bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 454: The landscape of PD-L1 expression in lung cancer harboring driver oncogene mutations except EGFR mutations
Authors: Liu Ningbo , Gong Fuyu
Published: July 2021

Background: Results from previous studies indicated that lung cancer patients harboring EGFR sensitizing mutations may receive unfavorable outcomes from immunotherapy. The present study aims to investigate the landscape of PD-L1 expression in lung cancer harboring driver oncogene mutations except EGFR mutations.

Methods: Tissue samples were subjected to NGS in a College of American Pathologists-certified and Clinical Laboratory Improvement Amendments-accredited lab for driver oncogene mutations and PD-L1 expression.

Results: A total of 22143 lung cancer patients were selected, there are 2120 patients have the driver oncogene mutation, including 1115 (5.04%) ALK positive cases,498 (2.25%) MET positive cases,239(1.08%) RET positive cases,182(0.82%) BRAF positive cases, 72 (0.33%) ROS1 positive cases and 14 (0.03%) NTRK positive cases. Among all the driver oncogene mutation patients, 481 patients have been collected tumor tissue, and the PD-L1 expression have been tested by FDA-approved 22C3 antibodies. Among all the driver oncogene mutation cases assessed PD-L1 expression (n=481), low PD-L1 expression levels (<1%) were 33.3% (n=160), PD-L1 expression level of 1%-49% accounted for 38.3% (n=184), PD-L1 expression level of 50%-79% accounted for 19.5% (n=94), PD-L1 expression level of 80%-89% accounted for 4.2% (n=20), and PD-L1 expression level higher than 90% accounted for 4.8% (n=23).

Conclusion: Our study supported that NSCLC patients harboring sensitizing oncogenic mutations may potentially benefit from anti-PD-1/L1 especially for those with positive indicators of immunotherapy with strong positive PD-L1 expression.

Citation Format: Ningbo Liu, Fuyu Gong. The landscape of PD-L1 expression in lung cancer harboring driver oncogene mutations except EGFR mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 454.
Abstract 471: Reference materials for tumor mutational burden transcriptome profiling
Authors: Butler Matthew G. , Konigshofer Yves , Dickens Jessica , Anekella Bharathi
Published: July 2021

Immune Checkpoint Inhibitor (ICI) therapies continue to revolutionize treatment of advanced malignancies. However, identification of individuals who respond to ICI treatment remains challenging. Along with programmed death ligand 1(PD-L1 aka CD274) expression and microsatellite instability, tumor mutational burden (TMB), defined as the number of nonsynonymous mutations per megabase of genome, has emerged as a promising biomarker for differentiating responders from non-responders, especially in non-small cell lung cancer. Although promising, TMB is not a perfect biomarker for ICI efficacy with some individuals responding conversely to expectations. The imperfection of TMB as a prognostic biomarker may result from it being a proxy measurement of potential neoantigens. Indeed, all mutations that contribute to TMB will not be expressed as neoantigens and not all neoantigens will illicit immune responses. In refining ICI response prediction, tumor abundance of nonsynonymous mutations has aided in neoantigen prediction. In order to begin development of quality reference materials for neoantigen prediction, we have characterized the transcriptomes of four tumor cell lines that were previously used to formulate TMB reference materials. Sequencing libraries were prepared with the TruSeq Stranded Total RNA with Illumina Ribo-Zero Plus rRNA Depletion Kit and Invitrogen Collibri Stranded RNA Library Prep Kit from Illumina with Collibri H/M/R rRNA Depletion Kit. The resultant transcriptome libraries were sequenced on an Illumina NextSeq2000 platform and relative transcript counts were determined. Broad ranges of expression were observed among transcripts containing nonsynonymous mutations in each of the tumor cell lines tested. These datasets will serve as benchmarks for others attempting to combine TMB and tumor abundance in predicting neoantigen potential.

Citation Format: Matthew G. Butler, Yves Konigshofer, Jessica Dickens, Bharathi Anekella. Reference materials for tumor mutational burden transcriptome profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 471.
Abstract 487: Genomic difference of CD4 CD8 double-positive T cells versus conventional CD4 T cells and CD8 T cells in responders undergoing immunotherapy in advanced HCC
Authors: Ting Vox , Wong Carmen Chak-Lui , Kwong Yok Lam , Yau Thomas Chung Cheung
Published: July 2021

Intro: The number of undergoing clinical trials using more than one immune checkpoint inhibitor is rising rapidly. Previously, we have observed CD4 CD8 double-positive T cells (Figure 1) from checkpoint inhibitor responder in advanced HCC patient. To further investigate the genomic difference between CD4 CD8 double-positive T (DP T) cell and conventional CD4, CD8 T cells, we have applied GO, KEGG, and Reactone database to compare.

Material and method: Two responders showed a partial response to PD-1/PD-L1 inhibitor treatment with advanced HCC were included. DP T cells were measured with Carl Zeiss Laser Scanning Microscopy (LSM) 780 (Zeiss) at Faculty Core Facility. Blood samples from responders were stained with an antibody cocktail containing CD3, CD4 and CD8 T cells. To visualise the labelling cells, CD3, CD4 and CD8 surface fluorescence was shown in yellow, violet and green dots respectively. Conventional CD4, CD8 T cells and DP T cells were further sorted using the same staining protocol before extraction. RNA extraction were immediately applied after cell sorting, where CD4 CD8 double-negative T (DN T) cells were also included. All patients were seen at the Department of Medical Oncology, Queen Mary Hospitals. Blood samples were collected after the treatment along with clinical routine blood test.

