Association Between Plasma Diacetylspermine and Tumor Spermine Synthase With Outcome in Triple-Negative Breast Cancer

BACKGROUND

MYC is an oncogenic driver of development and progression in triple-negative breast cancer (TNBC). Ornithine decarboxylase, the rate-limiting enzyme in polyamine metabolism, is a transcriptional target of MYC. We therefore hypothesized that a plasma polyamine signature may be predictive of TNBC development and progression.

METHODS

Using liquid chromatography mass spectrometry, polyamine levels were determined in plasma samples from newly diagnosed patients with TNBC (n = 87) and cancer-free controls (n = 115). Findings were validated in plasma samples from an independent prospective cohort of 54 TNBC, 55 estrogen receptor negative (ER-) and progesterone receptor negative (PR-) and HER2 positive (HER2+), and 73 ER+ case patients, and 30 cancer-free control subjects. Gene expression data and clinical data for 921 and 2359 breast cancer tumors were obtained from The Cancer Genome Atlas repository and the Oncomine database, respectively. Relationships between plasma diacetylspermine (DAS) and tumor spermine synthase (SMS) mRNA expression with metastasis-free survival and overall survival were determined using Cox proportional hazard models; Fisher exact tests were used to assess risk of distant metastasis in relation to tumor SMS mRNA expression.

RESULTS

An increase in plasma DAS, a catabolic product of spermine mediated through SMS, was observed in the TNBC subtype of breast cancer. Plasma levels of DAS in TNBC associated with increased risk of metastasis (plasma DAS value ≥ 1.16, hazard ratio = 3.06, 95% confidence interval [CI] = 1.15 to 8.13, two-sided P = .03). SMS mRNA expression in TNBC tumor tissue was also found to be predictive of poor overall survival (top 25th percentile hazard ratio = 2.06, 95% CI = 1.04 to 4.08, one-sided P = .04) and increased risk of distant metastasis in TNBC (comparison of lowest SMS quartile [reference] to highest SMS quartile relative risk = 1.90, 95% CI = 0.97 to 4.06, one-sided Fisher exact test P=.03).

CONCLUSIONS

Metabolomic profiling identified plasma DAS as a predictive marker for TNBC progression and metastasis.

Abstract 6593: PRGN-3005 UltraCAR-T™: multigenic CAR-T cells generated using non-viral gene delivery and rapid manufacturing process for the treatment of ovarian cancer

Ovarian cancer is the most lethal of gynecologic cancers. Chimeric antigen receptor (CAR)-T cells have improved clinical outcomes in hematological malignancies; however similar responses have not yet been achieved for solid tumors. Furthermore, traditional methods for CAR-T manufacturing utilize viral vectors and weeks of ex vivo expansion to achieve clinically relevant cell numbers. This leads to CAR-T cells with an exhausted T cell phenotype, high manufacturing costs, and treatment delays. We have developed the UltraCAR-T™ platform to overcome these limitations by utilizing an advanced non-viral gene delivery system and a rapid, decentralized manufacturing process. Our non-viral gene delivery platform is based on Sleeping Beauty transposon system precision engineered for optimal delivery of multiple genes of UltraCAR-T. UltraCAR-T cells are manufactured at medical center's cGMP facility using autologous T cells and administered back to patient only one day after gene transfer.

PRGN-3005 UltraCAR-T cells simultaneously co-express (i) a CAR specifically targeting MUC16 which is highly expressed on ovarian tumors with limited normal tissue expression; (ii) membrane bound IL-15 (mbIL15) for enhanced in vivo expansion and persistence; and (iii) a kill switch for improved therapeutic control. Healthy donor T cells were transfected with non-viral system encoding CAR, mbIL15 and kill switch to generate PRGN-3005 cells. Expression of transgenes was confirmed by flow cytometry and western blot analyses. PRGN-3005 demonstrated a robust MUC16-specific cytotoxicity of ovarian cancer cells in vitro. PRGN-3005 exhibited a stem-cell like memory phenotype, significant improvement in survival even in absence of exogenous cytokines and lacked autonomous proliferation in vitro in the absence of MUC16 compared to conventional CAR-T cells, demonstrating beneficial effects of mbIL15 on phenotype and persistence of UltraCAR-T cells. Furthermore, we demonstrated that PRGN-3005 cells were selectively and effectively eliminated by kill switch activator antibody via ADCC. For in vivo anti-tumor efficacy of PRGN-3005, an ovarian cancer model of MUC16+ SK-OV-3 cell line was evaluated in NSG mice. In tumor-bearing mice, a single administration of PRGN-3005 one day after gene transfer resulted rapid in vivo expansion and significant increase in UltraCAR-T cells, in particular T stem cell memory (TSCM) population compared to mbIL15neg CAR-T cells. PRGN-3005 demonstrated significantly higher anti-tumor effect (p<0.01) compared to mbIL15neg CAR-T and led to complete tumor regression in all treated mice. PRGN-3005 UltraCAR-T administered one day after non-viral gene transfer has superior anti-tumor efficacy and persistence compared traditional CAR-T cells and represent a promising opportunity for ovarian cancer treatment. Based on these results, FDA has approved an IND application and the first in human PRGN-3005 Phase I clinical trial for advanced ovarian cancer is currently under evaluation (NCT03907527).

