A Phase 1 Trial of Oncolytic Adenovirus ICOVIR-5 Administered Intravenously to Cutaneous and Uveal Melanoma Patients

Oncolytic viruses represent a unique type of agents that combine self-amplification, lytic, and immunostimulatory properties against tumors. A local and locoregional clinical benefit has been demonstrated upon intratumoral injections of an oncolytic herpes virus in melanoma patients, leading to its approval in the United States and Europe for patients without visceral disease (up to stage IVM1a). However, in order to debulk and change the local immunosuppressive environment of tumors that cannot be injected directly, oncolyitc viruses need to be administered systemically. Among different viruses, adenovirus has been extensively used in clinical trials but with few evidences of activity upon systemic administration. Preclinical efficacy of a single intravenous administration of our oncolytic adenovirus ICOVIR5, an adenovirus type 5 responsive to the retinoblastoma pathway commonly deregulated in tumors, led us to use this virus in a dose-escalation phase 1 trial in metastatic melanoma patients. The results in 12 patients treated with a single infusion of a dose up to 1 × 10¹³ viral particles show that ICOVIR5 can reach melanoma metastases upon a single intravenous administration but fails to induce tumor regressions. These results support the systemic administration of armed oncolytic viruses to treat disseminated cancer.

CAR-T Cells and Oncolytic Viruses: Joining Forces to Overcome the Solid Tumor Challenge

Adoptive transfer of chimeric antigen receptor (CAR)-modified T cells has resulted in unprecedented rates of long-lasting complete responses in patients with leukemia and lymphoma. However, despite the impressive results in patients with hematologic malignancies, CAR-T cells have showed limited effect against solid cancers. New approaches will need to simultaneously overcome the multiple challenges that CAR-T cells encounter in solid tumors, including the immunosuppressive tumor microenvironment and heterogeneity of antigen expression. Oncolytic viruses are lytic and immunogenic anti-cancer agents with the potential to synergize with CAR-T cells for the treatment of solid tumors. In addition, viruses can be further modified to deliver therapeutic transgenes selectively to the tumor microenvironment, which could enhance the effector functions of tumor-specific T cells. This review summarizes the major limitations of CAR-T cells in solid tumors and discusses the potential role for oncolytic viruses as partners for CAR-T cells in the fight against cancer.

Enhanced Antitumor Efficacy of Oncolytic Adenovirus-loaded Menstrual Blood-derived Mesenchymal Stem Cells in Combination with Peripheral Blood Mononuclear Cells

Several studies have evaluated the efficacy of using human oncolytic adenovirus (OAdv)-loaded mesenchymal stem cells (MSC) for cancer treatment. For example, we have described the antitumor efficacy of CELYVIR, autologous bone marrow-mesenchymal stem cells infected with the OAdv ICOVIR-5, for treatment of patients with neuroblastoma. Results from this clinical trial point out the role of the immune system in the clinical outcome. In this context, a better understanding of the immunophenotypic changes of human MSCs upon adenoviral infection and how these changes affect human autologous or allogeneic peripheral blood mononuclear cells (PBMC) could guide strategies to improve the antitumor efficacy of infected MSCs. In this work, we show how infection by an OAdv induces toll-like receptor 9 overexpression and activation of the NFĸB pathway in menstrual blood-derived MSCs, leading to a specific cytokine secretion profile. Moreover, a proinflammatory environment, mainly mediated by monocyte activation that leads to the activation of both T cells and natural killer cells (NK cell), is generated when OAdv-loaded MSCs are cocultured with allogeneic PBMCs. This combination of allogeneic PBMCs and OAdv-loaded MSCs enhances antitumor efficacy both in vitro and in vivo, an effect partially mediated by monocytes and NK cells. Altogether our results demonstrate not only the importance of the immune system for the OAdv-loaded MSCs antitumor efficacy, but in particular the benefits of using allogeneic MSCs for this therapy.

