PD-1 Blockade Induces Reactivation of Nonproductive T-Cell Responses Characterized by NF-κB Signaling in Patients with Pancreatic Cancer

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) trials have evaluated CTLA-4 and/or PD-(L)1 blockade in patients with advanced disease in which bulky tumor burden and limited time to develop antitumor T cells may have contributed to poor clinical efficacy. Here, we evaluated peripheral blood and tumor T cells from patients with PDAC receiving neoadjuvant chemoradiation plus anti-PD-1 (pembrolizumab) versus chemoradiation alone. We analyzed whether PD-1 blockade successfully reactivated T cells in the blood and/or tumor to determine whether lack of clinical benefit could be explained by lack of reactivated T cells versus other factors.

EXPERIMENTAL DESIGN

We used single-cell transcriptional profiling and TCR clonotype tracking to identify TCR clonotypes from blood that match clonotypes in the tumor.

RESULTS

PD-1 blockade increases the flux of TCR clonotypes entering cell cycle and induces an IFNγ signature like that seen in patients with other GI malignancies who respond to PD-1 blockade. However, these reactivated T cells have a robust signature of NF-κB signaling not seen in cases of PD-1 antibody response. Among paired samples between blood and tumor, several of the newly cycling clonotypes matched activated T-cell clonotypes observed in the tumor.

CONCLUSIONS

Cytotoxic T cells in the blood of patients with PDAC remain sensitive to reinvigoration by PD-1 blockade, and some have tumor-recognizing potential. Although these T cells proliferate and have a signature of IFN exposure, they also upregulate NF-κB signaling, which potentially counteracts the beneficial effects of anti-PD-1 reinvigoration and marks these T cells as non-productive contributors to antitumor immunity. See related commentary by Lander and DeNardo, p. 474.

Multicenter randomized controlled trial of neoadjuvant chemoradiotherapy alone or in combination with pembrolizumab in patients with resectable or borderline resectable pancreatic adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a challenging target for immunotherapy because it has an immunosuppressive tumor microenvironment. Neoadjuvant chemoradiotherapy can increase tumor-infiltrating lymphocyte (TIL) density, which may predict overall survival (OS). We hypothesized that adding programmed cell death protein 1 (PD-1) blockade to chemoradiotherapy would be well tolerated and increase TILs among patients with localized PDAC.

METHODS

Patients were randomized 2:1 to Arm A (receiving pembrolizumab plus chemoradiotherapy (capecitabine and external beam radiation)) or Arm B (receiving chemoradiotherapy alone) before anticipated pancreatectomy. Primary endpoints were (1) incidence and severity of adverse events during neoadjuvant therapy and (2) density of TILs in resected tumor specimens. TIL density was assessed using multiplexed immunofluorescence histologic examination.

RESULTS

Thirty-seven patients were randomized to Arms A (n=24) and B (n=13). Grade ≥3 adverse events related to neoadjuvant treatment were experienced by 9 (38%) and 4 (31%) patients in Arms A and B, respectively, with one patient experiencing dose-limiting toxicity in Arm A. Seventeen (71%) and 7 (54%) patients in Arms A and B, respectively, underwent pancreatectomy. Median CD8+ T-cell densities in Arms A and B were 67.4 (IQR: 39.2-141.8) and 37.9 (IQR: 22.9-173.4) cells/mm2, respectively. Arms showed no noticeable differences in density of CD8+Ki67+, CD4+, or CD4+FOXP3+ regulatory T cells; M1-like and M2-like macrophages; or granulocytes. Median OS durations were 27.8 (95% CI: 17.1 to NR) and 24.3 (95% CI: 12.6 to NR) months for Arms A and B, respectively.

CONCLUSIONS

Adding pembrolizumab to neoadjuvant chemoradiotherapy was safe. However, no convincing effect on CD8+ TILs was observed.

Mobile sensing to advance tumor modeling in cancer patients: A conceptual framework