Citation Format: Tim Chan, Marion Chakiath, Lindsey Shepard, Simon Metenou, Fernando Carvajal-Borda, Jose Velez, Adeline Govekung, Jacques Plummer, Carol Poortman, Padma Kamineny, Xiaohong Ma, Rutul R. Shah, Mary L. Disis, Helen Sabzevari. PRGN-3005 UltraCAR-T™: multigenic CAR-T cells generated using non-viral gene delivery and rapid manufacturing process for the treatment of ovarian cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6593.

A phase I dose-escalation trial of alpha-tocopheryloxyacetic acid and concurrent trastuzumab in patients with treatment refractory HER2+ metastatic breast cancer

TPS1103

Background: Metastatic HER2+ breast cancer, while initially responsive to trastuzumab, pertuzumab, and TDM-1, eventually progresses. The FDA recently approved trastuzumab deruxtecan, showing benefit in progression free survival but not in overall survival to date. Thus, additional therapies are needed for patients who progress on these HER2 directed agents. In metastatic HER2+ breast cancer, HER2-specific Th1 immune responses and higher CD4+ Th1 and CD8+ TIL levels are associated with a survival benefit. As this Type 1 immunity occurs in a minority of patients, additional immune modulation is needed. Alpha-tocopheryloxyacetic acid (α-TEA) has been reported to augment Type 1 immunity through increasing activated effector memory CD4+ and CD8+ T cells and decreasing immune suppressive CD4+CD25+ regulatory T cells in the tumor microenvironment. When given concurrently with an anti-HER2 antibody (7.16.4) in a pre-clinical tumor model, α-TEA synergized with 7.16.4 to induce tumor regression. We hypothesize that α-TEA and trastuzumab combination therapy in metastatic HER2+ breast cancer will be well tolerated, induce a clinical response, and augment anti-tumor Th1 immunity. Methods: Trial Design: Phase I dose escalation trial of α-TEA in combination with trastuzumab. Patients with metastatic HER2+ breast cancer will receive one of four doses sequentially of α-TEA: 0.6 mg/kg, 1.2 mg/kg, 2.4 mg/kg, and 4.8 mg/kg. Toxicity is assessed at baseline and through end of study. Blood and tumor tissue will be collected for immunologic monitoring and evaluation. Clinical response will be evaluated according to RECIST 1.1. Eligibility : Patients with progressive metastatic HER2+ breast cancer who have previously progressed on trastuzumab/pertuzumab and TDM-1. Specific Aims: Determine: (1) safety of four escalating doses of α-TEA with concurrent trastuzumab, (2) clinical response rate of α-TEA with concurrent trastuzumab (3) if concurrent α-TEA and trastuzumab increases activated effector memory CD4+ and CD8+ T cells, and (4) if concurrent α-TEA and trastuzumab increase the number of HER2-specific T cells. Statistical Methods: (1) The sample size of 24 and cohort size of 6 are determined by simulation experiments and practical consideration, (2) clinical response will be evaluated; overall PFS and OS will be calculated, (3) activated effector memory CD4+ and CD8+ T-cells will be analyzed (4) HER2-specific IFN-g/IL-10 ratios will be evaluated. Targeted Accrual : Twenty-four (24) patients. Clinical trial information: NCT04120246 .

Therapeutic and Prophylactic Antitumor Activity of an Oral Inhibitor of Fucosylation in Spontaneous Mammary Cancers

2-fluorofucose (2FF) inhibits protein and cellular fucosylation. Afucosylation of IgG antibodies enhances antibody-dependent cell-mediated cytotoxicity by modulating antibody affinity for FcγRIIIa, which can impact secondary T-cell activation. Immune responses toward most common solid tumors are dominated by a humoral immune response rather than the presence of tumor-infiltrating cytotoxic T cells. IgG antibodies directed against numerous tumor-associated proteins are found in the sera of both patients with breast cancer and transgenic mice bearing mammary cancer. We questioned whether 2FF would have antitumor activity in two genetically distinct transgenic models; TgMMTV-neu (luminal B) and C3(1)-Tag (basal) mammary cancer. 2FF treatment significantly improved overall survival. The TgMMTV-neu doubled survival time compared with controls [P < 0.0001; HR, 7.04; 95% confidence interval (CI), 3.31-15.0], and survival was significantly improved in C3(1)-Tag (P = 0.0013; HR, 3.36; 95% CI, 1.58-7.14). 2FF treated mice, not controls, developed delayed-type hypersensitivity and T-cell responses specific for syngeneic tumor lysates (P < 0.0001). Serum IgG from 2FF-treated mice enhanced tumor lysis more efficiently than control sera (P = 0.004). Administration of 2FF for prophylaxis, at two different doses, significantly delayed tumor onset in both TgMMTV-neu; 20 mmol/L (P = 0.0004; HR, 3.55; 95% CI, 1.60-7.88) and 50 mmol/L (P = 0.0002; HR: 3.89; 95% CI, 1.71-8.86) and C3(1)-Tag; 20 mmol/L (P = 0.0020; HR, 2.51; 95% CI, 1.22-5.18), and 50 mmol/L (P = 0.0012; HR, 3.36; 95% CI, 1.57-7.18). Mammary cancer was prevented in 33% of TgMMTV-neu and 26% of C3(1)-Tag. 2FF has potent antitumor effects in mammary cancer models. The agent shows preclinical efficacy for both cancer treatment and prevention.

