anti-CTLA4 Antibody Research Articles

TS01.02 Novel Anti–CTLA-4 Antibody Quavonlimab Plus Pembrolizumab as First-Line Therapy for NSCLC: Extended Follow-up From a Phase 1 Study

TS01.02 Novel Anti–CTLA-4 Antibody Quavonlimab Plus Pembrolizumab as First-Line Therapy for NSCLC: Extended Follow-up From a Phase 1 Study

A phase 1 study of NY-ESO-1 vaccine + anti-CTLA4 antibody Ipilimumab (IPI) in patients with unresectable or metastatic melanoma

ABSTRACT Ipilimumab (IPI) can enhance immunity to the cancer-testis antigen NY-ESO-1. A clinical trial was designed to assess safety, immunogenicity, and clinical responses with IPI + NY-ESO-1 vaccines and effects on the tumor microenvironment (TME). Patients with measurable NY-ESO-1+ tumors were enrolled among three arms: A) IPI + NY-ESO-1 protein + poly-ICLC (pICLC) + incomplete Freund’s adjuvant (IFA); B) IPI + NY-ESO-1 overlapping long peptides (OLP) + pICLC + IFA; and C) IPI + NY-ESO-1 OLP + pICLC. Clinical responses were assessed by irRC. T cell and Ab responses were assessed by ex vivo IFN-gamma ELIspot and ELISA. Tumor biopsies pre- and post-treatment were evaluated for immune infiltrates. Eight patients were enrolled: 5, 2, and 1 in Arms A-C, respectively. There were no DLTs. Best clinical responses were SD (4) and PD (4). T-cell and antibody (Ab) responses to NY-ESO-1 were detected in 6 (75%) and 7 (88%) patients, respectively, and were associated with SD. The breadth of Ab responses was greater for patients with SD than PD (p = .036). For five patients evaluable in the TME, treatment was associated with increases in proliferating (Ki67+) CD8+ T cells and decreases in RORγt+ CD4+ T cells. T cell densities increased for those with SD. Detection of T cell responses to NY-ESO-1 ex vivo in most patients suggests that IPI may have enhanced those responses. Proliferating intratumoral CD8+ T cells increased after vaccination plus IPI suggesting favorable impact of IPI plus NY-ESO-1 vaccines on the TME. List of Abbreviations: Ab = antibody; CTCAE = NCI Common Terminology Criteria for Adverse Events; DHFR/DHRP = dihydrofolate reductase; DLT = Dose-limiting toxicity; ELISA = enzyme-linked immunosorbent assay; IFA = incomplete Freund’s adjuvant (Montanide ISA-51); IFNγ = Interferon gamma; IPI = Ipilimumab; irRC = immune-related response criteria; mIFH = multispectral immunofluorescence histology; OLP = NY-ESO-1 overlapping long peptides; PBMC = peripheral blood mononuclear cells; PD = Progressive disease; pICLC = poly-ICLC (Hiltonol), a TLR3/MDA-5 agonist; RLT = Regimen-limiting Toxicity; ROI = regions of interest; RT = room temperature; SAE = serious adverse event; SD = stable disease; TEAE = treatment-emergent adverse events; TLR = toll-like receptor; TME = tumor microenvironment; TRAE = treatment-related adverse events.

Characteristics and risk factors for microbial infections during cancer immune checkpoint therapy.

ABSTRACTThe risk of infection in patients receiving immune checkpoint inhibitor (ICI) therapy is not well understood. Immune‐related adverse events requiring immunosuppressive therapy may impact infection risk. ICIs may induce an exaggerated immune response to latent infection. We assessed the incidence and risk factors for infections during cancer ICI therapy. A retrospective chart review of solid tumor patients treated with ICIs was conducted. Infectious episodes were defined as those where a microbial organism was cultured or identified through polymerase chain reaction. Infections which occurred during and up to 1 year following ICI therapy were considered “post‐ICI” infections. Of 327 patients, 47% had melanoma and 36% had non‐small cell lung cancer. The majority (77%) received single agent anti‐PD(L)1 antibody, 14% received combination anti‐PD(L)1 and anti‐CTLA4 antibody, and 9% single agent anti‐CTLA4 antibody. Infections occurred in 89 (27%) in the post‐ICI compared with 111 (34%) patients in the pre‐ICI period (p = 0.57). The most common types of infection were respiratory, genitourinary, and cutaneous infections. On multivariate analysis, only age over 67 years significantly predicted for development of infection on ICI (HR 1.73, p = 0.04). We did not find receipt of corticosteroids, combination ICI therapy, diabetes, or gender to significantly impact on infection risk. The rate of microbial infections among solid tumor patients receiving ICI therapy was 27%, comparable to the infection rate of 34% in the same cohort of patients in the period pre‐ICI therapy. Age over 67 years was significantly associated with infection post‐ICI.

Co-inhibitory Receptor Signaling in T-Cell-Mediated Autoimmune Glomerulonephritis.

