Solid Tumor Patients Research Articles

Abstract CT094: Targeting CSF1R with BLZ945 results in effective peripheral and tumor immune microenvironment modulation in advanced solid tumors and may be associated with limited efficacy in recurrent non-mesenchymal glioblastoma

Abstract Colony-stimulating factor 1 receptor (CSF-1R) signaling is involved in regulating monocyte differentiation, and the recruitment and survival of tumor-associated macrophages (TAMs). BLZ945 is a small molecule, highly selective, orally bioavailable, potent kinase inhibitor of CSF-1R that has shown the ability to reduce the recruitment of TAMs in animal models and promote infiltration of effector T cells into the tumor in preclinical models. Given the potential effects of BLZ945 on effector T-cell activity, a combination of BLZ945 with the programmed death 1 (PD-1) inhibitor spartalizumab was investigated in 1) a dose escalation phase I clinical trial with advanced solid tumor patients; and 2) an expansion phase II clinical trial in adult patients with relapsed/refractory glioblastoma (GBM) after standard of care and other lines of therapy (NCT02829723). The percentages of non-classical and intermediate monocytes in the PBMC fraction were decreased after treatment at multiple doses and schedules of treatment tested in the escalation phase. Screening and on-treatment paired tumor biopsy samples from the escalation phase were analyzed by RNA sequencing. Downregulated genes have been noted as macrophage-specific genes, suggesting that treatment with BLZ945 is downregulating macrophages in the tumor microenvironment. There appeared to be a trend for a reduction in TAM gene signatures and increase in T-cell inflammation signatures upon treatment with single-agent BLZ945 or BLZ945 + spartalizumab. RNA-sequencing analysis from archival surgical resection GBM samples from the expansion phase, revealed a potential correlation between PDGFRA gene expression and best percent change in tumor size. This suggests that non-mesenchymal GBM, for which PDGFRA is part of the defining signature, are more sensitive to the treatment. DNA-sequencing of these archival samples also revealed mutations in p53 in the tumors with partial responses but no mutations in EGFR or TERT. Citation Format: Carlos Rodrigo Gil Del Alcazar, Virginia Xu, Chia-chi Lin, Marta Gil-Martin, Aung Naing, Liqiong Fan, Fang Yang, David Quinn, Jincheng Wu, Cornelia Quadt, Jennifer Mataraza. Targeting CSF1R with BLZ945 results in effective peripheral and tumor immune microenvironment modulation in advanced solid tumors and may be associated with limited efficacy in recurrent non-mesenchymal glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT094.

A phase I open-label, dose-escalation study of NUC-3373, a targeted thymidylate synthase inhibitor, in patients with advanced cancer (NuTide:301)

Purpose5-fluorouracil (5-FU) is inefficiently converted to the active anti-cancer metabolite, fluorodeoxyuridine-monophosphate (FUDR-MP), is associated with dose-limiting toxicities and challenging administration schedules. NUC-3373 is a phosphoramidate nucleotide analog of fluorodeoxyuridine (FUDR) designed to overcome these limitations and replace fluoropyrimidines such as 5-FU.Patients and methodsNUC-3373 was administered as monotherapy to patients with advanced solid tumors refractory to standard therapy via intravenous infusion either on Days 1, 8, 15 and 22 (Part 1) or on Days 1 and 15 (Part 2) of 28-day cycles until disease progression or unacceptable toxicity. Primary objectives were maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) and schedule of NUC-3373. Secondary objectives included pharmacokinetics (PK), and anti-tumor activity.ResultsFifty-nine patients received weekly NUC-3373 in 9 cohorts in Part 1 (n = 43) and 3 alternate-weekly dosing cohorts in Part 2 (n = 16). They had received a median of 3 prior lines of treatment (range: 0–11) and 74% were exposed to prior fluoropyrimidines. Four experienced dose-limiting toxicities: two Grade (G) 3 transaminitis; one G2 headache; and one G3 transient hypotension. Commonest treatment-related G3 adverse event of raised transaminases occurred in < 10% of patients. NUC-3373 showed a favorable PK profile, with dose-proportionality and a prolonged half-life compared to 5-FU. A best overall response of stable disease was observed, with prolonged progression-free survival.ConclusionNUC-3373 was well-tolerated in a heavily pre-treated solid tumor patient population, including those who had relapsed on prior 5-FU. The MTD and RP2D was defined as 2500 mg/m2 NUC-3373 weekly. NUC-3373 is currently in combination treatment studies.Trial registrationClinicaltrials.gov registry number NCT02723240. Trial registered on 8th December 2015. https://clinicaltrials.gov/study/NCT02723240.

Abstract 3636: Myeloid cell rebound associated with GD2-CAR-T cell therapy in solid tumor patients