Results: A total number of 3723 and 4653 genes respectively were differentially expressed in DP T cell versus CD8 T cell and DP T cell versus CD4 T cell in responder 1, whereas a total 11117 differential expressed genes were measured in DP T cell and DN T cell. In responder 2, a total number of 6439 genes were differentially expressed in DP T versus CD8 T cell, while a total number of 316 and 488 differential expressed genes were measured in DP T cell versus CD4 T cell and DP T cell versus DN T cell. GO, KEGG and Reactone database analysis indicated cytokine receptor, cell cytotoxicity and cell activation enrichment in DP T cell compared to conventional CD4 or CD8 T cell.

Citation Format: Vox Ting, Carmen Chak-Lui Wong, Yok Lam Kwong, Thomas Chung Cheung Yau. Genomic difference of CD4 CD8 double-positive T cells versus conventional CD4 T cells and CD8 T cells in responders undergoing immunotherapy in advanced HCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 487.
Abstract 492: CNTN4 is a novel immune checkpoint protein that inhibits proliferation of T cell by interacting with APP
Authors: Cha Mi Young , Jeon Bu-Nam , Jeong Areum , Chung Joo-Yeon , Yang Hyunsuk , Park Kyung Mi , Park Hansoo
Published: July 2021

Contactin 4 (CNTN4, alias BIG-2) is a glycosylphosphatidylinositol (GPI)-anchored neuronal membrane protein that functions as cell adhesion, playing a key role in maintaining the mechanical integrity and signaling properties of the synapse. However, its function and crosstalk with immune cells have not been investigated. Therefore, we tried to find out what role CNTN4 plays in cell adhesion between T cells and antigen-presenting cells (APC). CNTN4 has several binding partners such as the amyloid precursor protein (APP), amyloid-like protein 1 (APLP1), and protein tyrosine phosphatase receptor γ (PTPRγ). In previous papers, the APP was reported to be expressed in T cells. We investigated whether CNTN4 can bind to T cells. The degree of binding of CNTN4 to T cells varied depending on the expression level of APP, and that the binding between these two proteins was in the form of trans-binding. And it was confirmed that the direct binding is achieved through fibronectin 1~2 domain of CNTN4 and KPI (Kunitz protease inhibitor) domain of APP. Furthermore, we investigated whether CNTN4 has any effect on T cell proliferation. T cell proliferation and cytokine secretion assays by using CNTN4 recombinant protein showed that CNTN4 significantly inhibits proliferation and cytokine secretion (IL-2, IFN-γ, TNF-α) of T cells more than PD-L1. Although the expression of CNTN4 in immune cells has not yet been clearly confirmed, the expression of CNTN4 in various carcinomas have confirmed by using western, IHC, and bioinformatic data analysis. In particular, the higher the expression of CNTN4 in tumor tissues of gastric cancer patients, the worse the prognosis is in the survival curve. Our findings suggest that CNTN4 may behave as an immune checkpoint protein similar to other B7 family members. Further investigation of the CNTN4 signaling pathway and its receptors are warranted by our data and may lead to novel therapeutic interventions.

Citation Format: Mi Young Cha, Bu-Nam Jeon, Areum Jeong, Joo-Yeon Chung, Hyunsuk Yang, Kyung Mi Park, Hansoo Park. CNTN4 is a novel immune checkpoint protein that inhibits proliferation of T cell by interacting with APP [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 492.
Abstract 496: Humanized SIRPA and double humanized SIRPA/CD47 B-NDG mouse models are promising tools for anti-SIRPα antibody in vivo efficacy studies
Authors: Hu Yuting , Zhao Lei , Liu Yujie , Hui Li , Yu Zhaoxue (Luke)
Published: July 2021

The CD47/Signal regulatory protein α (SIRPα) axis regulates myeloid cell activation and functions as a crucial myeloid specific immune checkpoint. CD47 is highly expressed on many different types of cancer and upon binding with SIRPα which is abundantly expressed on myeloid cells, transduces inhibitory signals that protect cancer cells from phagocytosis by macrophages and other myeloid cells. Therefore, antibodies that block CD47 and SIRPα binding become encouraging tools for cancer immunotherapy. Biocytogen developed humanized SIRPα B-NDG mice and double humanized SIRPα/CD47 B-NDG mice to provide solid platforms for in vivo efficacy assessment of SIRPα antibodies with or without other immune checkpoint regulators. These mice have a B-NDG mouse background (completely lacking mature T, B and NK cells and were deficient in cytokine signaling) and express human SIRPα protein only or with human CD47 IgV domain and no mouse counterpart expressed. Raji-Luc cells were injected into these mouse models for tumor xenografting and anti-tumor efficacy of anti SIRPα antibody in combination with other antibodies was evaluated. The results showed that the combination of antibodies could effectively control tumor growth in the two mouse models. In addition, B-NDG hSIRPα/hCD47 mice can be used for toxicity assessment for SIRPα or CD47 antibodies. In summary, both B-NDG hSIRPA and B-NDG hSIRPA/hCD47 mice are promising models for preclinical in vivo evaluation of SIRPα antibodies and combined therapy.