Autoimmune glomerulonephritis occurs as a consequence of autoantibodies and T-cell effector functions that target autoantigens. Co-signaling through cell surface receptors profoundly influences the optimal activation of T cells. The scope of this review is signaling mechanisms and the functional roles of representative T-cell co-inhibitory receptors in the regulation of autoimmune glomerulonephritis, along with current therapeutic challenges mainly on preclinical trials. Co-inhibitory receptors utilize both shared and unique signaling pathway, suggesting specialized functions that provide the rationale behind therapies for autoimmune glomerulonephritis by targeting these inhibitory receptors. These receptors largely suppress Th1 immunity, modify Th17 and Th2 immune response, and enhance Treg function. Anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA4) immunoglobulin (Ig), which is able to block both activating CD28 and inhibitory CTLA4 signaling, has been shown in preclinical and clinical investigations to have effects on glomerular disease. Other inhibitory receptors for treating glomerulonephritis have not been clinically tested, and efficacy of manipulating these pathways requires further preclinical investigation. While immune checkpoint inhibition using anti-CTLA4 antibodies and anti-programmed cell death 1 (PD-1)/PD-L1 antibodies has been approved for the treatment of several cancers, blockade of CTLA4 and PD-1/PD-L1 is associated with adverse effects that resemble autoimmune disorders, including systemic vasculitis. A renal autoimmune vasculitis model features an initial Th17 dominancy followed later by a Th1-dominant outcome and Treg cells that attenuate autoreactive T-cell function. Toward the development of effective therapies for T-cell-mediated autoimmune glomerulonephritis, it would be preferable to pay attention to the impact of the inhibitory pathways in immunological renal disease settings.

Infectious complications in patients treated with immune checkpoint inhibitors.

Immune checkpoint inhibitor (ICI) antibodies constitute a new generation of cancer treatments, associated with immune-related adverse events (irAEs). A previous retrospective study of patients with metastatic melanoma (treated mostly with anti-CTLA4 antibodies) reported a serious infection rate of 7.3%. The main risk factors were corticoids and infliximab use. We sought to describe infections and risk factors among patients receiving anti-PD-1/PD-L1 ICIs. We reviewed 200 medical records sampled randomly from a French prospective registry, which collates patients treated with anti-PD-1/PD-L1 ICIs. We recorded demographic data, the occurrence of irAEs, immunosuppressant use, and the outcome. Thirty-six patients (18%) experienced an infection by a median (interquartile range) of 47 (19.2-132) days after initiation of the ICI. Twenty-one patients (58.3%) had a lung infection, seven (19.4%) had a skin infection, seven (19.4%) had a urinary tract infection, and all of them received antibiotics. The infection was generally mild, and the patients were treated as outpatient. There were no infection-related deathsand no opportunistic infection. Sixty percent of the patients were being treated for metastatic melanoma and 35.5% for non-small cell lung cancer, and 106 irAEs (mostly grade II) were reported. Forty-seven patients received steroids for cancer symptoms or irAEs, and five received immunosuppressants during the immunotherapy. We did not observe any association between corticosteroid or immunosuppressant use and the occurrence of an infection. The infection rate in patients treated with an anti-PD-1/PD-L1 ICI was 18%, without any severe or opportunistic infection. The occurrence of an infection was not associated with corticosteroid or immunosuppressant use.

Multimodal Treatment of Advanced Mucosal Melanoma in the Era of Modern Immunotherapy

Simple SummaryImmunotherapy revolutionized the treatment of cutaneous melanoma and greatly improved treatment outcomes in this group of patients. Mucosal melanoma is a rare disease, biologically distinct from the cutaneous subtype. There is little real-world data on immunotherapy efficacy in mucosal melanoma. Therefore, we aimed to analyze and describe experiences in mucosal melanoma treatment in five high volume oncology centers in Europe. Furthermore, we evaluated if concomitant radiotherapy may improve the outcomes of these patients. We conclude that immunotherapy with anti-PD1 antibodies is a safe and effective treatment of mucosal melanoma. Concomitant radiotherapy may be beneficial in a selected subgroup of patients with advanced mucosal melanoma.Mucosal melanoma is a rare disease epidemiologically and molecularly distinct from cutaneous melanoma developing from melanocytes located in mucosal membranes. Little is known about its therapy. In this paper, we aimed to evaluate the results of immunotherapy and radiotherapy in a group of patients with advanced mucosal melanoma, based on the experience of five high-volume centers in Poland and Italy. There were 82 patients (53 female, 29 male) included in this retrospective study. The median age in this group was 67.5 (IQR: 57.25–75.75). All patients received anti-PD1 or anti-CTLA4 antibodies in the first or second line of treatment. Twenty-three patients received radiotherapy during anti-PD1 treatment. In the first-line treatment, the median progression-free survival (PFS) reached six months in the anti-PD1 group, which was statistically better than 3.1 months in the other modalities group (p = 0.004). The median overall survival (OS) was 16.3 months (CI: 12.1–22.3) in the whole cohort. Patients who received radiotherapy (RT) during the anti-PD1 treatment had a median PFS of 8.9 months (CI: 7.4–NA), whereas patients treated with single-modality anti-PD1 therapy had a median PFS of 4.2 months (CI: 3.0–7.8); this difference was statistically significant (p = 0.047). Anti-PD1 antibodies are an effective treatment option in advanced mucosal melanoma (MM). The addition of RT may have been beneficial in the selected subgroup of mucosal melanoma patients.