Abstract GD2 is a validated cancer immunotherapy target with highly restricted normal tissue expression. Promising activity of GD2-CAR-T cell therapy in diffuse midline glioma and neuroblastoma has promoted interest in this therapy. We initiated three phase 1 clinical trials of escalating doses of intravenously administered autologous GD2-CAR-T cells in patients with advanced GD2-positive solid tumors. Emerging evidence suggests that CAR-T cells may increase circulating myeloid derived suppressor cells (MDSCs) and that this event may be mediated and/or triggered by CAR-T cell-derived cytokines and chemokines. These findings may help to explain the limited persistence of CAR-T cell therapy in solid tumor patients. Hence, we sought evidence of MDSC generation and secretion of relevant cytokines and chemokines in our clinical trial patients. The CARPETS trial (www.anzctr.org.au: ACTRN12620000622909) recently closed to recruitment after enrolling 12 patients (7 melanoma, 4 colorectal cancer, and 1 sarcoma). No significant adverse events were attributable to CAR-T cell therapy. We opened two other GD2-CAR-T cell therapy trials in 2023: LEVI’S-CATCH (ACTRN12622000675729) in patients with diffuse midline glioma at Sydney Children’s Hospital and KARPOS (ACTRN12622001514796) in adult patients with recurrent glioblastoma at Royal Adelaide Hospital. To date, 3 patients have enrolled to LEVI’S-CATCH with the first patient clearing the dose limiting (DLT) evaluation period. Three patients completed enrolment to the first dose cohort of KARPOS without DLTs. In all CARPETS patients, CAR-T cell expansion, which was measured by by DNA quantitative PCR and flow cytometry, peaked during the 6-week post-CAR-T infusion DLT evaluation period. In 6 CARPETS patients for whom peripheral blood samples were available, we found by flow cytometry, newly formed or increased size of pre-existing subpopulations of non-classical monocytes and/or MDSCs of mononuclear and/or polymorphonuclear class, which peaked at or after the time of peak CAR-T cell expansion. Typically, serum levels of inflammatory cytokines and chemokines such as TNF, IL-6, IL-8, CCL2, GM-CSF, and CXCL10, were detected only after the CAR-T cell infusion with variable patterns of the timing and concentration of analyte observed among the 12 patients. At the time of writing, blood samples from the first KARPOS patient showed CAR-T cell expansion and the subsequent increases in circulating myeloid derived suppressor cells and inflammatory cytokines. We expect that full data sets for these parameters will be presented for current and future enrolled patients to both studies. To improve CAR-T cell persistence in solid tumor patients, these data indicate the need for new therapeutic strategies to mitigate effects of CAR-T cell induced myeloid cells with antitumor activity. Citation Format: Michael P. Brown, Tessa Gargett, Nga T. Truong, Orazio Vittorio, David S. Ziegler. Myeloid cell rebound associated with GD2-CAR-T cell therapy in solid tumor patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3636.

Abstract 5836: CRISPR/Cas9 screening identifies genes affecting the sensitivity to the copanlisib/venetoclax combination in lymphoma cells

Abstract Background: Copanlisib, a PI3K inhibitor with a higher selectivity on PI3Kα and PI3Kδ, is currently being evaluated as a single agent and in combination for lymphoma and solid tumor patients. We and others reported the synergism achieved by adding the BCL2 inhibitor venetoclax, and the combination is in its early clinical assessment (NCT04939272, NCT04572763, NCT03886649). To explore genes affecting the response to the combination, we performed a genome-wide CRISPR Cas9 screen in a marginal zone B cell lymphoma (MZL) cell line under drug exposure. Methods: We generated, via lentiviral infection, a stable Cas9-expressing VL51 line, which was then infected (MOI 0.3) with the genome-wide Brunello guide RNA library, interrogating 19114 genes. After puromycin selection, 40M cells underwent DNA extraction (T0), 40M were exposed to DMSO ( control arm), 40M to copanlisib (0.5nM) + venetoclax (25nM) (experimental arm) for 2 weeks. DNA at T0 and extracted at 2 weeks underwent Illumina sequencing according to the Broad Institute Genetic Perturbation Platform protocol. MAGeCK-MLE was used to model sgRNA read counts and assess the sgRNAs statistical enrichment (P&amp;lt;0.05 FDR&amp;lt; 0.15), GSEA for genesets enrichments. Results: In the DMSO-treated cells, 160 genes had a positive β value (i.e., the sgRNAs knocking down the genes were positively enriched after 2 weeks), while 1152 had a negative β value (i.e., the sgRNAs knocking down the genes were negatively enriched after two weeks), for a total of 1152 differential enriched targets. In the cells exposed to the drug combination, 207 genes had positive and 1324 negative β, for a total of 1531 differentially enriched targets. Genes defined as essential, according to DepMap, represented 768/1152 (67%) and 843/1531 (55%) in control and experimental arms, respectively. The experimental arm did not massively differ from the control arm as shown by 815 genes (615, 74%, defined as essential by DepMap) overlapping between the 2 conditions and by highly significant enrichments at GSEA. A few genes were relevant only in VL51 exposed to copanlisib/venetoclax and not to DMSO. Selected hits were individually validated. Knocking down VKORC1L1, XCL1, RFK, MAP2K6, POC1A, and WTN5A improved the activity of the combination. WTN5A was also validated using recombinant protein (10 ng/mL), which reduced the effect of copanlisib/venetoclax. SPARCL1, MAPK4, ID2, and MSTN silencing reduced the activity of the combination. MSTN, coding for myostatin, was also validated by adding the recombinant protein (10 ng/mL), which increased the drugs anti-tumor activity. Conclusions: A genome-wide genetic screening identified genes modulating the lymphoma cells response to the copanlisib/venetoclax combination, providing novel therapeutic targets or biomarkers. Citation Format: Sara Napoli, Alberto J. Arribas, Eleonora Cannas, Federica Fuzio, Luciano Cascione, Andrea Rinaldi, Emanuele Zucca, Andrea Alimonti, Anastasios Stathis, Francesco Bertoni. CRISPR/Cas9 screening identifies genes affecting the sensitivity to the copanlisib/venetoclax combination in lymphoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5836.