Bioselection Reveals miR-99b and miR-485 as Enhancers of Adenoviral Oncolysis in Pancreatic Cancer

Oncolytic viruses are designed for cancer treatment. Cell-virus interactions are key determinants for successful viral replication. Therefore, the extensive reprogramming of gene expression that occurs in tumor cells might create a hurdle for viral propagation. We used a replication-based approach of a microRNA (miRNA) adenoviral library encoding up to 243 human miRNAs as a bioselection strategy to identify miRNAs that facilitate adenoviral oncolytic activity in pancreatic ductal adenocarcinoma. We identify two miRNAs, miR-99b and miR-485, that function as enhancers of adenoviral oncolysis by improving the intra- and extracellular yield of mature virions. An increased adenoviral activity is the consequence of enhanced E1A and late viral protein expression, which is probably mediated by the downregulation of the transcriptional repressors ELF4, MDM2, and KLF8, which we identify as miR-99b or miR-485 target genes. Arming the oncolytic adenovirus ICOVIR15 with miR-99b or miR-485 enhances its fitness and its antitumoral activity. Our results demonstrate the potential of this strategy to improve oncolytic adenovirus potency, and they highlight miR-99b and miR-485 as sensitizers of adenoviral replication.

Antitumor-specific T-cell responses induced by oncolytic adenovirus ONCOS-102 (AdV5/3-D24-GM-CSF) in peritoneal mesothelioma mouse model

Oncolytic adenoviral immunotherapy activates the innate immune system with subsequent induction of adaptive tumor‐specific immune responses to fight cancer. Hence, oncolytic viruses do not only eradicate cancer cells by direct lysis, but also generate antitumor immune response, allowing for long‐lasting cancer control and tumor reduction. Their therapeutic effect can be further enhanced by arming the oncolytic adenovirus with costimulatory transgenes and/or coadministration with other antitumor therapies. ONCOS‐102 has already been found to be well tolerated and efficacious against some types of treatment‐refractory tumors, including mesothelin‐positive ovarian cancer (NCT01598129). It induced local and systemic CD8+ T‐cell immunity and upregulated programmed death ligand 1. These results strongly advocate the use of ONCOS‐102 in combination with other therapeutic strategies in advanced and refractory tumors, especially those expressing the mesothelin antigen. The in vivo work presented herein describes the ability of the oncolytic adenovirus ONCOS‐102 to induce mesothelin‐specific T‐cells after the administration of the virus in bagg albino (BALB/c) mice with mesothelin‐positive tumors. We also demonstrate the effectiveness of the interferon‐γ the enzyme‐linked immunospot (ELISPOT) assay to detect the induction of T‐cells recognizing mesothelin, hexon, and E1A antigens in ONCOS‐102‐treated mesothelioma‐bearing BALB/c mice. Thus, the ELISPOT assay could be useful to monitor the progress of therapy with ONCOS‐102.

Improving CART-Cell Therapy of Solid Tumors with Oncolytic Virus-Driven Production of a Bispecific T-cell Engager

T cells expressing chimeric antigen receptors (CART) have shown significant promise in clinical trials to treat hematologic malignancies, but their efficacy in solid tumors has been limited. Oncolytic viruses have the potential to act in synergy with immunotherapies due to their immunogenic oncolytic properties and the opportunity of incorporating therapeutic transgenes in their genomes. Here, we hypothesized that an oncolytic adenovirus armed with an EGFR-targeting, bispecific T-cell engager (OAd-BiTE) would improve the outcome of CART-cell therapy in solid tumors. We report that CART cells targeting the folate receptor alpha (FR-α) successfully infiltrated preestablished xenograft tumors but failed to induce complete responses, presumably due to the presence of antigen-negative cancer cells. We demonstrated that OAd-BiTE-mediated oncolysis significantly improved CART-cell activation and proliferation, while increasing cytokine production and cytotoxicity, and showed an in vitro favorable safety profile compared with EGFR-targeting CARTs. BiTEs secreted from infected cells redirected CART cells toward EGFR in the absence of FR-α, thereby addressing tumor heterogeneity. BiTE secretion also redirected CAR-negative, nonspecific T cells found in CART-cell preparations toward tumor cells. The combinatorial approach improved antitumor efficacy and prolonged survival in mouse models of cancer when compared with the monotherapies, and this was the result of an increased BiTE-mediated T-cell activation in tumors. Overall, these results demonstrated that the combination of a BiTE-expressing oncolytic virus with adoptive CART-cell therapy overcomes key limitations of CART cells and BiTEs as monotherapies in solid tumors and encourage its further evaluation in human trials. Cancer Immunol Res; 6(5); 605-16. ©2018 AACR.

