Local Antitumor Effects Research Articles

Radiation Followed by OX40 Stimulation Drives Local and Abscopal Antitumor Effects in an Anti-PD1-Resistant Lung Tumor Model.

Purpose: Radiation is used extensively to treat localized cancer, but improved understanding of its effects on the immune system has increased interest in its potential systemic (abscopal) effects, particularly in combination with checkpoint inhibitors such as anti-PD1. The majority of patients either do not respond or develop resistance to monotherapy over time. Here, we investigated the efficacy of OX40 (CD134) stimulation as an alternative immunotherapeutic approach in combination with radiotherapy (XRT) in a murine model of anti-PD1-resistant lung tumors.Experimental Design: We established a bilateral tumor model in 129Sv/Ev mice using an anti-PD1-resistant lung tumor cell line. Primary tumors were treated with intratumoral injection of an OX40 agonist antibody, given as adjuvant therapy after XRT (36 Gy in three 12-Gy fractions), whereas secondary tumors were left untreated to investigate abscopal outcomes.Results: The combination of XRT followed by OX40 stimulation effectively inhibited local and systemic antitumor growth, limited lung metastases, and improved survival rates. This treatment regimen augmented CD4+ and CD8+ T-cell expansion. XRT induced the expression of OX40 on T cells in tumors and spleens and increased the percentages of splenic CD103+ dendritic cells.Conclusions: Our data extend the benefits of radiation to systemic disease control, especially when combined with anti-OX40 agonist to promote immunologically mediated abscopal effects. Moreover, this study provides a rational treatment approach and sequence to overcome anti-PD1-resistant poorly immunogenic tumors. Clin Cancer Res; 24(22); 5735-43. ©2018 AACR.

Cement augmentation for vertebral osteolytic metastatic lesions: an evaluation on postoperative CT

Objective: To evaluate the effectiveness of cement augmentation on the osteolytic lesion in patients with vertebral metastasis. Methods: A total of consecutive 132 patients with 268 vertebral metastatic lesions treated with PVP from January 2008 to December 2016 in Zhongda Hospital were enrolled in this study. Retrospective analysis of preoperative, postoperative 3 days, 3 months, 6 months, 12 months and ≥ 18 months imaging data on CT, the local control and progression of the tumor were evaluated by MDA response criteria. The local control rates were compared between the groups with the different rate of cement filling by Chi2-test. Results: Vertebroplasty procedures were performed successfully in all 268 vertebrae under DSA guidance, and the mean volume of PMMA injected in each vertebra was 0.7-8.5(3.9±1.5)ml.The rate of local control at 3 months, 6 months, 12 months and ≥18 months after PVP was respectively 98.9%, 95.1%, 91.8%, and 85.2%, the difference was statistically significant(all P<0.05). The local control rate showed a statistically significant relationship to the groups with the rate of cement filling at 6 months, 12 months and ≥18 months after PVP, but there was no statistical difference at postoperative 3 months. The rate of local control was higher in 68 patients with lung or gastrointestinal cancer than in 17 patients with liver or kidney cancer at 3 months, 6 months and 12 months, the difference was statistically significant (P<0.05). Conclusion: Cement augmentation has a local anti-tumor effect on vertebral osteolytic metastatic lesion, and the anti-tumor effect will decrease as the follow-up time extended.

CD206-positive myeloid cells bind galectin-9 and promote a tumor-supportive microenvironment.

