Targeting pulmonary metastases of renal cell carcinoma by inhalation of interleukin-2

Aerosol pulmonary immune engineering

Aerosolization of immunotherapies poses incredible potential for manipulating the local mucosal-specific microenvironment, engaging specialized pulmonary cellular defenders, and accessing mucosal associated lymphoid tissue to redirect systemic adaptive and memory responses. In this review, we breakdown key inhalable immunoengineering strategies for chronic, genetic, and infection-based inflammatory pulmonary disorders, encompassing the historic use of immunomodulatory agents, the transition to biological inspired or derived treatments, and novel approaches of complexing these materials into drug delivery vehicles for enhanced release outcomes. Alongside a brief description of key immune targets, fundamentals of aerosol drug delivery, and preclinical pulmonary models for immune response, we survey recent advances of inhaled immunotherapy platforms, ranging from small molecules and biologics to particulates and cell therapies, as well as prophylactic vaccines. In each section, we address the formulation design constraints for aerosol delivery as well as advantages for each platform in driving desirable immune modifications. Finally, prospects of clinical translation and outlook for inhaled immune engineering are discussed.

Inhaled recombinant human IL-15 in dogs with naturally occurring pulmonary metastases from osteosarcoma or melanoma: a phase 1 study of clinical activity and correlates of response

PURPOSE

Although recombinant human interleukin-15 (rhIL-15) has generated much excitement as an immunotherapeutic agent for cancer, activity in human clinical trials has been modest to date, in part due to the risks of toxicity with significant dose escalation. Since pulmonary metastases are a major site of distant failure in human and dog cancers, we sought to investigate inhaled rhIL-15 in dogs with naturally occurring lung metastases from osteosarcoma (OSA) or melanoma. We hypothesized a favorable benefit/risk profile given the concentrated delivery to the lungs with decreased systemic exposure.

EXPERIMENTAL DESIGN

We performed a phase I trial of inhaled rhIL-15 in dogs with gross pulmonary metastases using a traditional 3+3 cohort design. A starting dose of 10 µg twice daily × 14 days was used based on human, non-human primate, and murine studies. Safety, dose-limiting toxicities (DLT), and maximum tolerated dose (MTD) were the primary objectives, while response rates, progression-free and overall survival (OS), and pharmacokinetic and immune correlative analyses were secondary.

RESULTS

From October 2018 to December 2020, we enrolled 21 dogs with 18 dogs reaching the 28-day response assessment to be evaluable. At dose level 5 (70 μg), we observed two DLTs, thereby establishing 50 µg twice daily × 14 days as the MTD and recommended phase 2 dose. Among 18 evaluable dogs, we observed one complete response >1 year, one partial response with resolution of multiple target lesions, and five stable disease for an overall clinical benefit rate of 39%. Plasma rhIL-15 quantitation revealed detectable and sustained rhIL-15 concentrations between 1-hour and 6 hour postnebulization. Decreased pretreatment lymphocyte counts were significantly associated with clinical benefit. Cytotoxicity assays of banked peripheral blood mononuclear cells revealed significant increases in peak cytotoxicity against canine melanoma and OSA targets that correlated with OS.

CONCLUSIONS

In this first-in-dog clinical trial of inhaled rhIL-15 in dogs with advanced metastatic disease, we observed promising clinical activity when administered as a monotherapy for only 14 days. These data have significant clinical and biological implications for both dogs and humans with refractory lung metastases and support exploration of combinatorial therapies using inhaled rhIL-15.

