Biomarkers For Patient Selection Research Articles

Targeting the tumor microenvironment, a new therapeutic approach for prostate cancer.

A growing number of studies have shown that in addition to adaptive immune cells such as CD8 + T cells and CD4 + T cells, various other cellular components within prostate cancer (PCa) tumor microenvironment (TME), mainly tumor-associated macrophages (TAMs), cancer-associated fibroblasts (CAFs) and myeloid-derived suppressor cells (MDSCs), have been increasingly recognized as important modulators of tumor progression and promising therapeutic targets. In this review, we aim to delineate the mechanisms by which TAMs, CAFs and MDSCs interact with PCa cells in the TME, summarize the therapeutic advancements targeting these cells and discuss potential new therapeutic avenues. We searched PubMed for relevant studies published through December 10 2023 on TAMs, CAFs and MDSCs in PCa. TAMs, CAFs and MDSCs play a critical role in the tumorigenesis, progression, and metastasis of PCa. Moreover, they substantially mediate therapeutic resistance against conventional treatments including anti-androgen therapy, chemotherapy, and immunotherapy. Therapeutic interventions targeting these cellular components have demonstrated promising effects in preclinical models and several clinical trials for PCa, when administrated alone, or combined with other anti-cancer therapies. However, the lack of reliable biomarkers for patient selection and incomplete understanding of the mechanisms underlying the interactions between these cellular components and PCa cells hinder their clinical translation and utility. New therapeutic strategies targeting TAMs, CAFs, and MDSCs in PCa hold promising prospects. Future research endeavors should focus on a more comprehensive exploration of the specific mechanisms by which these cells contribute to PCa, aiming to identify additional drug targets and conduct more clinical trials to validate the safety and efficacy of these treatment strategies.

Abstract 2560: Genomic biomarkers of survival in patients (pts) with metastatic castrate-sensitive prostate cancer (mCSPC) undergoing androgen deprivation therapy (ADT) intensification (ADTi)

Abstract Background: ADTi with androgen receptor pathway inhibitors (ARPI) with or without docetaxel improves survival outcomes in pts with mCSPC. Even with ADTi, 20% of these pts progress within a year and experience poor overall survival (OS). Identifying baseline genomic biomarkers predicting poor survival outcomes in pts receiving ADTi remains an unmet need. Methods: In this IRB-approved retrospective study, pts with a new diagnosis of mCSPC who underwent comprehensive genomic profiling of primary prostate tissue or metastatic site or cell-free DNA and treated with ADTi (ADT with ARPI or docetaxel) were included. Genomic alterations with an incidence > 5% were included in the analysis. Study endpoints: progression-free survival (PFS) was defined from the start of therapy for mCSPC to progression (per PCWG-2) or death from any cause. OS was defined from the start of therapy for mCSPC to the date of death from any cause or censored at the last follow-up. A multivariable analysis using the Cox proportional hazards model was used, adjusting for age at mCSPC diagnosis, disease volume (high vs. low), Gleason score (≥ 8 vs. < 8), Log2PSA at baseline, and initial timing of metastasis (de novo vs. non de novo). A subgroup analysis by intensification treatment received (ARPI vs. docetaxel) was also performed. Missing baseline characteristics such as volume of disease, Gleason score, and Log2PSA were multiply imputed on 50 chained equations using “mice” package in R. All the analyses were done using R version 4.3.1. Results: A total of 289 pts were included in the study. The baseline characteristics of the cohort will be presented in the meeting. The alterations included in the analysis were TP53 (31.8%), TMPRSS2 (30.4%), PTEN (17%), APC (10.4%), SPOP (9%), RB1 (6.2%), BRCA2 (5.2%), and CDK12 (5.2%). In the multivariable analysis, TP53 (HR 1.87, 95% CI 1.29-2.72, p = 0.001), RB1 (HR 2.56, 95% CI 1.45-4.53, p = 0.001), PTEN (HR 1.77, 95% CI 1.15-2.72, p = 0.009), and BRCA2 (HR 2.68, 95% CI 1.47-4.89, p = 0.002) were associated with significantly shorter PFS while TP53 (HR 1.78, 95% CI 1.1-2.88, p = 0.019), RB1 (HR 4.78, 95% CI 2.53-9.02, p < 0.001), and PTEN (HR 2.37, 95% CI 1.37-4.1, p = 0.003) were associated with significantly worse OS. Results of the subgroup analysis by intensification treatment (ARPI vs. docetaxel) will also be presented in the meeting. Conclusions: In this real-world study, we identified genomic biomarkers that could be associated with shorter PFS and OS in pts with mCSPC treated with ADTi. Upon external validation, these results may aid in developing a clinical-genomic risk stratification model, patient counseling, and treatment selection. Citation Format: Arshit Narang, Georges Gebrael, Chadi Hage Chehade, Nicolas Sayegh, Yeonjung Jo, Beverly Chigarira, Nishita Tripathi, Ayana Srivastava, Clara Tandar, Benjamin L. Maughan, Umang Swami, Neeraj Agarwal. Genomic biomarkers of survival in patients (pts) with metastatic castrate-sensitive prostate cancer (mCSPC) undergoing androgen deprivation therapy (ADT) intensification (ADTi) [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 2560.

