Benefit Of Immune Checkpoint Blockade Research Articles

Abstract PS17-14: Evaluating the efficacy of immunotherapy in triple negative breast cancer

Abstract The breast cancer microenvironment comprises a complex stroma including tumor-infiltrating lymphocytes (TILs), which can either stimulate tumor progression or promote anti-tumor immunity in response to tumor-derived cues. In general, of all clinical subtypes, triple-negative breast cancer (TNBC) is characterized by the most extensive infiltration of TILs within tumor stroma, which is consistent with the observation that TNBC seems to clinically respond to immunotherapies at the highest rates. Immune checkpoint blockade (ICB), an immunotherapy that promotes prolonged activation of cytotoxic immune cells to mount robust anti-tumorigenic responses, has yielded limited success in treating breast cancer. IMpassion130 was the first clinical trial to indicate that combining anti-PD-L1 with standard-of-care chemotherapy (nab-paclitaxel) to treat TNBC increases progression-free survival in patients exclusively those with PD-L1 positive tumors. Furthermore, the KEYSTONE-522 trial showed that administering anti-PD-1 in addition to various neoadjuvant chemotherapies increased the pathologic complete response in early stage TNBC patients. Despite promising evidence for immunotherapy success, both clinical trials lacked an experimental ICB-only group, and thus cannot address the therapeutic benefit of ICB alone, or which chemotherapy combination would maximize this benefit. Finally, mechanisms of resistance to ICB in breast cancer remain unexplored. We sought to model ICB response in vivo to elucidate the mechanisms responsible for immunotherapy efficacy in breast cancer, explore the synergistic effects of ICB with chemotherapies, and model ICB resistance.In this study, we investigated the efficacy of anti-PD-L1 as single-agent or in combination with paclitaxel or doxorubicin in the EMT6 (Balb/c) orthotopic mammary tumor model. In this model, single-agent immunotherapy was efficacious in reducing primary tumor growth compared to combination treatment, with a small proportion of complete responses, whereas modest benefit was observed with either chemotherapy alone. Following two rounds of treatment, we analyzed the tumor-immune microenvironment by flow cytometry and gene expression analysis. Anti-PD-L1 alone or in combination with either chemotherapy enhanced infiltration of cytotoxic and effector T cell as well as natural killer cells into the tumor microenvironment. Using gene expression analysis, we observed elevated expression of myeloid recruitment and activation markers in combination-treated tumors, supporting a known role of chemotherapy-induced cell death in myeloid recruitment; however as chemotherapy did not add benefit to tumor response or survival, it is unclear if this effect is detrimental or supportive. Interestingly, completely responsive anti-PD-L1 treated tumors that eventually recurred retained resistance to ICB upon re-implantation in naïve recipient mice, suggesting that tumor-intrinsic factors may contribute to resistance.Herein, we explore an in vivo model that corroborates clinical response to combinatorial immunotherapy approaches in breast cancer patients. We report the immunogenic efficacy of single-agent ICB that upregulates tumoricidal immune cell infiltration into the primary tumor, thereby controlling tumor growth, albeit without achieving complete response in all mice. Additionally, post-therapy recurrent tumors retain resistance upon transplantation, indicating tumor-specific adaptive resistance. This study has potentially significant clinical implications for re-evaluating the contributions of chemotherapy in combination with ICB in TNBC patients. Citation Format: Ann Hanna, Paula I. Gonzalez-Ericsson, Violeta Sanchez, Melinda E. Sanders, Justin M. Balko. Evaluating the efficacy of immunotherapy in triple negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-14.

Concurrent Dexamethasone Limits the Clinical Benefit of Immune Checkpoint Blockade in Glioblastoma.

Dexamethasone, a uniquely potent corticosteroid, is frequently administered to patients with brain tumors to decrease tumor-associated edema, but limited data exist describing how dexamethasone affects the immune system systemically and intratumorally in patients with glioblastoma (GBM), particularly in the context of immunotherapy. We evaluated the dose-dependent effects of dexamethasone when administered with programmed cell death 1 (PD-1) blockade and/or radiotherapy in immunocompetent C57BL/6 mice with syngeneic GL261 and CT-2A GBM tumors. Clinically, the effect of dexamethasone on survival was evaluated in 181 patients with isocitrate dehydrogenase (IDH) wild-type GBM treated with PD-(L)1 blockade, with adjustment for relevant prognostic factors. Despite the inherent responsiveness of GL261 to immune checkpoint blockade, concurrent dexamethasone administration with anti-PD-1 therapy reduced survival in a dose-dependent manner. Concurrent dexamethasone also abrogated survival following anti-PD-1 therapy with or without radiotherapy in immune-resistant CT-2A models. Dexamethasone decreased T-lymphocyte numbers by increasing apoptosis, in addition to decreasing lymphocyte functional capacity. Myeloid and natural killer cell populations were also generally reduced by dexamethasone. Thus, dexamethasone appears to negatively affect both adaptive and innate immune responses. As a clinical correlate, a retrospective analysis of 181 consecutive patients with IDH wild-type GBM treated with PD-(L)1 blockade revealed poorer survival among those on baseline dexamethasone. Upon multivariable adjustment with relevant prognostic factors, baseline dexamethasone administration was the strongest predictor of poor survival [reference, no dexamethasone; <2 mg HR, 2.16; 95% confidence interval (CI), 1.30-3.68; P = 0.003 and ≥2 mg HR, 1.97; 95% CI, 1.23-3.16; P = 0.005]. Our preclinical and clinical data indicate that concurrent dexamethasone therapy may be detrimental to immunotherapeutic approaches for patients with GBM.