As mobile and wearable devices continue to grow in popularity, there is strong yet unrealized potential to harness people's mobile sensing data to improve our understanding of their cellular and biologically-based diseases. Breakthrough technical innovations in tumor modeling, such as the three dimensional tumor microenvironment system (TMES), allow researchers to study the behavior of tumor cells in a controlled environment that closely mimics the human body. Although patients' health behaviors are known to impact their tumor growth through circulating hormones (cortisol, melatonin), capturing this process is a challenge to rendering realistic tumor models in the TMES or similar tumor modeling systems. The goal of this paper is to propose a conceptual framework that unifies researchers from digital health, data science, oncology, and cellular signaling, in a common cause to improve cancer patients' treatment outcomes through mobile sensing. In support of our framework, existing studies indicate that it is feasible to use people's mobile sensing data to approximate their underlying hormone levels. Further, it was found that when cortisol is cycled through the TMES based on actual patients' cortisol levels, there is a significant increase in pancreatic tumor cell growth compared to when cortisol levels are at normal healthy levels. Taken together, findings from these studies indicate that continuous monitoring of people's hormone levels through mobile sensing may improve experimentation in the TMES, by informing how hormones should be introduced. We hope our framework inspires digital health researchers in the psychosocial sciences to consider how their expertise can be applied to advancing outcomes across levels of inquiry, from behavioral to cellular.

Complete response to immunotherapy in a patient with high-risk stage III colorectal cancer after ctDNA-guided detection of early adjuvant treatment failure

The standard of care for stage III colorectal cancer (CRC) is curative resection with adjuvant chemotherapy (ACT). There is a high risk of recurrence particularly for high-risk patients with stage III disease, making close disease monitoring vital. Circulating tumor DNA (ctDNA) is now established as an effective method of early detection of disease relapse as well as postoperative risk stratification. However there remains a lack of established protocol for using ctDNA to assess response to ACT and in using that data to alter therapy in real time. A case is described of a patient with high-risk stage III CRC in whom failure of ACT was detected early and therapy was quickly changed based on rising ctDNA levels. The described patient had complete radiologic and clinical response to checkpoint inhibitor immunotherapy and remains free of disease after 18 months. This case demonstrates a promising example of how ctDNA can be used to both assess effectiveness of ongoing therapy and drive real-time change in treatment while sparing unnecessary chemotherapy toxicities.

Associations between context and affect within the daily lives of cancer caregivers

PURPOSE

This study used ecological momentary assessment (EMA) to test the association between activity, location, and social company contexts with cancer caregivers' in-the-moment affect to identify precisely when and where to deliver psychological interventions for caregivers.

METHODS

Current cancer caregivers (N = 25) received 8 EMA prompts per day for 7 consecutive days. At each prompt, caregivers reported their current positive affect and negative affect, as well as what they were doing, where they were located, and who they were with. Multilevel logistic regressions tested the associations between caregivers' contexts with their own person-mean-centered state (concurrent momentary level) and trait (overall weekly average) positive or negative affect.

RESULTS

Caregivers reported lower state negative affect, as well as higher state positive affect, when socializing (ps < .001), when at a public location (ps < .03), and when around their friends, family, spouse/partner, or care recipient (i.e., person with cancer, ps < .02), relative to when not endorsing the context. Caregivers also reported lower state negative affect when eating/drinking or engaging in leisure (ps < .01; but no parallel effects for state positive affect). Caregivers reported higher state negative affect while working, when at their workplace, or when around work colleagues (ps < .001) and lower state positive affect when at home or alone (ps < .03).

CONCLUSIONS

Results suggest the pertinence of a behavioral activation framework to mitigate the emotional strain of caregiving. Interventions that facilitate caregivers' ability to socialize with a range of friends and family, including their loved one with cancer, outside of the home may have the strongest positive emotional impact.

Multi-omic analysis in normal colon organoids highlights MSH4 as a novel marker of defective mismatch repair in Lynch syndrome and microsatellite instability

INTRODUCTION

Lynch syndrome (LS) is a hereditary condition that increases the risk of colorectal (CRC) and extracolonic cancers that exhibit microsatellite instability (MSI-H). MSI-H is driven by defective mismatch repair (dMMR), and approximately 15% of nonhereditary CRCs also exhibit MSI-H. Here, we aimed to better define mechanisms underlying tumor initiation in LS and MSI-H cancers through multi-omic analyses of LS normal colon organoids and MSI-H tumors.

METHODS

Right (n = 35) and left (n = 23) colon organoids generated from normal colon biopsies at routine colonoscopy of LS and healthy individuals were subjected to Illumina EPIC array. Differentially methylated region (DMR) analysis was performed by DMRcate. RNA-sequencing (n = 16) and bisulfite-sequencing (n = 15) were performed on a subset of right colon organoids. CRISPR-cas9-mediated editing of MMR genes in colon organoids of healthy individuals was followed by quantitative PCR of MSH4. The relationship between MSH4 expression and tumor mutational burden was further explored in three independent tumor data sets.