A Genomic Approach to Integration of T Category and the Tumor Immune Microenvironment As Part of A Decision Algorithm for Radiation in Prostate Cancer

The nature of the tumor immune microenvironment (TIME) has been shown to have prognostic significance and implications for therapeutic response in many different cancers. Emerging data suggests that radiation may alter the TIME by promoting accumulation of immunosuppressive regulatory T-cells (Treg). Radiation is a mainstay of treatment for prostate cancer (PCa), but the importance of TIME composition with respect to radiation response in PCa has not been fully elucidated. Here, we leverage clinical and genomic data from The Cancer Genome Atlas (TCGA) to further characterize the TIME in a cohort of irradiated T2-T3 PCa patients, and assess relationships between stage, TIME composition, and recurrence free survival (RFS) in the setting of radiation therapy. Tumors treated with radiation were stratified by T2 vs. T3 disease, as well as “High” or “Low” values for measurement of T-regulatory (Treg) cell-specific markers, calculated relative to the mean values of 490 tissue samples. Normalized RNA Seq by expectation maximization (RSEM) values from the TCGA were collected along with expression data for Treg specific markers (CD25, FOXP3, and CTLA4). Clinical data was obtained from the Broad Institute’s Firebrowse tool. RFS was defined as length of time from end of treatment to biochemical recurrence and/or locoregional recurrence and was assessed using Kaplan-Meier estimates. Survival curves were compared using the log-rank test. 490 PCa specimens were retrieved from the TCGA Pan-Cancer Atlas. Of these, 106 tumors were treated with radiation. Patients with T3 disease (n = 67) on initial pathologic diagnosis and high intratumoral co-expression of CD25, FOXP3, and CTLA4 treated with radiation demonstrated significantly decreased estimated 8-year RFS compared to those patients with T3 disease lacking high co-expression of all three markers (p = 0.0084). There was no significant difference in estimated 8-year RFS after radiation in T2 patients (n = 39) with high co-expression of all Treg specific markers compared to those lacking high co-expression of these markers (p = 0.40). Various studies have attempted to decipher the interplay of radiation and Treg cells, the majority having been conducted on mouse models. Our analysis of human specimens revealed that radiation in PCa with extracapsular extension (T3 disease) and Treg specific marker elevation portends significantly worse prognosis than irradiated T3 disease without Treg specific marker elevations - this relationship was not seen in T2 disease. These results suggest a prognostic benefit from risk stratification of PCa patients by both T category and Treg specific activation markers, and warrant investigation into immune checkpoint inhibitors such as anti-CTLA4 antibody as part of the treatment paradigm in this patient subset to enhance anti-tumor effects by inhibiting Treg activity.

Abstract A26: Humanized mouse model: A model to understand mechanisms of immune non-responsiveness to immune checkpoint inhibitors in melanoma

Abstract Immune checkpoint inhibitor therapy (anti-CTLA4 or anti-PD1 antibodies) is rapidly emerging as a front-line treatment option for many solid tumors. However, only a third of melanoma patients respond to immune checkpoint blockade. Currently available mouse xenograft and transgenic models have many shortcomings and are unable to address the basis of therapy resistance and immune nonresponsiveness that are observed in patients. Thus, there is an urgent need to establish an in vivo model with a human immune microenvironment that can address issues of therapy resistance. Our laboratory has developed a novel humanized mouse melanoma model. Immunodeficient NSG mice were reconstituted with human CD34+ cells and after 8-12 weeks, mice are fully reconstituted with human innate (monocyte/myeloid lineage cells, dendritic cells and NK cells) and adaptive (T and B cells) immune cells. Humanized mice were then challenged with HLA-matched melanoma cells, and the functional ability of human immune cells to restrict tumor growth was monitored. Delayed tumor growth was observed in humanized mice, indicating in vivo sensitization of human immune cells to melanoma. This was confirmed by in vitro demonstration of human lymphocytes from tumor-bearing mice showing enhanced cytokine expression after stimulation with melanoma antigen peptides. In therapy studies, tumor-bearing humanized mice treated with anti-PD-1 showed restricted tumor growth. Anti-PD-1 therapy resulted in enhanced infiltration of T cells that correlated with tumor response. MassCyTOF studies were performed using a panel of immune markers to understand the mechanism of therapy nonresponsiveness in some tumors. Downmodulation of HLA-class I molecules and increased presence of FOXP3+ cells in the tumor region were seen. Our results suggest that humanized mouse melanoma model can be explored further to understand the causes of therapy resistance and immune nonresponsiveness. Citation Format: Rajasekharan Somasundaram, Anastasia Samarkina, Thomas Connelly, Robin Choi, Hedy Choi, Kar Muthumani, Xiaowei Xu, Klaus Kaestner, Meenhard Herlyn. Humanized mouse model: A model to understand mechanisms of immune non-responsiveness to immune checkpoint inhibitors in melanoma [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr A26.

