- Email: [email protected]
Discovery of Bioactive Small Molecule Inhibitors of Human PD1-PDL1 Interaction
and irrespective of PD-L1 status, were eligible. Study treatment consisted of 21-day cycles (cy) of P 200mg on day 1 and Gem 1250mg/m2 on days 1 and 8 until progressive disease (PD) or unacceptable toxicity, whatever occurred first. Primary objective was Objective Response Rate (ORR). Results: Thirty-six pts were included in the first stage of a Simon’s design. Recruitment was stopped as only 5 pts presented an objective response (partial) ( 7 responses needed to continue recruiting pts). Median age was 52 years (range 31-77), 21 pts had triple negative disease, the majority of pts had an ECOG performance status 1 (n ¼ 35), visceral involvement (n ¼ 28) and 2 metastatic locations (n ¼ 27). Median number of prior lines (any therapy) for ABC was 4 (range 0-11). Pts received a median of 4.5 cy of Gem and 4 cy of P (same range for both drugs, 1-24). The median relative dose intensity of P and Gem was 100% and 80%, respectively. Treatment discontinuation due to PD was reported on 29 pts. The ORR was 15.2% (95% confidence interval (CI) 5.1-31.9) and the Clinical Benefit Rate was 17% (95% CI 33.5-69.2); median duration of objective response was 4.3 months (mo) (95% CI 2.3-7.4), median ProgressionFree Survival was 3.1 mo (95% CI, 2-4.3), and median Overall Survival was 7.9 mo (95% CI 6.5-10.3). Eight pts were on treatment 6 mo before PD (2 pts on 11.4 and 16.1 mo). Grade (G) 3 AEs related to the study treatment were reported on 14 pts (39%), being neutropenia the most common G3 (22.2%) and G4 (5.6%) AE. Conclusion: P can be safely combined with Gem, the combination did not meet the efficacy objective in terms of ORR but 22.2% pts were on treatment 6 mo. Clinical trial identification: NCT03025880. Legal entity responsible for the study: GEICAM Spanish Breast Cancer Group. Funding: MSD. Disclosure: J. Cruz: Honoraria (self), Advisory / Consultancy: Glaxo; Honoraria (self), Advisory / Consultancy: AstraZeneca; Honoraria (self), Advisory / Consultancy: Roche; Honoraria (self), Advisory / Consultancy: Novartis; Honoraria (self), Advisory / Consultancy: Pharmamar; Honoraria (self), Advisory / Consultancy: Eisai; Honoraria (self), Advisory / Consultancy: Lilly; Honoraria (self), Advisory / Consultancy: Celgene; Honoraria (self), Advisory / Consultancy: Astellas; Honoraria (self), Advisory / Consultancy: Amgen; Honoraria (self), Advisory / Consultancy: Pfizer. M. Ramos Vazquez: Honoraria (self), Advisory / Consultancy: AstraZeneca; Honoraria (self), Advisory / Consultancy: Roche; Honoraria (self), Advisory / Consultancy: Novartis; Honoraria (self), Advisory / Consultancy: Pfizer. J. Corte´s: Honoraria (self), Honoraria (institution), Advisory / Consultancy: Roche; Honoraria (self), Advisory / Consultancy: Celgene; Advisory / Consultancy: Cellestia; Honoraria (institution), Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Biothera Pharmaceutical; Advisory / Consultancy: Merus; Advisory / Consultancy: Seattle Genetics; Advisory / Consultancy: Daiichi Sankyo; Advisory / Consultancy: Erytech; Advisory / Consultancy: Athenex; Advisory / Consultancy: Polyphor; Honoraria (self), Advisory / Consultancy: Lilly; Honoraria (institution), Advisory / Consultancy: Servier; Honoraria (self), Honoraria (institution), Advisory / Consultancy: MSD; Advisory / Consultancy: GSK; Honoraria (self): Novartis; Honoraria (self), Honoraria (institution): Eisai; Honoraria (self), Honoraria (institution): Pfizer; Honoraria (self): Samsung Bioepis; Honoraria (institution), MedSIR (Stock, patent and intellectual property): Ariad Pharmaceuticals. Baxalta GMBH/Servier Affaires. Bayer Healthcare. Guardanth Health. Piqur Therapeutics. Puma C. Queen Mary University of London. Seagen. All other authors have declared no conflicts of interest.
103P
Combinatorial unique photothermal tumour immunotherapy against targeted triple negative breast cancer therapy of dual modal nanoplatform
V. Raju1, V. Yasothamani1, S. Shyamsivappan2, Y. Haldorai3, K. Saravanakumar4 Department of Zoology, Bharathiar University, Coimbatore, India, 2Department of Chemistry, Bharathiar University, Coimbatore, India, 3Department of Nanoscience and Technology, Bharathiar University, Coimbatore, India, 4Medical Biotechnology, Kangwon National University, Chuncheon, Republic of Korea
is more effective than either immunotherapy or photothermal therapy alone against primary treated and distant untreated tumours in a mouse breast cancer model. Legal entity responsible for the study: The authors. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.