In patients with metastatic melanoma, high blood levels of galectin-9 are correlated with worse overall survival and a bias towards a Th2 inflammatory state supportive of tumor growth. Although galectin-9 signaling through TIM3 on T cells has been described, less is known about the interaction of galectin-9 with macrophages. We aimed to determine whether galectin-9 is a binding partner of CD206 on macrophages and whether the result of this interaction is tumor-supportive. It was determined that incubation of CD68+ macrophages with galectin-9 or anti-CD206 blocked target binding and that both CD206 and galectin-9 were detected by immunoprecipitation of cell lysates. CD206 and galectin-9 had a binding affinity of 2.8 × 10-7 m. Galectin-9 causes CD206+ macrophages to make significantly more FGF2 and monocyte chemoattractant protein (MCP-1), but less macrophage-derived chemokine (MDC). Galectin-9 had no effect on classical monocyte subsets, but caused expansion of the non-classical populations. Lastly, there was a positive correlation between increasing numbers of CD206 macrophages and galectin-9 expression in tumors, and high levels of CD206 macrophages correlated negatively with melanoma survival. These results indicate that galectin-9 binds to CD206 on M2 macrophages, which appear to drive angiogenesis and the production of chemokines that support tumor growth and poor patient prognoses. Targeting this interaction systemically through circulating monocytes may therefore be a novel way to improve local anti-tumor effects by macrophages. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Investigation of tumor-tumor interactions in a double human cervical carcinoma xenograft model in nude mice.

Tumor-tumor distant interactions within one organism are of major clinical relevance determining clinical outcome. To investigate this poorly understood phenomenon, a double human cervical xenograft model in nude mice was developed. A first tumor was induced subcutaneously by injection of human papillomavirus positive cervical carcinoma cells into the mouse lower right flank and 3 weeks later, animals were challenged with the same tumor cell line injected subcutaneously into the upper left flank. These tumors had no direct physical contact and we found no systemic changes induced by the primary tumor affecting the growth of a secondary tumor. However, ablation of the primary tumor by local treatment with cidofovir, a nucleotide analogue with known antiviral and antiproliferative properties, resulted not only in a local antitumor effect but also in a temporary far-reaching effect leading to retarded growth of the challenged tumor. Cidofovir far-reaching effects were linked to a reduced tumor-driven inflammation, to increased anti-tumor immune responses, and could not be enhanced by co-administration with immune stimulating adjuvants. Our findings point to the potential use of cidofovir in novel therapeutic strategies aiming to kill tumor cells as well as to influence the immune system to fight cancer.

Abscopal Effects With Hypofractionated Schedules Extending Into the Effector Phase of the Tumor-Specific T-Cell Response

Hypofractionated radiation therapy (hRT) combined with immune checkpoint blockade can induce T-cell-mediated local and abscopal antitumor effects. We had previously observed peak levels of tumor-infiltrating lymphocytes (TILs) between days 5 and 8 after hRT. Because TILs are regarded as radiosensitive, hRT schedules extending into this period might be less immunogenic, prompting us tocompare clinically relevant, short and extended schedules with equivalent biologically effective doses combined with anti-programmed cell death 1 (PD1) antibody treatment. In mice bearing 2 B16-CD133 melanoma tumors, the primary tumor was irradiated with 3×9.18Gy in 3 or 5days or with 5×6.43Gy in 10days; an anti-PD1 antibody was given weekly. The mice were monitored for tumor growth and survival. T-cell responses were determined on days 8 and 15 of treatment. The role of regional lymph nodes was studied by administering FTY720, which blocks lymph node egress of activated T cells. Tumor growth measurements after combination treatment using short or extended hRT and control treatment were also performed in the wild-type B16 melanoma and 4T1 breast carcinoma models. In the B16-CD133 model, growth inhibition of irradiated primary andnonirradiated secondary tumors and overall survival were similar with all 3hRT/anti-PD1 combinations, superior to hRT and anti-PD1 monotherapy, and was strongly dependent on CD8+ T cells. TIL infiltration and local and systemic tumor-specific CD8+ T-cell responses were also similar, regardless of whether short or extended hRT was used. Administration of FTY720 accelerated growth of both primary and secondary tumors, strongly reduced their TIL infiltration, and increased tumor-specific CD8+ T cells in the lymph nodes draining the irradiated tumor. In the 4T1 model, local and abscopal tumor control was also similar, regardless of whether short or extended hRT was used, although the synergy between hRT and anti-PD1 was weaker. No synergies were found in the B16 wild-type model lacking an exogenous antigen. Our data suggest that combination therapy with hRT schedules extending into the period during which treatment-induced T cells infiltrate the irradiated tumor can provoke local and systemic antitumor effects similar to those with therapy using shorter schedules, if the regional lymph nodes supply sufficient tumor-specific T cells. This has implications for planning clinical RT/immune checkpoint blockade trials.