Evidence of Anti-tumoral Efficacy in an Immune Competent Setting with an iRGD-Modified Hyaluronidase-Armed Oncolytic Adenovirus

To enhance adenovirus-mediated oncolysis, different approaches that tackle the selectivity, tumor penetration, and spreading potential of oncolytic adenoviruses have been reported. We have previously demonstrated that insertion of the internalizing Arginine-Glycine-Aspartic (iRGD) tumor-penetrating peptide at the C terminus of the fiber or transgenic expression of a secreted hyaluronidase can improve virus tumor targeting and spreading. Here we report a new oncolytic adenovirus ICOVIR17K-iRGD in which both modifications have been incorporated. In xenografted A549 tumors in nude mice, ICOVIR17K-iRGD shows higher efficacy than the non-iRGD counterpart. To gain insights into the role of the immune system in oncolysis, we have studied ICOVIR17K-iRGD in the tumor isograft mouse model CMT64.6, partially permissive to human adenovirus 5 replication, in immunodeficient or immunocompetent mice. Whereas no efficacy was observed in the immunodeficient setting due to insufficient viral replication, partial efficacy and a polymorphonuclear and CD8+ T cell infiltrate were observed in the immunocompetent mice. The results indicate that the elicitation of a virus-induced anti-tumoral immune response is responsible for the observed partial anti-tumoral effect.

A NOTCH-sensitive uPAR-regulated oncolytic adenovirus effectively suppresses pancreatic tumor growth and triggers synergistic anticancer effects with gemcitabine and nab-paclitaxel

Notch signaling pathway is an embryonic program that becomes reactivated in pancreatic cancer and contributes to cancer stem cell (CSC) maintenance. We explored the concept of oncolytic adenoviral activity in response to Notch activation signaling, in the context of a chimeric promoter with uPAR regulatory sequences, as a strategy to drive its activity in neoplastic and CSC. We explored the advantages of a chemo-virotherapy approach based on synergistic combinations. Regulatory sequences recognized by the transcriptional factor CSL upstream a minimal uPAR promoter were engineered in adenoviral vectors and in the oncolytic adenovirus AdNuPARmE1A. Viral response to Notch signaling, and viral potency in cell lines and pancreatic cancer stem cells (PCSC) was tested. Preclinical toxicity and antitumor efficacy in xenografts and Patient-derived xenografts (PDX) mouse models was evaluated, as unimodal or in combination with gemcitabine+nab-paclitaxel. Mechanistic studies were conducted to explore the synergism of combined therapies.

We demonstrate that CSL-binding site optimized-engineered sequences respond to Notch activation in AdNuPARmLuc and AdNuPARmE1A. AdNuPARmE1A showed strong lytic effects in pancreatic cancer cell lines and PCSC. AdNuPARmE1A displayed attenuated activity in normal tissues, but robust antitumor effects in xenograft and PDX models, leading to a reduced capacity of treated tumors to form tumorspheres. Chemo-virotherapy treatment enlarged therapeutic response in both tumor models. Synergistic effects of the combination resulted from viral sensitization of apoptotic cell death triggered by chemotherapy.

In summary we present a novel effective oncolytic adenovirus, AdNuPARmE1A that reduces PCSC and presents synergistic effects with gemcitabine and nab-paclitaxel, supporting further clinical development.