Clinical responses to PD-1 inhibition and their molecular characterization in six patients with mismatch repair-deficient metastatic cancer of the digestive system

PurposeImmune checkpoint inhibitors have shown efficacy in patients with microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) gastrointestinal (GI) cancers. However, depth and duration of clinical response is not uniform. We assessed tumor mutation burden (TMB) as a response marker in patients with GI cancers treated with immune checkpoint inhibitors.MethodsDetailed clinical and response data were collected from six patients with metastatic MSI-H/dMMR GI cancers treated with immune checkpoint inhibitors. Efficacy was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Tumors and matched normal tissue were profiled by targeted next generation sequencing (127 gene panel, size 0.8 Mb). Impact of included mutation types, germline filtering methodology and different variant allele frequency thresholds on TMB estimation was assessed.ResultsObjective radiographic responses were observed in all six patients, and complete response was achieved in two of the six patients. Responses were durable (minimum 25 months). TMB estimates were clearly above the two recently reported cut-offs for metastatic colorectal cancer of 12 or 37 mutations per megabase for five of six patients, respectively, while one patient had borderline TMB elevation. TMB did not show an association with extent and duration of response but was influenced by included mutation types, germline filtering method and variant allele frequency threshold.ConclusionOur case series confirms the clinical benefit of immune checkpoint blockade in patients with metastatic MSI-H/dMMR GI cancers and illustrates the vulnerability of TMB as predictive marker in a subset of patients.

Abstract IA19: Immunotherapy in ovarian cancer: Challenges and novel opportunities

Abstract IA19: Immunotherapy in ovarian cancer: Challenges and novel opportunities

RIPK1-mediated immunogenic cell death promotes anti-tumour immunity against soft-tissue sarcoma.

Drugs that mobilise the immune system against cancer are dramatically improving care for many people. Dying cancer cells play an active role in inducing anti‐tumour immunity but not every form of death can elicit an immune response. Moreover, resistance to apoptosis is a major problem in cancer treatment and disease control. While the term “immunogenic cell death” is not fully defined, activation of receptor‐interacting serine/threonine‐protein kinase 1 (RIPK1) can induce a type of death that mobilises the immune system against cancer. However, no clinical treatment protocols have yet been established that would harness the immunogenic potential of RIPK1. Here, we report the first pre‐clinical application of an in vivo treatment protocol for soft‐tissue sarcoma that directly engages RIPK1‐mediated immunogenic cell death. We find that RIPK1‐mediated cell death significantly improves local disease control, increases activation of CD8+ T cells as well as NK cells, and enhances the survival benefit of immune checkpoint blockade. Our findings warrant a clinical trial to assess the survival benefit of RIPK1‐induced cell death in patients with advanced disease at limb extremities.

A Mutational Signature that Predicts Prognosis and Benefit of Immune Checkpoint Blockade in Colorectal Cancer

A Mutational Signature that Predicts Prognosis and Benefit of Immune Checkpoint Blockade in Colorectal Cancer

Deep neural network classification based on somatic mutations potentially predicts clinical benefit of immune checkpoint blockade in lung adenocarcinoma

ABSTRACT Although several biomarkers have been proposed to predict the response of patients with lung adenocarcinoma (LUAD) to immune checkpoint blockade (ICB) therapy, existing challenges such as test platform uniformity, cutoff value definition, and low frequencies restrict their effective clinical application. Here, we attempted to use deep neural networks (DNNs) based on somatic mutations to predict the clinical benefit of ICB to LUAD patients undergoing immunotherapy. We used DNNs to train and validate the predictive model in three cohorts. Kaplan-Meier estimates determined the overall survival (OS) and progression-free survival (PFS) between specific subgroups. Then, we performed a relevant analysis on the multiple-dimension data types including immune cell infiltration, programmed death receptor 1 ligand (PD-L1) expression, and tumor mutational burden (TMB) from cohorts of LUAD public database and immunotherapeutic patients. Two classification groups (C1 and C2) in the training and two validation sets were identified for the efficacy of ICB via the DNN algorithm. Patients in C1 showed remarkably long OS and PFS to programmed death 1 (PD-1) inhibitors. The C1 group was significantly associated with increased expression of immune cell infiltration, immune checkpoints, activated T-effectors, and interferon gamma signature. C1 group also exhibited significantly higher TMB, neoantigens, transversion, or transition than the C2 group. This work provides novel insights that classification of DNNs using somatic mutations in LUAD could serve as a potentially predictive approach in developing a strategy for anti-PD-1/PD-L1 immunotherapy.

Insights into Nanomedicine for Immunotherapeutics in Squamous Cell Carcinoma of the head and neck.