Antitumor efficacy of combined CTLA4/PD-1 blockade without intestinal inflammation is achieved by elimination of FcγR interactions

BackgroundProgrammed cell death protein 1 (PD-1) and CTLA4 combination blockade enhances clinical efficacy in melanoma compared with targeting either checkpoint alone; however, clinical response improvement is coupled with increased risk...

Abstract 4552: Preclinical characterization of BMS-986218, a novel nonfucosylated anti–CTLA-4 antibody designed to enhance antitumor activity

Abstract Background: Blockade of the CTLA-4 pathway with ipilimumab (IPI) as monotherapy or in combination with nivolumab (anti–PD-1) is an effective treatment for a variety of cancers. Antibody-dependent cellular cytotoxicity (ADCC) is a cellular process through which effector immune cells that express an Fc receptor (FcR) recognize and eliminate antibody-bound targets. Anti–CTLA-4 has been shown to mediate the ADCC depletion of tumor-infiltrating regulatory T cells (Tregs), which play an important role in suppressing antitumor immune response in the tumor microenvironment. A version of IPI that is nonfucosylated (NF) in the Fc region (BMS-986218; anti–CTLA-4 NF) was created to increase binding affinity to activating Fcγ receptors (FcγR, CD16) and improve ADCC, thus increasing intratumoral Treg depletion. Methods: Antibody binding to CD16 was studied by surface plasmon resonance. IL-2 release from staphylococcal enterotoxin B (SEB)–stimulated normal human peripheral blood mononuclear cells (PBMCs) and CD4+ T cells was measured; ADCC function was evaluated by IL-2–activated NK cell–induced lysis of CD4+ T cells or activated CD4+Foxp3+ Tregs. Tumor growth was measured in transgenic (human CD16) mice implanted with MC38 tumors. Peripheral pharmacodynamics (PD) was evaluated in cynomolgus (CYNO) macaques after administration of customized adenovirus-5 vector vaccines. Results: Binding affinity to human CD16 was enhanced by BMS-986218 compared with IPI. BMS-986218 induced greater NK cell–mediated lysis of CD4+ T cells (37%) and Tregs (100%) compared with that induced by IPI (7% and 58%, respectively). Anti–CTLA-4 NF was also more effective than IPI in enhancing IL-2 release from SEB-stimulated PBMCs. Addition of an anti-CD16 antibody blocked the IL-2 response, supporting the concept that CD16 was necessary for anti–CTLA-4 NF activity. In mice, anti–CTLA-4 NF produced greater dose-dependent tumor growth inhibition (99%) than anti–CTLA-4 (61%). Tumors from anti–CTLA-4 NF–treated mice compared with anti–CTLA-4–treated mice had a greater decrease in Treg levels (70% vs 30%, respectively) and a larger increase in CD8+ T-cell levels (82% vs 62%, respectively) and no changes in Treg or CD8+ cell levels in the spleen. A more pronounced vaccine-induced T-cell response in anti–CTLA-4 NF–treated vs anti–CTLA-4–treated CYNO macaques was observed over a 3-week period. Conclusions: Nonfucosylation of an anti–CTLA-4 antibody increased binding affinity to CD16, induced depletion of Tregs while increasing T-effector cells in mouse tumors, and enhanced tumor growth inhibition in a dose-dependent manner, thus demonstrating improved ADCC compared with IPI. An ongoing phase 1/2 study is evaluating the safety and antitumor activity of anti–CTLA-4 NF alone and in combination with nivolumab (NCT03110107) in patients with advanced solid cancers. Citation Format: John Engelhardt, Rahima Akter, John Loffredo, Paula So, Natalie Bezman, Karen Price. Preclinical characterization of BMS-986218, a novel nonfucosylated anti–CTLA-4 antibody designed to enhance antitumor activity [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 4552.