Abstract 3662: Activation of CD40 while inhibiting IL6/STAT3 using oncolytic viruses induces mature DCs with high cytokine production but blocks PDL1 expression

The tumor microenvironment (TME) consists of tumor cells and stroma, including fibroblasts, blood vessels, immune cells and extracellular matrix. The TME supports tumor progression, metastasis as well as resistance to cancer therapeutics. In pancreatic cancer, the TME is dense due to overproduction of collagen and the tumor is infiltrated with suppressive myeloid cells such as M2 macrophages and myeloid suppressor cells. One key regulator of myeloid cells is CD40, a receptor expressed on a variety of cell types. CD40/CD40L signaling results in production of cytokines and chemokines by myeloid cells but also endothelial and epithelial cells to alert the immune system of immediate danger. 4-1BB is expressed by lymphocytes and dendritic cells (DCs). Stimulation via 4-1BBL drives lymphocyte expansion and regulates memory formation. IL6 signaling leads to STAT3 phosphorylation in myeloid cells and tumor cells leading to suppressive phenotypes, tumor proliferation, and angiogenesis. Further, STAT3 signaling enhances production of TGFb, which in turn leads to overexpression of collagen. We have constructed a family of oncolytic adenoviruses (LOAd) activating the CD40, 4-1BB and/or inhibiting IL6 signaling. The LOAd viruses (-, 700, 703, 713) were investigated for their capacity to activate human monocyte-derived DCs as well as their effect on pancreatic tumor cells and stroma (fibroblastic stellate cells, endothelial cells) using flow cytometry, MTS assay and ProSeek Proteomics. The LOAd viruses expressing a trimerized CD40L, 4-1BBL and/or a scFv IL6R showed efficient oncolysis of tumor cells but primary stellate cells were unaffected. However, stellate cells reduced tumor-promoting factors such as FGF5, PlGF, amphiregulin, Gal3, TGFb and collagen type I. Dendritic cells increased costimulators, cytokines as well as chemokines but PDL1 was not expressed when IL6/STAT3 was blocked. Infected endothelial cells upregulated receptors important for lymphocyte transmigration (ICAM, VCAM and E-Selectin). Taken together, our data demonstrates that it is possible to utilize oncolytic adenoviruses to spark immune activation at the same time changing biological processes via STAT3 blockade and/or CD40/4-1BB pathway activation to reduce factors that promotes tumor progression.

Citation Format: Emma Eriksson, Ioanna Milenova, Jessica Wenthe, Anna Dimberg, Rafael Moreno, Gustav Ullenhag, Ramon Alemany, Angelica Loskog. Activation of CD40 while inhibiting IL6/STAT3 using oncolytic viruses induces mature DCs with high cytokine production but blocks PDL1 expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3662. doi:10.1158/1538-7445.AM2017-3662

Shaping the Tumor Stroma and Sparking Immune Activation by CD40 and 4-1BB Signaling Induced by an Armed Oncolytic Virus

Purpose: Pancreatic cancer is a severe indication with short expected survival despite surgery and/or combination chemotherapeutics. Checkpoint blockade antibodies are approved for several cancer indications, but pancreatic cancer has remained refractory. However, there are clinical data suggesting that stimulation of the CD40 pathway may be of interest for these patients. Oncolytic viruses armed with immunostimulatory genes represent an interesting approach. Herein, we present LOAd703, a designed adenovirus armed with trimerized CD40L and 4-1BBL that activates the CD40 and 4-1BB pathways, respectively. As many cells in the tumor stroma, including stellate cells and the infiltrating immune cells, express CD40 and some 4-1BB, we hypothesize that LOAd703 activates immunity and simultaneously modulates the biology of the tumor stroma.Experimental Design: Tumor, stellate, endothelial, and immune cells were infected by LOAd703 and investigated by flow cytometry, proteomics, and functional analyses.Results: LOAd703-infected pancreatic cell lines were killed by oncolysis, and the virus was more effective than standard-of-care gemcitabine. In in vivo xenograft models, LOAd703 efficiently reduced established tumors and could be combined with gemcitabine for additional effect. Infected stellate and tumor cells reduced factors that promote tumor growth (Spp-1, Gal-3, HGF, TGFβ and collagen type I), while chemokines were increased. Molecules involved in lymphocyte migration were upregulated on infected endothelial cells. Dendritic cells were robustly stimulated by LOAd703 to produce costimulators, cytokines and chemokines, and such DCs potently expanded both antigen-specific T cells and NK cells.Conclusions: LOAd703 is a potent immune activator that modulates the stroma to support antitumor responses. Clin Cancer Res; 23(19); 5846-57. ©2017 AACR.