Citation Format: Yuting Hu, Lei Zhao, Yujie Liu, Li Hui, Zhaoxue (Luke) Yu. Humanized SIRPA and double humanized SIRPA/CD47 B-NDG mouse models are promising tools for anti-SIRPα antibody in vivo efficacy studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 496.
Abstract 506: A homogenous PBMC ADCC bioassay enables bridging studies with ADCC reporter bioassays in immunotherapy monoclonal antibody development
Authors: Stecha Pete , Garvin Denise , Gilden Julia , Wang Jun , Grailer Jamison , Hartnett Jim , Krishnan Gopal B. , Fan Frank , Cong Mei , Cheng Zhijie Jey
Published: July 2021

Measurement of antibody-dependent cellular cytotoxicity (ADCC) is critical for understanding antibody Fc effector functions during monoclonal antibody development. Classic ADCC assays measure the short-term cytotoxicity of target cells, typically pre-loaded with radioactive or fluorescent dyes, after exposure to antibody bound primary PBMCs or NK cells. These assays are widely used in antibody discovery and characterization during early drug development. However, the reproducibility of these assays is not adequate and they have major issues on biosafety or weak assay sensitivity. Moreover, the use of primary effector cells makes them prone to donor variability, low-throughput and therefore not suitable for implementation in quality-control drug development. We previously developed an ADCC reporter bioassay using engineered ADCC effector cells and demonstrated its specificity and ability to measure ADCC mechanism of action. The assay is prequalified according to ICH guidelines; demonstrates precision, accuracy, linearity, and robustness; and is suitable for product release and stability studies in a quality-controlled environment. In order to enable bridging studies comparing primary PBMC-based ADCC assays and ADCC reporter bioassays, we report the development of an improved PBMC ADCC assay using ADCC-prequalified PBMCs and engineered HiBiT target cells for therapeutic monoclonal antibodies with Fc functions. When target cells expressing HaloTag-HiBiT are incubated with an antibody and PBMCs, the target cells are lysed and release HaloTag-HiBiT, which then bind to LgBiT in the detection reagent to form a functional Nano-luciferase to generate Bioluminescence signal. In addition, it can enable the quantitative measurement of antibody-mediated target cell lysis via specific HaloTag staining using a fluorescent HaloTag ligand by flow cytometry. We demonstrate that the new PBMC ADCC assay is simple, homogenous, highly sensitive, and gives a robust assay window, and is capable of measuring potency of rituximab, cetuximab or trastuzumab. Additionally, it shows antibody potency comparable with the ADCC reporter bioassay in ADCC bridging studies.

Citation Format: Pete Stecha, Denise Garvin, Julia Gilden, Jun Wang, Jamison Grailer, Jim Hartnett, Gopal B. Krishnan, Frank Fan, Mei Cong, Zhijie Jey Cheng. A homogenous PBMC ADCC bioassay enables bridging studies with ADCC reporter bioassays in immunotherapy monoclonal antibody development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 506.
Abstract 526: Novel mechanisms of Neuropilin-1 inhibition result in improved tumor growth inhibition in vivo
Authors: Sethumadhavan Shalini , Zhu Eric , Fulgham Aaron , Abbassi Mandana , Apte Ameya , Liao Tiffany , Merriman Chengfeng , Molloy Katherine , Stein Caitlin , Hanna Amber , Geoghegan James , Prinz Bianka , Dai Hongyue , Hurov Jonathan , Huang Pearl , Blom Daniel
Published: July 2021

Background Cygnal Therapeutics, pioneer in exoneuronal biology, has identified the neuronal protein, Neuropilin-1 (NRP1) as a critical regulator of tumor growth and anti-tumor immunity. NRP1 is a co-receptor that complexes with diverse ligands and their cognate receptors. As such, it plays a role in multiple different biological processes, including axon guidance and angiogenesis. NRP1 contains two CUB domains (a1 and a2) involved in binding the ligand Semaphorin3A (SEMA3A), two Factor V/VIII domains (b1 and b2) involved in VEGF ligand binding and one MAM domain (c domain). While functional antibodies with anti-tumor activity have been generated against the SEMA3A and VEGF binding domains, targeting other domains of NRP1 has not been well-studied. For example, the c-domain of NRP1 has been implicated in the dimerization of NRP1, a prerequisite for functionality. Thus c-domain blockers might inhibit multiple signaling pathways required for tumor growth. Alternatively, binders targeting the interface of two different domains might allow for simultaneous blocking of multiple ligands. We therefore hypothesized that these novel binders to alternative regions of NRP1 such as the b1/b2 interface and the c-domain would have improved and significant anti-tumor activity.

Methods Antibodies with diverse binding characteristics were tested for in vivo anti-tumor activity in multiple syngeneic models, including anti-PD1 non-responsive models. Ability of these of the anti-NRP1 antibodies to elicit an adaptive immune response was evaluated.

Results Novel binders to alternative regions of NRP1 such as domain interfaces and the c-domain resulted in significant tumor growth inhibition in multiple syngeneic models. Additionally, the NRP1 antagonists induced a robust CD8 T cell response, indicating immune-stimulatory role of these antibodies.

Conclusions Cygnal has developed fully human monoclonal antibodies against previously untargeted domains of NRP1. These novel domain binders show remarkable inhibition of tumor growth in multiple syngeneic models and offer a novel means of therapeutic intervention in patients.