Abstract 922: Expanding the therapeutic potential of anti-PD-1 and anti-CTLA-4 therapy with innovative Fc engineering and rationale combinations for the treatment of solid tumors

Abstract Immune checkpoint blockade (ICB) of cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death receptor 1 (PD-1) have shown durable responses in cancer patients. However, responses have been limited to a small subset of patients, and resistance to ICB therapy continues to be a limiting factor to achieving broad and more durable clinical benefit. Considering the emerging hallmarks of response to ICB, we investigated how response to anti-PD-1 and anti-CTLA-4 therapy could be improved through antibody engineering and combination with other therapeutic approaches such as with novel immune checkpoint inhibitors (e.g. TIGIT, LAG-3), adoptive T cell therapy (ACT), cancer vaccines or focal radiation. In preclinical studies, we demonstrated that anti-CTLA-4 antibodies engineered to selectively enhance binding to human FcyRIIIA or mouse FcyRIV, respectively, significantly improve T cell effector function and tumor clearance in preclinical models that are known to have high immunogenicity and responsiveness to ICB single therapy such as MC-38 and CT-26. To identify novel T cell-intrinsic resistance mechanisms to current ICB therapies, we emulated a progressive anti-PD-1 refractory state in primary CD4- and CD8-positive NY-ESO-1 TCR-transduced T cells upon repeat co-culture with an antigen-expressing glioblastoma cell line. In this model, the addition of anti-CTLA-4, anti-LAG-3, or anti-TIGIT enhanced T cell cytotoxicity and killing of tumor target cells. Gene expression signatures associated with the anti-PD-1 refractory state in this system predicted anti-PD-1 response in melanoma patients. Combination therapy with anti-PD-1 was further validated in a PD-1 refractory mouse syngeneic tumor models demonstrating improved tumor control. Finally, to further address resistance mechanisms to ICB therapy, we evaluated the combination potential of anti-PD-1 and Fc-engineered anti-CTLA-4 with tumor targeted therapies in syngeneic tumor models such as B16 melanoma which are resistant to co-blockade of PD-1 and CTLA-4. In these studies, anti-PD-1 and Fc-engineered anti-CTLA-4, promoted significantly improved tumor control when combined together or with CD4 or CD8 ACT, low dose focal radiation (10 Gy), or an antigen-specific heat shock protein-based (HSC70) cancer vaccine as compared to either therapy alone. Our preclinical data suggest that the limited activity of anti-PD-1 can be addressed by combining with a Fc engineered anti-CTLA4 antibody or with select novel ICB. Furthermore, we have demonstrated that PD1-CTLA4 activity could be further improved when combined with conventional focal radiation or other immune-modulating targeted therapies such as ACT or vaccines to significantly enhance tumor antigenicity and overcome resistance to conventional ICB. Citation Format: Antoine J. Tanne, Sylvia Vincent, Benjamin Duckless, Elena Paltrinieri, Simarjot Pabla, Andrew Basinski, Sudesh Pawaria, Vidur Patel, Margaret Wilkens, Bishnu Joshi, Matthew Hancock, Daniel Levey, Thomas Horn, Cailin Joyce, David Savitsky, Cori Gorman, Jennifer Buell, Dhan Chand. Expanding the therapeutic potential of anti-PD-1 and anti-CTLA-4 therapy with innovative Fc engineering and rationale combinations for the treatment of solid tumors [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 922.

Abstract 5734: Gut microbiota predicts response and toxicity with neoadjuvant immunotherapy

Abstract Introduction: Checkpoint blockade immunotherapy has revolutionized melanoma treatment. However, immune related adverse events (irAEs) are frequent, particularly when PD-1 and CTLA-4 blocking antibodies are combined. There is an urgent need for biomarkers to predict response as well as toxicity. The intestinal microbiome influences immune processes throughout the body and is therefore hypothesised to influence both immunotherapy response and well as development of irAEs. Methods: This study utilized sequencing to profile the fecal microbiome from Stage III melanoma patients (n= 38) treated with combination anti-PD1 and anti-CTLA4 antibodies in the neoadjuvant setting (OpacinNeo Trial; NCT02977052) at Melanoma Institute Australia. Absolute bacterial loads were determined with qPCR. Global microbial gene abundance was determined through metagenomic sequencing, allowing analysis of microbial metabolic capcity, and actual short chain fatty acid output (butyrate, acetate, propionate) was assessed by NMR. Matched PBMC were profiled in detail using mass cytometry and immune populations were correlated with microbial metrics. We tested the ability of machine learning to predict therapeutic response and irAEs from microbial data. Results: Patients who failed to respond (n=6), and those who developed severe (G3-G5) irAEs (n=11), had low microbial diversity before treatment (p=0.0234 and p=0.0226 respectively). Four of the six non-responders in this cohort failed to complete treatment and received immunosuppression before pathologic assessment of response, because of the development of severe irAEs. Thus, non-response may, in fact, have been a consequence of irAE development in those cases. High pre-treatment loads of Ruminococcaceae and methanogenic archaea, and greater relative abundance of butyrate production pathways, were significantly associated with response and protection from irAEs. Patients who had low bacterial diversity had increased proportions of effector and memory CD4 and CD8 T cells in the blood and increased numbers of circulating MAIT, NK and gdT cells prior to immunotherapy. Importantly, microbial taxa were predictive of patients who subsequently failed to respond to therapy while also developing severe irAEs with overall accuracy of 92.1%. Conclusions: A gut ecosystem enriched with beneficial microbial functions including production of butyrate is associated with protection from irAEs with neoadjuvant combination immunotherapy. The findings allow prediction of outcomes with combination immunotherapy and will inform development of therapeutic microbial interventions. Citation Format: Marcel Batten, Erin Shanahan, Rebecca Simpson, Mark Read, Ines P. Silva, Alexandra Angelatos, Jian Tan, Chandra Adhikari, Alexander M. Menzies, Robyn P. Saw, Laurence Macia, Maria Gonzalez, Kerwin Shannon, Rebecca Velickovic, Irene L. Reijers, Christian U. Blank, James S. Wilmott, Andrew J. Holmes, Richard A. Scolyer, Georgina V. Long. Gut microbiota predicts response and toxicity with neoadjuvant immunotherapy [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 5734.