Targeted PEG-poly(glutamic acid) complexes for inhalation protein delivery to the lung

Pulmonary delivery is increasingly seen as an attractive, non-invasive route for the delivery of forthcoming protein therapeutics. In this context, here we describe protein complexes with a new 'complexing excipient' - vitamin B₁₂-targeted poly(ethylene glycol)-block-poly(glutamic acid) copolymers. These form complexes in sub-200nm size with a model protein, suitable for cellular targeting and intracellular delivery. Initially we confirmed expression of vitamin B₁₂-internalization receptor (CD320) by Calu-3 cells of the in vitro lung epithelial model used, and demonstrated enhanced B₁₂ receptor-mediated cellular internalization of B₁₂-targeted complexes, relative to non-targeted counterparts or protein alone. To develop an inhalation formulation, the protein complexes were spray dried adopting a standard protocol into powders with aerodynamic diameter within the suitable range for lower airway deposition. The cellular internalization of targeted complexes from dry powders applied directly to Calu-3 model was found to be 2-3 fold higher compared to non-targeted complexes. The copolymer complexes show no complement activation, and in vivo lung tolerance studies demonstrated that repeated administration of formulated dry powders over a 3 week period in healthy BALB/c mice induced no significant toxicity or indications of lung inflammation, as assessed by cell population count and quantification of IL-1β, IL-6, and TNF-α pro-inflammatory markers. Importantly, the in vivo data appear to suggest that B₁₂-targeted polymer complexes administered as dry powder enhance lung retention of their protein payload, relative to protein alone and non-targeted counterparts. Taken together, our data illustrate the potential developability of novel B₁₂-targeted poly(ethylene glycol)-poly(glutamic acid) copolymers as excipients suitable to be formulated into a dry powder product for the inhalation delivery of proteins, with no significant lung toxicity, and with enhanced protein retention at their in vivo target tissue.

Inhaled Submicron Particle Paclitaxel (NanoPac) Induces Tumor Regression and Immune Cell Infiltration in an Orthotopic Athymic Nude Rat Model of Non-Small Cell Lung Cancer

Background: This study evaluated the antineoplastic and immunostimulatory effects of inhaled (IH) submicron particle paclitaxel (NanoPac^®) in an orthotopic non-small cell lung cancer rodent model.

Methods: Male nude rats were whole body irradiated, intratracheally instilled with Calu-3 cancer cells and divided into six treatment arms (n = 20 each): no treatment (Group 1); intravenous nab-paclitaxel at 5.0 mg/kg once weekly for 3 weeks (Group 2); IH NanoPac at 0.5 or 1.0 mg/kg, once weekly for 4 weeks (Groups 3 and 4), or twice weekly for 4 weeks (Groups 5 and 6). Upon necropsy, left lungs were paraffin embedded, serially sectioned, and stained for histopathological examination. A subset was evaluated by immunohistochemistry (IHC), anti-pan cytokeratin staining AE1/AE3⁺ tumor cells and CD11b⁺ staining dendritic cells, natural killer lymphocytes, and macrophage immune cells (n = 2, Group 1; n = 3 each for Groups 2–6). BCL-6 staining identified B lymphocytes (n = 1 in Groups 1, 2, and 6).

Results: All animals survived to scheduled necropsy, exhibited no adverse clinical observations due to treatment, and gained weight at the same rate throughout the study. Histopathological evaluation of Group 1 lung samples was consistent with unabated tumor growth. Group 2 exhibited regression in 10% of animals (n = 2/20). IH NanoPac-treated groups exhibited significantly higher tumor regression incidence per group (n = 11–13/20; p < 0.05, χ²). IHC subset analysis revealed tumor-nodule cluster separation, irregular borders between tumor and non-neoplastic tissue, and an increased density of infiltrating CD11b⁺ cells in Group 2 animals (n = 2/3) and in all IH NanoPac-treated animals reviewed (n = 3/3 per group). A single animal in Group 4 and Group 6 exhibited signs of pathological complete response at necropsy with organizing stroma and immune cells replacing areas presumed to have previously contained adenocarcinoma nodules.

Conclusion: Tumor regression and immune cell infiltration were observed in all treatment groups, with an increased incidence noted in animals receiving IH submicron particle paclitaxel treatment.