Abstract AP28: ANTITUMOR RESPONSE AFTER VACCINATION TARGETING INSULIN GROWTH FACTOR BINDING PROTEIN 2 IN A SYNGENEIC MOUSE MODEL OF OVARIAN CANCER LOCALIZED BY THREE-DIMENSIONAL IN VIVO OPTICAL IMAGING

INTRODUCTION: Ovarian cancer often disseminates as miliary implants throughout the peritoneal cavity presenting challenges for tumor quantitation in both the clinical and pre-clinical settings. The distribution of tumor implants shows affinity for areas such as the omentum and lymph nodes, which may be included in a cytoreductive surgery. Immunotherapies are being studied for ovarian cancer due to the high rate of relapse and resistance to available treatments in the recurrent setting. Pre-clinical models for ovarian cancer often do not allow meaningful assessment of novel immune-based therapies. We hypothesized vaccination targeting insulin growth factor binding protein 2 (IGFBP-2) will result in antitumor responses that can be both quantitated and localized spatially with optical imaging to identify tumor implants most resistant to vaccination.

METHODS: C57BL/6/BrdCrHsd-Tyrc mice received 4 immunizations with IGFBP-2 peptides corresponding to epitopes known to favor antitumor immunity with Freund's adjuvant (treated) or with adjuvant alone (control). 5 x 106 cells of a syngeneic mouse model expressing codon-optimized firefly luciferase (luc2) known to replicate the immune microenvironment of human ovarian cancers were injected intraperitoneally. After two weeks mice were anesthetized prior to injection of D-luciferin and during imaging via inhalation of isoflurane. Mice were placed in conforming animal molds (BCAM: InVivo Analytics, Inc.) and multi-view multi-spectral image acquired with the InVivoPLOT mirror-gantry. Bioluminescent tomographic (BLt) images were reconstructed using InVivoAX (InVivo Analytics, Inc.) cloud-based software and aligned to the organ probability map (OPM), a type of statistical mouse atlas.

RESULTS: Surface light intensity showed a 5.41 x 109 photons/second/mouse in control compared to 1.32 x 109 photons/second/mouse in IGFBP-2 vaccinated when measured in two dimensions. Multi-spectral tomographic reconstruction was able to show a greater than 2-fold decrease in the spatial light distribution of bioluminescent metastasis consistent with the surface light intensity distribution of the BLt image. BLt images mapped to the OPM discriminate the miliary distribution of metastases in the peritoneum. Individual metastasis in the control were shown to have a greater relative light density than the individual metastasis in the IGFBP-2 vaccinated group.

CONCLUSIONS: In vivo anatomic localization of antitumor activity in a disseminated ovarian cancer mouse model can be achieved using three-dimensional optical imaging. Local differences in antitumor response to immunotherapies may be exploited to optimize their application to ovarian cancer. Identifying where tumor implants resistant to immunotherapies are sequestered may improve pre-clinical testing of immunotherapy combinations and optimally integrate them into current standard therapies.

Citation Format: Denise L. Cecil, Neal Paragas, Katie M. Hitchcock-Bernhardt, Mary L. Disis, John B. Liao. ANTITUMOR RESPONSE AFTER VACCINATION TARGETING INSULIN GROWTH FACTOR BINDING PROTEIN 2 IN A SYNGENEIC MOUSE MODEL OF OVARIAN CANCER LOCALIZED BY THREE-DIMENSIONAL IN VIVO OPTICAL IMAGING [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr AP28.