Abstract 2228: PD1/CTLA4 humanized mice - A great model for pre-clinical toxicology and efficacy evaluation of macromolecular drugs

Abstract Immune checkpoint antibodies have conferred huge cancer immunotherapeutic effect (CITE). Besides, severe immunotherapy related adverse events (irAE) occurred in combination therapy such as anti-PD1 combines with anti-CTLA4 antibodies greatly limit the development of cancer therapy. Animal models which can recapitulate both clinical irAE and CITE will be benefit for developing safer immune-checkpoint-targeting reagents. However, no animal models were found can be used for preclinical safety evaluation of drugs up to now. Given this fact, PD1/CTLA4 double-humanized mice models were established in both BALB/c (BALB/c-hPD1/hCTLA4) and C57BL/6 (B6-hPD1/hCTLA4) background, which by replacing the mouse extracellular domain of CTLA4 and PD1 with human segments while retaining mouse intact intracellular part, respectively. Our data showed that strong CITE against anti-hCTLA4 treatment observed in models from both BALB/c and B6 background. Apparent inhibition of tumor growth also emerged on subcutaneously engrafted CT26 tumor in BALB/c-hPD1/hCTLA4 mice by anti-PD1/CTLA4 bispecific antibody treatment. Meanwhile, severe irAEs which have been observed in clinical patients, such as joint swelling, skin inflammation, heart damage and infiltration of inflammatory cells in different tissues and organs could be reproduced in BALB/c-hPD1/hCTLA4 mice. Consistent with previous reports, we could not observe similar irAEs under drugs treatment at the same dose in C57BL/6-hPD1/hCTLA4 mice. Our data indicated that adult BALB/c-hPD1/hCTLA4 mice, but not C57BL/6-hPD1/hCTLA4 mice, were more sensitive to irAEs. Taken together, adult PD1/CTLA4 humanized mice in BALB/c background can not only be used to screen humanized antibodies, but also have tremendous values for preclinical safety evaluation. Citation Format: Cunxiang Ju, Mingkun Zhang, Rui Mao, Ma Xiuying, Jin Tang, Shuai Li, Jingjing Wang, Hongyan Sun, Jing Zhao, Xiang Gao. PD1/CTLA4 humanized mice - A great model for pre-clinical toxicology and efficacy evaluation of macromolecular drugs [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 2228.

Abstract 5602: BT-001, an oncolytic vaccinia virus armed with a Treg-depletion-optimized recombinant human anti-CTLA4 antibody and GM-CSF to target the tumor microenvironment

Abstract Oncolytic virotherapy is a clinically validated class of immune modulatory drugs with activity in solid cancer. The mode of action of armed oncolytic Vaccinia viruses (oVV) includes cell death induction following selective replication in tumor cells, local inflammation and priming of adaptive immune responses, and intra-tumoral delivery of therapeutic modalities e.g. antibodies, cytokines, enzymes and engineered receptor ligands. BioInvent and Transgene are collaborating in the development of a next generation armed oncolytic viruses, bringing respectively their n-CoDeR F.I.R.S.T antibody (mAb) discovery and Invir.IO oVV platforms. The first product, named BT-001, consists of the Copenhagen oVV strain deleted in J2R and I4L viral genes allowing restricted replication in proliferating cells, and the human IgG1 4-E03 recognizing human CTLA4. 4-E03 shows improved Treg-depleting activity compared with ipilimumab. BT-001 also encodes GM-CSF, the cytokine expressed in clinically advanced products like T-Vec (Imlygic) or Pexa-Vec. A surrogate mAb with similar pronounced Treg-depleting properties to 4-E03 was vectorized into the same oVV (mBT-1) allowing for functional and mechanistic in vivo studies. Since virus replication and expression of recombinant transgenes are tightly linked, the armed oVV is an interesting design for intra-tumoral delivery of therapeutic proteins exhibiting toxicological limitation (e.g. anti-CTLA4) and/or pharmacokinetic issues (e.g. GM-CSF). Oncoviral tumor-localized delivery of anti-CTLA4 may also allow better tolerated and more effective combination therapy with approved antibodies targeting the PD-1/PDL1 axis. Our studies demonstrate that 4-E03 and GM-CSF were expressed at high level as functional molecules after infection by BT-001 of several human tumoral cell lines in vitro. Moreover, following intratumoral administration in immune competent and immune deficient mice transplanted with mouse or human tumors, transgene expression was sustained at levels associated with receptor saturation for days to weeks. In contrast, and supporting the tumor-selective nature of oVV, blood concentrations of anti-CTLA4 mAb were lower compared to those observed following I.V. administration of therapeutic doses (3 mg/kg) of mAb. The in vivo anti-tumor activity of mBT-1 was assessed in multiple syngeneic mouse tumor models including CT26, EMT6, A20, and C38. mBT-1 conferred cures in the majority of challenged mice irrespective of tumor origin. The excellent anti-tumoral profile depends on anti-CTLA4 expression and could be boosted by co-administration of anti-PD-1 mAb. A clinical batch of BT-001 has been produced and toxicological evaluation is ongoing. Transgene and BioInvent are preparing CTA and IND filings for a multicentre clinical trial targeting injectable superficial tumors. Citation Format: Jean-Baptiste Marchand, Monika Semmrich, Laetitia Fend, Matilda Rehn, Nathalie Silvestre, Ingrid Teige, Johann Foloppe, Linda Mårtensson, Eric Quéméneur, Björn Frendeus. BT-001, an oncolytic vaccinia virus armed with a Treg-depletion-optimized recombinant human anti-CTLA4 antibody and GM-CSF to target the tumor microenvironment [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 5602.