Citation Format: Shalini Sethumadhavan, Eric Zhu, Aaron Fulgham, Mandana Abbassi, Ameya Apte, Tiffany Liao, Chengfeng Merriman, Katherine Molloy, Caitlin Stein, Amber Hanna, James Geoghegan, Bianka Prinz, Hongyue Dai, Jonathan Hurov, Pearl Huang, Daniel Blom. Novel mechanisms of Neuropilin-1 inhibition result in improved tumor growth inhibition in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 526.
Abstract 591: Developing an immunofluorescence assay for detecting Rb and phospho-Rb on circulating tumor cells in breast cancer
Authors: Kumar Tanya , Thangavel Hariprasad , Abdulkareem Noor Mazin , Bhat Raksha , Trivedi Meghana V.
Published: July 2021

Endocrine therapies (ET) such as tamoxifen, fulvestrant, and aromatase inhibitors (AIs) are the standard-of-care first-line treatment in majority of estrogen receptor (ER)-positive breast cancers (BC). Recent clinical studies using cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) plus AIs or fulvestrant have shown significant improvement in survival outcomes in patients with ER+ metastatic BC compared to standalone ETs. CDK4/6i exert their action by inhibiting the phosphorylation of retinoblastoma (Rb) protein and consequently inducing cell cycle arrest. However, not all patients respond to this combination therapy and those, who initially respond, eventually develop resistance. Emerging studies suggest that the intrinsic resistance to CDK4/6i could be due to the loss of Rb or its mutations. Therefore, CDK4/6i resistance can be evaluated by measuring expression of total and phospho-Rb and Rb mutations. However, repeated biopsies to evaluate biomarkers in tumors is not feasible in patients. In this research, we aimed to develop an immunofluorescence assay to evaluate the expression of Rb and phospho-Rb using circulating tumor cells (CTCs) which can help predict response and resistance to CDK4/6i. CTCs serve as representative of the tumor bulk in patients and animal models and allow for less-invasive, frequent blood collection and real-time monitoring of treatment response. MCF7 cells treated with vehicle or abemaciclib (500 nM) for 48 hours were spiked into blood from non-tumor bearing mice. The MCF7 cells-spiked blood was processed using ScreenCell® device and the cells were transferred to slides and stained with DAPI, pan-cytokeratin, CD45, estrogen receptor, Rb and phospho-Rb. Tumor cells were defined as pan-cytokeratin-positive, CD45-negative, and nuclear stain-positive cells. Various antibody combinations were examined to increase the sensitivity of the IF assay for individual markers as well as the multiplexed assay. We also developed quantitative assessment approach to detect per-cell intensity of various markers. Treatment with abemaciclib reduced the intensity of phospho/Total Rb from 2.6 +/- 0.6 to 0.8 +/- 0.2 units (p < 0.05, t-test, n=8-9) in the vehicle-treated samples. There was no significant difference in the Rb intensity between the treatment groups. Ongoing studies focus on validation of the assay using preclinical models and clinical samples.

Citation Format: Tanya Kumar, Hariprasad Thangavel, Noor Mazin Abdulkareem, Raksha Bhat, Meghana V. Trivedi. Developing an immunofluorescence assay for detecting Rb and phospho-Rb on circulating tumor cells in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 591.
Abstract 61: Transient "rest" reinvigorates exhausted CAR T cells via epigenetic remodeling
Authors: Weber Evan W. , Mackall Crystal
Published: July 2021

The efficacy of chimeric antigen receptor (CAR) T cell therapy is limited by T cell exhaustion, whereby continuous CAR signaling induces hierarchical loss of effector function. Current methods to mitigate exhaustion in cancer, like immune checkpoint blockade, are not efficacious when combined with CAR T cells. Thus, new therapeutic approaches that target CAR T cell exhaustion are needed. To test the hypothesis that transient cessation of CAR signaling reverses CAR T cell exhaustion, we engineered human T cells to express a drug-regulatable CAR that demonstrates a high degree of antigen-independent tonic signaling and induces hallmarks of exhaustion within 10 days. Using this in vitro model of CAR T cell exhaustion, we discovered that transient CAR downregulation and concomitant cessation of tonic CAR signaling (i.e. “rest”) resulted in profound phenotypic changes, including decreased inhibitory receptor expression and increased memory-associated markers. Upon CAR re-expression and tumor challenge, rested CAR T cells exhibited improved killing, cytokine secretion, and sensitivity to antigen in vitro, as well as enhanced in vivo potency following adoptive transfer into tumor-bearing mice. Similar results were achieved via pharmacologic treatment with the Src kinase inhibitor dasatinib, which potently and reversibly inhibits CAR signaling. RNA- and ATAC-sequencing revealed that rest induces global transcriptional and epigenetic reprogramming, wherein rested CAR T cells closely resembled healthy, non-exhausted CAR T cells. Notably, epigenetic reprogramming and functional reinvigoration in rested cells were dependent on the activity of the histone methyltransferase EZH2, indicating that epigenetic alterations are required for functional reversal of CAR T cell exhaustion. Finally, providing multiple periods of rest in vivo by toggling CAR expression or pulsing with dasatinib reversed hallmarks of CAR T cell exhaustion and lead to more durable anti-tumor responses in xenograft murine models. This work demonstrates that transient cessation of CAR T cell signaling can enhance anti-tumor potency by preventing or reversing exhaustion and challenges the paradigm that exhaustion is an epigenetically fixed state. These results also raise the prospect that targeting proximal TCR/CAR signaling kinases might represent a novel immunotherapeutic strategy for mitigating exhaustion in human CAR T cells.

Citation Format: Evan W. Weber, Crystal Mackall. Transient "rest" reinvigorates exhausted CAR T cells via epigenetic remodeling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 61.
Abstract 716: Telehealth use among multiple myeloma patients during the COVID-19 pandemic
Authors: Sweeney Nathan W. , Goldsmith Scott R. , Ahlstrom Jennifer M.
Published: July 2021

Background:The rapid outbreak of coronavirus disease 2019 (COVID-19) led to delays of non-urgent or routine medical care. Regulatory waivers and policy changes from the Centers of Medicare and Medicaid Services (CMS) for the use of telehealth came as a solution to help fight the outbreak. The aim of this project was to survey the change in the frequency of use of telehealth services among multiple myeloma (MM) patients during the COVID-19 pandemic.