If we build it they will come: targeting the immune response to breast cancer

Historically, breast cancer tumors have been considered immunologically quiescent, with the majority of tumors demonstrating low lymphocyte infiltration, low mutational burden, and modest objective response rates to anti-PD-1/PD-L1 monotherapy. Tumor and immunologic profiling has shed light on potential mechanisms of immune evasion in breast cancer, as well as unique aspects of the tumor microenvironment (TME). These include elements associated with antigen processing and presentation as well as immunosuppressive elements, which may be targeted therapeutically. Examples of such therapeutic strategies include efforts to (1) expand effector T-cells, natural killer (NK) cells and immunostimulatory dendritic cells (DCs), (2) improve antigen presentation, and (3) decrease inhibitory cytokines, tumor-associated M2 macrophages, regulatory T- and B-cells and myeloid derived suppressor cells (MDSCs). The goal of these approaches is to alter the TME, thereby making breast tumors more responsive to immunotherapy. In this review, we summarize key developments in our understanding of antitumor immunity in breast cancer, as well as emerging therapeutic modalities that may leverage that understanding to overcome immunologic resistance.

Two may be better than one: PD-1/PD-L1 blockade combination approaches in metastatic breast cancer

Antibodies blocking programmed death 1 (anti-PD-1) or its ligand (anti-PD-L1) are associated with modest response rates as monotherapy in metastatic breast cancer, but are generally well tolerated and capable of generating dramatic and durable benefit in a minority of patients. Anti-PD-1/L1 antibodies are also safe when administered in combination with a variety of systemic therapies (chemotherapy, targeted therapies), as well as with radiotherapy. We summarize preclinical, translational, and preliminary clinical data in support of combination approaches with anti-PD-1/L1 in metastatic breast cancer, focusing on potential mechanisms of synergy, and considerations for clinical practice and future investigation.

AACR White Paper: Shaping the Future of Cancer Prevention - A Roadmap for Advancing Science and Public Health

The recent pace, extent, and impact of paradigm-changing cancer prevention science has been remarkable. The American Association for Cancer Research (AACR) convened a 3-day summit, aligned with five research priorities: (i) Precancer Atlas (PCA). (ii) Cancer interception. (iii) Obesity-cancer linkage, a global epidemic of chronic low-grade inflammation. (iv) Implementation science. (v) Cancer disparities. Aligned with these priorities, AACR co-led the Lancet Commission to formally endorse and accelerate the NCI Cancer Moonshot program, facilitating new global collaborative efforts in cancer control. The expanding scope of creative impact is perhaps most startling-from NCI-funded built environments to AACR Team Science Awarded studies of Asian cancer genomes informing global primary prevention policies; cell-free epigenetic marks identifying incipient neoplastic site; practice-changing genomic subclasses in myeloproliferative neoplasia (including germline variant tightly linked to JAK2 V617F haplotype); universal germline genetic testing for pancreatic cancer; and repurposing drugs targeting immune- and stem-cell signals (e.g., IL-1β, PD-1, RANK-L) to cancer interception. Microbiota-driven IL-17 can induce stemness and transformation in pancreatic precursors (identifying another repurposing opportunity). Notable progress also includes hosting an obesity special conference (connecting epidemiologic and molecular perspectives to inform cancer research and prevention strategies), co-leading concerted national implementation efforts in HPV vaccination, and charting the future elimination of cancer disparities by integrating new science tools, discoveries and perspectives into community-engaged research, including targeted counter attacks on e-cigarette ad exploitation of children, Hispanics and Blacks. Following this summit, two unprecedented funding initiatives were catalyzed to drive cancer prevention research: the NCI Cancer Moonshot (e.g., PCA and disparities); and the AACR-Stand Up To Cancer bold "Cancer Interception" initiative.

The Effect of Mouse Strain, Sex, and Carcinogen Dose on Toxicity and the Development of Lung Dysplasia and Squamous Cell Carcinomas in Mice

In order to translate new treatments to the clinic, it is necessary to use animal models that closely recapitulate human disease. Lung cancer develops after extended exposure to carcinogens. It has one of the highest mutation rates of all cancer and is highly heterogenic. Topical treatment with N-nitrosotris-(2-chloroethyl)urea (NTCU) induces lung squamous cell carcinoma (SCC) with nonsynonymous mutation rates similar to those reported for human non-small cell lung cancer. However, NTCU induces lung cancer with variable efficacy and toxicity depending on the mouse strain. A detailed characterization of the NTCU model is needed. We have compared the effect of three different NTCU doses (20, 30, and 40 mmol/L) in female and male of NIH Swiss, Black Swiss, and FVB mice on tumor incidence, survival, and toxicity. The main findings in this study are (1) NIH Swiss mice present with a higher incidence of SCC and lower mortality compared with Black Swiss and FVB mice; (2) 30 mmol/L NTCU dose induces SCC at the same rate and incidence as the 40 mmol/L dose with lower mortality; (3) female mice present higher grade and incidence of preinvasive lesions and SCC compared with males; (4) NTCU-induced transformation is principally within the respiratory system; and (5) NTCU treatment does not affect the ability to elicit a specific adaptive immune response. This study provides a reference point for experimental designs to evaluate either preventive or therapeutic treatments for lung SCC, including immunotherapies, before initiating human clinical trials.