104P
A novel immunological role of hydrogen sulphide in shaping natural killer cells cytoxicity in breast cancer patients
R.A. Youness1, A. Abdelmotaal2, M. Gad3 Pharmaceutical Biology Department, German University in Cairo, Cairo, Egypt, 2 Pharmacognosy Department, Faculty of Pharmacy, King Khalid University, Abha, Saudi Arabia, 3Biochemistry Department, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo, Egypt
1
Background: Triple Negative Breast cancer (TNBC) is a complex challenging disease that is not amenable to conventional treatment. Our research group has recently portrayed hydrogen sulphide (H2S) and its synthesizing enzymes, cystathionine b-synthase (CBS) and cystathionine-c-lyase (CSE), as potent oncogenic mediators for TNBC progression. Recently, H2S has been casted as a potential modulator of cancer immune surveillance as well. Yet, the impact of H2S on the immunological profile of TNBC cells has never been investigated. Natural Killer (NK) cells are the native sentinels of the immune system that plays an indisputable role in TNBC-immune surveillance. TNBC immune suppressive tumour microenvironment is also rate-limiting step when immunotherapeutic approaches are tackled in case of TNBC patients. Thus the main aim of this study is to identify the role of endogenous H2S on NK cells’ activating ligands present on TNBC cells, immune suppressive tumour microenvironment and net effect on NK cells cytotoxicity. Methods: Breast tissues were collected from 80 BC patients. ER, PR, HER-2 and Ki-67 levels were quantified using immunohistochemistry. MDA-MB-231 and MCF7 cells were cultured and transfected with different oligonucleotides. Total RNA was extracted and quantified by qRT-PCR. IFN-c and TNF-a in cellular supernatant was measured using representative ELISA kits. NK cells were isolated from 30 healthy controls. The cytotoxicity of NK cells was measured using LDH Cytotoxicity Assay. Results: MICA, MICB and ULBP2 were significantly down-regulated in TNBC tissues and cell lines. Knocking down of CBS and CSE using siRNAs resulted in a marked increase in MICA/B and ULBP2 expression in MDA-MB-231 cells. Nonetheless, knocking down of CBS and CSE resulted in a marked induction in IFN-c production and attenuation of TNF-a levels. Upon co-culturing with healthy NK cells, Knocking down of endogenous H2S resulted in a marked increase in NK cells cytotoxicity. Conclusion: This study showed that knocking down of CBS and CSE resulted in a improving NK cells cytotoxicity and alleviating tumor-induced immune suppressive microenvironment in TNBC patients. Legal entity responsible for the study: German University in Cairo. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.
1
Background: Combinatorial therapy including the immunotherapy is revolutionizing the effective treatment of cancer. It achieved unprecedented responses in advancedstage patients, including complete cures and long-term survival. However, immunotherapy also has limitations, such as its relatively low response rates and the development of severe side effects. These drawbacks are gradually being overcome by improving our understanding of the immune system, as well as by establishing combination regimens in which immunotherapy is combined with other treatment modalities. Methods: Herein, we report the method of coassembly of two structurally defined materials, each comprised of photothermal agent and a small molecule immunostimulant molecularly self-assembled. One organic polymer has excellent photothermal properties; the other one has designed for efficient immmune activation, contributing to superior stability during circulation. Results: The coassembled nanoparticles (NPs) possesses superior photothermal conversion efficiency as well as efficient encapsulation and controlled release of cytotoxic molecules and immunomodulatory agents. NPs loaded with immunostimulant has proven to be a highly efficacious combination photothermal/immunotherapeutic nanoplatform against Triple Negative Bresat Cancer xenograft model. When loaded with imiquimod, a potent small molecule immunostimulant, NPs is found to be highly effective against breast cancer model, particularly when photothermal/immuno-therapy is given. Such dual therapy not only eradicates the light-irradiated primary tumours, but also activates systemic antitumor immunoactivity, causing tumour death at light-unexposed distant tumour sites. Conclusion: In conclusion, this “photothermal immunotherapy” approach, photothermal ablation of tumour cell death reduces tumour growth and releases tumour antigens into the surrounding milieu, while the immunoadjuvants potentiate host antitumor immunity. Our results indicated that combined photothermal immunotherapy
Volume 30 | Supplement 11 | December 2019
105P
Discovery of bioactive small molecule inhibitors of human PD1-PDL1 interaction
S.P. Patil, J. Diflumeri, E. Fattakhova Chemical Engineering, Widener University, Chester, PA, USA Background: The antibody-based cancer immunotherapies targeting the Programmed cell Death1-Programmed Cell Death Ligand 1 (PD1-PDL1) interaction have shown unprecedented clinical success again several types of cancer. Our present study aims to discover small molecule PD1-PDL1 inhibitors that may offer several advantages as compared to antibodies, such as higher oral bioavailability, lower cost, better tumor infiltration, and relatively shorter half-life that is especially helpful in controlling any potential adverse immune reactions. Methods: We identified several small molecule inhibitors based on the available crystal structures of human PD1-PDL1 complex as well as apo forms of PD1 and PDL1. Specifically, we first carried out long molecular dynamics simulations to identify “druggable” binding pockets on the binding interfaces of PD1 and PDL1 proteins, followed by molecular docking and consensus-scoring of approved and experimental drugs into those pockets. The top virtually selected compounds were then tested in AlphaLISA and ELISA assays measuring inhibition of the PD1-PDL1 interaction, followed by functional cell-based assays. Results: Through integrated virtual and experimental screening protocols, we have identified several potent PD1-PDL1 inhibitors with remarkable activities in both the cell-free and cell-based assays. Notably, one of our top active molecules showed activity as comparable to that of the anti-PD1 antibody used as the positive control in these studies. This is remarkable considering the newly-discovered molecules have relatively low molecular weight and still are capable of inhibiting PD1-PDL1 protein-protein interaction with large binding interface of 1,970 A˚2. Our results provide support for future investigation of these molecules in vivo.