Methods:We utilized HealthTree Cure Hub For Multiple Myeloma (healthree.org) and invited patients with active MM cancer or precursor conditions to participate in an online survey. We analyzed patient responses to doctor visits, the use of telehealth before and after the COVID-19 pandemic, and whether they had sufficient access to their doctor.

Results:1,301 MM pts participated in the survey between April 15, 2020, and June 8, 2020. During the pandemic, 36% of patients indicated visiting with their physician less often than before, 2% visited more often, and 62% had no change in the frequency of their visits. The percent of patients responding “Sometimes” or “Yes” to the use of telehealth are reported here. Before the pandemic, 10% of patients used telehealth, while 62% of patients indicated using telehealth during the pandemic, a 523% increase. When asked if they had sufficient access to their MM healthcare provider 90% of patients indicated that they did, while 10% indicated they did not.

Conclusions:There were significantly fewer in-person visits during the COVID-19 pandemic likely due to the CDC-recommended physical distancing practices. During this time, telehealth use among MM patients dramatically increased compared to telehealth use before the pandemic. It is reasonable to assume that patients indicated having sufficient access to their healthcare provider as a result of patients receiving care through telehealth visits. The authors encourage readers to think more broadly about the benefits of telehealth. Maintaining sufficient access to one healthcare provider addressed in this abstract is only a fraction of the benefits telehealth offers. MM is a rare cancer and as a result, some states have few if any specialists. Maintaining telehealth policy changes made during the pandemic would remove geographical barriers and open access to specialists across the country.

Citation Format: Nathan W. Sweeney, Scott R. Goldsmith, Jennifer M. Ahlstrom. Telehealth use among multiple myeloma patients during the COVID-19 pandemic [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 716.
Abstract 780: Racial disparities in death from cardiovascular disease for patients with prostate cancer: A population-based study
Authors: Nikita Nikita , Banks Joshua , Keith Scott , Yamoah Kosj , Naik Ulhas P. , Kim Felix J. , Shipon David M. , Kelly Wm Kevin , Rebbeck Timothy R. , Yao Grace Lu
Published: July 2021

Introduction: Prostate cancer (PCa) is the most common cancer diagnosis among men in the United States. However, a vast majority of patients with PCa die of causes other than PCa, the most common being cardiovascular disease (CVD). We hypothesize that CVD-related mortality in PCa patients is disproportionately higher among Blacks as compared to Whites.

Methods: We identified patients with PCa from the Surveillance, Epidemiology and End Results (SEER)-Medicare linked files between 1/1/2004 and 12/31/2015. The PCa risk groups were created based on the National Comprehensive Cancer Network criteria: low, intermediate, and high risk. The primary endpoint was CVD-related mortality. The following CVD conditions were included in the CVD-specific mortality: acute myocardial infarction, stroke, congestive heart failure, atrial fibrillation, and ischemic heart disease. A proportional hazards model that considered the competing risks was fitted to address the hypothesis. The model was adjusted for age, year of diagnosis, marital status, income level, SEER-region, state buy-in, radiation, surgery, and education level.

Results: We identified 394,323 patients with PCa. Among these 80% were Whites, 15% were Blacks, and 5% were other races. The median age at diagnosis for Whites, Blacks, and other races was 69, 66, and 70 years, respectively. The incidence of CVD-related mortality was 5.6%, 6.6%, and 5% among Whites, Blacks, and Other races, respectively. Compared to Whites, Blacks had a significantly higher risk of mortality due to CVD across all PCa risk groups (Table). Similar results were not seen when the Other races was compared to Whites.

Conclusion: Blacks with PCa have a significantly higher risk of mortality due to CVD as compared to Whites across all PCa risk groups. Our study highlights the importance of cardio-oncology in the setting of PCa. Further studies are warranted to confirm the findings.

Table: Risk of CVD-related mortality among PCa patients; stratified by PCa risk group.Low-Risk (N=84,367)Intermediate-Risk(N=146,411)High-Risk(N=96,502)HR (95%CI); p-valueHR (95%CI); p-valueHR (95%CI); p-valueWhites(N=316,803)RefRefRefBlacks(N=58,046)1.23 (1.09-1.39); p<0.0011.24 (1.14-1.34); p<0.0011.09 (1.01-1.20); p=0.029Other Races(N=19,474)0.79 (0.60-1.04); p=0.0890.87 (0.74-1.03); p=0.1120.79 (0.69-0.91); p<0.001

Citation Format: Nikita Nikita, Joshua Banks, Scott Keith, Kosj Yamoah, Ulhas P. Naik, Felix J. Kim, David M. Shipon, Wm Kevin Kelly, Timothy R. Rebbeck, Grace Lu Yao. Racial disparities in death from cardiovascular disease for patients with prostate cancer: A population-based study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 780.
Abstract 920: Harnessing multiple mechanisms of action to target Nectin-4 as anti-tumor therapeutics
Authors: Pei Yi , Pohl Thomas , Hassan Ahmed , Przybyla Anna , Yu Raymond , Lu Huarui , Tang Fangqiang , Chen Kevin , Jin Wei , Dominguez Krizia , Huang Haichun , Lei Ming , Liu Zhong , Li Han
Published: July 2021