Carriers for the targeted delivery of aerosolized macromolecules for pulmonary pathologies

INTRODUCTION

Macromolecules with unique effects and potency are increasingly being considered for application in lung pathologies. Numerous delivery strategies for these macromolecules through the lung have been investigated to improve the targeting and overall efficacy.

AREAS COVERED

Targeting approaches from delivery devices, formulation strategies and specific targets are discussed.

EXPERT OPINION

Although macromolecules are a heterogeneous group of molecules, a number of strategies have been investigated at the macro, micro, and nanoscopic scale for the delivery of macromolecules to specific sites and cells of lung tissues. Targeted approaches are already in use at the macroscopic scale through inhalation devices and formulations, but targeting strategies at the micro and nanoscopic scale are still in the laboratory stage. The combination of controlling lung deposition and targeting after deposition, through a combination of targeting strategies could be the future direction for the treatment of lung pathologies through the pulmonary route.

Interleukin-2: Old and New Approaches to Enhance Immune-Therapeutic Efficacy

Interleukin-2 (IL-2) is a very well-known cytokine that has been studied for the past 35 years. It plays a major role in the growth and proliferation of many immune cells such NK and T cells. It is an important immunotherapy cytokine for the treatment of various diseases including cancer. Systemic delivery of IL-2 has shown clinical benefit in renal cell carcinoma and melanoma patients. However, its use has been limited by the numerous toxicities encountered with the systemic delivery. Intravenous IL-2 causes the well-known "capillary leak syndrome," or the leakage of fluid from the circulatory system to the interstitial space resulting in hypotension (low blood pressure), edema, and dyspnea that can lead to circulatory shock and eventually cardiopulmonary collapse and multiple organ failure. Due to the toxicities associated with systemic IL-2, an aerosolized delivery approach has been developed, which enables localized delivery and a higher local immune cell activation. Since proteins are absorbed via pulmonary lymphatics, after aerosol deposition in the lung, aerosol delivery provides a means to more specifically target IL-2 to the local immune system in the lungs with less systemic effects. Its benefits have extended to diseases other than cancer. Delivery of IL-2 via aerosol or as nebulized IL-2 liposomes has been previously shown to have less toxicity and higher efficacy against sarcoma lung metastases. Dogs with cancer provided a highly relevant means to determine biodistribution of aerosolized IL-2 and IL-2 liposomes. However, efficacy of single-agent IL-2 is limited. As in general, for most immune-therapies, its effect is more beneficial in the face of minimal residual disease. To overcome this limitation, combination therapies using aerosol IL-2 with adoptive transfer of T cells or NK cells have emerged.Using a human osteosarcoma (OS) mouse model, we have demonstrated the efficacy of single-agent aerosol IL-2 and combination therapy aerosol IL-2 and NK cells or aerosol IL-2 and interleukin 11 receptor alpha-directed chimeric antigen receptor-T cells (IL-11 receptor α CAR-T cells) against OS pulmonary metastases. Combination therapy resulted in a better therapeutic effect. A Phase-I trial of aerosol IL-2 was done in Europe and proved to be safe. Others and our preclinical studies provided the basis for the development of a Phase-I aerosol IL-2 trial in our institution to include younger patients with lung metastases. OS, our disease of interest, has a peak incidence in the adolescent and young adult years. Our goal is to complete this trial in the next 2 years.In this chapter, we summarize the different effects of IL-2 and cover the advantages of the aerosol delivery route for diseases of the lung with an emphasis on some of our most recent work using combination therapy aerosol IL-2 and NK cells for the treatment of OS lung metastases.

Protein stability in pulmonary drug delivery via nebulization

Protein inhalation is a delivery route which offers high potential for direct local lung application of proteins. Liquid formulations are usually available in early stages of biopharmaceutical development and nebulizers are the device of choice for atomization avoiding additional process steps like drying and enabling fast progression to clinical trials. While some proteins were proven to remain stable throughout aerosolization e.g. DNase, many biopharmaceuticals are more susceptible towards the stresses encountered during nebulization. The main reason for protein instability is unfolding and aggregation at the air-liquid interface, a problem which is of particular challenge in the case of ultrasound and jet nebulizers due to recirculation of much of the generated droplets. Surfactants are an important formulation component to protect the sensitive biomolecules. A second important challenge is warming of ultrasound and vibrating mesh devices, which can be overcome by overfilling, precooled solutions or cooling of the reservoir. Ultimately, formulation development has to go hand in hand with device evaluation.