RESULTS

We identified a hypermethylated region of MSH4 in both the right and left colon organoids of LS versus healthy controls, which we validated using bisulfite-sequencing. DMR analysis in three gastrointestinal and one endometrial data set revealed that this region was also hypermethylated in MSI-H versus microsatellite stable (MSS) tumors. MSH4 expression was increased in colon organoids of LS versus healthy subjects and in publicly available MSI-H versus MSS tumors across four RNA-seq and four microarray data sets. CRISPR-cas9 editing of MLH1 and MSH2, but not MSH6, in normal colon organoids significantly increased MSH4 expression. MSH4 expression was significantly associated with tumor mutational burden in three publicly available data sets.

CONCLUSIONS

Our findings implicate DNA methylation and gene expression differences of MSH4 as a marker of dMMR and as a potential novel biomarker of LS. Our study of LS colon organoids supports the hypothesis that dMMR exists in the colons of LS subjects prior to CRC.

Phase II Single-Arm Study of Palbociclib and Cetuximab Rechallenge in Patients with KRAS/NRAS/BRAF Wild-Type Colorectal Cancer

BACKGROUND

Cetuximab is often administered to patients with KRAS wild-type (KRAS-WT) metastatic colorectal cancer (mCRC), although resistance inevitably develops. We hypothesized that co-inhibition of the epidermal growth factor receptor (EGFR) with cetuximab and downstream cyclin-dependent kinases (CDK) 4/6 with palbociclib would be effective for anti-EGFR rechallenge in KRAS-WT mCRC.

METHODS

We designed a single-arm, Simon's 2-stage, phase II trial of cetuximab and palbociclib in KRAS-WT mCRC treated with ≥2 prior lines of therapy. We report here on cohort B rechallenging patients with anti-EGFR-based therapy who had disease control of at least 4 months on prior anti-EGFR therapy. Primary endpoint was disease control rate (DCR) at 4 months.

RESULTS

Ten evaluable patients were enrolled in this cohort. The 4-month DCR was 20%, which did not fulfill the prespecified 4-month DCR rate to continue. Median progression-free survival was 1.8 months and median overall survival was 6.6 months. Three patients had stable disease, although overall response rate was 0%. Most common treatment-related grades 3-4 adverse events were lymphopenia and leukopenia.

CONCLUSION

Selection of patients for anti-EGFR rechallenge using clinical criteria alone was insufficient to identify response to palbociclib + cetuximab. Additional biomarkers are needed to select anti-EGFR rechallenge and circulating tumor DNA (ctDNA) analysis is planned for samples collected in this study. (ClinicalTrials.gov Identifier: NCT03446157).

Abstract 3591: First in class drug ZB131 shows efficacy in cholangiocarcinoma models

Cholangiocarcinoma (CCA) is a lethal cancer with a high unmet need. The survival rate is low (5-year survival &lt;20%), most non-palliative patients relapse within two years, and treatments in the advanced setting are limited. While FGFR2 and IDH1 inhibitors are effective in patients with select genomic alterations, they address only a small fraction (&lt;20%) of biliary tract cancers. We now present the discovery and characterization of ZB131, a first in class humanized monoclonal antibody targeted to cancer specific plectin (CSP). CSP is a pro-tumorigenic protein exclusively expressed on the cancer cell surface. Previously, we demonstrated remarkable tumor regressions in preclinical murine models of pancreatic and ovarian cancer using a tool anti-CSP murine antibody. Here, we show that intra- and extra-hepatic CCA are 92% and 86% positive for membranous plectin staining by IHC, respectively, suggesting that anti-CSP therapy could be broadly effective against CCA. Indeed, in CCA cell lines in vitro, ZB131 (0.4nM binding affinity) arrests cell cycle, inhibits cell migration, and triggers intracellular ROS accumulation. In addition, both ZB131 and its murine version significantly suppressed tumor growth in 83% of the mice in a xenograft model and caused complete regression in the remaining 17%. Previous data from our group and others suggesting that CSP plays a role in chemoresistance led us to evaluate the efficacy of ZB131 in combination with gemcitabine. In vitro, we treated CSP-positive WITT cells with combinations of 0-500nM gemcitabine plus 0-1000nM ZB131 and found pockets of synergy or additivity. In a CCA xenograft model, the combination of 1mg/kg ZB131 and 100mg/kg gemcitabine showed 91% suppression in tumor growth compared with 74% in gemcitabine alone and 77% in huIgG plus gemcitabine at day 32. Collectively, our results suggest that ZB131 renders CCA tumors more chemosensitive and enhances the antitumor effects of gemcitabine. In contrast to the standard-of-care CCA treatment regimen, ZB131 showed remarkably low toxicity, likely because the antibody bypasses any non-malignant cells where plectin remains strictly cytoplasmic. Fc effector functional studies revealed a lack of antibody-dependent cell-mediated and complement-dependent cytotoxicity. Hemolysis and cytokine release studies suggested that ZB131 is compatible with human blood and unlikely to cause adverse cytokine release. Furthermore, in GLP toxicology studies, no signs of toxicity were observed at the highest dose evaluated of 100mg/kg/week, providing a &gt;30-fold safety margin from the estimated human efficacious dose of 3mg/kg/week. In summary, ZB131 is an exciting new avenue for the treatment of CCA and other CSP-positive cancers with an excellent safety profile and strong antitumor activity in vitro and in murine models. Phase I clinical trials of ZB131 have been initiated.