First-in-human clinical trial with intratumoral BO-112 in solid malignancies: A novel immunotherapy based in double-stranded RNA (dsRNA).

3082 Background: BO-112 is a double stranded synthetic RNA, formulated with the cationic carrier polyethyleneimine that preclinically improves its intracellular delivery and resistance towards nuclease degradation. In melanoma mouse models, systemic administration activates MDA-5 and NOXA, leading to anti-tumoral activity connected to a sustained and extended expression of IFN-response genes. Intratumoral (IT) delivery, seeking a safer and more focused enhancement of local and systemic antitumor effects has been tested in transplanted mouse models. The potential of its IT use as an immune-modulatory treatment, as well as its toxicity profile, is being analyzed in this first in human, proof of concept, clinical trial (NCT02828098). Methods: Four patients with malignant solid tumors and palpable cutaneous/subcutaneous or lymph node metastases &gt;1 cm were treated with a single BO-112 dose of 0.6 mg/ml IT. Pre and post treatment biopsies from the injected metastatic lesion were obtained. Pharmacokinetics, serum cytokines and circulating immune cells were sequentially studied in pre and post treatment samples. Results: Patients did not experience relevant toxicity with the exception of a single episode of completely reversible grade 4 thrombocytopenia in one patient, attributed to the drug. BO-112 was not detectable in bloodstream following IT delivery. No changes in circulating cytokines were detected. Main immunobiological effects are summarized in the table. Conclusions: BO-112 has shown changes in tumoral immune cells in 1/4 patients, while in 3/4 induced both necrosis and changes in circulating immune cells. This ongoing trial will compile more safety data with repeated sequential administrations, escalated to higher doses of BO-112, and will thoroughly characterize its biological effects in humans with solid malignancies amenable to IT injection. Clinical trial information: NCT02828098. [Table: see text]

40P - Antitumoral effect and reduced systemic toxicity in mice after intra-tumoral injection of an in vivo solidifying calcium sulfate formulation with docetaxel

Background: Docetaxel is a cytostatic agent approved for treatment of non-small cell lung cancer as well as other cancers. Its effectiveness in clinical practice is associated with a variety of acute and long term side effects. To reduce the systemic side effects, a local slow-release depot formulation based on calcium sulfate with docetaxel for intra-tumoral administration was developed. Methods: Two formulations with a twofold difference in docetaxel drug load (corresponding to 12.5 and 25.0 mg/kg body weight) were manufactured with the calcium sulfate based NanoZolid™ technology. The formulations were injected intra-tumorally as a paste which solidified within the tumor. The effects of the two local depot formulations were tested in female mice (n = 60) inoculated with subcutaneous Lewis lung carcinoma cells. The slow-release depots were compared to systemic intraperitoneal injections of docetaxel (25.0 mg/kg) and a calcium sulfate placebo formulation. Tumor volumes were measured and systemic side effects were evaluated using body weight and cell counts from whole blood as well as plasma concentrations. In addition, a histological evaluation was performed. Results: Both docetaxel formulations showed a significantly higher antitumor efficacy compared to placebo, which was comparable to that of systemic administration of docetaxel. Moreover, the intra-tumoral depot formulations with docetaxel showed reduced systemic toxicity compared to systemic treatment, including less weight loss and no decrease in blood cell counts. The extracellular deposits of calcium sulfate, observed in all groups with intra-tumoral injections, did not lead to significant inflammatory changes. Conclusions: It was shown that intra-tumoral slow-release depots of calcium sulfate with docetaxel were well tolerated and released docetaxel at amounts sufficient for satisfactory local antitumor effect and for a low level plasma detection. The use of such depots can be an alternative to intravenous injection as an efficient antitumoral treatment with reduced systemic toxicity. Legal entity responsible for the study: Uppsala University, Department of Immunology, Genetics and Pathology, Marie Jeansson Funding: This study was supported by an IGP Young Investigator grant (MJ), the Swedish Research Council (521-2012-865, MJ), Åke Wiberg Foundation (738866289, MJ), Magnus Bergvalls Foundation (24942-1-2013, 2014-00055, MJ), and Ture Stenholms Foundation for Surgical Research (MS) Disclosure: S. Grudén: Consultant for LIDDS AB. N. Axén: Consultant for LIDDS AB and have equity interests in LIDDS AB. All other authors have declared no conflicts of interest.

