receptor alpha chain (thought to be critical for both IL-2-driven expansion of T regulatory cells and IL-2-mediated toxic effects). Despite the successful results of the mutein in several tumor models, characterization of its interactions was still to be performed. The current work, based on phage display of IL-2-derived variants, showed the individual contribution of each mutation to the impairment of alpha chain binding. A more sensitive assay, based on the ability of phage-displayed IL-2 variants to induce proliferation of the IL-2-dependent CTLL-2 cell line, revealed differences between the mutated variants. The results validated the mutein design, highlighting the importance of the combined effects of the four mutations. The developed phage display-based platform is robust and sensitive, allows a fast comparative evaluation of multiple variants, and could be broadly used to engineer IL-2 and related cytokines, accelerating the development of cytokine-derived therapeutics.

NK cells from malignant pleural effusions are potent antitumor effectors: A clue for adoptive immunotherapy?

Natural killer (NK) cells exert potent antitumor activity. However, NK cells infiltrating solid tumors are severely impaired in their function. Remarkably, NK cells isolated from malignant pleural effusions kill very efficiently tumor cells upon exposure to interleukin-2, offering an important clue for the development of novel approaches for tumor immunotherapy.

High dose interleukin-2 (Aldesleukin) - expert consensus on best management practices-2014

Interleukin-2 (IL-2) was historically one of the few treatments for adults with stage IV solid tumors that could produce complete responses (CRs) that were often durable for decades without further therapy. The majority of complete responders with metastatic renal cell carcinoma (mRCC) and metastatic melanoma (mM) could probably be classified as "cures". Recent publications have suggested improved efficacy, perhaps due to improved patient selection based on a better understanding of clinical features predicting outcomes. Guidelines for clinical management were established from experience at the National Cancer Institute (NCI) and an affiliation of institutions known as the Cytokine Working Group (CWG), who were among the first to utilize HD IL-2 treatment outside of the NCI. As new centers have opened, further management variations have emerged based upon center-specific experience, to optimize administration of IL-2 and provide high quality care for patients at each individual site. Twenty years of evolution in differing environments has led to a plethora of clinical experience and effective management approaches. The goal of this review is to summarize the spectrum of HD IL-2 treatment approaches, describing various effective strategies that incorporate newer adjunctive treatments for managing the side effects of IL-2 in patients with mRCC and mM. The goal for IL-2 therapy is typically to administer the maximum number of doses of IL-2 without putting the patient at unacceptable risk for severe, irreversible toxicity. This review is based upon a consensus meeting and includes guidelines on pre-treatment screening, criteria for administration and withholding doses, and defines consensus criteria for safe administration and toxicity management. The somewhat heterogeneous best practices of 2014 will be compared and contrasted with the guidelines provided in 2001 and the package inserts from 1992 and 1998.

Co-expression of tumor antigen and interleukin-2 from an adenoviral vector augments the efficiency of therapeutic tumor vaccination

We have previously shown that for the majority of antigens, adenoviral vaccines expressing the target antigen fused to the MHC associated invariant chain (Ii) induce an accelerated, augmented, and prolonged transgene-specific CD8(+) T-cell response. Here we describe a new adenoviral vaccine vector approach where the target antigen fused to Ii is expressed from the adenoviral E1 region and IL-2 is expressed from the E3 region. Immunization of mice with this new vector construct resulted in an augmented primary effector CD8(+) T-cell response. Furthermore, in a melanoma model we observed significantly prolonged tumor control in vaccinated wild type (WT) mice. The improved tumor control required antigen-specific cells, since no tumor control was observed, unless the melanoma cells expressed the vaccine targeted antigen. We also tested our new vaccine in immunodeficient (CD80/86 deficient) mice. Following vaccination with the IL-2 expressing construct, these mice were able to raise a delayed but substantial CD8(+) T-cell response, and to control melanoma growth nearly as efficaciously as similarly vaccinated WT mice. Taken together, these results demonstrate that current vaccine vectors can be improved and even tailored to meet specific demands: in the context of therapeutic vaccination, the capacity to promote an augmented effector T-cell response.