Citation Format: Samantha M. Perez, Randall Burton, Denise Krawitz, Christopher Sheth, Pina Cardarelli, Molly Owens, Brian Murphy, Matthew J. Reilley, Lindsey T. Brinton, Kimberly A. Kelly. First in class drug ZB131 shows efficacy in cholangiocarcinoma models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3591.

Abstract CT126: A phase 2 trial of first-line AZD0171 + durvalumab and chemotherapy (CT) in patients with metastatic pancreatic ductal adenocarcinoma (PDAC) and CD8+ T cell infiltration

Background: Leukemia inhibitory factor (LIF) is an immunosuppressive cytokine linked to tumor growth and metastasis. LIF overexpression correlates with poor prognosis and chemoresistance in multiple tumor types including PDAC. Preclinical data show that LIF promotes an immunosuppressive tumor microenvironment, hindering cytotoxic CD8+ T cell recruitment; low T cell infiltration also correlates with mortality in patients with PDAC. Preclinical studies show LIF-blocking antibodies sensitize tumors to PD-1/PD-L1 inhibition, inhibit epithelial-mesenchymal transition, and prolong survival in combination with CT. In patients with PDAC, higher LIF levels correlate with more aggressive pathology, elevated CA19-9 (a PDAC biomarker), and lower response and survival rates. AZD0171 (formerly MSC-1), a first-in-class, humanized, IgG1 monoclonal antibody, binds specifically and potently to LIF, preventing downstream signaling. In a phase 1 dose escalation study (NCT03490669), AZD0171 monotherapy had manageable safety and led to stable disease (SD) in 34.2% of patients with advanced solid tumors across all dose levels. AZD0171 + CT may improve survival outcomes vs CT alone. Based on preclinical data, AZD0171 may function to stimulate antitumor immune response, and combination with the PD-L1 inhibitor durvalumab could prolong that response and overcome peripheral tolerance in patients with metastatic PDAC.

Methods: This is a phase 2, open-label, single-arm, multicenter study of AZD0171 + durvalumab and CT in treatment-naive patients with metastatic PDAC (NCT04999969). Eligible patients must have an ECOG performance status 0 or 1, a Gustave Roussy Immune Score 0 or 1, ≥1 measurable target lesion per RECIST v1.1, and confirmed presence of tumoral CD8+ T cells. Patients with central nervous system metastasis, history of leptomeningeal disease or cord compression, a thromboembolic event ≤3 months prior to study treatment, unresolved grade ≥2 toxicities from prior therapy, or a sensitizing mutation or tumor characteristic for which there is a preferred treatment, are excluded. As PDAC is poorly immune infiltrated, a novel clinical trial assay will be used to select for patients who have existing resident CD8+ T cells and may therefore be more likely to respond. About 115 patients will receive intravenous AZD0171, durvalumab and CT until disease progression or unacceptable toxicity. The primary endpoints are safety and overall survival (OS) rate at 12 months. Secondary endpoints include objective response rate, disease control rate (confirmed response or SD ≥16 weeks), duration of response, median progression-free survival (PFS), PFS rate at 4 months, median OS, pharmacokinetics, pharmacodynamics (changes in serum CA19-9 level and tumor CD8+ T cell infiltration) and immunogenicity. The trial is currently recruiting.

Citation Format: Grainne O'Kane, Teresa Macarulla, Fiyinfolu Balogun, Antoine Hollebecque, Matthew J. Reilley, Sreenivasa R. Chandana, Jim Eyles, Oluwaseun Ojo, Philip Overend, Douglas C. Palmer, Nadia Luheshi, Mayukh Das, Antoine Italiano, Joan Seoane. A phase 2 trial of first-line AZD0171 + durvalumab and chemotherapy (CT) in patients with metastatic pancreatic ductal adenocarcinoma (PDAC) and CD8+ T cell infiltration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT126.

