Background/Aim: Satraplatin is an oral platinum analog with proven clinical efficacy and a more favorable toxicity profile, although with increased hematotoxicity, when compared to cisplatin. Hence, we carried out a systematic biomarker analysis to identify hematological malignancies with high susceptibility to satraplatin. Materials and Methods: Halfmaximal inhibitory concentrations (IC 50 ) for satraplatin and cisplatin were determined for 66 different cancer cell lines by CTG Luminescent Cell Viability Assay. In a second step, whole transcriptome RNA sequencing and whole-exome DNA sequencing technology followed by unbiased analysis of gene expression, gene mutation and copy number levels were performed and correlated with drug efficacy. Results: Satraplatin was significantly more active against hematological malignancies compared to solid organ cancer. In addition, satraplatin showed a significantly more potent antiproliferative activity compared to cisplatin in most lymphoma cell lines achieving sub micromolar IC 50 values. Single BCL2 apoptosis regulator (BCL2) gene mutation and 9p21 copy-number deletions including S-methyl-5'-thioadenosine phosphorylase (MTAP) deficiency were identified as key characteristics for high sensitivity to satraplatin. Conclusion: Satraplatin demonstrated a high cytotoxic activity in genetically welldefined hematological malignancies which is distinct from that of cisplatin. MTAP deficiency was identified as biomarker of enhanced satraplatin efficacy in hematological cancer-derived cell lines. These data in combination with the lipophilicity of satraplatin provide the rationale for targeting specific lymphatic entities such as primary central nervous system lymphoma and cutaneous T-cell lymphoma to improve clinical outcome.Cisplatin, carboplatin and oxaliplatin are platinum-based drugs that are used throughout the world for cancer treatment (1). All three are intravenously administered and primarily hydrophilic, with similar or even overlapping side-effects including nephrotoxicity, ototoxicity, neurotoxicity, cardiotoxicity, hematological toxicity, hepatotoxicity, and gastrointestinal toxicity. Platinum toxicity is usually the main reason for dose adaptations or even treatment suspension. This is particularly true for cisplatin, with the two most common nephrotoxic sideeffects being acute kidney injury and hypomagnesemia, which is reported to affect up to 90% of cisplatin-treated patients (2). Neurotoxicity and ototoxicity (60-90% of all patients) are the second and third most common platinum toxicities experienced with oxaliplatin, primarily causing neurotoxicity, and cisplatin causing ototoxicity.In order to develop better tolerated platinum compounds with less toxicity, platinum(IV) complexes featuring an octahedral geometry with two additional ligand sites were developed. They follow a classical prodrug concept since it is essential for their anticancer activity that they are reduced to the corresponding platinum(II) analogs in the tumor cell, leading to apoptosis (3). Satrap...

BACKGROUND: Immune checkpoint inhibitors (ICIs) have revolutionized the cancer therapy landscape in recent years. Despite the success of the checkpoint blockade strategies targeting cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed death receptor 1 (PD-1), many cancer patients cannot benefit from these therapies. T cell immunoglobulin and mucin domain 3 (TIM-3) has emerged as one of the next generation ICI targets, with potentially lower toxicity and higher safety compared to CTLA-4 and PD-1 blockades. TIM-3 is widely expressed in different immune lineages playing various roles such as mediating immune tolerance and regulating innate immune response. However, the mechanism of action of TIM-3 inhibition in different malignancies is not completely understood. Whether the expression and genomic status of TIM-3 and its ligands, Ceacam-1, galectin-9, HMGB1 and phosphatidyl serine (PtdSer) are associated with clinical outcome or any indication would be essential for patient selection for TIM-3 targeting therapies. METHODS: Human PD-1/TIM-3 double-knock-in mice (PD-1/TIM-3 dKI HuGEMM™) engrafted with CT26.WT tumor model were used to test human PD-1 antibody (Keytruda) and TIM-3 antibody (MBG453). Immune phenotyping of blood, tumor draining lymph node (TDLN) and spleen tissues were assessed by flow cytometry at different time points after dosing. Cytokine levels in serum were measured by MSD assays at 48 hours post the 3rd dose and at study termination. Patient genomic and clinical data for various cancer types such as colorectal adenocarcinoma and pancreatic adenocarcinoma were collected for prognostic biomarker analysis. RESULTS: In the in vivo efficacy study of single and combination treatment with Keytruda and MBG453, we observed that NK cells were induced by anti-TIM-3 treatment, alone and in combination, in both blood and TDLN. This indicates TIM-3 blockade may lead to NK cell proliferation in the TME to enhance tumor killing. Transcriptomic analysis on thousands of patients from TCGA showed that high expression of TIM-3 was highly associated with MSI-H and MSI/CIMP subtypes of colorectal adenocarcinoma, suggesting the potential of Tim-3 target therapy in combination with PD-1 blockade in colorectal cancers. By survival analysis, we observe that one of the TIM-3 ligands, HMGB1, expression is associated with patient OS and PFS with pancreatic adenocarcinoma, but not in colorectal cancers. Furthermore, TIM-3 expression was associated with many immune cell signatures, including macrophages, dendritic cells, CD8+ memory T cells, CD4+ memory T cells and Tregs in both colorectal and pancreatic adenocarcinoma. CONCLUSIONS: Evaluation in preclinical model demonstrated that TIM-3 blockade may cause NK cell proliferation to enhance anti-tumor immunity. In addition, the expression and genomic alteration of TIM-3 and its ligand have prognostic values for certain cancers. Citation Format: Jia Xue, Yu Zhang, Xianfei He, Henry Q. Li, Sheng Guo. Tim-3 as an immune therapy target, mechanism and action, and prognostic values with its ligands in patient stratification [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 615.

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Background: The established classification of acute lymphoblastic leukemia (ALL) does not cover all high-risk patients because of the difficulty in detecting novel or rare structural variants (SVs). Furthermore, many SVs and formed gene fusions have adverse prognostic effects on hematological malignancies. This study aims to investigate SVs in 22 patient-derived xenografts (PDX) of ALL and to assess rare SVs and chromosomal aberrations, particularly hematological malignancy genes and gene fusions in different individuals detected by optical genome mapping (OGM). Methods: Leukemia cells from 16 patients with B-cell precursor acute lymphoblastic leukemia (B-ALL) and 6 patients with T-cell acute lymphoblastic leukemia (T-ALL) were inoculated into immuno-deficient mice, growth curves were monitored, and leukemia cells were collected after human CD45 was more than 80%. OGM (Bionano Genomics), RNA sequencing (RNA-seq) and whole genome sequencing (WGS) techniques were used to detect SVs and gene fusions. In validation, polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH) tests were performed to identify specific SVs. Results: On average, each model detected 42 rare SVs with known overlapping genes in different types by OGM: 12 insertions, 25 deletions, 1 inversion, 3 duplications, 2 inter-chromosomal translocations and 1 intra-chromosomal translocation. 5 rare SVs were found in multiple models (>=5), and two of them were never reported in B-ALL and T-ALL. Gene fusions were detected in all ALL models by OGM, and 17% were novel fusions. At the mRNA level, gene fusions were detected only in 19 models, and 24% of the predicted gene fusions by OGM were identical to the results of RNA-seq (high confidence results including pseudogenes). These two technologies could detect different fusion partners. For example, MLLT1 was seen at the mRNA level, and ACER1 was detected at the DNA level in the same KMT2A rearrangement model. Of the 16 B-ALL models, 6 were p190 BCR-ABL1 (a fusion of BCR exon 1 and ABL1 exon 2), 1 was p210 BCR-ABL1 (a fusion of BCR exon 13 and ABL1 exon 2) and 5 of 7 had IKZF1 gene deletions. 2 p190 BCR-ABL1 models were insensitive to imatinib and 2 p190 BCR-ABL1 models as well as the model with IKZF1 exons 4-7 deletion were sensitive to imatinib when treatment was initiated early in the disease. A novel ARL15-IKZF1 fusion was identified in one of the sensitive models. Deletion of the PRKAR2B gene was another rare SV in both models sensitive to imatinib besides the IKZF1 deletion. Conclusion: OGM assays were more comprehensive, and novel rare SVs were identified in ALL. Combining the results of gene fusions between different technologies will provide more accurate predictions for ALL classifications. The combination of aberrant SVs may synergize to influence the efficacy of imatinib, which warrants further investigations. Citation Format: Yueying Wang, Mengting Qin, JinPing Liu, Xiaobo Chen, Jia Xue, Sheng Guo. Structural variants detected by optical genome mapping in acute lymphoblastic leukemia patient-derived xenografts models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2053.