doi:10.1093/annonc/mdz451 | xi39
Downloaded from https://academic.oup.com/annonc/article-abstract/30/Supplement_11/mdz451.014/5675238 by McMaster University Library , Collections - Serials Processing user on 22 December 2019
abstracts
Annals of Oncology
abstracts
106P
A single dose of local IL-12 promotes anti-tumor effect of antiEGFRvIII-CAR-T cells in a syngeneic murine model of glioblastoma
A.R. Liuzzi1, G. Agliardi2, B. Becher1, M. Pule2 Institute of Experimental Immunology, UZH - University of Zurich - Irchel Campus, Zurich, Switzerland, 2University College London, Cancer Institute, London, UK
1
Background: Glioblastoma multiforme (GBM) is one of the most devastating brain tumors with poor prognosis and high mortality. Immunotherapy with chimeric antigen receptor (CAR) T cells is gaining attention as a promising strategy to treat this disease. An ideal candidate to target with CAR T cells is the tumor specific variant III of the epidermal growth factor receptor (EGFRvIII), which represents a mutation found in more than 30% of glioblastoma patients. However, anti-EGFRvIII-CAR modified T cell therapy has shown only limited effects in GBM patients, in all likelihood due to the immunosuppressive microenvironment that CAR T cells encounter in the tumor microenvironment (TME) of gliomas. To make gliomas susceptible to CAR T cell therapy, combinatorial approaches to convert the TME are required. Methods: Mice received 5Gy TBI on day 15 post implantation, followed by intratumoral injection of IL-12:Fc on day 20 and infusion of EGFRvIII-directed CAR or non-transduced T cells on day 21. To perform functional analysis, we adopted highparametric flow-cytometric characterization of the TME using 23 independent parameters 8 days after CAR T cells injection. We utilized unsupervised validated clustering approaches (FlowSOM and CellCNN) to discriminate between different cell populations. Results: Here, we demonstrate that the combination of a single dose of local IL-12 with anti-EGFRvIII-CAR T cells synergizes to increase long-term survival in a syngeneic mouse model of GBM. IL-12 not only boosted the pro-inflammatory and cytotoxic activity of anti-EGFRvIII-CAR T cells, but also induced a complete remodelling of the tumor microenvironment (TME) with strong endogenous anti-tumor immune T cell responses. These findings highlight the capacity of IL-12 to induce an immunologically “cold” tumor such as GMB to acquire responsiveness to CAR T cells therapy. Conclusion: This study demonstrates the capacity of IL-12 as local “adjuvant” therapy to boost the efficacy of CAR T cells and to awake the endogenous anti-tumor T cell responses. Legal entity responsible for the study: University of Zurich. Funding: University Research Priority Project and Advanced T-cell Engineered for Cancer Therapy. Disclosure: M. Pule: Honoraria (self), Honoraria (institution): Autolus LTD. All other authors have declared no conflicts of interest.