Genetically engineered Newcastle disease virus expressing interleukin-2 and TNF-related apoptosis-inducing ligand for cancer therapy

Recombinant Newcastle disease virus (rNDV) have shown oncolytic therapeutic efficacy in preclinical studies and are currently in clinical trials. In this study, we have evaluated the possibility to enhance the cancer therapeutic potential of NDV by means of inserting both interleukin-2 (IL-2) and tumor necrosis factor-related apoptosis inducing ligand (TRAIL) delivered by rNDV. We demonstrated that rNDV expressing TRAIL (rNDV-TRAIL) or both human IL-2 and TRAIL (rNDV-IL-2-TRAIL) significantly enhanced inherent anti-neoplastic of rNDV by inducing apoptosis. And we showed that apoptosis-related genes mRNA expression was increased after treated with rNDV-TRAIL or rNDV-IL-2-TRAIL compared with rNDV and rNDV-IL-2. We also demonstrated that both rNDV-IL-2 and rNDV-IL-2-TRAIL induced proliferation of the CD4(+) and CD8(+) in treated mice and elicited expression of TNF-α and IFN-γ antitumor cytokines. These mice treated with oncolytic agents exhibited significant reduction in tumor development compared with mice treated with the parental virus. In addition, experiments in both hepatocellular carcinoma and melanoma-bearing mice demonstrated that the genetically engineered rNDV-IL-2-TRAIL exhibited prolonged animals' survival compared with rNDV, rNDV-IL-2, and rNDV-TRAIL. In conclusion, the immunotherapy and oncolytic virotherapy properties of NDV can be enhanced by the introduction of IL-2 and TRAIL genes, whose products initiated a broad cascade of immunological affects and induced tumor cells apoptosis in the microenvironment of the immune system.

High-dose interleukin-2 therapy for metastatic renal cell carcinoma: a contemporary experience

OBJECTIVE

To present our experience of high-dose interleukin-2 (HDIL-2) in a high-volume National Cancer Institute-designated center for patients with metastatic renal cell carcinoma (mRCC).

METHODS

Patients with mRCC who received HDIL-2 monotherapy as a first- or second-line therapy during 2004-2011 were identified. Demographics, pathologic variables, renal function, time until the start of HDIL-2 therapy, number of cycles (1-3), responses (complete response, partial response, stable disease, and progressive disease), and primary renal cell carcinoma treatment were analyzed. Progression-free survival and overall survival (OS) were determined.

RESULTS

Of 906 patients in the kidney cancer database, 91 patients with mRCC were treated with HDIL-2 and 18 patients (20.5%) underwent prior cytoreductive nephrectomy. Median age was 51 years, and 73.9% were men. Median follow-up was 45 months. Pretreatment renal function impairment led to more treatment cycles (2-3) than in those with adequate initial kidney function (92.3% vs 50.6%, respectively; P = .002). Lower tumor stage correlated with a better response (P = .023) and with longer time from diagnosis to initiation of HDIL-2 (P = .011). Complications included hypotension (67.4%), renal impairment (63%), impaired liver function (42.4%), and thrombocytopenia (31.5%). Four patients (4.5%) had a complete response, 10 (11.4%) had a partial response, and 28 (31.8%) had a stable disease. Median progression-free survival and OS were 8.6 and 35.5 months, respectively. The estimated 2-year OS rate was 60.6%.

CONCLUSION

Incorporating HDIL-2 therapy in the treatment strategies for mRCC added to the patients' survival in this series. HDIL-2 therapy is well tolerated in patients with pre-existing renal impairment with no long-term renal toxicity.

Recombinant IL-21 and anti-CD4 antibodies cooperate in syngeneic neuroblastoma immunotherapy and mediate long-lasting immunity