Radiotherapy and tumor immunity

Infiltrated immune cells and cytokines in the tumor microenvironment may play different functions that appear tightly related to clinical outcomes. Radiotherapy mainly kills tumor cells through radiobiological effect, meanwhile it can indirectly change tumor immunologic microenvironment, and has a local or distant anti-tumor immunological effect cooperatively. Animal experiments and clinical trials of radiotherapy combined with immunotherapy display well applied prospects, but the mode of radiotherapy in combined treatment needs further research. Key words: Radiotherapy; Immunity

Abstract SY39-02: Direct activation of STING in the tumor microenvironment leads to potent and systemic tumor regression and immunity

Abstract SY39-02: Direct activation of STING in the tumor microenvironment leads to potent and systemic tumor regression and immunity

Controlled gene delivery can enhance therapeutic outcome for cancer immune therapy for melanoma.

Effective delivery still remains a major hurdle in the development of gene based therapies. While technological advances have occurred that have improved delivery in general, there is still a need for controlled delivery in order to achieve therapeutic effects. Gene electrotransfer (GET) can be utilized to accomplish this. Careful selection of parameters used for delivery such as amplitude, duration and number of pulses as well as plasmid construct can be manipulated in order to achieve appropriate levels of local expression. Previously we have shown that direct delivery of the therapeutic cytokine, interleukin 12 (IL-12), to tumors using electrotransfer can generate local and systemic anti-tumor effects in pre-clinical and clinical studies. Using this model we hypothesized that modulating local gene expression using GET can affect therapeutic outcome. To test this, we used multiple GET protocols and plasmids to achieve varying levels of local IL-12 expression. We found that high local gene expression did not give rise to a better therapeutic outcome. This suggests the level and possibly the duration of gene expression are important in mediating the host immune response against melanoma. These data also emphasize the importance of considering the desired immune outcome of the therapy when selecting parameters for GET.

Biodistribution and Efficacy Studies of the Proteasome Inhibitor BSc2118 in a Mouse Melanoma Model

Inhibition of the proteasome offers many therapeutic possibilities in inflammation as well as in neoplastic diseases. However, clinical use of proteasome inhibitors is limited by the development of resistance or severe side effects. In our study we characterized the anti-tumor properties of the novel proteasome inhibitor BSc2118. The sensitivity of tumor lines to BSc2118 was analyzed in comparison to bortezomib using crystal violet staining in order to assess cell viability. The In Vivo distribution of BSc2118 in mouse tissues was tracked by a fluorescent-modified form of BSc2118 (BSc2118-FL) and visualized by confocal microscopy. Inhibition of the 20S proteasome was monitored both in cultured cell lines and in mice, respectively. Finally, safety and efficacy of BSc2118 was evaluated in a mouse melanoma model. BSc2118 inhibits proliferation of different tumor cell lines with a similar potency as compared with bortezomib. Systemic administration of BSc2118 in mice is well tolerated, even when given in a dose of 60 mg/kg body weight. After systemic injection of BSc2118 or bortezomib similar proteasome inhibition patterns are observed within the murine organs. Detection of BSc2118-FL revealed correlation of distribution pattern of BSc2118 with inhibition of proteasomal activity in cells or mouse tissues. Finally, administration of BSc2118 in a mouse melanoma model shows significant local anti-tumor effects. Concluding, BSc2118 represents a novel low-toxic agent that might be alternatively used for known proteasome inhibitors in anti-cancer treatment.