107P
Increasing responses to T-cell therapies in solid tumours by the use of an engineered adenovirus coding for TNFa and IL-2
V. Cervera-Carrascon1, R. Havunen1, J.M. Santos1, D.C.A. Quixabeira2, A. Hemminki1, S. Zafar2 1 Translational Immunology Research Program and Department of Oncology, University of Helsinki and TILT Biotherapeutics, Helsinki, Finland, 2Translational Immunology Research Program and Department of Oncology, University of Helsinki, Helsinki, Finland Background: During the last decade, a revived enthusiasm about T-cell related therapies emerged after promising clinical outcomes. Nevertheless, many patients (especially with solid tumours) still do not have adequate therapeutic options. The complexity of the tumour microenvironment is a likely factor acting in detriment of many of those therapies by multiple suppressive mechanisms. To tackle a complex mechanism, an oncolytic adenovirus 2 (Ad5/3-E2F-d24-hTNFa-IRES-hIL2, a.k.a. TILT-123) was engineered to enable T-cell therapies in those circumstances. Methods: To study the efficacy of TILT-123 together with different T-cell related therapies (adoptive cell transfer, checkpoint inhibitors and CAR T cell therapy) different models were used including mouse, Syrian Hamster and patient derived in vivo models for different indications were tested. Results: Antitumor efficacy analyses showed complete responses in all animals receiving a T-cell therapy or checkpoint inihibitor (aPD1 or aPDL-1) and the T-cell enabling virus. Further, other aspects such as safety, influence on different immune populations, abscopal effect, antitumor memory and ability to replace lympho-depleting chemotherapy and postconditioning with high-dose IL-2 treatment were studied. Conclusion: The use of TILT-123 to enable T-cell therapies (including checkpointinhibiting antibodies) delivered encouraging preclinical results pointing to it as a
xi40 | Therapeutic Development
valuable approach to increase the number of patients that benefit from T-cell therapies. Those results include not only cell based therapies but also checkpoint inhibitors, a kind of therapy that is making the difference in the field and becoming first-line treatment for an increasing number of indications. Because of the favourable preclinical studies, the first in human clinical trials with TILT-123 will start in the upcoming months. Legal entity responsible for the study: The authors. Funding: TILT Biotherapeutics. Disclosure: V. Cervera-Carrascon: Full / Part-time employment: TILT Biotherapeutics. R. Havunen: Full / Part-time employment: TILT Biotherapeutics. J.M. Santos: Full / Part-time employment: TILT Biotherapeutics. A. Hemminki: Shareholder / Stockholder / Stock options, Full / Parttime employment, Officer / Board of Directors: TILT Biotherapeutics. All other authors have declared no conflicts of interest.
108P
Phosphatidylserine suppresses T cells through GPR174, and coinhibition of adenosine receptors and GPR174 synergistically enhances Th1 cytokine production
M.A. Gavin, A. Gragerov, E. Espling, A. Rohde, T. Sexton, C. Doulami, G. Gaitanaris Discovery, Omeros Corporation, Seattle, WA, USA Background: Extracellular phosphatidylserine (PS) is a potent modulator of immune responses. In addition to exposure during apoptosis, PS is observed on activated platelets, leukocytes, endothelial cells, tumor cells, and exosomes. While PS exposed during apoptosis is known to suppresses inflammatory responses in phagocytic cells, whether either form of exposed PS acts directly on T lymphocytes has not been extensively studied. Methods: HEK293 cells expressing GPR174 and GloSensor were used to detect GPR174 agonism. Immune cells were stimulated with anti-CD3/CD28 with GPCR inhibitors, NECA, or PS liposomes; and cytokines in media were measured. WT or GPR174-KO mice inoculated with syngeneic tumor cells and treated with anti-GITR (DTA-1) were evaluated for tumor growth. Results: Here we show that PS suppresses T cells through GPR174, a Gas-coupled GPCR. PS liposomes were more potent than lyso-PS in stimulating GPR174, and PS exposed on various cell types agonized GPR174. Several GPR174 inhibitors of different chemical classes were identified. PS liposomes attenuated Th1 cytokine production from human T cells and WT but not GPR174-KO mouse T cells, and GPR174 inhibitors reversed this suppression. Th1 cytokines were increased by GPR174 inhibition in the presence of tumor exosomes. GPR174 inhibition or genetic deletion also reduced CTLA-4 expression, an immune checkpoint known to be induced by cAMP. Compared to WT mice, GPR174-KO mice significantly controlled tumor growth when Treg were transiently depleted with anti-GITR. GPR174 is similar to A2A/B adenosine receptors in that both suppress Th1 immunity through cAMP in response to products of cell stress and death abundant in the tumor microenvironment. Inhibition of GPR174 and A2A/B synergistically increased cytokine production, GPR174 and A2A/B agonists suppressed T cells to the same extent as both combined, and A2A/B inhibition was more effective on GPR174-KO T cells vs. WT T cells. Conclusion: Our findings suggest that for T cells to effectively overcome cAMPmediated immunosuppression in the tumor microenvironment, both GPR174 and the adenosine pathway must be inhibited. Legal entity responsible for the study: Omeros Corporation. Funding: Omeros Corporation. Disclosure: M.A. Gavin: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation. A. Gragerov: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation. E. Espling: Shareholder / Stockholder / Stock options, Full / Parttime employment: Omeros Corporation. A. Rohde: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation. T. Sexton: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation. C. Doulami: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation. G. Gaitanaris: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation.