Abstract 5128: Circulating H3K27me3 modified nucleosomes as a biomarker to monitor anti EZH2-based treatment in advanced solid tumour patients: Translational analyses from CAIRE trial

Abstract CAIRE is a phase 2 umbrella study which assessed activity of combined anti-EZH2 tazemetostat and anti-PDL1 durvalumab (T+D) in advanced pretreated pancreatic, colorectal and sarcoma cancer patients. The are currently no plasma biomarkers for anti-EZH2 treatment monitoring or outcome. EZH2 catalyzes tri-methylation of Lysine 27 (K27me3) on nucleosomal histone 3 (H3, H3K27me3). Circulating, cell free H3K27me3 modified nucleosomes are thus a potential biomarker for tazemetostat activity. We evaluated the concentration of circulating H3K27me3 modified nucleosomes normalized to H3.1 nucleosomes (the most common isoform of H3) in T+D treated patients, irrespective of the tumor primary site, to determine target engagement during anti-EZH2 treatment. Plasma from patients receiving T+D was collected before the first cycle administration (C1D1), on the following two cycles administration (C2D1, C3D1) and at end of treatment (EOT). H3.1 and H3K27me3 containing nucleosomes were quantified by Nu.Q®-H3.1 and Nu.Q®-H3K27me3 Chemiluminescent Immunoassays. Concentrations are reported as ng/ml and the comparison of their median values at the different timepoints were tested with Kruskal-Wallis and Mann Whitney (independent samples) or Wilcoxon tests (paired samples), with SciPy.stat package (1.6.2). Bonferroni correction was applied to multiple comparisons. Of 197 total samples, 191 were evaluable for both biomarkers (6 higher than top standard after 5x dilution): 69 at C1D1, 63 at C2D1, 50 at C3D1 and 9 at EOT. For 58 patients paired C1D1 and C1D2 levels were available, 46 from C1D1 to C3D1 and 8 from C1D1 to EOT. The normalized Nu.Q®-H3K27me3 C1D1 median value (0.56) was significantly higher than C2D1 (0.31, p: e-12), C3D1 (0.31, p: e-12) and EOT ones (0.28, p: 0.001). Conversely, Nu.Q®-H3.1 levels were similar from C1D1 to C3D1 (range of the medians: 122.16-133.25 ng/ml) and increased at EOT (290.09 ng/ml), but with no significant difference between pairwise timepoints. Regarding paired-samples comparison, the normalized Nu.Q®-H3K27me3 was significantly higher at C1D1 than at C2D1 (p: e-8) and C3D1 (p: e-9) and at EOT (p: 0.02). Conversely, H3.1 concentration was significantly higher at EOT than at C1D1 (p: 0.02), at C2D1 (p: 0.02) and C3D1 (p: 0.05).In conclusion, we described for the first time that normalized circulating nucleosomal H3K27me3 values significantly decrease during T-based treatment in metastatic solid tumor patients, irrespective of the primary disease site, supporting its potential role as a pharmacodynamic biomarker for EZH2 inhibition. Moreover, total nucleosomal H3.1 seems to represent a surrogate of disease burden in metastatic pancreatic, colorectal and sarcoma cancers, as suggested previously in other hematological malignancies. Citation Format: Francesca Salani, Mark Eccleston, Lola-Jade Palmieri, Simon Pernot, Sophie Cousin, Gianluca Masi, Francesco Crea, Antoine Italiano. Circulating H3K27me3 modified nucleosomes as a biomarker to monitor anti EZH2-based treatment in advanced solid tumour patients: Translational analyses from CAIRE trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5128.

Abstract 1118: Mitigating radiation-induced lymphopenia using interleukin-15: Preclinical rationale for clinical translation

Abstract Background: Radiation therapy is a common treatment for cancer patients, with nearly 50% of them undergoing this procedure. While radiation is effective at targeting tumor cells, it also has the unintended consequence of killing lymphocytes, which are among the most sensitive cells to radiation within the erythroid, myeloid, and lymphoid lineages. This phenomenon is known as radiation-induced lymphopenia (RIL) and is considered a negative prognostic factor in various malignant solid tumors. It occurs severely in over 40% of solid tumor patients who receive radiotherapy. Some previous studies have shown promising results with IL15 therapy in increasing circulating lymphocytes in cancer patients. However, until now, no studies have investigated the impact of IL15 in the context of radiation-induced lymphopenia. Our study aims to investigate whether IL15 can boost lymphocyte numbers and decrease tumor burden following radiation treatment in a mouse model. Methods: To conduct our study, we subcutaneously injected TSA tumor cells into the flank region of mice. Once the tumors reached a palpable size, approximately 50mm3, we divided the mice into four groups: Control (Con), Irradiation (IR), Control with IL15 (Con+IL15), and Irradiation with IL15 (IR+IL15). The irradiated mouse groups received a radiation dose of 2 Gray in the thorax and 1 Gray in the spleen for five consecutive days, simulating the severe radiation-induced lymphopenia observed in cancer patients. After the radiation treatment, the IL15-treated groups received IL15 in combination with recombinant IL15 in a 1:6 ratio weekly. Throughout the experiment, we monitored the circulating lymphocytes and tumor growth. After two weeks following the last radiation dose, we euthanized the mice, collected blood, spleen, and tumor samples, and identified immune cells using flow cytometry. Results: The radiation treatment significantly increased tumor growth while decreasing the number of lymphocytes, including B cells, T cells, and NK cells, in the blood. IL15 administration led to an increase in the number of lymphocytes both in the blood and within the tumor compared to the irradiated group. We observed a trend toward reduced tumor growth in the group that received both IL15 and radiation (IR+IL15) compared to the group that received radiation alone (IR). Conclusion: IL15 effectively boosted the number of lymphocytes in both the bloodstream and tumors, resulting in slower tumor growth in the IL15-treated group compared to the irradiated group. This study is of significant importance as it demonstrates the potential of IL15 to counteract radiation-induced lymphopenia in mice with TSA tumors. Further testing of these findings is currently underway in MC38 tumor-bearing mice, a cell line known to be more radiation-sensitive. Citation Format: Priti Gupta, Min Wang, Steven Lin. Mitigating radiation-induced lymphopenia using interleukin-15: Preclinical rationale for clinical translation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1118.