Current Landscape of Immunotherapy in Breast Cancer: A Review

Importance

There is tremendous interest in using immunotherapy to treat breast cancer, as evidenced by the more than 290 clinical trials ongoing at the time of this narrative review. The objective of this review is to describe the current status of immunotherapy in breast cancer, highlighting its potential in both early-stage and metastatic disease.

Observations

After searching ClinicalTrials.gov on April 24, 2018, and PubMed up to June 30, 2018, to identify breast cancer immunotherapy trials, we found that immune checkpoint blockade (ICB) is the most investigated form of immunotherapy in breast cancer. Use of ICB as monotherapy has achieved objective responses in patients with breast cancer, with higher rates seen when administered in earlier lines of therapy. For responding patients, those responses are durable. More recent data suggest clinical efficacy when ICB is given in combination with chemotherapy. Ongoing studies are evaluating combination strategies pairing ICB with additional chemotherapeutic agents, targeted therapy, vaccines, and local ablative therapies to enhance response. To date, robust predictive biomarkers for response to ICB have not been established.

Conclusions and Relevance

It is anticipated that combination therapy strategies will be the way forward for immunotherapy in breast cancer, with an improved understanding of tumor, microenvironment, and host factors informing treatment combination decisions. Thoughtful study design incorporating appropriate end points and correlative studies will be critical in identifying optimal strategies for enhancing the immune response against breast tumors.

Abstract 1184: Comprehensive analysis with interactive exploration of immune response signatures in 10,000 tumor samples

In recent years, analysis of cancer genomics data using methods of immunogenomics has yielded valuable insight into how cancer cells interact with immune cells in the tumor microenvironment. A recent analysis of the multiple molecular platforms by The Cancer Genome Atlas (TCGA) of over 10,000 tumors comprising 33 cancer types identified six immune subtypes, spanning multiple tumor types, that are characterized by differences in: macrophage vs. lymphocyte signatures; Th1:Th2 cell ratio; extent of intratumoral heterogeneity; aneuploidy; extent of neoantigen load; signatures of cell proliferation; expression of immunomodulatory genes; and disease outcome [1]. Particular driver mutations correlate with variation in leukocyte levels across all cancers or with the fraction of individual immune cell types. Intracellular and extracellular networks (involving transcription, microRNAs, copy number and epigenetic processes) are predicted to play a role in establishing the observed tumor-immune cell interactions, both across and within immune subtypes. Additionally, machine learning methods have been applied to H&E images to extract information on which tissue regions contain tumor infiltrating lymphocytes (TILs), yielding TIL maps of whole slide images from digital pathology[2]. Spatial patterns of TILs are associated with a variety of genomic alterations, including cancer subtypes.

The CRI iAtlas (www.cri-iatlas.org) is a cloud-based platform for data exploration and discovery, allowing researchers to study TCGA immune response characterizations, and the relationships among them in individual tumor types, tumor subtypes, and immune subtypes. iAtlas supports the adaptive exploration of correlations within the cellularity of the tumor microenvironment, immune expression signatures, tumor mutation burden, cancer driver mutations, adaptive cell clonality, patient survival, and expression of key immunomodulators. iAtlas was launched in April 2018, and has since been expanded to include new capabilities such as (1) user-defined loading of cohorts, (2) a tool for classifying expression data into immune subtypes, (3) integration of TIL mapping from digital pathology images, and (4) addition of annotated genomics datasets from immunotherapy clinical trials as comparative data sources. As the resource evolves, we expect that the CRI iAtlas will help to accelerate discovery and improve patient outcomes by providing researchers greater access to immunogenomics data to better understand the immunological characteristics of the tumor microenvironment and its potential impact on patient responses to immunotherapy.

[1] Thorsson, V, et al., The Immune Landscape of Cancer; Immunity 48, p812 - 830.e14 (2018)

[2] Saltz, J et al. Spatial Organization and Molecular Correlation of Tumor-Infiltrating Lymphocytes Using Deep Learning on Pathology Images; Cell Reports 23 pp.181-193.e7 (2018)

Citation Format: Vesteinn Thorsson, David L. Gibbs, Mary L. Disis, Elizabeth G. Demicco, Alexander J. Lazar, Jonathan S. Serody, James A. Eddy, Ilya Shmulevich, Justin Guinney, Benjamin G. Vincent. Comprehensive analysis with interactive exploration of immune response signatures in 10,000 tumor samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1184.