109P
Phase I clinical study for validation of fimaporfin-based photochemical internalisation: A novel technology for enhancing cellular immune responses important for therapeutic effect of peptide-and proteinbased vaccines
P.K. Selbo1, S. Janetzki2, M.J.P. Welters3, M. Ha˚kerud1, A.G. Nedberg1, V.T. Edwards1, H. Olivecrona4, S.H. van der Burg3, T. Otterhaug4, A. Hogset5 1 Department of Radiation Biology, Oslo University Hospital - The Norwegian Radium Hospital, Oslo, Norway, 2ZellNet Consulting Suite 25-S, ZellNet Consulting, Inc., Fort Lee, NJ, USA, 3Department of Medical Oncology, Leiden University Medical Center, Leiden, Netherlands, 4Medical, PCI Biotech AS, Oslo, Norway, 5Research, PCI Biotech AS, Oslo, Norway Background: FimaVacc is a vaccine formulated by the photosensitising compound fimaporfin and a toll-like receptor (TLR) agonist, and is administered intradermally followed by illumination of the vaccination site. In preclinical studies, fimaVacc has been shown to improve MHC class I antigen presentation, resulting in strongly enhanced cytotoxic and helper T-cell responses to various types of peptide and protein vaccines.
Volume 30 | Supplement 11 | December 2019
Downloaded from https://academic.oup.com/annonc/article-abstract/30/Supplement_11/mdz451.014/5675238 by McMaster University Library , Collections - Serials Processing user on 22 December 2019
Conclusion: In summary, we have been successful in identifying novel, non-peptide small molecule inhibitors of PD1-PDL1 interaction through rational design. Considering their remarkable activity and clinical status, they may present immediate clinical potential against cancers expressing PDL1. They may also prove to be ideal starting points for the design of more potent, selective drug-like inhibitors of PD1PDL1 interaction. Legal entity responsible for the study: Widener University, Chester, PA, USA. Funding: W. W. Smith Charitable Trust. Disclosure: All authors have declared no conflicts of interest.
Annals of Oncology
103P
Combinatorial unique photothermal tumour immunotherapy against targeted triple negative breast cancer therapy of dual modal nanoplatform
V. Raju1, V. Yasothamani1, S. Shyamsivappan2, Y. Haldorai3, K. Saravanakumar4 Department of Zoology, Bharathiar University, Coimbatore, India, 2Department of Chemistry, Bharathiar University, Coimbatore, India, 3Department of Nanoscience and Technology, Bharathiar University, Coimbatore, India, 4Medical Biotechnology, Kangwon National University, Chuncheon, Republic of Korea
is more effective than either immunotherapy or photothermal therapy alone against primary treated and distant untreated tumours in a mouse breast cancer model. Legal entity responsible for the study: The authors. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.
104P
A novel immunological role of hydrogen sulphide in shaping natural killer cells cytoxicity in breast cancer patients
R.A. Youness1, A. Abdelmotaal2, M. Gad3 Pharmaceutical Biology Department, German University in Cairo, Cairo, Egypt, 2 Pharmacognosy Department, Faculty of Pharmacy, King Khalid University, Abha, Saudi Arabia, 3Biochemistry Department, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo, Egypt
1
Background: Triple Negative Breast cancer (TNBC) is a complex challenging disease that is not amenable to conventional treatment. Our research group has recently portrayed hydrogen sulphide (H2S) and its synthesizing enzymes, cystathionine b-synthase (CBS) and cystathionine-c-lyase (CSE), as potent oncogenic mediators for TNBC progression. Recently, H2S has been casted as a potential modulator of cancer immune surveillance as well. Yet, the impact of H2S on the immunological profile of TNBC cells has never been investigated. Natural Killer (NK) cells are the native sentinels of the immune system that plays an indisputable role in TNBC-immune surveillance. TNBC immune suppressive tumour microenvironment is also rate-limiting step when immunotherapeutic approaches are tackled in case of TNBC patients. Thus the main aim of this study is to identify the role of endogenous H2S on NK cells’ activating ligands present on TNBC cells, immune suppressive tumour microenvironment and net effect on NK cells cytotoxicity. Methods: Breast tissues were collected from 80 BC patients. ER, PR, HER-2 and Ki-67 levels were quantified using immunohistochemistry. MDA-MB-231 and MCF7 cells were cultured and transfected with different oligonucleotides. Total RNA was extracted and quantified by qRT-PCR. IFN-c and TNF-a in cellular supernatant was measured using representative ELISA kits. NK cells were isolated from 30 healthy controls. The cytotoxicity of NK cells was measured using LDH Cytotoxicity Assay. Results: MICA, MICB and ULBP2 were significantly down-regulated in TNBC tissues and cell lines. Knocking down of CBS and CSE using siRNAs resulted in a marked increase in MICA/B and ULBP2 expression in MDA-MB-231 cells. Nonetheless, knocking down of CBS and CSE resulted in a marked induction in IFN-c production and attenuation of TNF-a levels. Upon co-culturing with healthy NK cells, Knocking down of endogenous H2S resulted in a marked increase in NK cells cytotoxicity. Conclusion: This study showed that knocking down of CBS and CSE resulted in a improving NK cells cytotoxicity and alleviating tumor-induced immune suppressive microenvironment in TNBC patients. Legal entity responsible for the study: German University in Cairo. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.