Oncolytic Adenoviral Delivery of an EGFR-Targeting T-cell Engager Improves Antitumor Efficacy

Antiviral immune responses present a major hurdle to the efficacious use of oncolytic adenoviruses as cancer treatments. Despite the existence of a highly immunosuppressive tumor environment, adenovirus-infected cells can nonetheless be efficiently cleared by infiltrating cytotoxic T lymphocytes (CTL) without compromising tumor burden. In this study, we tested the hypothesis that tumor-infiltrating T cells could be more effectively activated and redirected by oncolytic adenoviruses that were armed with bispecific T-cell-engager (BiTE) antibodies. The oncolytic adenovirus ICOVIR-15K was engineered to express an EGFR-targeting BiTE (cBiTE) antibody under the control of the major late promoter, leading to generation of ICOVIR-15K-cBiTE, which retained its oncolytic properties in vitro cBiTE expression and secretion was detected in supernatants from ICOVIR-15K-cBiTE-infected cells, and the secreted BiTEs bound specifically to both CD3⁺ and EGFR⁺ cells. In cell coculture assays, ICOVIR-15K-cBiTE-mediated oncolysis resulted in robust T-cell activation, proliferation, and bystander cell-mediated cytotoxicity. Notably, intratumoral injection of this cBiTE-expressing adenovirus increased the persistence and accumulation of tumor-infiltrating T cells in vivo, compared with the parental virus lacking such effects. Moreover, in two distinct tumor xenograft models, combined delivery of ICOVIR-15K-cBiTE with peripheral blood mononuclear cells or T cells enhanced the antitumor efficacy achieved by the parental counterpart. Overall, our results show how arming oncolytic adenoviruses with BiTE can overcome key limitations in oncolytic virotherapy. Cancer Res; 77(8); 2052-63. ©2017 AACR.

Abstract 1474: A novel oncolytic adenovirus expressing tumor microenvironment modulators that activates myeloid cells, lymphocytes and endothelial cells

Immunotherapy is becoming a cornerstone in cancer treatment of many indications. So far, pancreatic cancer has shown little response to so called checkpoint blockade antibodies. However, animal data suggests that activating immunotherapies releases the effect of checkpoint blockade also in pancreatic cancer. The tumor microenvironment (TEM) supports the growth of the tumor cells and consists of stroma cells, fibroblasts, blood vessels and immune cells. In some tumor lesions, such as those in pancreatic cancer, the TEM is dense and comprises most of the lesion. The TEM regulates immune activity via its high content of M2 macrophages, myeloid derived suppressor cells and T regulatory cells. Further, the dysfunctional blood vessels in lesions are not optimal for recruiting lymphocytes. With these aspects in mind, LOAd703 was developed. LOAd703 is an oncolytic adenovirus carrying TEM modulators.

LOAd703 was constructed from the ICOVIR system of oncolytic adenoviruses in which replication depends on a dysfunctional, hyperphosphorylated retinoblastoma pathway. The genome was further altered by removing E3-6.7K and gp19K, changing the serotype 5 fiber to a serotype 35 fiber to target CD46 expressed by most tumors, as well as by adding a CMV-driven transgene cassette with the human transgenes for TMZ-CD40L and 4-1BBL. Hence, the transgenes will be expressed in both tumor and stroma while oncolysis is initiated in the tumor cells. We demonstrate herein that LOAd703 infection of a panel of pancreatic cancer cell lines efficiently induced tumor cell death within 48-72 hrs post infection while LOAd703 infection of dendritic cells demonstrated an increased maturation of myeloid cells including dendritic cells (DCs). These DCs could in turn potently activate and promote expansion of both T- and NK cells. Further, LOAd703 infection of endothelial cells (HUVEC) induced upregulation of molecules involved in lymphocyte attachment, rolling and transmigration. In conclusion, LOAd703 is a novel oncolytic virus that targets both the tumor and its TME and a clinical trial is underway to elucidate its effect in pancreatic cancer.