Nectin-4 belongs to an immunoglobulin superfamily (IgSF) of cell adhesion molecules that mediate cell-cell adhesion through homophilic or heterophilic interactions. In addition to the role in cell-cell adhesion, the Nectin family plays important role in regulating a diverse range of physiologic cellular activities, in viral entry, and in immune modulation. Nectin-4 has been reported to be upregulated in various epithelial cell cancers, such as breast cancer, lung cancer, and bladder cancer. The therapeutic value of Nectin-4 as an anti-tumor target has been demonstrated by a recently approved antibody-drug conjugate (ADC), Enfortumab vedotin. To fully exploit the potential of Nectin-4 as an anti-tumor target, we discovered a panel of monoclonal antibodies. These antibodies not only bind specifically to human Nectin-4 with high affinity, but also show differentiating characteristics including cell internalization, blockage of interaction with Nectin-1, blockage of interaction with TIGIT, and ADC-independent cytotoxicity. Our results suggest that in addition to ADC, other mechanisms targeting Nectin-4 can be utilized for therapeutics, such as immunomodulation and antibody- or immune cell-mediated tumor cell killing.

Citation Format: Yi Pei, Thomas Pohl, Ahmed Hassan, Anna Przybyla, Raymond Yu, Huarui Lu, Fangqiang Tang, Kevin Chen, Wei Jin, Krizia Dominguez, Haichun Huang, Ming Lei, Zhong Liu, Han Li. Harnessing multiple mechanisms of action to target Nectin-4 as anti-tumor therapeutics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 920.
Abstract 972: Pharmacological targeting CDC7 sensitizes oxaliplatin treatment in colorectal cancer
Authors: Chen Yufeng , Yu Zhaoliang , Deng Peng , Wu Xiaojian
Published: July 2021

The cell division cycle 7 (CDC7) is a serine/threonine kinase that plays a critical role in the initiation of DNA replication by phosphorylating MCM 2-7 complex, which is frequently overexpressed in various human cancers. This study aimed to investigate the roles of CDC7 in colorectal cancer (CRC) and its potential pharmacological value. We found CDC7 expression was associated with tumor recurrence and poor outcome in CRC patients. We depleted CDC7 expression with siRNA and found CDC7 depletion dramatically inhibits colony formation in CRC cells treated with oxaliplatin. Importantly, pharmacological inhibition of CDC7 with inhibitor (XL413 or PHA767491) could overcome oxaliplatin resistance of CRC cells in cells proliferation, clone formation and tumorsphere formation. To further validated these findings in vivo, we examined the efficacy of CDC7 inhibitor and oxaliplatin in a DLD1-derived xenograft mouse model and two PDX models. The combination of oxaliplatin and XL413 significantly inhibit xenograft tumor growth, which showed remarkably decreased Ki-67 and increased cleaved-caspase 3 by IHC analysis. Collectively, our findings unveil the critical role of CDC7 in colon cancer cells and targeting CDC7 is a potential effective therapeutic for CRC patients.

Citation Format: Yufeng Chen, Zhaoliang Yu, Peng Deng, Xiaojian Wu. Pharmacological targeting CDC7 sensitizes oxaliplatin treatment in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 972.
Abstract 989: Tetraarsenic hexoxide enhances generation of mitochondrial ROS to promote pyroptosis by inducing the activation of caspase-3/GSDME in triple-negative breast cancer cells
Authors: An Haein , Heo Jin Sun , Ooshima Akira , Wu Zhaoyan , Kim Seong-Jin , BAE ILLJU , Yang Kyung-Min
Published: July 2021

Modified arsenic derivative compounds such as arsenic trioxide (As2O3), arsenic trisulfide (As2S3), and tetraarsenic hexoxide (As4O6) have been known to be one of the potent anti-cytotoxic effects in various cancer cells, including leukemia, glioma, colon, breast, and cervix cancer cells. Particularly, tetraarsenic hexoxide was developed as a chemotherapeutic agent for patients with advanced cancers. Although anti-cancer effect of tetraarsenic hexoxide has been extensively studied in various cancer cells, the molecular basis of its tumor inhibitory activity remains poorly understood. In this study, we suggest a mechanism of tetraarsenic hexoxide induces pyroptosis through the increase of mitochondrial ROS by targeting phosphorylation of mitochondrial STAT3, subsequently activating caspase-3/GSDME that eventually leads to suppression of cancer progression of TNBC cells. Interestingly, we first found that tetraarsenic hexoxide markedly induced pyroptotic cell death through caspase-3 in releading N-terminal fragments of GSDME in TNBC cells. Indeed, tetraarsenic hexoxide-treated TNBC cells exhibited pyroptotic cell death and the release of LDH. Supporting this observation, inhibition of active caspase-3 attenuated tetraarsenic hexoxide-induced pyroptotic features by blocking the cleavage of GSDME. In conclusion, our results suggest a mechanism of tetraarsenic hexoxide by inducing pyroptosis through the increase of mitochondrial ROS by targeting phosphorylation of mitochondrial STAT3, subsequently activating caspase-3/GSDME that eventually leads to suppression of cancer progression of TNBC cells. Also, given that traditional chemotherapeutic agents, tetraarsenic hexoxide may be useful for aggressive TNBC cells showing resistance to apoptosis as a new GSDME-targeted therapeutic strategy.