Toward a comprehensive view of cancer immune responsiveness: a synopsis from the SITC workshop

Tumor immunology has changed the landscape of cancer treatment. Yet, not all patients benefit as cancer immune responsiveness (CIR) remains a limitation in a considerable proportion of cases. The multifactorial determinants of CIR include the genetic makeup of the patient, the genomic instability central to cancer development, the evolutionary emergence of cancer phenotypes under the influence of immune editing, and external modifiers such as demographics, environment, treatment potency, co-morbidities and cancer-independent alterations including immune homeostasis and polymorphisms in the major and minor histocompatibility molecules, cytokines, and chemokines. Based on the premise that cancer is fundamentally a disorder of the genes arising within a cell biologic process, whose deviations from normality determine the rules of engagement with the host's response, the Society for Immunotherapy of Cancer (SITC) convened a task force of experts from various disciplines including, immunology, oncology, biophysics, structural biology, molecular and cellular biology, genetics, and bioinformatics to address the complexity of CIR from a holistic view. The task force was launched by a workshop held in San Francisco on May 14-15, 2018 aimed at two preeminent goals: 1) to identify the fundamental questions related to CIR and 2) to create an interactive community of experts that could guide scientific and research priorities by forming a logical progression supported by multiple perspectives to uncover mechanisms of CIR. This workshop was a first step toward a second meeting where the focus would be to address the actionability of some of the questions identified by working groups. In this event, five working groups aimed at defining a path to test hypotheses according to their relevance to human cancer and identifying experimental models closest to human biology, which include: 1) Germline-Genetic, 2) Somatic-Genetic and 3) Genomic-Transcriptional contributions to CIR, 4) Determinant(s) of Immunogenic Cell Death that modulate CIR, and 5) Experimental Models that best represent CIR and its conversion to an immune responsive state. This manuscript summarizes the contributions from each group and should be considered as a first milestone in the path toward a more contemporary understanding of CIR. We appreciate that this effort is far from comprehensive and that other relevant aspects related to CIR such as the microbiome, the individual's recombined T cell and B cell receptors, and the metabolic status of cancer and immune cells were not fully included. These and other important factors will be included in future activities of the taskforce. The taskforce will focus on prioritization and specific actionable approach to answer the identified questions and implementing the collaborations in the follow-up workshop, which will be held in Houston on September 4-5, 2019.

Pembrolizumab with low dose carboplatin for recurrent platinum resistant ovarian, fallopian tube, and primary peritoneal cancer-interim results

5519

Background: Pembrolizumab has shown activity in advanced recurrent ovarian cancer (AOC) with an 8% response rate and median progression-free survival (PFS) of 2.1 months reported in KEYNOTE-100. Because platinum chemotherapies also induce T cell proliferation and enhance tumor cell recognition through PD-1/PD-L, we assessed the safety and activity of pembrolizumab with carboplatin in platinum resistant AOC. Methods: Key eligibility criteria for this Phase 1/2 single arm trial were platinum resistant AOC, fallopian tube, or peritoneal cancer, progression after subsequent systemic therapy, and ECOG PS 0-1. Pembrolizumab 200mg was given on Day 1 and carboplatin AUC 2 on Day 8 and 15 of a 3 week cycle until progression, unacceptable toxicity, or consent withdrawal. Imaging was done before cycles 4 and 8, then every 3 months and unconfirmed objective response assessed by blinded independent review per RECIST 1.1. Adverse events (AEs) were reported per Common Terminology for Adverse Events v5.0. PD-L1 expression was assessed by immunohistochemistry. Results: 27 patients (median age: 64) had received a median of 5 (range: 2-9) prior lines of systemic therapy, which included bevacizumab in 74% of patients. The most common treatment related (TR) AEs were lymphopenia (18%) and anemia (9%). The majority of TR AEs were grade 1 or 2 (93%). 6% of AEs were grade 3 with lymphopenia the most common. Two grade 4 AEs were neutropenia and lymphopenia. Of 23 patients evaluable for best objective response, 13.0% (95% CI, 2.7-33.6) had partial response (PR), 65.2% (95% CI, 42.7-83.6) had stable disease (SD), and 21.7% (95% CI, 7.4-43.7) had progression. 7 of the 23 evaluable patients (30.4%) had archival tumor with modified percent scoring ≥5 for PD-L1 and all achieved PR (3/7, 42.8%) or SD (4/7, 57.2%). Overall median PFS was 4.6 months (95% CI, 2.7-6.2). Rate of PFS at 6 months was 40.4% (95% CI, 25.5-65.5). Median follow-up is 6.2 months and PFS is based on current data, but 8 patients remain on study and estimates will be updated. Conclusions: Pembrolizumab with low dose carboplatin was well tolerated and showed activity in heavily pretreated platinum resistant AOC. Survival and biomarker analyses are ongoing. Clinical trial information: NCT03029598.

Efficacy and Safety of Avelumab for Patients With Recurrent or Refractory Ovarian Cancer: Phase 1b Results From the JAVELIN Solid Tumor Trial

Importance

Current treatment options for progressive ovarian cancer provide limited benefit, particularly in patients whose disease has become resistant to platinum-based chemotherapy.