Immunotherapies such as immune checkpoint blockade benefit only a portion of patients with head and neck squamous cell carcinoma. The multidisciplinary field of nanomedicine is emerging as a promising strategy to achieve maximal anti-tumor effect in cancer immunotherapy and to turn non-responders into responders. Various methods have been developed to deliver therapeutic agents that can overcome bio-barriers, improve therapeutic delivery into the tumor and lymphoid tissues and reduce adverse effects in normal tissues. Additional modification strategies also have been employed to improve targeting and boost cytotoxic T cell-based immune responses. Here, we review the state-of-the-art use of nanotechnologies in the laboratory, in advanced preclinical phases as well as those running through clinical trials assessing their advantages and challenges.

533PD - BACCI: A phase II randomized, double-blind, multicenter, placebo-controlled study of capecitabine (C) bevacizumab (B) plus atezolizumab (A) or placebo (P) in refractory metastatic colorectal cancer (mCRC): An ACCRU network study

BackgroundThe benefit of immune checkpoint blockade in mCRC is currently limited to mismatch repair (MMR) deficient tumours. Increasing evidence suggests that the vascular endothelial growth factor (VEGF) pathway plays a role in cancer immune evasion. Co-targeting the PD-1/PD-L1 and VEGF axes may result in clinical activity in mCRC. Methods133 patients (pts) were randomized 2:1 to receive C/B/P (Arm A) or C/B/A (Arm B), stratifying by ECOG and RAS. Pts had progressed on 5-FU, oxaliplatin, irinotecan, bevacizumab, and anti-EGFR therapy (if RAS wt). Prior anti-PD-1/PD-L1 therapy was not permitted. Doses were C 850 or 1000mg/m² d1-14, B 7.5mg/kg d1, and A 1200mg d1 in 21day cycles. Primary endpoint was progression free survival (PFS). 110 events were required to detect PFS hazard ratio (HR) of 0.65 at 1-sided α=0.1 with 80% power. Secondary endpoints were objective response rate (ORR), overall survival (OS), and safety/tolerability. Primary and secondary efficacy analyses were performed using modified intent to treat analysis (mITT). ResultsAnalysis includes 46 pts (Arm A) and 82 pts (Arm B) with median age 58 yo, 40% female, 47% ECOG 0. As of 4/12/19, median follow-up was 12.35 months (mo). Proficient MMR or microsatellite stable (MSS) is present in 86.7% vs 85.7%. In mITT analysis, median PFS is 3.3mo (2.1-6.2) vs 4.4mo (4.1-6.4) with a HR of 0.725 (0.491-1.07), 1-sided log-rank p-value 0.051. In MSS only pts, HR for PFS is 0.67 (0.44-1.03). ORR is 4.35% (0.5-14.8) vs 8.54% (3.5-16.8), p=0.5. The 12mo OS is 43% (29-63) vs 52% (42-65), HR 0.94 (0.56-1.56), p=0.4. Most common grade>= 3 related adverse events are hypertension (7% vs 9%), hand-foot syndrome (4% vs 6%), and diarrhea (2% vs 7%). ConclusionsThe study reached its prespecified primary endpoint and the addition of A to CB results in a significantly longer PFS. No new or increased safety signals are identified. Further investigation in a larger phase III study may be warranted. This is the first positive study co-targeting PD-1/PD-L1 and VEGF axes in mCRC and correlative analyses may help identify predictors of benefit. Clinical trial identificationNCT0287319. Legal entity responsible for the studyACCRU. FundingGenentech Roche. DisclosureH.J. Lenz: Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): Genentech Roche; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): Bayer; Advisory / Consultancy, Research grant / Funding (institution): Bristol-Myers Squibb. P.M. Boland: Research grant / Funding (institution): Merck; Research grant / Funding (institution): Genentech; Research grant / Funding (institution): Boehringer Ingelheim; Research grant / Funding (institution): Hemispherx; Research grant / Funding (institution): Boston Biomedical; Research grant / Funding (institution): Isofol Medical; Research grant / Funding (institution), Travel / Accommodation / Expenses: Ipsen; Research grant / Funding (institution): Athenex; Research grant / Funding (institution): Bayer; Research grant / Funding (institution): Clinical Genomics. A.B. Nixon: Research grant / Funding (self): Seattle Genetics; Research grant / Funding (self): MedPacto; Research grant / Funding (self): Genentech Roche; Advisory / Consultancy, Research grant / Funding (self): Tracon Pharma; Research grant / Funding (self): Acceleron Pharma; Research grant / Funding (self): Leadiant Biosciences; Research grant / Funding (self): Sanofi-Aventis; Advisory / Consultancy: Eli Lilly. H. Hurwitz: Shareholder / Stockholder / Stock options, Full / Part-time employment: Genentech Roche. M.G. Fakih: Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self): Amgen; Advisory / Consultancy: Array; Advisory / Consultancy: Bayer; Research grant / Funding (self): AstraZeneca; Research grant / Funding (self): Novartis. All other authors have declared no conflicts of interest.

A phase II study of dual immune checkpoint blockade (ICB) plus androgen receptor (AR) blockade to enhance thymic T-cell production and immunotherapy response in metastatic breast cancer (MBC).