Local and systemic antitumor effects of activated autologous dendritic cells for intratumoral injection: A phase I/II trial.

TPS3133 Background: Dendritic cells (DC) are antigen presenting cells proficient in inducing de novo immune responses, and the presence of intratumoral DCs confers a survival advantage to patients,...

Gene Therapy with Beta-Defensin 2 Induces Antitumor Immunity and Enhances Local Antitumor Effects

Beta-defensins, small antimicrobial peptides, are involved in host immune responses to tumors. In this study, we used beta-defensin 2 (BD2) to explore the possible role of beta-defensins in cancer gene therapy. A recombinant plasmid expressing a secretable form of BD2 was constructed. The biological activities of BD2 in immature dendritic cells (iDCs) were tested in vitro and in vivo. The antitumor effects were investigated in three established tumor models. The secreted BD2 was detected and exhibited chemotactic activity in iDCs both in vitro and in vivo. Recruitment and activation of iDCs in tumor niches resulted in significant tumor growth inhibition. Adoptive transfer of splenocytes and depletion of immune cell subsets revealed that CD8(+) T lymphocyte responses mediated the increased tumor inhibition. Furthermore, we also found that chemotactic and maturation-inducing activities in iDCs in tumor milieu contributed to enhanced local antitumor effects. Our study indicates that gene therapy with BD2 can mediate specific antitumor immunity and augment local antitumor effects. Our study also suggested that beta-defensins may merit further exploration for cancer immunotherapy as promising immunogenes.

Recipient leukocyte infusion enhances the local and systemic graft-versus-neuroblastoma effect of allogeneic bone marrow transplantation in mice

Allogeneic hematopoietic stem cell transplantation and donor leukocyte infusion (DLI) may hold potential as a novel form of immunotherapy for high-risk neuroblastoma. DLI, however, carries the risk of graft-versus-host disease (GvHD). Recipient leukocyte infusion (RLI) induces graft-versus-leukemia responses without GvHD in mice and is currently being explored clinically. Here, we demonstrate that both DLI and RLI, when given to mixed C57BL/6→A/J radiation chimeras carrying subcutaneous Neuro2A neuroblastoma implants, can slow the local growth of such tumors. DLI provoked full donor chimerism and GvHD; RLI produced graft rejection but left mice healthy. Flow cytometric studies showed that the chimerism of intratumoral leukocytes paralleled the systemic chimerism. This was associated with increased CD8/CD4 ratios, CD8+ T-cell IFN-γ expression and NK-cell Granzyme B expression within the tumor, following both DLI and RLI. The clinically safe anti-tumor effect of RLI was further enhanced by adoptively transferred naïve recipient-type NK cells. In models of intravenous Neuro2A tumor challenge, allogeneic chimeras showed superior overall survival over syngeneic chimeras. Bioluminescence imaging in allogeneic chimeras challenged with luciferase-transduced Neuro2A cells showed both DLI and RLI to prolong metastasis-free survival. This is the first experimental evidence that RLI can safely produce a local and systemic anti-tumor effect against a solid tumor. Our data indicate that RLI may provide combined T-cell and NK-cell reactivity effectively targeting Neuro2A neuroblastoma.

Local antitumor effects of intratumoral delivery of rlL-2 loaded sustained-release dextran/PLGA–PLA core/shell microspheres

In this study, we formulated a rIL-2 loaded sustained-release dextran/PLGA-PLA core/shell microsphere, mimicking the paracrine mechanisms of cytokine action, to investigate its local antitumor efficacy. The presented microspheres were formed in two steps: rIL-2 was firstly loaded into dextran particles to keep its bioactivity by a unique method of stabilizing aqueous-aqueous "emulsion"; subsequently, the particles were encapsulated into poly(dl-lactide-co-glycolide)/polylactic acid (PLGA/PLA). A stable sustained release behavior in vitro was achieved for a period of about 25 days. In the subcutaneous colon carcinoma BALB/c mice models, a single dose of microspheres was introtumorally administrated and compared with multiple doses of rIL-2 solution to investigate the long acting effect of microspheres on tumor. The animal experiments showed the local efficacy at tumor site mediated by rIL-2 from a single dose of microspheres was better than that of multiple rIL-2 solution injections. Based on the experimental results, we conclude that rlL-2 loaded sustained-release dextran/PLGA-PLA core/shell microspheres represent a promising approach for local cancer treatment in animals.