Feasibility of ecological momentary assessment to study depressive symptoms among cancer caregivers

OBJECTIVE

Ecological momentary assessment (EMA) may help with the development of more targeted interventions for caregivers' depression, yet the use of this method has been limited among cancer caregivers. This study aimed to demonstrate the feasibility of EMA among cancer caregivers and the use of EMA data to understand affective correlates of caregiver depressive symptoms.

METHODS

Caregivers (N = 25) completed a depressive symptom assessment (Patient Health Questionnaire-8) and then received eight EMA survey prompts per day for 7 days. EMA surveys assessed affect on the orthogonal dimensions of valence and arousal. Participants completed feedback surveys regarding the EMA protocol at the conclusion of the week-long study.

RESULTS

Of 32 caregivers approached, 25 enrolled and participated (78%), which exceeded the a priori feasibility cutoff of 55%. The prompt completion rate (59%, or 762 of 1,286 issued) did not exceed the a priori cutoff of 65%, although completion was not related to caregivers' age, employment status, physical health quality of life, caregiving stress, or depressive symptoms or the patients' care needs (ps > 0.22). Caregivers' feedback about their study experience was generally positive. Mixed-effects location scale modeling showed caregivers' higher depressive symptoms were related to overall higher reported negative affect and lower positive affect, but not to affective variability.

CONCLUSIONS

Findings from this feasibility study refute potential concerns that an EMA design is too burdensome for distressed caregivers. Clinically, findings suggest the potential importance of not only strategies to reduce overall levels of negative affect, but also to increase opportunities for positive affect.

Integrating Storytelling into a Communication Skills Teaching Program for Medical Oncology Fellows

Oncology training focuses primarily on biomedical content rather than psychosocial content, which is not surprising in light of the enormous volume of technical information that oncology fellows assimilate in a short time. Nonetheless, the human connection, and specifically communication skills, remains as important as ever in caring for highly vulnerable patients with cancer. We previously described a year-long communication skills curriculum for oncology fellows that consisted of monthly 1-hour seminars with role play as the predominant teaching method (Epner and Baile, Acad Med. 89:578-84, 2014). Over several years, we adapted the curriculum based on learner feedback and reflection by faculty and teaching assistants and consolidated sessions into quarterly 3-4-hour workshops. We now describe integrating stories into the curriculum as a way of building empathy and warming fellows to the arduous task of dealing with highly emotional content, such as conversations with young patients about transitioning off disease-directed therapy. Learners read and discussed published, medically themed stories; discussed their own patient care stories; and completed brief writing reflections and discussions. They then worked in small groups facilitated by faculty and upper level fellows who functioned as teaching assistants to work on applying specific skills and strategies to scenarios that they chose. Fellows completed anonymous surveys on which they rated the curriculum highly for relevance, value, organization, content, and teaching methods, including storytelling aspects. We conclude that sharing stories can help highly technical learners build reflective ability, mindfulness, and empathy, which are all critical ingredients of the art of medicine.

TLR9 activation cooperates with T cell checkpoint blockade to regress poorly immunogenic melanoma

Tumors that lack pre-existing immune infiltration respond poorly to T cell checkpoint blockade immunotherapy. These cancers often surround themselves with high densities of suppressive myeloid stroma while excluding immunostimulatory dendritic cells. Tumor-resident myeloid cells and selected lymphocyte populations retain expression of Toll-like Receptors (TLR) that sense common features of pathogens and activate innate immunity in response. We explored whether agonists of TLR9 could augment innate immunity to promote tumor regression alone or in combination with T cell checkpoint blockade. In the setting of the immunogenic B16-Ova (Ovalbumin) expressing melanoma model, local injection of the CpG oligonucleotide TLR9 agonist ODN1826 combined with systemic CTLA-4 blockade cured 45% of mice of both their treated and an untreated tumor on the opposite flank demonstrating the synergistic potential of this combination. Next, in the non-immunogenic B16-F10 melanoma model, we showed that only intra-tumoral, but not systemic TLR9 activation augments the therapeutic potential of checkpoint blockade. In this setting, intra-tumoral TLR9 activation cooperated equally with either CTLA-4 or PD-1 blockade co-administered locally or given systemically; however, the uninjected tumor rarely regressed. Anti-CTLA-4 combinations were associated with improved intra-tumoral CD8 to regulatory T cell ratios, while anti-PD-1 combinations elicited improved ratios of CD8 T cells relative to suppressive myeloid stroma. Using both a TLR9 agonist (MGN1703) and a CTLA-4 antibody (9D9-IgG2a) of increased potency cured 50% of bi-lateral B16-F10 melanoma. These findings suggest that intra-tumoral TLR9 agonists can improve sensitivity of poorly immunogenic tumors to T cell checkpoint blockade, and that newer, higher potency TLR agonists and checkpoint antibodies can raise the therapeutic ceiling for this combination therapy.