TPS1106 Background: ICB (atezolizumab, anti-PD-L1) is known to improve survival when added to chemo, however only in PD-L1-positive, triple-negative MBC. ICB is less effective in hormone receptor positive (HR+) MBC, or when administered following palliative chemo. Novel approaches are required to broaden clinical benefit of ICB, particularly in PD-L1-negative, HR+, or chemo-experienced MBC. Dual ICB with anti-PD-1 (nivolumab) and anti-CTLA-4 (ipilimumab) is associated with enhanced activity in melanoma other malignancies, but has not been explored extensively in MBC. Androgen receptor (AR) blockade, in addition to known direct cytostatic effects in AR-expressing MBCs (50% of TNBC, &gt; 75% of HR+ MBC), may also modulate immune response. AR blockade has been shown experimentally to stimulate thymic production of naïve T-cell clones, which in turn can facilitate de novo anti-tumor immune responses. Concurrent ICB can enhance the activity of these T-cell clones by interfering with PD-1-mediated peripheral tolerance. This combination approach is promising in MBC in light of known AR positivity, and the routine use of lymphodepleting chemo regimens in the curative-intent setting. Methods: This is a phase II trial of dual immune checkpoint blockade (nivolumab 240mg IV q2w; ipilimumab 1mg/kg IV q6w) plus AR blockade (bicalutamide, 150mg PO daily, dose reduction allowed) in triple-negative MBC (cohort A: AR-positive [ &gt; 1% by IHC]; cohort B: AR-negative) or HR+ MBC (cohort C) in subjects who received 0/1 prior chemotherapies in the non-curative setting. Objectives include 24-week clinical benefit rate by iRECIST (primary), safety (CTCAE v4.0), and other response measures (RECIST1.1, PFS, OS). Efficacy for each cohort is defined as &gt; 20% improvement in response over historical control (30% per EMBRACE clinical trial) employing a Simon 2-stage design to minimize futility (n = 46/cohort, stage I n = 15). Thymic generation of T-cells will be measured via quantitative deep sequencing of T-cell receptors (TcR, ImmunoSEQ assay) and TcR excision circles (TRECs), as well as real-time flow cytometry using surrogate cell surface markers of recent thymic emigration. Enrollment has commenced, sites: Earle A. Chiles Research Institute (Portland, OR), Memorial Sloan Kettering Cancer Center (New York, NY). Clinical trial information: NCT03650894.

Intrinsic β-catenin signaling suppresses CD8+ T-cell infiltration in colorectal cancer

Colorectal cancer is the third most common cancer worldwide and shows resistance to immune checkpoint inhibitors which have been demonstrated to be effective in many other types of cancers. Pre-existing T-cell response in tumor microenvironment often determines the therapeutic benefit of immune checkpoint blockade. Tumor-infiltrating CD8+ T-cells are considered as the major effector immune cells in antitumor immunity. In this study, we aimed to identify the intrinsic oncogenic pathway that contributes to a reduction of CD8+ T-cell infiltration in colorectal cancer. To achieve this, human colon adenocarcinoma samples derived from The Cancer Genome Altas (TCGA) were stratified into low T-cell-inflamed and high T-cell-inflamed groups based on the expression of T-cell signature genes. Gene set enrichment analysis of revealed a close correlation between activation of the Wnt/β-catenin signaling pathway and absence of T-cell infiltration. By immunohistochemical analysis of 155 colorectal cancer tissues, we found that tumors with high β-catenin expression showed a significant reduction of CD8+ T-cell infiltration. Mechanistically, β-catenin can regulate CCL4 expression to recruit CD103+ dendritic cells to enable CD8+ T cell activation. Collectively, our data indicate that oncogenic β-catenin signal may mediate colorectal cancer resistance to immunotherapies, pointing to the combined PD-1-immunotherapy with targeting β-catenin in colorectal cancer.

Abstract B015: T-cell recognition profiling of CD8+ T-cells in tumor-infiltrating lymphocytes expanded for adoptive cell transfer