Abstract 2938: Comprehensive genomic profiling of solid tumor patients with the OncoDEEP assay for broad analysis in clinical diagnostics

Abstract Somatic multi-gene analysis by Next Generation Sequencing (NGS) becomes standardly integrated in medical oncology for clinical decision making. However, with the fast-growing number of recommended and required genomic biomarkers, small panels have become vastly insufficient for most tumor types. Comprehensive Genomic Profiling (CGP) is amenable to screen for single nucleotide variants (SNVs) and subtle insertions and deletions (indels) in several hundreds of genes. Moreover, it provides information on copy number variations (CNVs) and gene fusions of the most relevant genes for optimal patient management. Currently, most comprehensive panels also allow for screening of tumor-agnostic genomic biomarkers, including microsatellite instability (MSI), tumor mutation burden (TMB) and homologous recombination deficiency (HRD), which are implemented as prognostic and therapeutic signatures in a wide variety of solid tumors. So far, only a handful of CGP assays have been validated for their diagnostic utility in routine laboratory practice for the care of cancer patients. In this study we report on an extensive multicentric analysis across multiple centers in Belgium and The Netherlands comparing the novel OncoDEEP CGP assay (OncoDNA) with the diagnostically validated TSO500 assay (Illumina). We describe the technical differences between both assays as well as their outcome and shortcomings. Detection of clinically relevant SNVs, indels and CNVs was very similar and differences were often due to assay-specific settings. Similarly, TMB, MSI and HRD data were concordant for most samples but those with scores close to the cut-offs could deviate. For fusion detection, concordance was found for the limited number of 11 clinically-actionable driver genes covered by the OncoDEEP kit. The uniformity of coverage was much higher with the OncoDEEP assay thereby allowing to pool 2- to 3-times more samples per NGS run. For the diagnostic implementation of the OncoDEEP assay we then performed an extensive validation with clinical samples representing a wide variety of solid tumor types, as well as reference samples. All performance metrics passed the validation criteria. In conclusion, the OncoDEEP kit can be used for reliable diagnostic comprehensive profiling of solid tumors, but currently, extensive fusion analysis requires an additional screening method. Citation Format: Ernst-Jan M. Speel, Pieter-Jan Volders, Joni Van der Meulen, Aaron De Cock, Stefanie Vermeire, Jacques Van Huysse, Marie De Barsy, Gabriela Beniuga, Wendy de Leng, Anne Jansen, Sharon Thijssen, Hendrikus Jan Dubbink, Zeliha Ozgur, Wilfred van Ijcken, Brigitte Maes, Guy Froyen. Comprehensive genomic profiling of solid tumor patients with the OncoDEEP assay for broad analysis in clinical diagnostics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2938.

Abstract 28: A CRISPR/Cas9 screening platform ImmuT Finder® enables in vivo T cell functional screening and identification of potent immunoregulatory targets for next-generation T cell therapy

Abstract Insufficient tumor infiltration and the presence of various immunosuppressive mechanisms in tumor microenvironment (TME) are two major challenges compromising the anti-tumor efficacy of T cell therapy post infusion. PD-1/PD-L1 blockade has been proven to benefit a portion of late-stage solid tumor patients, however KO of PD-1 may impact the long-term persistence of CAR-T cells, indicating target selection strategies for gene editing of cell therapy products may differ from antibody drugs. To discover potent and/or novel immunoregulatory targets that could maximize the function of T cell therapy, we established an in vivo CRISPR/Cas9 screening platform, ImmuT Finder®, to identify functional gene targets in primary mouse T cells. Notably, T cells carrying sgRNA library have been collected at different harvest time points post transfer based on different screening purposes; library size has been rationally designed to ensure good coverage of the whole library in harvest samples. We selected top targets from in vivo screening and quickly validated their function in primary human T cells in a 96-well array. Then, the top targets that showed significant enhancement in proliferation and function of human T cells were further selected, and their combinational effects on human peripheral T cells and TIL were tested both in vitro and in vivo. Finally, GT307 stands out as the most potent KO combination, which significantly improves serial tumor killing of TCR-T and CAR-T as well as autologous tumor cytotoxicity of TIL in vitro. Furthermore, GT307 KO TCR-T and TIL demonstrated significantly improved tumor control in mouse models than their unedited counterparts and promoted long-term persistence with low support of IL-2. In summary, these data demonstrated that our ImmuT Finder® platform enables discovery of potent and/or novel targets for the development of T cell product and supports the clinical assessment of GT307 as a next-generation T cell therapy. Citation Format: Jingwei Sun, Jiahui Jin, Jingman Wang, Yao Sheng, Fei Li, Lingyun Chen, Yongchao Tan, Zhao Xu, Yanbin Liu, Ke Liu, Yarong Liu. A CRISPR/Cas9 screening platform ImmuT Finder® enables in vivo T cell functional screening and identification of potent immunoregulatory targets for next-generation T cell therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 28.

Abstract 5099: Prevalence of fibroblast growth factor receptor (FGFR) alterations (alts) and programmed death-ligand 1 (PD-L1) expression (exp) in Chinese solid tumor patients (pts)