Nanotechnology approaches for inhalation treatment of lung diseases

Local administration of therapeutics by inhalation for treatment of lung diseases has the ability to deliver drugs, nucleic acids and peptides specifically to the site of their action and therefore enhance the efficacy of the treatment, limit the penetration of nebulized therapeutic agent(s) into the bloodstream and consequently decrease adverse systemic side effects of the treatment. Nanotechnology allows for a further enhancement of the treatment efficiency. The present review analyzes modern therapeutic approaches of inhaled nanoscale-based pharmaceutics for the detection and treatment of various lung diseases.

Heterogeneous drug target expression as possible basis for different clinical and radiological response to the treatment of primary and metastatic renal cell carcinoma: suggestions from bench to bedside

Metastatic disease occurs in a significant percentage of patients with renal cell carcinoma (RCC) and is usually associated with an overall poor prognosis. However, not all of the sites of metastases seem to have the same prognostic significance in patients receiving targeted agents. Indeed, patients with lung-only metastases seem to present a better survival than patients with other sites, whereas liver and bone metastases are associated with a worst prognosis. Some clinical studies suggest that metastatic sites are more responsive than primary tumors. This event may be due to intratumor heterogeneity in terms of somatic mutations, chromosome aberrations, and tumor gene expression, primarily centered around Von Hippel-Lindau (VHL) pathway, such as VHL mutations, HIF levels, vascular endothelial growth factor (VEGF) isoforms, and VEGF receptor levels. Nevertheless, these data do not completely explain the discordant biological behavior between primary tumor and metastatic sites. Understanding the causes of this discordance will have profound consequences on translational research and clinical trials in RCC. In this review, we overview current data on the differences between primary RCC and metastases in terms of drug target expression and clinical/radiological response to targeted agents, thus describing the prognostic role of different metastatic sites in RCC patients.

NK cell-based immunotherapies in Pediatric Oncology

The past decade has seen several anticancer immunotherapeutic strategies transition from "promising preclinical models" to treatments with proven clinical activity or benefit. In 2013, the journal Science selected the field of Cancer Immunotherapy as the overall number-1 breakthrough for the year in all of scientific research. In the setting of cancer immunotherapy for adult malignancies, many of these immunotherapy strategies have relied on the cancer patient's endogenous antitumor T-cell response. Although much promising research in pediatric oncology is similarly focused on T-cell reactivity, several pediatric malignancies themselves, or the chemo-radiotherapy used to achieve initial responses, can be associated with profound immune suppression, particularly of the T-cell system. A separate component of the immune system, also able to mediate antitumor effects and less suppressed by conventional cancer treatment, is the NK-cell system. In recent years, several distinct immunotherapeutic approaches that rely on the activity of NK cells have moved from preclinical development into clinical testing, and some have shown clear antitumor benefit. This review provides an overview of NK cell-based immunotherapy efforts that are directed toward childhood malignancies, with an emphasis on protocols that are already in clinical testing.