Abstract Adoptive T-cell therapy (ACT) has proven to be a highly effective therapy option for melanoma and other immunogenic cancer types, however only a subset of 40% of the patients respond. Due to the intensive and costly regimen, it is important to find predictive biomarkers to identify patients that more likely respond to therapy.Melanoma-associated tissue antigens play an important role in melanoma immunotherapy, as they are expressed in the majority of tumors across different patients and can elicit T-cell recognition. Furthermore, such melanoma-associated T-cell responses may serve as a surrogate marker for T-cell reactivity in general and hence potentially also reflect the level of neoepitope reactivity. Several recent reports point towards the importance of mutation-derived neo-epitopes for cancer immunotherapy, as the mutational and putative neoantigen load correlates with therapeutically benefit of immune checkpoint blockade and ACT. In this study, we analyzed the impact of the number and size of T-cell responses against a library of shared antigens and predicted neoantigens to correlate the number of responses with the outcome of the ACT. We screened expanded tumor-infiltrating lymphocytes (TILs) from stage IV melanoma patients within a phase I/II clinical trial of ACT for CD8+ T-cell reactivity. A library of classical melanoma-associated shared antigens as well as a personalized library of predicted neoantigens for each patient was selected. CD8+ T-cell recognition in the TIL product was investigated by use of a novel technology based on DNA-barcode labeled MHC multimers, enabling high-throughput screening for &amp;gt;1,000 specific T-cell-populations in a single sample. Specific T-cell responses against shared antigens could be found and verified among the TIL samples. The number of CD8+ T-cells responses against tumor-associated shared antigens does not seem to correlate with progression-free or overall survival in this patient cohort, but further screenings have to be conducted. The analysis of neoantigen-reactive CD8+ T-cells within the TILs is ongoing.Identification of predictive biomarkers is an important step towards higher effectiveness of adoptive cell transfer as immunotherapeutic approach and the recognition pattern of melanoma by CD8+ T-cells associated with favorable clinical outcome provides mechanistic insights important for future developments. Citation Format: Christina Heeke, Anne-Mette Bjerregaard, Amalie Kai Bentzen, Marco Donia, Rikke Andersen, Marie Stentoft Svane, Sine Reker Hadrup. T-cell recognition profiling of CD8+ T-cells in tumor-infiltrating lymphocytes expanded for adoptive cell transfer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B015.

The Risks and Benefits of Immune Checkpoint Blockade in Anti-AChR Antibody-Seropositive Non-Small Cell Lung Cancer Patients.

Background: Anti-programmed cell death 1 (PD-1) monoclonal antibodies (Abs) unleash an immune response to cancer. However, a disruption of the immune checkpoint function by blocking PD-1/PD-ligand 1(PD-L1) signaling may trigger myasthenia gravis (MG) as a life-threatening immune-related adverse event. MG is a neuromuscular disease and is closely associated with being positive for anti-acetylcholine receptor (anti-AChR) Abs, which are high specific and diagnostic Abs for MG. Methods: A 72-year-old man was diagnosed with chemotherapy-refractory lung squamous cell carcinoma and nivolumab was selected as the third-line regimen. We describe the first report of an anti-AChR Ab-seropositive lung cancer patient achieving a durable complete response (CR) to an anti-PD-1 antibody therapy. To further explore this case, we performed multiplex immunofluorescence analysis on a pretreatment tumor. Results: The patient achieved a durable CR without developing MG. However, the levels of anti-AChR Abs were elevated during two years of anti-PD-1 antibody therapy. The tumor of the subclinical MG patient had high PD-L1 expression and an infiltrated–inflamed tumor immune microenvironment. Conclusions: This study suggests that immune checkpoint inhibitors can be safely used and provide the benefits for advanced cancer patients with immunologically ‘hot’ tumor even if anti-AChR Abs are positive. Although careful monitoring clinical manifestation in consultation with neurologist is needed, immune checkpoint inhibitors should be considered as a treatment option for asymptomatic anti-AChR Ab-seropositive cancer patients.

Immune Checkpoint Inhibitors in the Treatment of Gastroesophageal Cancer.

Immune checkpoint blockade has revolutionised the treatment of multiple cancers including melanoma, non-small cell lung cancer, urothelial and renal cell cancers. For patients with chemorefractory gastroesophageal cancer, treatment with anti-PD-1 therapy results in modest benefits in overall survival; nivolumab and pembrolizumab have been licenced in Japan and the USA, respectively, for this indication. However, initial enthusiasm has been tempered by the results of several large negative trials; immune checkpoint blockade is not superior to chemotherapy in the second-line setting or beyond in unselected or low PD-L1-expressing patients. Microsatellite instability is uncommon in patients with metastatic gastric cancer; however, it is associated with response rates of more than 50% and long-term survival benefit. Combining anti-PD-1 with cytotoxic chemotherapy and targeted therapies also shows promise to extend the benefit of immune checkpoint blockade to a larger proportion of gastroesophageal cancer patients. In this review we discuss recently reported and ongoing clinical research in immunotherapy for gastroesophageal cancer, and consider molecular biology associated with sensitivity and resistance to immune checkpoint blockade in gastroesophageal cancer patients.

Challenges and unanswered questions for the next decade of immune-oncology research in NSCLC.

Over the last 20 years there have been great advances in the treatment of lung cancer. Immune checkpoint blockade together with targeted therapies have provided oncologists with the means to improve survival of non-small cell lung cancer (NSCLC) and patients with a better quality of life and therapies with manageable toxicity. Maybe in a short period of time the possibility of a cure in metastatic NSCLC will be raised. Therefore, continued research into new drugs, biomarkers and especially combination therapies is necessary in order to expand the clinical benefit of the current treatments to a broader population of NSCLC patients. The purpose of our review is to highlight our thoughts about potential mechanisms of resistance to immunotherapy that, if better explored, can provide us with both biomarkers to predict response to these therapies and partners to combine with and prolong the benefit of immune checkpoint blockade. We are presenting our own experience of immunotherapy with a case report from our institution.