Abstract Background: PD-L1 expression drives anti-PD(L)-1 treatment decisions across many cancer indications. FGFR inhibitors have been approved for the treatment of metastatic urothelial cancer (UC) and cholangiocarcinoma with FGFR alts. BALVERSA (erdafitinib), a selective pan-FGFR kinase inhibitor, has shown clinical activity against FGFR altered solid tumors in pts who exhausted standard treatment options. It is important to understand the prevalence of FGFR alts and relationship between FGFR alts and PD-L1 expression levels in different cancer types. Methods: In this real-world study, 9937 Chinese solid tumor pts with the PD-L1 (22C3) immunohistochemistry and OrigiMed 450-gene next-generation sequencing panel results were selected. Chi-square test and Fisher test were used to explore the association between the FGFR alts and PD-L1 expression. Results: FGFR1-4 somatic alts were found in 9.0% of Chinese cancer pts evaluated. FGFR1 amplification (amp) was the most prevalent alts identified (1.9%). There were no significant differences in frequency of FGFR alts between the Chinese cohort and MSK-IMPACT cohort in each cancer type tested. Up to 40.6% of pts evaluated were PD-L1 positive (CPS ≥1 or TPS ≥1%). The PD-L1 positive rate (TPS ≥1%) in SCLC (12.4%, n=121) and NSCLC adenocarcinoma tumors (LUAD) (26.1%, n=2902) was relatively low. In few tumor types, higher expression of PD-L1 in FGFR altered samples was observed compared with FGFR unaltered samples in pan-tumor (mean TPS 14.8% vs.8.6%, P=6.0*E-9; mean CPS 6.3 vs. 6.1, P=3*E-4). Those includes LUAD (mean TPS 14.2% vs. 7.4%, P = 1.7*E-16), colorectal tumor (mean CPS 4.6 vs. 3.9, P = 4.6*E-8), and uterine tumor (mean CPS 8.1 vs. 6.5, P = 9.6*E-5). While PD-L1 expression is lower in FGFR altered samples than FGFR unaltered samples in UC (n=154; mean CPS 3.9 vs. 6.8, P = 0.004). No relationship was observed between FGFR alts and PD-L1 expression in cholangiocarcinoma (n=610). Specific FGFR alts eligible for erdafitinib UC treatment were further investigated in UC and observed with rate 10.4%, including FGFR3 short variants (9.7%) as main alts. Specific FGFR altered tumors showed similar trend with lower PD-L1 expression than FGFR unaltered tumors in UC. The inverse relationship between FGFR alts and PD-L1 expression in UC compared to other solid tumors may explain variable role of FGFRs since the predominant FGFR alt types vary among different cancer types (FGFR3 short variants enriched in UC vs no such predominant FGFR alt types in other cancer types). Conclusion: The large Chinese solid tumor cohort analysis showed comparable FGFR alts prevalence between Chinese and Western population. Differences in relationship between FGFR alts and PD-L1 expression across tumor types reflect the differential role of predominant FGFR types in each tumor type. Citation Format: Min Qing, Fei Yang, Xiaowei Chen, Xuesong Lyu, Aodi Wang, Yanfei Yu, Shibu Thomas, Longen Zhou. Prevalence of fibroblast growth factor receptor (FGFR) alterations (alts) and programmed death-ligand 1 (PD-L1) expression (exp) in Chinese solid tumor patients (pts) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5099.

Differential Effects of a Telemonitoring Platform in the Development of Chemotherapy-Associated Toxicity: A Randomized Trial Protocol.

Chemotherapy requires careful monitoring, but traditional follow-up approaches face significant challenges that were highlighted by the COVID-19 pandemic. Hence, exploration into telemonitoring as an alternative emerged. The objective is to assess the impact of a telemonitoring platform that provides clinical data to physicians overseeing solid tumor patients, aiming to enhance the care experience. The methodology outlines a parallel-group randomized clinical trial involving recently diagnosed patients with solid carcinomas preparing for curative intent chemotherapy. Eligible adult patients diagnosed with specific carcinoma types and proficient in Spanish, possessing smartphones, will be invited to participate. They will be randomized using concealed allocation sequences into two groups: one utilizing a specialized smartphone application called Contigo for monitoring chemotherapy toxicity symptoms and accessing educational content, while the other receives standard care. Primary outcome assessment involves patient experience during chemotherapy using a standardized questionnaire. Secondary outcomes include evaluating severe chemotherapy-associated toxicity, assessing quality of life, and determining user satisfaction with the application. The research will adhere to intention-to-treat principles. This study has been registered at ClinicalTrials.gov (NCT06077123).

Sarcoid-like reaction of the orbit in diffuse large B-cell lymphoma.

Sarcoid-like reaction (SLR) has been reported in patients with solid tumor malignancies, lymphomas, and patients receiving immunotherapy. SLR is often incidentally found during positron emission tomography/computed tomography scans as hilar and/or mediastinal lymphadenopathy. SLR has also been found in the lung, spleen, bone marrow, and skin. Biopsy of these lesions shows noncaseating granulomas. When systemic criteria are not met for sarcoidosis, these noncaseating granulomas are termed SLR. We present the first case in the literature of a case of orbital SLR in a patient with concomitant diffuse large B-cell lymphoma and inverted papilloma of the maxillary sinus. This case highlights the importance of including malignancy in the differential for the presence of a noncaseating granuloma in the orbit.

Abstract IA020: Targeting transposable elements with epigenetic modulators to reverse ovarian cancer immune evasion

Abstract Transposable elements (TEs) comprise the majority of the human genome. In most somatic tissues, TEs are silenced by DNA methylation and other epigenetic modifications. Tumors exhibit changes in DNA methylation including global loss of methylation at regions that are silenced for genome stability, like TEs, and gain of methylation at the promoter regions of tumor suppressor genes. We showed that low doses of DNMT inhibitors (DNMTis) upregulate immune signaling in solid tumor cell lines and patient samples. DNMTis activate type I interferon signaling by reducing methylation and increasing expression of endogenous retroviruses (ERVs), a type of TE, that activate dsRNA sensors. DNMTis plus HDACis (histone deacetylase inhibitors, which increase histone acetylation) increase TEs in a mouse model of ovarian cancer, activating interferon signaling and recruiting CD8+ T cells to kill cancer cells and sensitize to immune checkpoint blockade therapy. We performed a genome-wide analysis of the response to DNMTi, HDACi, and combination HDACi/DNMTi in four ovarian cancer cell lines (RNA-Seq, global methylome profiling, ATAC-Seq, and P53 chIP-Seq). The addition of HDACis to DNMTis augments the upregulation of specific ERVs and the resulting downstream interferon response in human ovarian cancer cell lines. Other TE species, including LINE1 and Alu elements, are increased by DNMTi and HDACi and may contribute to the interferon response. Alu elements, which can directly bind to the dsRNA sensor MDA5, are the most significantly demethylated TEs after DNMTi treatment. Importantly, we find considerable overlap between TEs upregulated by DNMTi in cell lines and TEs upregulated by DNMTi in ovarian cancer patients from a DNMTi clinical trial. We observed that ovarian cancer cell lines with TP53 mutations exhibited significantly fewer upregulated TEs with epigenetic therapy than wild-type TP53 cell lines. This observation was validated using isogenic cell lines; the CRISPR-edited TP53-mutant cell line had significantly higher baseline expression of TEs but upregulated fewer upon epigenetic treatment. p53 bound directly to TE DNA by chIP-Seq analysis and upregulated TEs in wild type but not mutant cell lines. In addition, our RNA-sequencing analysis indicated that A-to-I RNA editing of TEs by ADAR1 was increased after DNMTi treatment. This A-to-I editing makes TE RNA less immunogenic and inhibits the immune response to DNMTi. We find that combining ADAR1 knockdown and DNMTi treatment significantly increases type I interferon signaling, recruitment and activation of host immune cells, and survival in a murine model of ovarian cancer. These data thus give a comprehensive, genome-wide picture of TE chromatin and transcription-related changes in ovarian cancer after epigenetic treatment and implicate novel regulators (p53 and ADAR1) in response to epigenetic therapies for cancer. Citation Format: Katherine B. Chiappinelli. Targeting transposable elements with epigenetic modulators to reverse ovarian cancer immune evasion [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr IA020.