Retrospective review in patients with pulmonary metastases of renal cell carcinoma receiving inhaled recombinant interleukin-2

Pulmonary metastases of renal cell carcinoma are associated with poor prognosis. Systemic interleukin-2 is used to treat pulmonary metastases of renal cell carcinoma; however, its toxicity limits its use. The objective of this study was to evaluate the efficacy and safety of inhaled interleukin-2 in pulmonary metastases of renal cell carcinoma patients. The study was designed as a retrospective chart review in pulmonary metastases of renal cell carcinoma patients treated with inhaled interleukin-2. Between 2000 and 2004, 19 centres in Spain and two in Portugal recruited 51 patients. The treatment schedule was as follows: three cycles of 36 MIU interleukin-2 per day for 5 days/week for 12 weeks (with 1 treatment-free week between cycles) in Spain and for 3 weeks (out of each 4 weeks) for 12 weeks in Portugal. Efficacy was assessed by best response following each treatment cycle and at final evaluation. Kaplan-Meier method was used to estimate progression-free survival and overall survival. Safety data were analysed using descriptive statistics, with toxicities expressed in number of weeks, which were reported. Overall objective response rate was 13.7% (95% confidence interval: 5.7-26.3). Median progression-free survival and overall survival were 8.6 (95% confidence interval: 3.45-16.5) and 23 (95% confidence interval: 11.5-34.5) months. The most common toxicities were cough (40% of cycles) and fatigue (7%). The majority of weeks of toxicities were reported to be only grade 1 or 2 in severity. Inhaled interleukin-2 shows efficacy and mild toxicity of pulmonary metastases of renal cell carcinoma patients, and might be considered as an alternative treatment to the systemic administration of this drug in these patients.

Ipsilateral right testicular metastasis from renal cell carcinoma in a responder patient to interleukine-2 treatment

We present a case of metastatic spreading to the testicle in a 46-year-old patient with renal cell carcinoma, "clear-cell" type, during interleukin-2 combined subcutaneous plus aerosol treatment. Testicular metastasis occurred while the patient showed a response to the treatment with disappearance of lung lesions and reduction of lymph-nodes lesions. After orchiectomy with spermatic cord resection and disease re-evaluation confirming the previous response, the patient re-started immunotherapy. The contrast between systemic disease response to treatment and disease testicular progression might be explained by a relative insensitivity of the testicle to interleukin-2 immunotherapy as a result of a possible establishment of an immunosuppressive microenvironment. We believe that the rarity of this metastatic site and the intriguing possible mechanisms at its base, makes an interesting case for clinicians.

Inhaled cytokines and cytokine antagonists

Cytokine and cytokine antagonist have provided novel and effective therapies for many human diseases. A number of approved cytokines including the interferons (alpha, beta and gamma), interleukin-2 (IL-2), granulocyte macrophage colony stimulating factor (GM-CSF) as well as novel cytokine antagonists have been administered by the pulmonary route for both local lung disease and as a non-invasive method for systemic delivery. We review the published clinical experience of inhaled cytokines and cytokine antagonists. We discuss the limitations of the existing data and the type of clinical data desired to establish the advantages and safety of inhaled cytokines and cytokine antagonists.

Interleukin-2/interferon-alpha2a/13-retinoic acid-based chemoimmunotherapy in advanced renal cell carcinoma: results of a prospectively randomised trial of the German Cooperative Renal Carcinoma Chemoimmunotherapy Group (DGCIN)

We performed a prospectively randomised clinical trial to compare the efficacy of four subcutaneous interleukin-2-(sc-IL-2) and sc interferon-alpha2a (sc-IFN-alpha2a)-based outpatient regimens in 379 patients with progressive metastatic renal cell carcinoma. Patients with lung metastases, an erythrocyte sedimentation rate < or =70 mm h(-1) and neutrophil counts < or =6000 microl(-1) (group I) were randomised to arm A: sc-IL-2, sc-IFN-alpha2a, peroral 13-cis-retinoic acid (po-13cRA) (n=78), or arm B: arm A plus inhaled-IL-2 (n=65). All others (group II) were randomised to arm C: arm A plus intravenous 5-fluorouracil (iv-5-FU) (n=116), or arm D: arm A plus po-Capecitabine (n=120). Median overall survival (OS) was 22 months (arm A; 3-year OS: 29.7%) and 18 months (arm B; 3-year OS: 29.2%) in group I, and 18 months (arm C; 3-year OS: 25.7%) and 16 months (arm D; 3-year OS: 32.6%) in group II. There were no statistically significant differences in OS, progression-free survival, and objective response between arms A and B, and between arms C and D, respectively. Given the known therapeutic efficacy of sc-IL-2/sc-INF-alpha2a/po-13cRA-based outpatient chemoimmunotherapies, our results did not establish survival advantages in favour of po-Capecitabine vs iv-5-FU, and in favour of short-term inhaled-IL-2 in patients with advanced renal cell carcinoma receiving systemic cytokines.