Intratumoral Delivery of Low Doses of Anti-CD40 mAb Combined With Monophosphoryl Lipid A Induces Local and Systemic Antitumor Effects in Immunocompetent and T Cell-Deficient Mice

In this study, an agonistic anti-CD40 monoclonal antibody was combined with monophosphoryl lipid A (MPL), a nontoxic derivative of lipopolysaccharide and agonist of toll-like receptor-4, to assess the immunomodulatory and antitumor synergy between the 2 agents in mice. Anti-CD40 was capable of priming macrophages to subsequent ex vivo activation by MPL in immunocompetent and T-cell-depleted mice. Intraperitoneal injections of anti-CD40+MPL induced additive to synergistic suppression of poorly immunogenic B16-F10 melanoma growing subcutaneously in syngeneic mice. When anti-CD40+MPL were injected directly into the subcutaneous tumor, the combination treatment was more effective, even with a 25-fold reduction in dose. Low-dose intratumoral treatment also slowed the growth of a secondary tumor growing simultaneously at a distant, untreated site. Antitumor effects were also induced in severe combined immunodeficiency mice and in T-cell-depleted C57BL/6 mice. Taken together, our results show that the antitumor effects of anti-CD40 are enhanced by subsequent treatment with MPL, even in T-cell-deficient hosts. These preclinical data suggest that an anti-CD40+MPL combined regimen is appropriate for clinical testing in human patients, including cancer patients who may be immunosuppressed from prior chemotherapy.

Recipient-Type Leucocyte Infusion After Allohsct in Mice Slows Local Growth of Neuroblastoma and Elicits Activation of Intratumoral Cytotoxic NK Cells