Citation Format: Angelica Loskog, Emma Eriksson, Ioanna Milenova, Rafael Moreno, Ramon Alemany. A novel oncolytic adenovirus expressing tumor microenvironment modulators that activates myeloid cells, lymphocytes and endothelial cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1474.

Joint Modelling of Survival and Emergency Medical Care Usage in Spanish Insureds Aged 65+

BACKGROUND

We study the longevity and medical resource usage of a large sample of insureds aged 65 years or older drawn from a large health insurance dataset. Yearly counts of each subject's emergency room and ambulance service use and hospital admissions are made. Occurrence of mortality is also monitored. The study aims to capture the simultaneous dependence between their demand for healthcare and survival.

METHODS

We demonstrate the benefits of taking a joint approach to modelling longitudinal and survival processes by using a large dataset from a Spanish medical mutual company. This contains historical insurance information for 39,137 policyholders aged 65+ (39.5% men and 60.5% women) across the eight-year window of the study. The joint model proposed incorporates information on longitudinal demand for care in a weighted cumulative effect that places greater emphasis on more recent than on past service demand.

RESULTS

A strong significant and positive relationship between the exponentially weighted demand for emergency, ambulance and hospital services is found with risk of death (alpha = 1.462, p < 0.001). Alternative weighting specifications are tested, but in all cases they show that a joint approach indicates a close connection between health care demand and time-to-death. Additionally, the model allows us to predict individual survival curves dynamically as new information on demand for services becomes known.

CONCLUSIONS

The joint model fitted demonstrates the utility of analysing demand for medical services and survival simultaneously. Likewise, it allows the personalized prediction of survival in advanced age subjects.

Abstract A25: Immunotherapy using LOAd700 armed with CD40 ligand controls experimental pancreatic cancer and activates immune responses

The aim of this study was to evaluate the efficacy of LOAd immunotherapy to treat pancreatic cancer in a xenograft model as well as to determine the capacity of LOAds to stimulate the immune system in in vitro models. LOAd viruses are oncolytic adenoviruses (5/35) armed with immunostimulatory genes in order to shift the tumor milieu towards immune activation at the same time providing release and spread of tumor antigens due to oncolysis. In this manner, LOAd virus is an antigen-independent immunotherapy for various solid tumors.

LOAd armed with CD40 ligand (LOAd700) was constructed from the ICOVIR system by changing the virus shaft and knob to that of serotype 35 to broaden virus binding and entry into cells (pending patent EP14163704). Oncolysis in OCOVIRs is restricted to cells with a disrupted Rb pathway. Viruses were produced using A549 cells. The pancreatic cancer cell lines BxPC3, Panc01, MiaPaCa2 and PaCa3 were used for in vitro evaluation and Panc01 was used in the xenograft model in Nu/Nu mice. Human dendritic cells (DCs) were obtained by differentiation of CD14+ monocytes with GM-CSF and IL4 for 7 days.

LOAd viruses infected both the panel of pancreatic tumor cell lines and human DCs with high efficacy and both the cell lines and the DCs expressed the CMV driven transgene/s post transduction. The oncolytic LOAd virus did not kill DCs nor healthy pancreatic cells present in donor islet cell isolation surplus material. In contrast, oncolysis was restricted to the tumor cell lines. The LOAd-transduced DCs increased markers of maturation such as MHC II, CD86, CD70 and CD83 and produced high levels of IL12. LOAd stimulated DCs were able to activate and expand antigen-specific T cells and NK cells as demonstrated in a CMV in vitro system. LOAd viruses could control tumor growth in a xenograft immunodeficient model due to oncolysis alone.

In conclusion, LOAd700 can kill pancreatic tumor cells in vitro and control growing tumor in mice due to oncolysis alone. Further, upon DC transduction, LOAd viruses mature DCs to efficient antigen presenters and stimulators of Th1 effector cells such as T cells and NK cells. LOAd is an interesting new immunotherapy for solid malignancies including pancreatic cancer.

Citation Format: Emma Svensson, Rafael Moreno, Ioanna Milenova, Lisa Christiansson, Ramon Alemany, Angelica Loskog. Immunotherapy using LOAd700 armed with CD40 ligand controls experimental pancreatic cancer and activates immune responses. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr A25.