Objective

To assess the efficacy and safety of avelumab, an anti-programmed death-ligand 1 agent, in a cohort of patients with previously treated recurrent or refractory ovarian cancer.

Design, Setting, and Participants

In an expansion cohort of a phase 1b, open-label study (JAVELIN Solid Tumor), 125 patients with advanced ovarian cancer who had received chemotherapy including a platinum agent were enrolled between November 6, 2013, and August 27, 2015. Statistical analysis was performed from December 31, 2016, to October 9, 2018.

Intervention

Patients received avelumab, 10 mg/kg, every 2 weeks until disease progression, unacceptable toxic effects, or withdrawal from the study.

Main Outcomes and Measures

Prespecified end points in this cohort included confirmed best overall response (per Response Evaluation Criteria In Solid Tumors, version 1.1), immune-related best overall response, duration of response, progression-free survival, overall survival, results of programmed death-ligand 1 expression-based analyses, and safety.

Results

A total of 125 women (median age, 62.0 years [range, 27-84 years]) who had received a median of 3 prior lines of treatment (range, 0-10) for advanced disease were enrolled in the study. Patients received avelumab for a median of 2.8 months (range, 0.5-27.4 months), with a median follow-up of 26.6 months (range, 16-38 months). A confirmed objective response occurred in 12 patients (9.6%; 95% CI, 5.1%-16.2%), including a complete response in 1 patient (0.8%) and a partial response in 11 patients (8.8%). The 1-year progression-free survival rate was 10.2% (95% CI, 5.4%-16.7%) and median overall survival was 11.2 months (95% CI, 8.7-15.4 months). Infusion-related reactions occurred in 25 patients (20.0%). Other frequent treatment-related adverse events (any grade event occurring in ≥10% of patients) were fatigue (17 [13.6%]), diarrhea (15 [12.0%]), and nausea (14 [11.2%]). Grade 3 or higher treatment-related adverse events occurred in 9 patients (7.2%), of which only the level of lipase increased (3 [2.4%]) occurred in more than 1 patient. Twenty-one patients (16.8%) had an immune-related adverse event of any grade. No treatment-related deaths occurred.

Conclusions and Relevance

Avelumab demonstrated antitumor activity and acceptable safety in heavily pretreated patients with recurrent or refractory ovarian cancer.

Trial Registration

ClinicalTrials.gov identifier: NCT01772004.

Efficacy and Safety of Avelumab for Patients With Recurrent or Refractory Ovarian Cancer: Phase 1b Results From the JAVELIN Solid Tumor Trial

Importance

Current treatment options for progressive ovarian cancer provide limited benefit, particularly in patients whose disease has become resistant to platinum-based chemotherapy.

Objective

To assess the efficacy and safety of avelumab, an anti-programmed death-ligand 1 agent, in a cohort of patients with previously treated recurrent or refractory ovarian cancer.

Design, Setting, and Participants

In an expansion cohort of a phase 1b, open-label study (JAVELIN Solid Tumor), 125 patients with advanced ovarian cancer who had received chemotherapy including a platinum agent were enrolled between November 6, 2013, and August 27, 2015. Statistical analysis was performed from December 31, 2016, to October 9, 2018.

Intervention

Patients received avelumab, 10 mg/kg, every 2 weeks until disease progression, unacceptable toxic effects, or withdrawal from the study.

Main Outcomes and Measures

Prespecified end points in this cohort included confirmed best overall response (per Response Evaluation Criteria In Solid Tumors, version 1.1), immune-related best overall response, duration of response, progression-free survival, overall survival, results of programmed death-ligand 1 expression-based analyses, and safety.

Results

A total of 125 women (median age, 62.0 years [range, 27-84 years]) who had received a median of 3 prior lines of treatment (range, 0-10) for advanced disease were enrolled in the study. Patients received avelumab for a median of 2.8 months (range, 0.5-27.4 months), with a median follow-up of 26.6 months (range, 16-38 months). A confirmed objective response occurred in 12 patients (9.6%; 95% CI, 5.1%-16.2%), including a complete response in 1 patient (0.8%) and a partial response in 11 patients (8.8%). The 1-year progression-free survival rate was 10.2% (95% CI, 5.4%-16.7%) and median overall survival was 11.2 months (95% CI, 8.7-15.4 months). Infusion-related reactions occurred in 25 patients (20.0%). Other frequent treatment-related adverse events (any grade event occurring in ≥10% of patients) were fatigue (17 [13.6%]), diarrhea (15 [12.0%]), and nausea (14 [11.2%]). Grade 3 or higher treatment-related adverse events occurred in 9 patients (7.2%), of which only the level of lipase increased (3 [2.4%]) occurred in more than 1 patient. Twenty-one patients (16.8%) had an immune-related adverse event of any grade. No treatment-related deaths occurred.

Conclusions and Relevance

Avelumab demonstrated antitumor activity and acceptable safety in heavily pretreated patients with recurrent or refractory ovarian cancer.