A Sampling of Highlights from the Literature

Breast cancer cells responding to MDSCs (from Wu et al. Cancer Res 2018)Wu et al. show that CD11c+ myeloid cells in breast tumors produce IL1β in response to interactions with tumor cell TGFβ, an inflammatory signature with a poor prognosis, but blocking either cytokine inhibits tumor progression. Azizi et al. use high-dimensional single-cell analysis to compare breast tumor T and myeloid cells to cells in other tissues. T cells do not have a limited number of discrete activation states but operate in a continuum. Michea et al.'s complementary study focuses on the differences in DC subsets between luminal and triple-negative breast tumors and shows how distinct microenvironments affected different DC subsets.Wu T-C, …, Palucka K. Cancer Res 2018 Jul 16. DOI: 10.1158/0008-5472.CAN-18-0413.Azizi E, …, Pe'er D. Cell 2018 Aug 23. doi: 10.1016/j.cell.2018.05.060.Michea P, …, Soumelis V. Nat Immunol 2018 Jul 16;19:885–97.Different signal strengths (from D. Edmundson Jr, Computing Concepts, LLC)How important is TCR signal strength to specific immune responses? Snook et al. find that the strength of TCR signals affects CD4+ T-cell fate: strong signals lead to development of TH1 cells, whereas lower strength leads to development of memory and follicular TH cells. Richard et al. analyzed single-cells and find that the frequency of CD8+ T cell activation is increased by stronger TCR signals, but crossing the cell's activation threshold gives similar effector function for high- and low-affinity stimulation.Richard AC, …, Griffiths GM. Nat Immunol 2018 Jul 16;19:849–58.Snook JP, …, Williams MA. Sci Immunol 2018 Jul 20;3:eaas9103.Rapid and efficient engineered assembly (by Siyuwj via Wikimedia Commons)A CRISPR-Cas9 targeting system allowed for efficient insertion of over one kilobase of DNA at specific sites in primary human T cells, without affecting their function or viability. Using this platform, a pathogenic mutation was corrected that improved cell function, and T cells with TCRs engineered with a desired tumor antigen specificity were generated and showed effective antitumor responses. This provides a useful technique for rapidly and efficiently engineering immune cells for therapeutic purposes.Roth TL, …, Marson A. Nature 2018 Jul 11;559:405–9.MHC class is key to checkpoint responses (from Locker Singapore)Immune checkpoint blockade with combination anti–CTLA-4 and anti–PD-1 has benefited patients with advanced melanoma more than either therapy alone. Low, or complete lack of, MHC class I on tumor cells is a key predictor of anti–CTLA-4 resistance in patients, whereas tumor cell MHC class II expression and a pre-existing IFNγ response can predict anti–PD-1 responsiveness. Thus, the benefits of immune checkpoint blockade may be partly attributable to distinct antigen presentation pathways and the antitumor responses induced.Rodig SJ, …, Hodi FS. Sci Transl Med 2018 Jul 18;10:eaar3342.Breaking adenosine-based resistance to checkpoint blockade (from Chen et al. Cancer Discovery 2018)Chen et al. find that blocking PD-1/PD-L1 interactions in solid tumors can induce resistance through upregulation of CD38 on tumor cells, resulting in suppression of T cells. Combining CD38 blockade with anti–PD-L1 improves antitumor responses. Calcinotto et al. find that the mechanism for resistance to androgen-deprivation therapy in prostate cancer relies on the IL23 produced by MDSCs, which sustains androgen receptor signaling in prostate tumor cells. Inactivation of IL23 restores sensitivity to deprivation therapy in mice.Chen L, …, Gibbons DL. Cancer Discov 2018 Jul 16. DOI: 10.1158/2159-8290.CD-17-1033.Calcinotto A, …, Alimonti A. Nature 2018 Jun 27;559:363–9.Cis interference (from Chaudhri et al. Cancer Immunol Res 2018)Interaction of PD-1 on T cells and PD-L1 on APCs or tumor cells inhibits T-cell responses. Zhao et al. find that PD-1 is co-expressed with PD-L1 on tumor cells and tumor-infiltrating APCs, which allows for binding in cis. This interaction blocks T-cell PD-1 binding in trans and prevents inhibitory signaling. Chaudhri et al. show that B7-1 also binds PD-L1, but only in cis. This B7-1/PD-L1 cis interaction can competitively block PD-1 binding. Thus, competition for binding to PD-L1 in cis and in trans needs to be considered when developing immunotherapies.Zhao Y, …, Hui E. Cell Reports 2018; 24:379–90.Chaudhri A, …, Freeman G. Cancer Immunol Res 2018 Jun 5; DOI: 10.1158/2326-6066.CIR-17-0316.