Gut microbiome-derived bacterial extracellular vesicles in patients with solid tumours

IntroductionGut microbiome–derived nanoparticles, known as bacterial extracellular vesicles (bEVs), have garnered interest as promising tools for studying the link between the gut microbiome and human health. The diverse composition of bEVs, including their proteins, mRNAs, metabolites, and lipids, makes them useful for investigating diseases such as cancer. However, conventional approaches for studying gut microbiome composition alone may not be accurate in deciphering host–gut microbiome communication. In clinical microbiome research, there is a gap in the knowledge on the role of bEVs in solid tumor patients. ObjectivesAnalyzing the functionality of bEVs using (meta)genomics and proteomics could highlight the unique aspects of host–gut microbiome interactions in solid tumor patients. Therefore, we performed a comparative analysis of the proteome and microbiota composition of gut microbiome-derived bEVs isolated from patients with solid tumors and healthy controls. MethodsAfter isolating bEVs from the feces of solid tumor patients and healthy controls, we performed spectrometry analysis of their proteomes and next-generation sequencing (NGS) of the 16S gene. We also investigated the gut microbiomes of feces from patients and controls using 16S sequencing and machine learning to classify the samples into patients and controls based on their bEVs and fecal microbiomes. ResultsSolid tumor patients showed decreased microbiota richness and diversity in both the bEVs and feces. However, the bEV proteomes were more diverse in patients than in the controls and were enriched with proteins associated with the metabolism of amino acids and carbohydrates, nucleotide binding, and oxidoreductase activity. Metadata classification of samples was more accurate using fecal bEVs (100%) compared with fecal samples (93%). ConclusionOur findings suggest that bEVs are unique functional entities. There is a need to explore bEVs together with conventional gut microbiome analysis in functional cancer research to decipher the potential of bEVs as cancer diagnostic or therapeutic biomarkers.

Understanding Sorafenib-Induced Cardiovascular Toxicity: Mechanisms and Treatment Implications.

Tyrosine kinase inhibitors (TKIs) have been recognized as crucial agents for treating various tumors, and one of their key targets is the intracellular site of the vascular endothelial growth factor receptor (VEGFR). While TKIs have demonstrated their effectiveness in solid tumor patients and increased life expectancy, they can also lead to adverse cardiovascular effects including hypertension, thromboembolism, cardiac ischemia, and left ventricular dysfunction. Among the TKIs, sorafenib was the first approved agent and it exerts anti-tumor effects on hepatocellular carcinoma (HCC) and renal cell carcinoma (RCC) by inhibiting angiogenesis and tumor cell proliferation through targeting VEGFR and RAF. Unfortunately, the adverse cardiovascular effects caused by sorafenib not only affect solid tumor patients but also limit its application in curing other diseases. This review explores the mechanisms underlying sorafenib-induced cardiovascular adverse effects, including endothelial dysfunction, mitochondrial dysfunction, endoplasmic reticulum stress, dysregulated autophagy, and ferroptosis. It also discusses potential treatment strategies, such as antioxidants and renin-angiotensin system inhibitors, and highlights the association between sorafenib-induced hypertension and treatment efficacy in cancer patients. Furthermore, emerging research suggests a link between sorafenib-induced glycolysis, drug resistance, and cardiovascular toxicity, necessitating further investigation. Overall, understanding these mechanisms is crucial for optimizing sorafenib therapy and minimizing cardiovascular risks in cancer patients.

Vitamin D Deficiency in Pediatric Oncology Patients: A Single-Center Experience in Saudi Arabia.