1
Background: Combinatorial therapy including the immunotherapy is revolutionizing the effective treatment of cancer. It achieved unprecedented responses in advancedstage patients, including complete cures and long-term survival. However, immunotherapy also has limitations, such as its relatively low response rates and the development of severe side effects. These drawbacks are gradually being overcome by improving our understanding of the immune system, as well as by establishing combination regimens in which immunotherapy is combined with other treatment modalities. Methods: Herein, we report the method of coassembly of two structurally defined materials, each comprised of photothermal agent and a small molecule immunostimulant molecularly self-assembled. One organic polymer has excellent photothermal properties; the other one has designed for efficient immmune activation, contributing to superior stability during circulation. Results: The coassembled nanoparticles (NPs) possesses superior photothermal conversion efficiency as well as efficient encapsulation and controlled release of cytotoxic molecules and immunomodulatory agents. NPs loaded with immunostimulant has proven to be a highly efficacious combination photothermal/immunotherapeutic nanoplatform against Triple Negative Bresat Cancer xenograft model. When loaded with imiquimod, a potent small molecule immunostimulant, NPs is found to be highly effective against breast cancer model, particularly when photothermal/immuno-therapy is given. Such dual therapy not only eradicates the light-irradiated primary tumours, but also activates systemic antitumor immunoactivity, causing tumour death at light-unexposed distant tumour sites. Conclusion: In conclusion, this “photothermal immunotherapy” approach, photothermal ablation of tumour cell death reduces tumour growth and releases tumour antigens into the surrounding milieu, while the immunoadjuvants potentiate host antitumor immunity. Our results indicated that combined photothermal immunotherapy
Volume 30 | Supplement 11 | December 2019
105P
Discovery of bioactive small molecule inhibitors of human PD1-PDL1 interaction
S.P. Patil, J. Diflumeri, E. Fattakhova Chemical Engineering, Widener University, Chester, PA, USA Background: The antibody-based cancer immunotherapies targeting the Programmed cell Death1-Programmed Cell Death Ligand 1 (PD1-PDL1) interaction have shown unprecedented clinical success again several types of cancer. Our present study aims to discover small molecule PD1-PDL1 inhibitors that may offer several advantages as compared to antibodies, such as higher oral bioavailability, lower cost, better tumor infiltration, and relatively shorter half-life that is especially helpful in controlling any potential adverse immune reactions. Methods: We identified several small molecule inhibitors based on the available crystal structures of human PD1-PDL1 complex as well as apo forms of PD1 and PDL1. Specifically, we first carried out long molecular dynamics simulations to identify “druggable” binding pockets on the binding interfaces of PD1 and PDL1 proteins, followed by molecular docking and consensus-scoring of approved and experimental drugs into those pockets. The top virtually selected compounds were then tested in AlphaLISA and ELISA assays measuring inhibition of the PD1-PDL1 interaction, followed by functional cell-based assays. Results: Through integrated virtual and experimental screening protocols, we have identified several potent PD1-PDL1 inhibitors with remarkable activities in both the cell-free and cell-based assays. Notably, one of our top active molecules showed activity as comparable to that of the anti-PD1 antibody used as the positive control in these studies. This is remarkable considering the newly-discovered molecules have relatively low molecular weight and still are capable of inhibiting PD1-PDL1 protein-protein interaction with large binding interface of 1,970 A˚2. Our results provide support for future investigation of these molecules in vivo.