Abstract CT077: Nivolumab (nivo) + ipilimumab (ipi) vs platinum-doublet chemotherapy (PT-DC) as first-line (1L) treatment (tx) for advanced non-small cell lung cancer (NSCLC): initial results from CheckMate 227

Abstract Background: Nivo + ipi showed promising clinical activity and tolerability as 1L tx for advanced NSCLC in a phase 1 study. Tumor mutation burden (TMB) has emerged as an important biomarker for benefit of immune checkpoint blockade in lung cancer. CheckMate 227 (NCT02477826) is a large, open-label, phase 3 study of 1L nivo + ipi, nivo, or nivo + PT-DC vs PT-DC in advanced NSCLC. A preplanned co-primary endpoint was based on TMB to evaluate progression-free survival (PFS) of nivo + ipi vs PT-DC. This is the first phase 3 study to evaluate TMB as a predictive biomarker for immunotherapy as a co-primary endpoint. We report initial results from Part 1 of the study. Methods: Patients (pts; N=1739) with chemotherapy-naive, histologically confirmed stage IV or recurrent NSCLC, ECOG PS 0−1, and no known sensitizing EGFR/ALK mutations were enrolled in 2 groups: PD-L1 ≥1% or PD-L1 &amp;lt;1%. Pts with ≥1% tumor PD-L1 expression were randomized 1:1:1 to nivo + ipi, nivo, or PT-DC; pts with &amp;lt;1% tumor PD-L1 expression were randomized 1:1:1 to nivo + ipi, nivo + PT-DC, or PT-DC. Tx regimens were nivo 3 mg/kg Q2W + ipi 1 mg/kg Q6W, nivo 240 mg Q2W, or nivo 360 mg Q3W with PT-DC. Pts were treated until disease progression or unacceptable toxicity, up to 2 y. TMB was determined from tumor tissue using the validated FoundationOne CDx™ assay (Foundation Medicine, Inc.). Co-primary endpoints were overall survival (OS) for nivo + ipi vs PT-DC in pts with PD-L1-selected tumors and PFS (blinded independent central review) for nivo + ipi vs PT-DC in pts with TMB ≥10 mutations (mut)/Mb. Results: Baseline characteristics were similar in pts with evaluable TMB and all randomized pts and were balanced between nivo + ipi and PT-DC arms. Minimum follow-up was 11.5 mo. PFS was significantly longer with nivo + ipi vs PT-DC in pts with TMB ≥10 mut/Mb (HR=0.58 [97.5% CI: 0.41, 0.81]; P=0.0002); results were broadly consistent across subgroups, including PD-L1 and histology. The HR for PFS was 1.07 (95% CI: 0.84, 1.35) in pts with TMB &amp;lt;10 mut/Mb. In all randomized pts, the HR for PFS with nivo + ipi vs PT-DC was 0.83 (95% CI: 0.72, 0.96). Objective response rate was 45.3% with nivo + ipi vs 26.9% with PT-DC in pts with TMB ≥10 mut/Mb; median duration of response (95% CI) was not reached (12.2 mo, NR) vs 5.4 (4.2, 6.9) mo, respectively. In treated pts, grade 3-4 treatment-related adverse events rates were 31.3% and 36.1% with nivo + ipi and PT-DC, respectively. Part 1 continues for final OS in the PD-L1-selected co-primary population. Conclusions: CheckMate 227 met its co-primary endpoint of significantly prolonged PFS with 1L nivo + ipi vs PT-DC in NSCLC with TMB ≥10 mut/Mb regardless of PD-L1 expression. Safety was consistent with previous reports of 1L nivo + ipi for this dose regimen. These results validate the benefit of dual immune checkpoint blockade and the role of TMB as a biomarker to select pts in 1L NSCLC. Citation Format: Matthew D. Hellmann, Tudor Eliade Ciuleanu, Adam Pluzanski, Jong Seok Lee, Gregory Otterson, Clarisse Audigier-Valette, Elisa Minenza, Helena Linardou, Sjaak Burgers, Pamela Salman, Hossein Borghaei, Suresh S. Ramalingam, Julie Brahmer, Martin Reck, Kenneth J. O'Byrne, William J. Geese, George Green, Han Chang, Joseph D. Szustakowski, Prabhu Bhagavatheeswaran, Diane Healey, Yali Fu, Faith Nathan, Luis Paz-Ares. Nivolumab (nivo) + ipilimumab (ipi) vs platinum-doublet chemotherapy (PT-DC) as first-line (1L) treatment (tx) for advanced non-small cell lung cancer (NSCLC): initial results from CheckMate 227 [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 CT077.