STAT3 antisense oligonucleotide AZD9150 in a subset of patients with heavily pretreated lymphoma: results of a phase 1b trial

Background

The Janus kinase (JAK) and signal transduction and activation of transcription (STAT) signaling pathway is an attractive target in multiple cancers. Activation of the JAK-STAT pathway is important in both tumorigenesis and activation of immune responses. In diffuse large B-cell lymphoma (DLBCL), the transcription factor STAT3 has been associated with aggressive disease phenotype and worse overall survival. While multiple therapies inhibit upstream signaling, there has been limited success in selectively targeting STAT3 in patients. Antisense oligonucleotides (ASOs) represent a compelling therapeutic approach to target difficult to drug proteins such as STAT3 through of mRNA targeting. We report the evaluation of a next generation STAT3 ASO (AZD9150) in a non-Hodgkin’s lymphoma population, primarily consisting of patients with DLBCL.

Methods

Patients with relapsed or treatment refractory lymphoma were enrolled in this expansion cohort. AZD9150 was administered at 2 mg/kg and the 3 mg/kg (MTD determined by escalation cohort) dose levels with initial loading doses in the first week on days 1, 3, and 5 followed by weekly dosing. Patients were eligible to remain on therapy until unacceptable toxicity or progression. Blood was collected pre- and post-treatment for analysis of peripheral immune cells.

Results

Thirty patients were enrolled, 10 at 2 mg/kg and 20 at 3 mg/kg dose levels. Twenty-seven patients had DLBCL. AZD9150 was safe and well tolerated at both doses. Common drug-related adverse events included transaminitis, fatigue, and thrombocytopenia. The 3 mg/kg dose level is the recommended phase 2 dose. All responses were seen among DLBCL patients, including 2 complete responses with median duration of response 10.7 months and 2 partial responses. Peripheral blood cell analysis of three patients without a clinical response to therapy revealed a relative increase in proportion of macrophages, CD4+, and CD8+ T cells; this trend did not reach statistical significance.

Conclusions

AZD9150 was well tolerated and demonstrated efficacy in a subset of heavily pretreated patients with DLBCL. Studies in combination with checkpoint immunotherapies are ongoing.

Trial registration

Registered at ClinicalTrials.gov: NCT01563302. First submitted 2/13/2012.

Electronic supplementary material

The online version of this article (10.1186/s40425-018-0436-5) contains supplementary material, which is available to authorized users.

Abstract A21: Activation of 4-1BB on liver myeloid cells triggers hepatitis via an interleukin-27 dependent pathway

Purpose: Agonist antibodies targeting the T cell co-stimulatory receptor 4-1BB (CD137) are among the most effective immunotherapeutic agents across multiple preclinical models of cancer. In the clinic, however, development of these agents has been stymied by dose-limiting liver toxicity. Lack of knowledge of the mechanisms underlying this toxicity has limited the potential to separate 4-1BB agonist driven anti-tumor immunity from hepatotoxicity.

Experimental Design: The capacity of 4-1BB agonist antibodies to induce liver toxicity was investigated in immune competent mice, with or without co-administration of checkpoint blockade, via measurement of serum transaminase levels, through imaging of liver immune infiltrates, and via qualitative and quantitative assessment of liver myeloid and T cells via flow cytometry. Knockout mice were used to clarify the contribution of specific cell subsets, cytokines and chemokines.

Results: We find that activation of 4-1BB on liver myeloid cells is essential to initiate hepatitis. Once activated, these cells produce interleukin-27, which is required for liver toxicity. CD8 T cells infiltrate the liver in response to this myeloid activation and mediate tissue damage triggering transaminase elevation. FoxP3+ regulatory T cells limit liver damage and their removal dramatically exacerbates 4-1BB agonist hepatitis. Co-administration of CTLA-4 blockade ameliorates transaminase elevation, whereas PD-1 blockade exacerbates it. Loss of the chemokine receptor CCR2 blocks 4-1BB agonist hepatitis without diminishing tumor-specific immunity against B16 melanoma.

Conclusions: 4-1BB agonist antibodies trigger hepatitis via activation of myeloid cells to produce Interleukin-27. Co-administration of CTLA-4 and/or CCR2 blockade may minimize hepatitis but yields equal or greater antitumor immunity.