62. PRESENCE OF EXTRACRANIAL TUMORS INFLUENCES RESPONSE TO IMMUNE CHECKPOINT INHIBITORS IN A PRE-CLINICAL MODEL OF MELANOMA BRAIN METASTASIS

Up to 75% of patients with melanoma develop brain metastases. While immune checkpoint inhibitors (ICI) targeting PD-1 and CTLA4 have revolutionized the treatment of metastatic melanoma, responses within the immune-specialized microenvironment of the brain are not well understood and there is a paucity of animal models to investigate the effect of ICI intracranially. We characterized responses to checkpoint inhibitors in a syngeneic mouse model of melanoma brain metastasis with concurrent intracranial and subcutaneous melanoma. D3UV3 cells (obtained from David Fisher’s laboratory) were derived using UVB irradiation from D4M.3A melanoma cell line and implanted into the striatum using stereotactic injection or subcutaneously injected into the flank of C57BL/6 mice. Mice were then treated with anti-PD-1 antibody, anti-CTLA4 antibody, a combination of anti-PD-1 and anti-CTLA4, or isotype controls. While mice with intracranial melanoma alone had no response to monotherapy with anti-PD-1 or anti-CTLA4 antibody (p=1 and 0.1, respectively), and only a slight response to combination therapy (p=0.049), mice with concurrent subcutaneous tumors had significantly improved responses to anti-PD-1, anti-CTLA4 and combination treatment (p=0.002, 0.01 and 0.01 respectively compared to mice with intracranial tumors alone with equivalent treatment). These results demonstrate that the presence of an extracranial tumor influences response to ICI in pre-clinical mouse models of melanoma brain metastasis. We have therefore established a pre-clinical model with concurrent intracranial and extracranial tumors to better recapitulate the clinically observed context of melanoma brain metastases and lead to a better understanding of the setting in which ICI are effective for patients with this devastating complication.

Tumor Genotype Is Shaping Immunophenotype and Responses to Immune Checkpoint Inhibitors in Solid Tumors

A major breakthrough in cancer treatment was ushered in by the development of immune checkpoint blockade therapy such as anti-CTLA4 antibody and anti-PD-1 and anti-programmed cell death-ligand 1 antibodies that are now approved for use in an increasing number of malignancies. Despite the relative success of immune checkpoint inhibitors with certain tumor types, many patients still fail to respond to such therapies, and the field is actively trying to understand the mechanisms of resistance, intrinsic or acquired, to immune checkpoint blockade. Herein, we discuss the roles that somatic genomic mutations in oncogenic pathways play in immune editing, as well as some of the current approaches toward improving response to immunotherapy.

Immuno-related endocrinopathy in patients treated with immune checkpoint inhibitors

Recently immune checkpoint inhibitors amazingly changed the landscape of cancer therapy worldwide. The number of immune checkpoint molecules in clinical practice is constantly increasing. There are some monoclonal antibodies recently registered in the Russian Federation: anti-PD1 antibodies (nivolumab, pembrolizumab), anti-PD-L1 (atezolizumab, durvalumab), anti-CTLA-4 (ipilimumab). Immune-mediated endocrinopathies are some of the most common complications of immunotherapy. According to the results of clinical studies, the incidence of serious endocrine immuno-mediated adverse events with anti-PD1 monoclonal antibodies is low (3.5–8%). The use of anti-CTLA4 antibodies, combined regimens, and the use of immunotherapy after chemoradiotherapy significantly increase the incidence of serious adverse events to 30%. In clinical practice of N.N. Blokhin Cancer Research Center among 245 non-small cell lung cancer and hepatocellular carcinoma patients treated with immunotherapy, 22 (8,9%) developed an immune-mediated endocrinopathy. Most patients developed adverse events of 1–2 degrees, in two patients – 3 degrees, requiring discontinuation of treatment. The aim of this article was to provide useful information and recommendations regarding the management of common immuno-related endocrine adverse events (including hypothyroidism, hyperthyroidism, pituitary, adrenal insufficiency) for clinical oncologists.