AbstractAbstract 4102Donor leucocyte infusion (DLI) after alloHSCT can induce strong graft-versus-leukemia (GvL) effects, inspiring investigators to examine this approach for solid tumors resistant to conventional therapies (Grivas et al. Curr Clin Pharmacol. 2011). However, DLI produces graft-versus-host disease (GvHD). Recipient-type leucocyte infusion (RLI) is currently being explored clinically as a means to induce GvL without risk of GvHD (clinicaltrials.gov; Rubio et al. Blood 2003; De Somer et al. Haematologica. 2011). High-risk neuroblastoma carries a bleak prognosis despite aggressive treatment with chemo-, radiotherapy and autologous HSCT. Clinical observations in such patients suggest that alloHSCT may produce a graft-vs-neuroblastoma effect (Kanold et al. Bone Marrow Transplantation. 2008). In mice, alloHSCT delays local neuroblastoma growth, and adoptive transfer of tumor-pulsed donor dendritic cells and donor leucocytes enhances this effect (Ash et al. Cancer Immunol Immunother. 2009, Br J Cancer 2010). In this study, we show that not only DLI by itself, but also RLI enhances the local anti-neuroblastoma effect of alloHSCT in mice.MHC-mismatched [C57BL/6 (H-2Kb) → A/J (H-2Kk)] bone marrow chimeras were given a subcutaneous inoculation with 1 × 106 Neuro2A cells (A/J neuroblastoma) on day 14 post HSCT. On day 21, we performed adoptive transfer of 10 × 106 donor splenocytes (DLI), 50 × 106 recipient splencoytes (RLI) and/or 1 × 106 recipient-type MACS-isolated DX5+ NK cells. We measured tumor volume twice weekly using a caliper (volume = width2 × length × 0,4). Validation of this model showed progressive tumor growth and mortality as a result of metastasis. Peripheral blood chimerism and tumor infiltrating lymphocytes were studied using flow cytometry.AlloHSCT chimeras developed mixed donor T cell chimerism by day 21 and full donor chimerism by day 76 post HSCT. DLI induced a conversion to full donor T cell chimerism and RLI induced a complete loss of donor T cells chimerism, both within 1 week. AlloHSCT chimeras showed reduced local growth of subcutaneous neuroblastoma tumors relative to synHSCT chimeras. This delay in tumor growth was enhanced not only by DLI, but also by RLI; DLI provoked lethal GvHD whereas mice treated with RLI remained healthy. Within tumor-infiltrating lymphocytes, T and NK cell chimerism mirrored the systemic chimerism changes seen after RLI and DLI, associated with an increased intratumoral CD8/CD4 ratio, CD8+ T-cell IFN-γ-expression and NK-cell Granzyme B-expression. This indicates a close relation between lymphohematopoietic alloreactivity and the anti-tumor effect, and suggests that the anti-tumor mechanism of DLI and RLI involves not only CD8+ T cells but also cytotoxic NK cells. The baseline antitumor effect seen in alloHSCT chimeras was also accompanied by increased Granzyme B expression by intratumoral NK-cells, supporting a role for NK cells also in this baseline antitumor effect. In vivo Neuro2A-inoculation experiments in (poly(I:C)-treated) C57BL/6, TCR−/− C57BL/6 and A/J mice, and in vitro NK cytotoxicity experiments showed that 1° donor T cells critically resist Neuro2A cells, 2° donor NK cells exhibit spontaneous cytotoxic reactivity to Neuro2A that is enhanced by NK activation, but also that 3° syngeneic NK cells may acquire reactivity to Neuro2A cells provided they are activated. Interestingly, when RLI was given, the intratumoral NK-cell frequency declined markedly, and adoptive transfer of additional NK cells obtained from naïve A/J mice enhanced the local antitumor effect of RLI. This supports the hypothesis that, in addition to donor NK cells, also syngeneic NK cells can play a critical role in mediating a growth-limiting effect on local neuroblastoma. Along this line, we observed that also in synHSCT mice, which showed a reduced local neuroblastoma growth relative to naïve mice, the intratumoral NK cells showed increased FasL-expression.These are the first experimental data showing that RLI after alloHSCT may induce immune-mediated anti-neuroblastoma effects, and that NK cells, in particular syngeneic NK cells, may play a critical role herein. Our data support the exploration of post alloHSCT adoptive cell therapy with recipient-type T and NK cells to produce enhanced immune antitumor effects for high-risk neuroblastoma, and potentially for other solid tumors that are unresponsive to traditional therapies, without the risk of GvHD. Disclosures:No relevant conflicts of interest to declare.

Intratumoral hu14.18–IL-2 (IC) Induces Local and Systemic Antitumor Effects That Involve Both Activated T and NK Cells As Well As Enhanced IC Retention

hu14.18-IL-2 (IC) is an immunocytokine consisting of human IL-2 linked to hu14.18 mAb, which recognizes the GD2 disialoganglioside. Phase 2 clinical trials of i.v. hu14.18-IL-2 (i.v.-IC) in neuroblastoma and melanoma are underway and have already demonstrated activity in neuroblastoma. We showed previously that intratumoral hu14.18-IL-2 (IT-IC) results in enhanced antitumor activity in mouse models compared with i.v.-IC. The studies presented in this article were designed to determine the mechanisms involved in this enhanced activity and to support the future clinical testing of intratumoral administration of immunocytokines. Improved survival and inhibition of growth of both local and distant tumors were observed in A/J mice bearing s.c. NXS2 neuroblastomas treated with IT-IC compared with those treated with i.v.-IC or control mice. The local and systemic antitumor effects of IT-IC were inhibited by depletion of NK cells or T cells. IT-IC resulted in increased NKG2D receptors on intratumoral NKG2A/C/E⁺ NKp46⁺ NK cells and NKG2A/C/E⁺ CD8⁺ T cells compared with control mice or mice treated with i.v.-IC. NKG2D levels were augmented more in tumor-infiltrating lymphocytes compared with splenocytes, supporting the localized nature of the intratumoral changes induced by IT-IC treatment. Prolonged retention of IC at the tumor site was seen with IT-IC compared with i.v.-IC. Overall, IT-IC resulted in increased numbers of activated T and NK cells within tumors, better IC retention in the tumor, enhanced inhibition of tumor growth, and improved survival compared with i.v.-IC.