Citation Format: Haein An, Jin Sun Heo, Akira Ooshima, Zhaoyan Wu, Seong-Jin Kim, ILLJU BAE, Kyung-Min Yang. Tetraarsenic hexoxide enhances generation of mitochondrial ROS to promote pyroptosis by inducing the activation of caspase-3/GSDME in triple-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 989.
Abstract CT172: Phase 2 clinical trial of dianhydrogalactitol (VAL-083) in patients with newly diagnosed MGMT-unmethylated GBM
Authors: Chen Zhong-ping , Guo Cheng-cheng , Yang Qun-ying , Li Jia-wei , Wu Shao-xiong , Langlands John , Johnson Gregory , Kwan Claire , Kanekal Sarath , Schwartz Richard , Bacha Jeffrey , Steino Anne , Brown Dennis
Published: July 2021

Glioblastoma (GBM) is the most common and aggressive primary brain cancer. The majority of glioblastoma multiforme (GBM) patients have an unmethylated MGMT promoter status, leading to limited response to TMZ and decreased survival. Current standard-of-care includes surgery followed by chemoradiation and TMZ. An unmethylated promoter for O6-methylguanine DNA methyltransferase (MGMT) is a validated biomarker for TMZ-resistance and is strongly correlated with poor outcomes. VAL-083 is a novel bi-functional DNA targeting agent that induces inter-strand cross-links at N7-guanine, leading to DNA double-strand breaks and ultimately cell death. VAL-083 circumvents MGMT-mediated drug-resistance and has demonstrated cytotoxicity in MGMT-unmethylated GBM cell lines, cancer stem cells (CSCs) and in vivo models. Furthermore, VAL-083 acts as a radiosensitizer in GBM CSCs and non-CSCs. A Phase 2, open-label, biomarker-driven, study is being conducted to evaluate the tolerability and efficacy of VAL-083 in combination with radiation therapy (RT) in newly diagnosed MGMT-unmethylated GBM patients. A treatment regimen, consisting of a 6-week induction period of VAL-083 given IV at 20, 30, or 40 mg/m2/day x 3 days every 21 days and concurrent radiation (2 Gy daily, 5 days/week) followed by up to 24 weeks of maintenance therapy with single-agent VAL-083, is being evaluated. The study has 2 stages: Stage 1, dose-escalation, has identified a recommended dose of 30 mg/m2/day of VAL-083 in combination with RT as generally safe and well-tolerated. Stage 2, an expansion stage, has enrolled 20 additional patients at 30 mg/m2/day IV infusion on days 1, 2, and 3 of 21-day cycles. As of January 11, 2021, all 29 subjects in the study have been enrolled and completed the treatment stage of the study. Tumor response are assessed by MRI, according to RANO criteria. Efficacy endpoints include progression-free survival (PFS) and overall survival (OS). Additional endpoints include safety evaluations and pharmacokinetic assessments of plasma and CSF samples. The trial is continuing as planned and an update on primary results on safety and efficacy, and pharmacokinetics will be provided at the meeting. Clinicaltrials.gov identifier: NCT03050736.

Citation Format: Zhong-ping Chen, Cheng-cheng Guo, Qun-ying Yang, Jia-wei Li, Shao-xiong Wu, John Langlands, Gregory Johnson, Claire Kwan, Sarath Kanekal, Richard Schwartz, Jeffrey Bacha, Anne Steino, Dennis Brown. Phase 2 clinical trial of dianhydrogalactitol (VAL-083) in patients with newly diagnosed MGMT-unmethylated GBM [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT172.
Abstract CT239: ENVASARC: A Pivotal Trial of Envafolimab, and Envafolimab in Combination with Ipilimumab, in Patients with Advanced or Metastatic Undifferentiated Pleomorphic Sarcoma or Myxofibrosarcoma who have Progressed on Prior Chemotherapy
Authors: D'Angelo Sandra , Robinson Steven , Lam Joelle , Adams Bonne , Freddo James , Theuer Charles P. , Maki Robert
Published: July 2021

Background: Metastatic undifferentiated pleomorphic sarcoma (UPS) and the genetically related myxofibrosarcoma (MFS) are soft tissue sarcoma (STS) subtypes with poor prognoses. While responses to front line chemotherapy can approach 20%, in the 2nd line setting and beyond, efficacy remains limited. Pazopanib, the only approved treatment in the refractory setting has demonstrated an objective response rate (ORR) of 4%. Envafolimab is a single domain PD-L1 antibody administered rapidly by subcutaneous (SQ) injection that is being studied in two additional pivotal trials: MSI-H cancer and biliary tract cancer. The activity of envafolimab is similar to other PD-1 antibodies administered intra-venously. Envafolimab demonstrated a 32% ORR in MSI-H colorectal cancer that failed three approved chemotherapeutics, similar to the ORR of 28% and 33%, with nivolumab and pembrolizumab, respectively. The rationale for the ENVASARC trial is based on the previously reported efficacy of checkpoint inhibition in UPS/MFS. Single agent pembrolizumab demonstrated a 23% ORR, while the combination of nivolumab and ipilimumab demonstrated a 29% ORR in refractory UPS/MFS. Methods: ENVASARC (NCT 04480502) is a pivotal multicenter (at ~25 U.S. centers) open-label, randomized, non-comparative, parallel cohort study of treatment with envafolimab 300 mg every 3 weeks by SQ injection (cohort A; n=80) or envafolimab 300 mg every 3 weeks by SQ injection combined with ipilimumab 1 mg/kg every 3 weeks intra-venously for four doses (cohort B; n=80) in patients with locally advanced, unresectable or metastatic UPS/MFS who have progressed on one or two lines of prior therapy. The primary objective of each of parallel cohort is to demonstrate an ORR with a lower limit of the 95% confidence interval that excludes 5.0% in each cohort. If ≥ 9 responders are observed of the 80 patients enrolled in each cohort, then the lower bound of the 95% confidence interval will exclude 5.0%. Secondary endpoints include duration of response (DOR), PFS and OS. Key inclusion criteria: ≤ 2 prior lines of therapy (neoadjuvant and adjuvant therapy excluded), ECOG ≤ 1.