Trial Registration

ClinicalTrials.gov identifier: NCT01772004.

Immuno-Oncology in the Era of Personalized Medicine

Personalized medicine in oncology utilizes evidence derived from genetic, immune, and proteomic profiling to inform therapeutic options as well as provide prognostic information for each unique individual and their tumor. Our ability to biologically and immunologically define each patient's tumor has been driven by the development of assays characterizing the genomic and proteomic profiles of tumors that in turn have led to the development of large biologic databases and computational tools for the analysis of these large data sets. In Immuno-oncology, the introduction of checkpoint inhibitors and their approval across multiple tumor types has led to the recognition that the majority of patients will not clinically respond to these therapies but will remain at risk for the development of significant immunologic side effects. This challenge highlights the need for the development and validation of both predictive biomarkers for response to such therapies as well as biomarkers prognostic of disease course. Despite extensive investigation into predictive biomarkers using these biologic databases and computational methods, only recently has progress been made in this area. This progress is the first step allowing us to identify patients likely to benefit from these therapies and moving our field closer to a truly personalized approach to the use of immune therapies in oncology.

SITC 2018 workshop report: Immuno-Oncology Biomarkers: State of the Art

Identification of biomarkers in cancer immunotherapy that predict therapeutic response and/or limit adverse events are a critical need in the field. To address recent progress and hurdles around cancer biomarker development and utilization, the Society for Immunotherapy of Cancer (SITC) convened a workshop, “Immuno-Oncology Biomarkers: State of the Art,” on May 16–17, 2018. Topics discussed included challenges in handling biospecimens, identification and validation of new biomarkers, data sharing, and collaborating across disciplines to advance biomarker development. Panel discussions followed session presentations to help foster participant conversation and discuss future projects and collaborations. The results of the Workshop include the development of new initiatives for the SITC Biomarkers Committee.

Abstract 1266: Downregulation of PD-L1 by NSAID administration augments the effects of a multi-antigen vaccine for the prevention of adenomatous polyps in APC(Min/+) mice

Introduction: We have shown that treatment of APC(Min/+) mice with NSAIDs will inhibit development of adenomatous polyps and induce significant levels of polyp-infiltrating CD8 T-cells. We sought to identify the mechanism of NSAID induced immune stimulation and questioned whether administration of NSAIDs concurrent with vaccination could further reduce polyp formation.

Methods: PD-L1 expression and T-cell infiltrates were assessed by IHC and flow cytometry. MC38 and RKO (murine/human colorectal carcinoma cell lines) were treated with naproxen (200uM-1000 uM) and harvested at 24, 48 and 72h. At 4-6 weeks, APC(Min/+) mice were given a multi-antigen peptide vaccine (COX2, CDC25B, EGFR) with CFA/IFA or adjuvant alone. Two groups received 400ppm naproxen orally 7d/wk for 18 weeks. Polyps were quantified at ≤24 weeks. Spleens and polyps were collected for IFN-gamma ELISPOT, flow cytometry, and IHC.

Results: Polyps from the APC(Min/+) mouse and both cancer cell lines highly express PD-L1. PD-L1 expression was significantly decreased in MC38 (p&lt;0.01) and RKO (p&lt;0.01) as compared to control after incubation with naproxen at all doses. The inhibitory effect of NSAIDs on PD-L1 expression was both time and dose dependent. We evaluated the in vivo effect of combination immunoprevention in the APC(Min/+). Animals receiving vaccine alone showed a 33% inhibition of polyp formation while naproxen alone showed 54% inhibition (p&lt;0.0001) compared to adjuvant alone. Combination treatment demonstrated significantly greater inhibition of polyps than either modality (p&lt;0.001), 81% inhibition vs. adjuvant. Antigen specific T-cells could be detected at higher levels than control antigen in both the vaccine alone (p=0.0001) and combination-treated animals (p&lt;0.0001). The antigen specific responses seen in combination treated animals were nearly two-fold that of vaccine alone (p=0.008). No antigen specific immunity was detected in naproxen and adjuvant only treated mice. The magnitude of the immune response was significantly correlated with lower polyp counts, with a Pearson correlation coefficient of -0.55 (p=0.0014). Detailed immunologic analysis of tumors will be presented.

Conclusions: NSAIDs, via modulation of PD-L1, synergize with vaccines to increase immunogenicity and enhance influx of polyp infiltrating lymphocytes. This synergy results in superior prevention of polyp formation compared to treatment with NSAID or vaccine alone and has high potential for clinical application.

Citation Format: Mary L. Disis, Lauren R. Corulli, Clinton Grubbs, Ronald A. Lubet, Paul Cowan, Ekram Gad. Downregulation of PD-L1 by NSAID administration augments the effects of a multi-antigen vaccine for the prevention of adenomatous polyps in APC(Min/+) mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1266.