IL-21 is an immune-enhancing cytokine, which showed promising results in cancer immunotherapy. We previously observed that the administration of anti-CD4 cell-depleting antibody strongly enhanced the anti-tumor effects of an IL-21-engineered neuroblastoma (NB) cell vaccine. Here, we studied the therapeutic effects of a combination of recombinant (r) IL-21 and anti-CD4 monoclonal antibodies (mAb) in a syngeneic model of disseminated NB. Subcutaneous rIL-21 therapy at 0.5 or 1 μg/dose (at days 2, 6, 9, 13 and 15 after NB induction) had a limited effect on NB development. However, coadministration of rIL-21 at the two dose levels and a cell-depleting anti-CD4 mAb cured 28 and 70 % of mice, respectively. Combined immunotherapy was also effective if started 7 days after NB implant, resulting in a 30 % cure rate. Anti-CD4 antibody treatment efficiently depleted CD4(+) CD25(high) Treg cells, but alone had limited impact on NB. Combination immunotherapy by anti-CD4 mAb and rIL-21 induced a CD8(+) cytotoxic T lymphocyte response, which resulted in tumor eradication and long-lasting immunity. CD4(+) T cells, which re-populated mice after combination immunotherapy, were required for immunity to NB antigens as indicated by CD4(+) T cell depletion and re-challenge experiments. In conclusion, these data support a role for regulatory CD4(+) T cells in a syngeneic NB model and suggest that rIL-21 combined with CD4(+) T cell depletion reprograms CD4(+) T cells from immune regulatory to anti-tumor functions. These observations open new perspectives for the use of IL-21-based immunotherapy in conjunction with transient CD4(+) T cell depletion, in human metastatic NB.

Prolonged repeated vaccine immuno-chemotherapy induces long-term clinical responses and survival for advanced metastatic melanoma

BACKGROUND

Repetitive long-term Vaccinia Melanoma Cell Lysate (VMCL) vaccination schedules have proved clinically effective in producing Complete Responses and strong durable survivals for up to 6.1 years in a previous study of patients with advanced Stage IV and Stage IIIc melanoma. These studies were expanded to include 54 patients for further evaluation of these findings.

METHODS

54 patients comprising 48 Stage IV (6 M1a, 14 M1b, 28 M1c) and 6 advanced Stage III (5 IIIc; 1 IIIb) were studied using repeated intra-dermal VMCL vaccine therapy. If disease progressed, vaccine was continued together with standard chemotherapy (DTIC and/or Fotemustine). Overall survival was the primary end-point assessed, with clinical responses and toxicity recorded.

RESULTS

From vaccine commencement, median overall survival was 14 months, ranging from 4 to 121 months. Kaplan-Meier survival analysis demonstrated overall 1, 2 and 3-year survival estimates of 57%, 26% and 18.5% respectively, and overall 5-year survival of 15.4%. No appreciable toxicity was observed. Complete Responses (CR) occurred in 16.7% (9) and partial responses (PR) in 14.8% (8) of patients. Stable disease was noted in a further 25 patients (46.3%). No response to therapy was apparent in 12 patients (22.2%). The overall response rate was 31.5% (CR + PR), with clinically significant responses (CR + PR + SD) in 77.8% of patients. Strong, durable clinical responses with overall survivals ≥ 23 months occurred in 29.6% of patients treated with repeated VMCL vaccine for advanced melanoma, (+/- concurrent chemotherapy).

CONCLUSIONS

Prolonged, repetitive VMCL vaccination immunotherapy appears to be a clinically effective means of generating relatively high CR rates, useful clinical responses and long-term survivals, with little toxicity, but remains notably under-explored. Successive immunomodulation might explain the results. Closer analysis of repetitive dosing is required to improve clinical response rates and survival, perhaps by optimising the timing of immunotherapy delivery.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry ANZCTRN12605000425695.

Low-dose inhalation of interleukin-2 bio-chemotherapy for the treatment of pulmonary metastases in melanoma patients

Background:

Interleukin-2 (IL-2) treatment for patients with metastatic melanoma has shown remarkable durable responses. Systemic administration of IL-2 may cause severe side effects, whereas local administration is considered to be a safe alternative. The lungs are common sites of metastases in melanoma patients causing considerable respiratory problems. We sought to evaluate the potential antitumoral effect of a low-dose inhalative IL-2 (lh-IL-2) regimen for patients with melanoma lung metastases. In addition, we explored the prophylactic potential of Ih-IL-2 after surgical removal of lung metastases in a study carried out in an outpatient setting.