Acrolein in cigarette smoke inhibits T-cell responses

BACKGROUND

Cigarette smoking inhibits T-cell responses in the lungs, but the immunosuppressive compounds have not been fully identified. Cigarette smoke extracts inhibit IL-2, IFN-gamma, and TNF-alpha production in stimulated lymphocytes obtained from peripheral blood, even when the extracts were diluted 100-fold to 1000-fold.

OBJECTIVE

The objective of these studies was to identify the immunosuppressive compounds found in cigarette smoke.

METHODS

Gas chromatography/mass spectroscopy and HPLC were used to identify and quantitate volatile compounds found in cigarette smoke extracts. Bioactivity was measured by viability and production of cytokine mRNA and protein levels in treated human lymphocytes.

RESULTS

The vapor phase of the cigarette smoke extract inhibited cytokine production, indicating that the immunosuppressive compounds were volatile. Among the volatile compounds identified in cigarette smoke extracts, only the alpha,beta-unsaturated aldehydes, acrolein (inhibitory concentration of 50% [IC50] = 3 micromol/L) and crotonaldehyde (IC50 = 6 micromol/L), exhibited significant inhibition of cytokine production. Although the levels of aldehydes varied 10-fold between high-tar (Camel) and ultralow-tar (Carlton) extracts, even ultralow-tar cigarettes produced sufficient levels of acrolein (34 micromol/L) to suppress cytokine production by >95%. We determined that the cigarette smoke extract inhibited transcription of cytokine genes. The inhibitory effects of acrolein could be blocked with the thiol compound N-acetylcysteine.

CONCLUSION

The vapor phase from cigarette smoke extracts potently suppresses cytokine production. The compound responsible for this inhibition appears to be acrolein.

Renal cell carcinoma - innovative medical treatments

PURPOSE OF REVIEW

This review highlights recent innovations of medical treatments in advanced renal cell carcinoma. Because of significant toxicity many patients do not benefit from standard systemic cytokine therapy using interleukin-2, interferon-alpha, or both. Their median progression-free survival is about 2 months and their overall survival is poor. Here we report improvements in patient outcome, focusing on overall survival, progression-free survival and quality of life to meet their needs.

RECENT FINDINGS

Rating treatment results requires analysis of patient selection and risk stratification. In well-selected patients systemic interleukin-2 therapy as well as combinations of cytokines (interleukin-2 and interferon-alpha) improve outcome, induce long-term survival and, in a minority of patients, even produce long-lasting complete remissions. Within the group of patients who are not candidates for systemic cytokines, interleukin-2 for pulmonary metastases given locally by inhalation achieves long-term progression-free survival and long-term overall survival similar to high-dose systemic interleukin-2 but without the toxicity associated with it. In patients at high risk for metastatic disease progression-free survival is prolonged by autologous tumor vaccine as reported in a recent randomized study. However, in established metastatic disease no clear benefit has been demonstrated by any of the many recent vaccine protocols. Chemotherapeutic agents and thalidomide generally fail to improve patient outcome but produce significant and sometimes irreversible toxicity.

SUMMARY

Cytokine-based immunotherapy can be considered standard in the treatment of metastatic renal cell carcinoma today. Long-term survival and sometimes even cure seems possible in patients using systemic and local (inhaled) applications of interleukin-2 alone or in combination with interferon-alpha. Noncytokine treatment approaches are scientifically interesting but still disappointing from a patient's perspective.