doi:10.1093/annonc/mdz451 | xi39
Downloaded from https://academic.oup.com/annonc/article-abstract/30/Supplement_11/mdz451.014/5675238 by McMaster University Library , Collections - Serials Processing user on 22 December 2019
abstracts
Annals of Oncology
abstracts
106P
A single dose of local IL-12 promotes anti-tumor effect of antiEGFRvIII-CAR-T cells in a syngeneic murine model of glioblastoma
A.R. Liuzzi1, G. Agliardi2, B. Becher1, M. Pule2 Institute of Experimental Immunology, UZH - University of Zurich - Irchel Campus, Zurich, Switzerland, 2University College London, Cancer Institute, London, UK
1
Background: Glioblastoma multiforme (GBM) is one of the most devastating brain tumors with poor prognosis and high mortality. Immunotherapy with chimeric antigen receptor (CAR) T cells is gaining attention as a promising strategy to treat this disease. An ideal candidate to target with CAR T cells is the tumor specific variant III of the epidermal growth factor receptor (EGFRvIII), which represents a mutation found in more than 30% of glioblastoma patients. However, anti-EGFRvIII-CAR modified T cell therapy has shown only limited effects in GBM patients, in all likelihood due to the immunosuppressive microenvironment that CAR T cells encounter in the tumor microenvironment (TME) of gliomas. To make gliomas susceptible to CAR T cell therapy, combinatorial approaches to convert the TME are required. Methods: Mice received 5Gy TBI on day 15 post implantation, followed by intratumoral injection of IL-12:Fc on day 20 and infusion of EGFRvIII-directed CAR or non-transduced T cells on day 21. To perform functional analysis, we adopted highparametric flow-cytometric characterization of the TME using 23 independent parameters 8 days after CAR T cells injection. We utilized unsupervised validated clustering approaches (FlowSOM and CellCNN) to discriminate between different cell populations. Results: Here, we demonstrate that the combination of a single dose of local IL-12 with anti-EGFRvIII-CAR T cells synergizes to increase long-term survival in a syngeneic mouse model of GBM. IL-12 not only boosted the pro-inflammatory and cytotoxic activity of anti-EGFRvIII-CAR T cells, but also induced a complete remodelling of the tumor microenvironment (TME) with strong endogenous anti-tumor immune T cell responses. These findings highlight the capacity of IL-12 to induce an immunologically “cold” tumor such as GMB to acquire responsiveness to CAR T cells therapy. Conclusion: This study demonstrates the capacity of IL-12 as local “adjuvant” therapy to boost the efficacy of CAR T cells and to awake the endogenous anti-tumor T cell responses. Legal entity responsible for the study: University of Zurich. Funding: University Research Priority Project and Advanced T-cell Engineered for Cancer Therapy. Disclosure: M. Pule: Honoraria (self), Honoraria (institution): Autolus LTD. All other authors have declared no conflicts of interest.
107P
Increasing responses to T-cell therapies in solid tumours by the use of an engineered adenovirus coding for TNFa and IL-2
V. Cervera-Carrascon1, R. Havunen1, J.M. Santos1, D.C.A. Quixabeira2, A. Hemminki1, S. Zafar2 1 Translational Immunology Research Program and Department of Oncology, University of Helsinki and TILT Biotherapeutics, Helsinki, Finland, 2Translational Immunology Research Program and Department of Oncology, University of Helsinki, Helsinki, Finland Background: During the last decade, a revived enthusiasm about T-cell related therapies emerged after promising clinical outcomes. Nevertheless, many patients (especially with solid tumours) still do not have adequate therapeutic options. The complexity of the tumour microenvironment is a likely factor acting in detriment of many of those therapies by multiple suppressive mechanisms. To tackle a complex mechanism, an oncolytic adenovirus 2 (Ad5/3-E2F-d24-hTNFa-IRES-hIL2, a.k.a. TILT-123) was engineered to enable T-cell therapies in those circumstances. Methods: To study the efficacy of TILT-123 together with different T-cell related therapies (adoptive cell transfer, checkpoint inhibitors and CAR T cell therapy) different models were used including mouse, Syrian Hamster and patient derived in vivo models for different indications were tested. Results: Antitumor efficacy analyses showed complete responses in all animals receiving a T-cell therapy or checkpoint inihibitor (aPD1 or aPDL-1) and the T-cell enabling virus. Further, other aspects such as safety, influence on different immune populations, abscopal effect, antitumor memory and ability to replace lympho-depleting chemotherapy and postconditioning with high-dose IL-2 treatment were studied. Conclusion: The use of TILT-123 to enable T-cell therapies (including checkpointinhibiting antibodies) delivered encouraging preclinical results pointing to it as a
xi40 | Therapeutic Development
valuable approach to increase the number of patients that benefit from T-cell therapies. Those results include not only cell based therapies but also checkpoint inhibitors, a kind of therapy that is making the difference in the field and becoming first-line treatment for an increasing number of indications. Because of the favourable preclinical studies, the first in human clinical trials with TILT-123 will start in the upcoming months. Legal entity responsible for the study: The authors. Funding: TILT Biotherapeutics. Disclosure: V. Cervera-Carrascon: Full / Part-time employment: TILT Biotherapeutics. R. Havunen: Full / Part-time employment: TILT Biotherapeutics. J.M. Santos: Full / Part-time employment: TILT Biotherapeutics. A. Hemminki: Shareholder / Stockholder / Stock options, Full / Parttime employment, Officer / Board of Directors: TILT Biotherapeutics. All other authors have declared no conflicts of interest.