Background There is a lack of local studies on vitamin D deficiency in children with cancer. This study aims to estimate the prevalence of vitamin D deficiency in the pediatric oncology population at King Abdul-Aziz Medical City (KAMC) in Jeddah, addressing knowledge gaps for improved clinical practice and future research. Methods This retrospective observational studywas conducted from 2016 to 2021 at the pediatric oncology clinic in National Guard Hospital, Jeddah. The study focused on children aged 14 or younger at cancer diagnosis, data encompassed patient demographics, cancer details, and treatment information, including serum measurements of vitamin D (25(OH)D, calcium, phosphate, alkaline phosphatase). Vitamin D levels were categorized as deficient (<25 ng/ml), insufficient (25-49 ng/ml), sufficient (≥50- 125 ng/ml), or hypervitaminosis (>125 ng/ml), based on our center reference range and the validation of the assay. Results In this retrospective study of 155 pediatric oncology patients, the majority aged 0 to 10 years (78%), findings reveal a male preponderance (54.2%) and a more prevalent in patients with hematological malignancies (85%). Chemotherapy was administered to 98%, with 7% underwent radiotherapy, and 89% received steroids. Analysis of serum 25-OH vitamin D levels indicated an overall deficiency and insufficiency at diagnosis (63%) and post-therapy (43%). Age and gender had a significant influence on vitamin D levels at diagnosis, with older children and females exhibiting lower concentrations. However, these differences diminished by the end of therapy. Notably, hematological malignancy patients often presented insufficient vitamin D levels, while solid tumor patients frequently had sufficient levels. Clinical outcomes showed a high survival rate (90.7%), limited bone density assessments (18.1%), and a 14.2% prevalence of hypervitaminosis. Conclusion In summary, our study reveals that over two-thirds of pediatric oncology patients experience vitamin D deficiency and insufficiency at the time of diagnosis, particularly notable in females and older children. Notably, those with solid tumors exhibit higher baseline 25-OH vitamin D concentrations compared to counterparts with hematological malignancies. The findings underscore the importance of educating both patients and caregivers on supplementation and sun exposure to mitigate the prevalence of deficient and insufficient vitamin D levels in pediatric oncology cases.

Evaluating the effectiveness of the Charlson Comorbidity Index in predicting immune checkpoint inhibitor-related adverse events.

Aims: Our study aimed to evaluate the effectiveness of the Charlson Comorbidity Index (CCI) in predicting immune-related adverse events (irAEs) in solid tumor patients receiving immunotherapy. Patients & methods/materials: The CCI score at the time of initiation of immunotherapy was calculated in 164 solid tumor patients receiving immunotherapy and the correlation between the CCI score and immune toxicity was evaluated. Results: A significant relationship was found between CCI score and irAEs in lung cancer and renal cell cancer patients. In malignant melanoma, no significant relationship was found between the CCI score and the occurrence of irAEs. Conclusion: We argue that CCI can be used to predict irAEs, but we believe that a specific comorbidity index that includes autoimmune diseases should be developed.

First-in-human phase 1/2 trial evaluating TAC01-CLDN18.2 autologous T cells in CLDN18.2-positive solid tumors.

TPS419 Background: CLDN18.2 is a tight junction protein expressed in differentiated gastric epithelial cells and is abnormally expressed in various solid tumor types, serving as a promising target for therapy. To date, there are no approved therapies directed against this target, but compelling data exist using monoclonal antibodies and conventional CAR T therapy. The T Cell Antigen Coupler (TAC) technology is an approach to modifying T cells ex vivo, which allows recognition and cytotoxicity of tumor cells by co-opting the natural T cell receptor. The TAC technology has a safer profile than conventional CAR T therapies and is used to create an autologous TAC01-CLDN18.2 T cell product targeting CLDN18.2. Methods: This first in-human trial (NCT05862324) is designed to assess both the safety profile and preliminary antitumor activity of TAC01-CLDN18.2 in patients with CLDN18.2+/HER2- solid tumors after ≥ 2 lines of therapy. The phase 1 dose escalation segment employs a traditional 3+3 dose-escalation design to evaluate increasing doses of TAC01-CLDN18.2 with estimated enrollment numbers of 9 to 24 subjects. The subsequent phase 2 will further evaluate the efficacy, safety, and pharmacokinetics of the optimal TAC01-CLDN18.2 dose. With 3 cohorts, Group A will enroll up to 57 subjects with gastric and esophageal adenocarcinoma, Group B aims to enroll 10 subjects with pancreatic ductal adenocarcinoma (PDAC) while Group C will examine up to 22 subjects with ovarian and non-small cell lung cancer (NSCLC). Groups A and C will leverage a Simon 2-stage design to assess whether the treatment achieves efficacy, while Group B will be exploratory with an opportunity for cohort enrichment based on clinical data. Prior to TAC01-CLDN18.2 infusion, subjects will undergo leukapheresis and may receive bridging anticancer therapy as appropriate during cell manufacturing. CLDN18.2 expression levels will be determined centrally using a clinical trial assay validated across relevant indications. Subjects will then undergo low intensity lymphodepletion chemotherapy. A second dose of TAC01-CLDN18.2 may be administered based on prespecified safety and clinical criteria. Evaluation of DLTs will take place within a 28-day window following the first infusion. In both phases, CLDN18.2+/HER2- solid tumor patients must have completed at least two prior therapy lines except for PDAC patients who may qualify after one prior antineoplastic regimen. For phase 2, up to four prior treatment lines is permissible and definitions of eligible CLDN18.2 expression levels will be based on retrospective analysis of data from Phase 1 in association with clinical efficacy. The trial is currently in the open-enrollment stage, awaiting the inclusion of the inaugural patient. No data analysis is available as of the submission deadline. Clinical trial information: NCT05862324 .

Response to COVID-19 vaccination in patients on cancer therapy: Analysis in a SARS-CoV-2-naïve population.

Cancer patients have increased morbidity and mortality from COVID-19, but may respond poorly to vaccination. The Evaluation of COVID-19 Vaccination Efficacy and Rare Events in Solid Tumors (EVEREST) study, comparing seropositivity between cancer patients and healthy controls in a low SARS-CoV-2 community-transmission setting, allows determination of vaccine response with minimal interference from infection. Solid tumor patients from The Canberra Hospital, Canberra, Australia, and healthy controls who received COVID-19 vaccination between March 2021 and January 2022 were included. Blood samples were collected at baseline, pre-second vaccine dose and at 1, 3 (primary endpoint), and 6months post-second dose. SARS-CoV-2 anti-spike-RBD (S-RBD) and anti-nucleocapsid IgG antibodies were measured. Ninety-six solid tumor patients and 20 healthy controls were enrolled, with median age 62years, and 60% were female. Participants received either AZD1222 (65%) or BNT162b2 (35%) COVID-19 vaccines. Seropositivity 3months post vaccination was 87% (76/87) in patients and 100% (20/20) in controls (p=.12). Seropositivity was observed in 84% of patients on chemotherapy, 80% on immunotherapy, and 96% on targeted therapy (differences not satistically significant). Seropositivity in cancer patients increased from 40% (6/15) after first dose, to 95% (35/37) 1month after second dose, then dropped to 87% (76/87) 3months after second dose. Most patients and all controls became seropositive after two vaccine doses. Antibody concentrations and seropositivity showed a decrease between 1 and 3months post vaccination, highlighting need for booster vaccinations. SARS-CoV-2 infection amplifies S-RBD antibody responses; however, cannot be adequately identified using nucleocapsid serology. This underlines the value of our COVID-naïve population in studying vaccine immunogenicity.