Pilot trial of endoscopic ultrasound-guided interstitial chemoradiation of UICC-T4 pancreatic cancer.

Background and aims:Both interstitial brachytherapy and interstitial chemotherapy are effective in improving local control in patients with local UICC-T4 pancreatic cancer. In this study, we report the results of endoscopic ultrasound (EUS)-guided interstitial chemoradiation (EUS-ICR) in patients with advanced pancreatic cancer, with respect to tumor response, clinical response, safety, and complications.Patients and methods:A total of 8 patients (3 men, 5 women; median age of 69) with T4 pancreatic adenocarcinoma were the subjects of this study. A mean of 18 radioactive seeds and 36 intratumoral implants for sustained delivery of 5-fluorouracil in each patient were implanted into the tumors using EUS-guided needle puncture. The mean total implanted radioactive activity was 13.68 mCi, the mean total dose of intratumoral 5-fluorouracil was 3.6 g, and the mean volume of implants was 28 cm3. The conditions of the patients were followed-up by examination and imaging tests every two months. Clinical endpoints included the Karnofsky performance status, pain response, tumor response (assessed by computed tomography and/or EUS), and survival.Results:During a median follow-up period of 8.3 months, the objective tumor response was classified as “partial” in 1 of 8 patients (with a median duration of partial response of 3 months), “minimal” in 2 patients, and indicative of “stable disease”, in 3 of 8 patients. Clinical benefit was shown in 4 of 8 patients, which was mostly due to pain reduction, and lasted for 3.5 months. No local complications or hematologic toxicity occurred.Conclusions:EUS-ICR had a moderate local anti-tumor effect, showed some clinical benefits in 4 of the 8 patients, and was well tolerated by all the patients in this study.

Pilot trial of endoscopic ultrasound-guided interstitial chemoradiation of UICC-T4 pancreatic cancer

Background and aims: Both interstitial brachytherapy and interstitial chemotherapy are effective in improving local control in patients with local UICC-T4 pancreatic cancer. In this study, we report the results of endoscopic ultrasound (EUS)-guided interstitial chemoradiation (EUS-ICR) in patients with advanced pancreatic cancer, with respect to tumor response, clinical response, safety, and complications. Patients and methods: A total of 8 patients (3 men, 5 women; median age of 69) with T4 pancreatic adenocarcinoma were the subjects of this study. A mean of 18 radioactive seeds and 36 intratumoral implants for sustained delivery of 5-fluorouracil in each patient were implanted into the tumors using EUS-guided needle puncture. The mean total implanted radioactive activity was 13.68 mCi, the mean total dose of intratumoral 5-fluorouracil was 3.6 g, and the mean volume of implants was 28 cm3. The conditions of the patients were followed-up by examination and imaging tests every two months. Clinical endpoints included the Karnofsky performance status, pain response, tumor response (assessed by computed tomography and/or EUS), and survival. Results: During a median follow-up period of 8.3 months, the objective tumor response was classified as 'partial' in 1 of 8 patients (with a median duration of partial response of 3 months), 'minimal' in 2 patients, and indicative of 'stable disease, in 3 of 8 patients. Clinical benefit was shown in 4 of 8 patients, which was mostly due to pain reduction, and lasted for 3.5 months. No local complications or hematologic toxicity occurred. Conclusions: EUS-ICR had a moderate local anti-tumor effect, showed some clinical benefits in 4 of the 8 patients, and was well tolerated by all the patients in this study.