108P
Phosphatidylserine suppresses T cells through GPR174, and coinhibition of adenosine receptors and GPR174 synergistically enhances Th1 cytokine production
M.A. Gavin, A. Gragerov, E. Espling, A. Rohde, T. Sexton, C. Doulami, G. Gaitanaris Discovery, Omeros Corporation, Seattle, WA, USA Background: Extracellular phosphatidylserine (PS) is a potent modulator of immune responses. In addition to exposure during apoptosis, PS is observed on activated platelets, leukocytes, endothelial cells, tumor cells, and exosomes. While PS exposed during apoptosis is known to suppresses inflammatory responses in phagocytic cells, whether either form of exposed PS acts directly on T lymphocytes has not been extensively studied. Methods: HEK293 cells expressing GPR174 and GloSensor were used to detect GPR174 agonism. Immune cells were stimulated with anti-CD3/CD28 with GPCR inhibitors, NECA, or PS liposomes; and cytokines in media were measured. WT or GPR174-KO mice inoculated with syngeneic tumor cells and treated with anti-GITR (DTA-1) were evaluated for tumor growth. Results: Here we show that PS suppresses T cells through GPR174, a Gas-coupled GPCR. PS liposomes were more potent than lyso-PS in stimulating GPR174, and PS exposed on various cell types agonized GPR174. Several GPR174 inhibitors of different chemical classes were identified. PS liposomes attenuated Th1 cytokine production from human T cells and WT but not GPR174-KO mouse T cells, and GPR174 inhibitors reversed this suppression. Th1 cytokines were increased by GPR174 inhibition in the presence of tumor exosomes. GPR174 inhibition or genetic deletion also reduced CTLA-4 expression, an immune checkpoint known to be induced by cAMP. Compared to WT mice, GPR174-KO mice significantly controlled tumor growth when Treg were transiently depleted with anti-GITR. GPR174 is similar to A2A/B adenosine receptors in that both suppress Th1 immunity through cAMP in response to products of cell stress and death abundant in the tumor microenvironment. Inhibition of GPR174 and A2A/B synergistically increased cytokine production, GPR174 and A2A/B agonists suppressed T cells to the same extent as both combined, and A2A/B inhibition was more effective on GPR174-KO T cells vs. WT T cells. Conclusion: Our findings suggest that for T cells to effectively overcome cAMPmediated immunosuppression in the tumor microenvironment, both GPR174 and the adenosine pathway must be inhibited. Legal entity responsible for the study: Omeros Corporation. Funding: Omeros Corporation. Disclosure: M.A. Gavin: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation. A. Gragerov: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation. E. Espling: Shareholder / Stockholder / Stock options, Full / Parttime employment: Omeros Corporation. A. Rohde: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation. T. Sexton: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation. C. Doulami: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation. G. Gaitanaris: Shareholder / Stockholder / Stock options, Full / Part-time employment: Omeros Corporation.
109P
Phase I clinical study for validation of fimaporfin-based photochemical internalisation: A novel technology for enhancing cellular immune responses important for therapeutic effect of peptide-and proteinbased vaccines
P.K. Selbo1, S. Janetzki2, M.J.P. Welters3, M. Ha˚kerud1, A.G. Nedberg1, V.T. Edwards1, H. Olivecrona4, S.H. van der Burg3, T. Otterhaug4, A. Hogset5 1 Department of Radiation Biology, Oslo University Hospital - The Norwegian Radium Hospital, Oslo, Norway, 2ZellNet Consulting Suite 25-S, ZellNet Consulting, Inc., Fort Lee, NJ, USA, 3Department of Medical Oncology, Leiden University Medical Center, Leiden, Netherlands, 4Medical, PCI Biotech AS, Oslo, Norway, 5Research, PCI Biotech AS, Oslo, Norway Background: FimaVacc is a vaccine formulated by the photosensitising compound fimaporfin and a toll-like receptor (TLR) agonist, and is administered intradermally followed by illumination of the vaccination site. In preclinical studies, fimaVacc has been shown to improve MHC class I antigen presentation, resulting in strongly enhanced cytotoxic and helper T-cell responses to various types of peptide and protein vaccines.
Volume 30 | Supplement 11 | December 2019
Downloaded from https://academic.oup.com/annonc/article-abstract/30/Supplement_11/mdz451.014/5675238 by McMaster University Library , Collections - Serials Processing user on 22 December 2019
Conclusion: In summary, we have been successful in identifying novel, non-peptide small molecule inhibitors of PD1-PDL1 interaction through rational design. Considering their remarkable activity and clinical status, they may present immediate clinical potential against cancers expressing PDL1. They may also prove to be ideal starting points for the design of more potent, selective drug-like inhibitors of PD1PDL1 interaction. Legal entity responsible for the study: Widener University, Chester, PA, USA. Funding: W. W. Smith Charitable Trust. Disclosure: All authors have declared no conflicts of interest.
Annals of Oncology