Citation Format: Ashvin R. Jaiswal, Todd Bartkowiak, Casey R. Ager, Renee Chin, Chao Hsien Chen, Pratha Budhani, Midan Ai, Matthew J. Reilley, Manu M. Sebastian, David Hong, Michael A. Curran. Activation of 4-1BB on liver myeloid cells triggers hepatitis via an interleukin-27 dependent pathway [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A21.

Activation of 4-1BB on Liver Myeloid Cells Triggers Hepatitis via an Interleukin-27-Dependent Pathway

Purpose: Agonist antibodies targeting the T-cell costimulatory receptor 4-1BB (CD137) are among the most effective immunotherapeutic agents across preclinical cancer models. In the clinic, however, development of these agents has been hampered by dose-limiting liver toxicity. Lack of knowledge of the mechanisms underlying this toxicity has limited the potential to separate 4-1BB agonist-driven tumor immunity from hepatotoxicity.Experimental Design: The capacity of 4-1BB agonist antibodies to induce liver toxicity was investigated in immunocompetent mice, with or without coadministration of checkpoint blockade, via (i) measurement of serum transaminase levels, (ii) imaging of liver immune infiltrates, and (iii) qualitative and quantitative assessment of liver myeloid and T cells via flow cytometry. Knockout mice were used to clarify the contribution of specific cell subsets, cytokines, and chemokines.Results: We find that activation of 4-1BB on liver myeloid cells is essential to initiate hepatitis. Once activated, these cells produce interleukin-27 that is required for liver toxicity. CD8 T cells infiltrate the liver in response to this myeloid activation and mediate tissue damage, triggering transaminase elevation. FoxP3⁺ regulatory T cells limit liver damage, and their removal dramatically exacerbates 4-1BB agonist-induced hepatitis. Coadministration of CTLA-4 blockade ameliorates transaminase elevation, whereas PD-1 blockade exacerbates it. Loss of the chemokine receptor CCR2 blocks 4-1BB agonist hepatitis without diminishing tumor-specific immunity against B16 melanoma.Conclusions: 4-1BB agonist antibodies trigger hepatitis via activation and expansion of interleukin-27-producing liver Kupffer cells and monocytes. Coadministration of CTLA-4 and/or CCR2 blockade may minimize hepatitis, but yield equal or greater antitumor immunity. Clin Cancer Res; 24(5); 1138-51. ©2018 AACR.

Intratumoral STING Activation with T-cell Checkpoint Modulation Generates Systemic Antitumor Immunity

Coordinated manipulation of independent immune regulatory pathways in the tumor microenvironment-including blockade of T-cell checkpoint receptors and reversal of suppressive myeloid programs-can render aggressive cancers susceptible to immune rejection. Elevated toxicity associated with combination immunotherapy, however, prevents translation of the most efficacious regimens. We evaluated T-cell checkpoint-modulating antibodies targeting CTLA-4, PD-1, and 4-1BB together with myeloid agonists targeting either STING or Flt3 in the TRAMP-C2 model of prostate cancer to determine whether low-dose intratumoral delivery of these agents could elicit systemic control of multifocal disease. Intratumoral administration of the STING agonist cyclic di-GMP (CDG) or Flt3 Ligand (Flt3L) augmented the therapeutic effect of systemic triple checkpoint modulation and promoted the cure of 75% of mice with bilateral TRAMP-C2; however, when all agents were administered locally, only CDG mobilized abscopal immunity. Combination efficacy correlated with globally enhanced ratios of CD8⁺ T cells to regulatory T cells (Treg), macrophages, and myeloid-derived suppressor cells, and downregulation of the M2 marker CD206 on tumor-associated macrophages. Flt3L improved CD8⁺ T-cell and dendritic cell infiltration of tumors, but was diminished in efficacy by concomitant Treg expansion. Although intratumoral CDG/checkpoint therapy invokes substantial ulceration at the injection site, reduced CDG dosing can preserve tissue integrity without sacrificing therapeutic benefit. For high-order combinations of T-cell checkpoint antibodies and local myeloid agonists, systemic antibody administration provides the greatest efficacy; however, local administration of CDG and antibody provides substantial systemic benefit while minimizing the potential for immune-related adverse events. Cancer Immunol Res; 5(8); 676-84. ©2017 AACR.

Phase I clinical trial of combination imatinib and ipilimumab in patients with advanced malignancies

Background

Imatinib mesylate can induce rapid tumor regression, increase tumor antigen presentation, and inhibit tumor immunosuppressive mechanisms. CTLA-4 blockade and imatinib synergize in mouse models to reduce tumor volume via intratumoral accumulation of CD8+ T cells. We hypothesized that imatinib combined with ipilimumab would be tolerable and may synergize in patients with advanced cancer.