Citation Format: Sandra D'Angelo, Steven Robinson, Joelle Lam, Bonne Adams, James Freddo, Charles P. Theuer, Robert Maki. ENVASARC: A Pivotal Trial of Envafolimab, and Envafolimab in Combination with Ipilimumab, in Patients with Advanced or Metastatic Undifferentiated Pleomorphic Sarcoma or Myxofibrosarcoma who have Progressed on Prior Chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT239.
Abstract LB045: Identification of plasma-derived, EV-based biomarkers for glioblastoma
Authors: Khodor Yevgenia L. , Chakrabortty Sudipto K. , Fischer Christian , Rauscher Martina , Balaj Leonora , Carter Bob S. , Yu Seth , Skog Johan
Published: July 2021

Background: Glioblastoma (GBM) is the most malignant and aggressive primary brain cancer in adults, with an incidence of 3.2 per 100,000 people. Currently, diagnosis is only performed via histopathological investigation of a tissue sample from a GBM lesion, complemented with molecular diagnostics for identification of select biomarkers. MRI is the standard of care for follow-up and monitoring of treatment response. Therefore, development of a “liquid biopsy” to obtain disease-relevant information from body fluids is highly desirable.Methods: We present the results from a clinical study in which extracellular vesicle (EV)-derived mRNAs were profiled from the plasma of GBM patients and control individuals for a total of 32 individual RNAseq libraries. Initial biomarker discovery was performed on plasma from 16 patients (8 GBM patients at the time of initial diagnosis and 8 age and sex matched controls). Hybrid capture and RNA-seq were performed via our proprietary pipeline on EV-associated mRNA isolated from 1-2mL plasma. Sequencing data was analyzed for differential gene expression. Validation was done with plasma samples from a new cohort of 8 patients and 8 control individuals.Results: We observed 98 mRNAs as differentially detected between GBM and control samples, with 83 mRNAs enriched in GBM samples and 15 mRNAs decreased (p < 0.05). Correlation based on differentially detected mRNAs separated GBM and control samples into two unique populations. We were able to use the differentially expressed gene signature from the first cohort to separate GBM patients and control individuals in the second cohort. We are currently following up these results with a larger patient population. These data, while preliminary, provide a potential basis for the further development of a GBM gene panel test.Conclusions: We have identified a novel gene signature for GBM in plasma-derived EVs, which differs from previously identified biomarkers isolated from tissue. Further work will refine this signature to enable detection, characterization, and patient monitoring for GBM with less invasive and intensive methods.

Citation Format: Yevgenia L. Khodor, Sudipto K. Chakrabortty, Christian Fischer, Martina Rauscher, Leonora Balaj, Bob S. Carter, Seth Yu, Johan Skog. Identification of plasma-derived, EV-based biomarkers for glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB045.
Abstract LB064: Long-term application of TTFields in anaplastic astrocytoma - a case study
Authors: Markovic Darko
Published: July 2021

Background: Anaplastic astrocytomas WHO III° (AA) represent diffusely infiltrating, high grade gliomas (HGG). Despite advancements in the molecular characterization of HGG treatment options are limited and are often in analogy to grade IV glioblastoma treatment. Tumor Treating Fields therapy (TTF) is an established modality for newly diagnosed and recurrent glioblastoma (GBM) shown to significantly improve progression-free and overall survival. While TTF is under investigation in grade III gliomas in several clinical trials, we present an exemplary case of an AA undergoing mid-term TTF therapy and adjuvant chemotherapy to explore treatment adherence, feasibility and safety. Methods: We present case details of a patient from our specialized neurosurgical oncology center, with an anaplastic astrocytoma (WHO grade III) who began TTF treatment at first diagnosis while being in the adjuvant chemotherapy phase at the time of TTF commencement. We describe treatment details and the course of disease under continuous and ongoing TTF therapy. Results: In December 2016 a 43year-old male patient was diagnosed with an anaplastic astrocytomaIDH 1/2 mutant, MGMT promoter-hypermethylation without 1p/19q codeletion. After biopsy and consequent partial tumor resection, he received concomitant radiochemotherapy and adjuvant chemotherapy with temozolomide. TTF was started six months after initial diagnosis. He has now completed 1328 days of treatment with an average daily usage of 90% and has survived 48 months from first diagnosis (cutoff January, 8th, 2021). Since beginning TTF, he has undergone temozolomide treatment for 6 cycles. He continues TTF without further adjuvant therapy. The patient is symptomatically stable and his quality of life is maintained. Significant adverse events or longer treatment interruptions have not occurred. Conclusion: The treatment with TTFields was well tolerated and seems to be feasible in this patient with an anaplastic astrocytoma. Considering the long treatment duration and favorable average daily usage, this treatment might be suitable for a long-term treatment in high grade gliomas. Ongoing clinical trials will provide more information on safety and efficacy for the use of TTFields in patients with grade III gliomas.

Citation Format: Darko Markovic. Long-term application of TTFields in anaplastic astrocytoma - a case study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB064.