Increased serum CCL26 level is a potential biomarker for the effectiveness of anti-PD1 antibodies in patients with advanced melanoma.

Nivolumab plus ipilimumab combined therapy is among the most effective therapies for advanced melanoma. However, this therapy is also associated with a high frequency of immune-related adverse events (irAEs). To avoid such severe irAEs caused by additional administration of anti-CTLA4 antibodies, biomarkers to distinguish responders from non-responders among patients treated with anti-PD1 antibodies are important. The purpose of this study is to evaluate the increased serum levels of CCL11, CCL24, and CCL26 as a predictive biomarker for the efficacy of anti-PD1 antibodies in advanced cutaneous melanoma patients. This study analyzed increased serum levels of CCL11, CCL24, and CCL26 in 46 cases of advanced cutaneous melanoma treated with anti-PD1 antibodies. Serum levels on day 42 were compared to baseline (day 0) and analyzed statistically. Receiver operating characteristic curves were established to evaluate the correlation between serum levels of CCL11, CCL24, and CCL26 and efficacy of anti-PD1 antibodies. Increased serum levels of CCL26 correlated significantly with the efficacy of anti-PD1 antibodies. In contrast, no significant correlations were seen between increased serum levels of CCL11 and CCL24 and efficacy of anti-PD1 antibodies. Increased serum levels of CCL26 may be a useful biomarker for identifying those patients with advanced cutaneous melanoma most likely to benefit from anti-melanoma immunotherapy.

Pickering emulsions with ethiodized oil and nanoparticles for slow release of intratumoral anti-CTLA4 immune checkpoint antibodies

BackgroundIntratumorous immunotherapy for cancer is currently thriving. The aim of such local strategy is to improve the therapeutic index of these treatments, for higher on-target/on-tumor activity and less on-target/off-tumor adverse...

PTPRD/PTPRT mutations as potential positive predictor for response of immune checkpoint inhibitors in non-small cell lung cancer (NSCLC).

e15112 Background: Immune checkpoint inhibitors (ICIs) have demonstrated positive results in non-small cell lung cancer (NSCLC) patients, with durable responses and prolonged overall survival (OS). Nevertheless, the response rate to immunotherapy is still limited. It is necessary to identify clinically useful biomarkers that can distinguish patients who can respond to ICIs. PTPRD/PTPRT are the phosphatases of JAK-STAT signaling, which may be associated with response to ICIs. Here we aimed to demonstrate the association between PTPRD/PTPRT and ICIs. Methods: Genomic and survival data of NSCLC patients administrated with anti–PD-1/PD-L1 or anti–CTLA-4 antibodies (Rizvi2015; Hellmann2018; Rizvi2018 Samstein2019) were retrieved from publicly accessible data. Genomic, survival and mRNA data of 1007 patients with NSCLC was obtained from The Cancer Genome Atlas (TCGA). Association between PTPRD/PTPRT mutation and progression-free survival (PFS) and overall survival (OS) were analyzed. Gene set enrichment analysis (GSEA) was used to determine potentially relevant gene expression signatures between specific subgroups. Results: PTPRD/PTPRT mutations were significantly associated with better PFS in Rizvi2015 cohort (HR = 0.16; 95% CI, 0.02-1.17; P = 0.03), Hellmann2018 cohort (HR, 0.49; 95% CI, 0.26-0.94; P = 0.03) and Rizvi2018 cohort (HR = 0.64; 95% CI, 0.44-0.92; P = 0.01). PTPRD/PTPRT mutation was also significantly associated with better OS in Samstein2019 cohort (HR, 0.66; 95% CI, 0.45-0.97; P = 0.03). In TCGA, no association between PTPRD/PTPRT mutations and OS was observed (P = 0.91), suggesting that PTPRD/PTPRT mutations were not prognostic factor. PTPRD/PTPRT mutations were associated with increased TMB (P < 0.0001). The mRNA expression of STAT1 and CD4 was higher in patients with PTPRD/PTPRT mutant type than PTPRD/PTPRT wild type. Gene Set Enrichment Analysis revealed prominent enrichment of signatures related to inflammatory response, interferon gamma response and antigen processing and presentation in patients with PTPRD/PTPRT mutation. Conclusions: Our results suggest that PTPRD/PTPRT mutation is associated with better PFS and OS in NSCLC patients receiving ICIs by increasing immune-related gene signatures. The role of PTPRD/PTPRT in immunotherapy is needed to be further studied.