Methods

Primary objective of the dose-escalation study (3 + 3 design) was to establish the maximum tolerated dose (MTD) and recommended phase II dose. Secondary objectives included evaluation of antitumor activity of the combination based on KIT mutation status and the capacity of tumor-associated immune biomarkers to predict response.

Results

The primary objective to establish the maximum tolerated dose (MTD) was achieved, and the recommended phase II doses are ipilimumab at 3 mg/kg every 3 weeks and imatinib 400 mg twice daily. Of the 35 patients treated in the escalation and GIST expansion, none experienced dose-limiting toxicities. The most common grade 1/2–related adverse events (AEs) were fatigue (66%), nausea (57%), anorexia, vomiting (each 31%), edema (29%), and anemia, diarrhea, and rash (each 23%). Grade 3 AEs occurred in 6 patients (17%) and included fatigue, anemia, fever, rash, and vomiting. There were no grade 4 AEs. In general, the combination was well tolerated. Among all patients, 2 responses were seen: 1 partial response (GIST) and 1 partial response (melanoma). Stable disease was seen in 6 patients lasting an average of 6 months. The melanoma responder was KIT mutated and the GIST responder was wild-type.

Conclusions

Our findings suggest that this combination of a targeted agent with checkpoint blockade is safe across multiple tumor types. Low activity with no clear signal for synergy was observed in escalation or GIST expansion cohorts. Assessment of antitumor activity of this combination in the KIT-mutant melanoma population is being evaluated.

Trial registration

Clinicaltrials.gov NCT01738139, registered 28 November 2012.

Electronic supplementary material

The online version of this article (doi:10.1186/s40425-017-0238-1) contains supplementary material, which is available to authorized users.

Health behaviors among testicular cancer survivors

BACKGROUND

With modern treatment, more than 95% of American men who are diagnosed with testicular cancer will be cured. Although there is growing evidence that these individuals may face heightened risk of cardiovascular disease after chemotherapy, there is a paucity of research to objectively classify health-promoting behaviors in this population and to identify the barriers to improving their health behaviors.

OBJECTIVES

To identify health behavior patterns in a group of testicular cancer survivors (TCSs) and the barriers to more positive health behaviors and to examine the relationship between barriers, health behaviors, and quality of life (QOL).

METHODS

TCSs from the Pennsylvania State Cancer Registry who had been diagnosed during 1990-2005 completed a comprehensive survey about QOL, health behaviors, and barriers to optimal healthy behaviors. QOL, health behaviors, and the barriers were assessed for 189 respondents.

RESULTS

Smoking (25%), risky drinking (35%), elevated body-mass index (83%), poor diet (95% did not meet the guidelines for fruit and vegetable intake), and inadequate exercise (50%) were common. Barriers to achieving optimal health behaviors were categorized as either cancer-related or competing demands. Cancer-related barriers contributed to worse physical QOL, whereas competing demands related to worse mental-health-related QOL.

LIMITATIONS

Our sample size was moderate and self-selected. In addition, we used self-reports rather than the more standardized observation or interview-based data collection.

CONCLUSION

TCSs demonstrate behaviors that put them at increased risk for future cardiovascular disease and complications. Interventions aimed at reducing tobacco and risky alcohol use and improving dietary and physical activity levels are needed.

FUNDING/SPONSORSHIP

NCI grant number 1R03CA124217; the Livestrong Foundation.

DISCLOSURES

The authors have no disclosures.

Stoichiometry of STAT3 and mitochondrial proteins: Implications for the regulation of oxidative phosphorylation by protein-protein interactions

The signal transducer and activator of transcription 3 (STAT3) is a transcription factor and downstream product of cytokine and growth factor pathways. Among members of the STAT family, STAT3 has garnered particular interest due to its role in cancer and development. Recently, it was proposed that STAT3 regulates cardiac ATP generation in vivo through protein interaction with the mitochondrial complexes of oxidative phosphorylation, specifically Complexes I/II. For this mechanism to work effectively, the cellular ratio of Complexes I/II and STAT3 must approach one. However, using three different proteomic approaches in cardiac tissue, we determined the ratio of Complexes I/II and STAT3 to be ∼10⁵. This finding suggests that direct protein interaction between Complexes I/II and STAT3 cannot be required for optimal ATP production, nor can it dramatically modulate oxidative phosphorylation in vivo. Thus, STAT3 is likely altering mitochondrial function via transcriptional regulation or indirect signaling pathways that warrant further investigation.