Abstract A010: Insights into the Impact of Fanconi Anemia Repair Genes on Immunotherapy Response in Solid Tumors

Abstract Title: Insights into the Impact of Fanconi Anemia Repair Genes on Immunotherapy Response in Solid Tumors Background: Fanconi anemia repair (FAR) genes have crucial involvement in determining immunogenicity of solid tumors due to their substantial involvement in DNA damage repair (DDR). Previous work has alluded to the significance of DDR pathways such as mismatch repair and homologous recombination genes in treatment guidance. Herein, we study the potential impact of FAR genes mutations on immunotherapy parameters in solid tumors. Methods: We used the MSK immunotherapy and Tumor Mutational Burden (TMB) dataset was used in our analysis, which includes mutational and clinical data for 1661 patients on immune checkpoint inhibitors (anti-PD-1/L1, anti-CTLA-4, or combinational therapy) from ten cancer types (bladder, breast, colorectal, esophagogastric, glioma, head and neck, melanoma, non- small cell lung, renal cell, and unknown primary cancer). All clinical ang genomic data was retrieved through the cBioPortal database. Patients were categorized into the FAR mutated group if they harbored a mutation in at least one of the FAR genes (FANCA, FANCC, BRCA2, BRIP1, PALB2, RAD51C, SLX4) included in the MSK-IMPACT targeted next-generation sequencing panel. The log rank test and the Wilcoxon test, Chi-squared test were used to compare overall survival (OS), continuous and categorical data between FAR mutated and wildtype groups. Results: The MSK TMB cohort included 220 (13%) patients with FAR mutations, of which melanoma comprised the highest percentage (26.4%) followed by non-small cell lung cancer (NSCLC; 19.6%). The most common altered FAR gene was BRCA2 (6%), followed by SLX4 (5%), while the least altered gene was RAD51C (0.7%). FAR mutated patients had significantly higher OS compared to the wildtype group (median OS (mOS): 29 vs 17 months, log rank p &amp;lt; 0.001). Among melanoma patients (n = 320), there was no significant difference in OS between the mutated and FAR groups, whereas the NSCLC (n = 350) and colorectal cancer (CRC, n = 110) subgroups had significantly higher OS in the FAR mutated groups (NSCLC - mOS: 19 vs 10 months, p = 0.0256, CRC – mOS: not reached vs 13 months, p &amp;l; 0.001). TMB was significantly higher in the FAR mutated group (median TMB: 22.3 vs 5.2, p &amp;lt; 0.001). Notably, the most frequent co-mutations in the FAR mutated group included CTLA4, STK19, E2F3, CD276, MYCL. Conclusion: Our analysis highlights the potential role of FAR genes mutations in predisposing solid tumor patients to ICI benefit, specifically in NSCLC and CRC patients. Insights into the potential interactions between FAR genes and other DDR pathways as well as their impact on tumor immune microenvironment parameters are needed in future research to understand the drivers of ICI benefit in this subset of patients. Citation Format: Ahmed M. Ashour, Amro M. Al-Omari, Mohammad S. Bani Amer, Zaid R. Kamal. Insights into the Impact of Fanconi Anemia Repair Genes on Immunotherapy Response in Solid Tumors [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr A010.

Oral microbiome characteristics in patients with pediatric solid tumor.

Pediatric solid tumor, the abnormal proliferation of solid tissues in children resulting in the formation of tumors, represent a prevailing malignant ailment among the younger population. Extensive literature highlights the inseparable association linking oral microbiome and adult tumors, but due to differences in age of onset, characteristics of onset, etc., there are many differences between Pediatric solid tumors and adult tumors, and therefore, studying the relationship between Pediatric solid tumor and the oral microbiota is also essential. To unravel the distinct characteristics of the oral microbiota within Pediatric solid tumor patients, 43 saliva samples, encompassing 23 Pediatric solid tumor patients and 20 healthy controls, were diligently procured. A meticulous screening process ensued, and conducted microbial MiSeq sequencing after screening. We documented the oral microbiome attributes among pediatric diagnosed with solid tumors (PST), and meanwhile, we observed a significant trend of decreased oral microbiota diversity in the pediatric solid tumor group. There were notable disparities in microbial communities observed between the two groups, 18 genera including Veillonellaceae, Firmicutes unclassified, Coriobacteriia, Atopobiaceae, Negativicutes, were significantly enriched in PST patients, while 29 genera, including Gammaproteobacteria, Proteobacteria, Burkholderiales, Neisseriaceae, were dominant in the HCs group. It was found that PST group had 16 gene functions, including Amino acid metabolism, Cysteine and methionine metabolism, Photosynthesis antenna proteins, Arginine and proline metabolism, and Aminoacyl tRNA biosynthesi, were significantly dominant, while 29 gene functions that prevailed in HCs. This study characterized the oral microbiota of Pediatric solid tumor patients for the first time, and importantly, targeted biomarkers of oral microbiota may serve as powerful and non-invasive diagnostic tools for pediatric solid tumor patients.