Abstract 4940: Nonredundant roles for immune checkpoint blockade and agonistic CD40 in mediating T-cell responses in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDA) is a highly aggressive cancer that is resistant to most treatments, with a five-year survival rate of ~10%. Immune checkpoint blockade (ICB) has had dramatic effects in many tumor histologies, but is ineffective in PDA. CD40 lies upstream of the immune checkpoints in the T-cell activation pathway, presenting a unique opportunity to intercede with T-cell activation independently of ICB. We hypothesized that administering agonistic CD40 antibody would prime effector T-cell populations, synergizing with ICB to provide therapeutic benefit in PDA. We administered agonistic CD40 monoclonal antibody (clone FGK45, anti-CD40) combined with anti-PD1 and anti-CTLA4 monoclonal antibodies (ICB) to mice bearing subcutaneous PDA tumors established using syngeneic tumor cell lines derived from the KrasG12D+/-;Trp53R172H+/-;Pdx-1 Cre (KPC) genetically engineered mouse model of PDA. While tumor regressions were rare in mice treated with ICB or anti-CD40 alone (1/7 mice in each group), 100% of mice treated with ICB + anti-CD40 experienced tumor regressions (7/7 mice). Cell depletion experiments showed early tumor regressions depended primarily on CD4 T cells, although both CD4 and CD8 T cells were required for long-term remission. 50% of mice (4/8) treated with ICB + anti-CD40 remained tumor-free (median survival 112 days) and 3/4 mice resisted tumor rechallenge, indicative of a long-lived memory T-cell response against PDA. Treatment with ICB + anti-CD40, but neither alone, increased the total intratumoral CD3+ T-cell population 3.8-fold (p&amp;lt;0.01), with increases in both the CD4+ and CD8+ T-cell compartments (6.7-fold and 3.3-fold, respectively, p &amp;lt;0.016). CD40 stimulation, but not ICB, modulated the CD4 compartment in the TME, increasing the proportion of CD43+CD11a+ antigen-specific CD4 T helpers (41 - 43% v. 10%, +/-ICB v. control, p &amp;lt;0.03) and reducing FoxP3+ CD4+ T regulatory cells (Tregs) 2.7 to 3.7-fold (+/- ICB, p &amp;lt; 0.0001). This resulted in an increased ratio of CD8 T effector cells to Tregs (7.5 to 10.7 CD8/Treg, anti-CD40 +/-ICB, p&amp;lt;0.01) specifically after treatment with anti-CD40, regardless of ICB addition. ICB alone increased the proportion of proliferating CD8 T cells in the tumor draining lymph node that were ‘"reinvigorated" Eomes+Tbet-Ki67+ (17-19% +/- CD40 v. 8% control, p &amp;lt;0.01), but was unable to increase the same CD8 T-cell population in the tumor. However, the addition of CD40 to ICB reduced the frequency of PD1+ CD8 T effectors in the tumor (25% v. 52% control, p &amp;lt; 0.05), suggesting a tumor-specific benefit of ICB on the exhausted T-cell compartment. These studies reveal the nonredundant roles that agonistic CD40 and ICB play in generating a robust T-cell response against PDA, and highlight the clinical potential of combining CD40 activation with ICB as a novel therapeutic approach in ICB-resistant tumors. Citation Format: Alexander H. Morrison, Katelyn T. Byrne, Robert H. Vonderheide. Nonredundant roles for immune checkpoint blockade and agonistic CD40 in mediating T-cell responses in pancreatic ductal adenocarcinoma [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 4940.

Non-tumor cell IDO1 predominantly contributes to enzyme activity and response to CTLA-4/PD-L1 inhibition in mouse glioblastoma

Glioblastoma (GBM) is the most common malignant brain tumor in adults with a median survival of 14.6months. A contributing factor to GBM aggressiveness is the intratumoral expression of the potently immunosuppressive enzyme, indoleamine 2,3 dioxygenase 1 (IDO1). The enzymatic activity of IDO1 is associated with the conversion of tryptophan into downstream kynurenine (Kyn), which has previously been hypothesized to contribute toward the suppression of tumor immunity. Utilizing the syngeneic, immunocompetent, intracranial GL261 cell GBM model, we previously demonstrated that tumor cell, but not non-tumor cell IDO1, suppresses T cell-mediated brain tumor regression in mice. Paradoxically, we also showed that the survival advantage mediated by immune checkpoint blockade is abrogated by non-tumor cell IDO1 deficiency. Here, we have built on our past observations and confirm the maladaptive role of tumor cell IDO1 in a novel mouse GBM model. We also demonstrate that, non-tumor cells, rather than mouse GBM cells, are the dominant contributor to IDO1-mediated enzyme activity. Finally, we show the novel associations between maximally-effective immune-checkpoint blockade-mediated survival, non-tumor cell IDO1 and intra-GBM Kyn levels. These data suggest for the first time that, GBM cell-mediated immunosuppression is IDO1 enzyme independent, while the survival benefits of immune checkpoint blockade require non-tumor cell IDO1 enzyme activity. Given that current clinical inhibitors vary in their mechanism of action, in terms of targeting IDO1 enzyme activity versus enzyme-independent effects, this work suggests that choosing an appropriate IDO1 pharmacologic will maximize the effectiveness of future immune checkpoint blockade approaches.

Combining chemotherapy and immune checkpoint blockade.

Immune checkpoint blockade results in durable responses in a subset of patients with advanced urologic tumors. However, the majority of patients do not respond to single agent therapy raising the hypothesis that combination regimens may extend the benefits of immune checkpoint blockade to an even broader patient population. Preclinical data support combining immunotherapy with various classes of anticancer agents including standard cytotoxic chemotherapy. Herein, we provide an overview of the preclinical and clinical efforts to combine chemotherapy with immunotherapeutic approaches focusing on immune checkpoint blockade. Immune checkpoint blockade has achieved regulatory approval for the treatment of renal cancer and urothelial cancer. Preclinical and clinical studies have begun to explore these immunotherapeutic approaches in combination with cytotoxic chemotherapy though clinical proof-of-concept has not yet been fully established. There are several arguments in favor, and against, combining immunotherapeutic approaches with standard cytotoxic chemotherapy. Ultimately, clinical trials carefully considering the particular drugs, doses, and schedules will be needed to determine if such approaches become part of our standard treatment armamentarium.