Methods:

Twenty patients with American Joint Committee on Cancer stage-IV (M1b and M1c) melanoma were enrolled in this study and treated with 3 × 3 million IU inhalative IL-2 q.d. together with monthly dacarbazine bolus injections. Five patients received lh-IL-2 after surgical resection of lung metastases to prevent recurrence of the disease (prophylaxis group, N=5). All other patients were enrolled in the treatment group (N=15). Clinical evaluations were carried out monthly and radiological follow-up was performed every third month.

Results:

Nine patients in the treatment group had a clinical benefit with partial regression (27%) or stable disease (33%). Four patients had progression of lung metastases (26.7%) and two patients were not evaluable (13.3%). In the prophylaxis group, none of the patients developed new lung metastases during lh-IL-2 therapy. The median follow-up period was 7.8 months in the treatment group and 25.7 months in the prophylaxis group. In the majority of patients, treatment was well tolerated.

Conclusions:

Low-dose IL-2 inhalation might offer an effective and safe treatment option for lung metastases in melanoma patients. In addition, lh-IL-2 may have a prophylactic potential to prevent recurrence in the lungs after pulmonary melanoma metastasectomy. Administration can easily be performed in an outpatient setting, thus offering an attractive treatment option.

Recent developments in the treatment of renal cell carcinoma

Renal cell carcinoma (RCC) management has been imbued with new interest, in large part due to the recent success of new treatment options for advanced and metastatic disease. This has also been accompanied by less generally well known advances in the understanding of the molecular characterizations of subtypes of RCC with potential to lead to new therapeutic options. Additionally, the urologic oncology community is focusing on nephron-sparing surgical approaches with limited surgery if possible, and in conjunction with interventional radiologists, on ablative procedures for incidentally determined small renal masses. This report reviews some of the new biologic findings of adenocarcinoma of the kidney, and reviews the new therapeutics which continue to change the landscape for treatment of RCC.

PD-1 expression on peripheral blood cells increases with stage in renal cell carcinoma patients and is rapidly reduced after surgical tumor resection

Programmed death-1 (PD-1) receptor is an inhibitory receptor on hematopoietic cells that can negatively regulate immune responses, particularly responses to tumors, which often upregulate PD-1 ligands. PD-1/PD-1 ligand blocking antibodies can reverse the inhibition and show significant therapeutic promise in treating renal cell carcinoma (RCC), lung cancer, and melanoma. While PD-1 expression on tumor-infiltrating lymphocytes has been associated with poor outcome in RCC, we sought to define immune cell biomarkers, including PD-1, on peripheral blood mononuclear cells (PBMC) that could predict disease progression of RCC patients before and after nephrectomy. We analyzed expression of numerous immune cell markers on fresh PBMCs from 90 RCC patients preoperatively and 25 age-matched healthy controls by 10-color flow cytometry. Postoperative blood samples were also analyzed from 23 members of the RCC patient cohort. The most striking phenotypic immune biomarker in RCC patients was a significant increase in PD-1 expression on certain PBMCs in a subset of patients. Increased PD-1 expression on CD14(bright) myelomonocytic cells, effector T cells, and natural killer (NK) cells correlated to disease stage, and expression was significantly reduced on all cell types soon after surgical resection of the primary tumor. The results indicate that PD-1 expression on fresh peripheral blood leukocytes may provide a useful indicator of RCC disease progression. Furthermore, measuring PD-1 levels in peripheral blood may assist in identifying patients likely to respond to PD-1 blocking antibodies, and these therapies may be most effective before and immediately after surgical resection of the primary tumor, when PD-1 expression is most prominent.

Production of recombinant immunotherapeutics for anticancer treatment: the role of bioengineering

Cancer is one of the most important health problems because many cases are difficult to prevent. Cancer still has unknown mechanisms of pathogenesis, and its capacity to produce temporary or permanent damage, besides death, is very high. Although many anticancer therapies are available, finding a cure for cancer continues to be a difficult task. Thus, many efforts have been made to develop more effective treatments, such as immunotherapy based on a new class of tumor-specific products that are produced using recombinant DNA technology. These recombinant products are used with the main objectives of killing the tumor and stimulating immune cells to respond to the cancer cells. The principal recombinant products in anticancer therapy are immunostimulants, vaccines, antibodies, immunotoxins and fusion proteins. This review focuses on the general aspects of these genetically engineered products, their clinical performance, current advances and future prospects for this type of anticancer therapy.