Abstract 2485: A combined mregDC and Treg signature associates with antitumor efficacy of CCR4 antagonist tivumecirnon FLX475

Abstract Cancers evade immune surveillance through multiple mechanisms including the recruitment of immunosuppressive regulatory T cells (Treg). Tivumecirnon (formerly known as FLX475), a small molecule oral CCR4 antagonist under clinical evaluation, blocks the binding of CCR4 to its ligands CCL17 and CCL22 and thereby reduces Treg infiltration into the tumor microenvironment (TME). This relieves Treg-mediated immune suppression resulting in increased antitumor immunity. Our clinical study (NCT03674567) demonstrated that tivumecirnon can block the local accumulation of Treg in the TME and has clinical activity as monotherapy as well as in combination with pembrolizumab. In both mouse and human tumors, we identified a subset of tumor infiltrating dendritic cells (DC) producing high levels of CCL22, previously identified as mregDC, suggesting a potential role in the CCR4-dependent recruitment of Treg. To study the role of mregDC in the recruitment of Treg, non-clinical studies were performed. CD45+ immune cells from the TME of MB49 tumor bearing mice treated with tivumecirnon or vehicle and were analyzed by flow cytometry, scRNA-seq and CITE-seq. We confirmed that mregDC cells are the primary producer of CCL22 in the TME and that tivumecirnon treatment reduced the number of Treg cells in the TME and increased the percentage of IFN gamma and granzyme B expressing CD4+ T cells. Based on these findings we interrogated tumor biopsies from patients from our clinical study prior to (n = 33), and after approximately 6 weeks of treatment (n = 22, pre/post-treatment paired samples) with tivumecirnon +/- pembrolizumab. We performed RNAseq and compared to published biopsy data from anti-PD-1 treated patients. We found that higher mregDC + Treg signature levels at baseline significantly (p < 0.001) associated with response to tivumecirnon and pembrolizumab therapy. Importantly, analysis of published datasets revealed that higher baseline mregDC and Treg levels are not associated with response to anti-PD-1 monotherapy. Analysis of TCGA gene expression data demonstrated a positive correlation with mregDC and Treg cells across human tumor types, indicating a previously unknown relationship between these cell types. Further application of this mregDC and Treg signature to the TCGA dataset identified a subset of cancer types resistant to prior treatments that could potentially benefit from combinatorial treatment with tivumecirnon. Overall, this study demonstrated that inhibition of the CCR4 pathway using tivumecirnon can disrupt the immunosuppressive mregDC – Treg axis leading to enhanced antitumor activity. Furthermore, the levels of mregDC and Treg may be used as a biomarker for selection of patients more likely to respond to tivumecirnon in combination with anti-PD-1. Additional studies are required to confirm these results Citation Format: Adam Grant, Juraj Adamik, Jingtao Qiu, Jacob Wert, Molly Grandcolas, Scott Jacobson, Rakesh K. Goyal, William Ho, Shoji Ikeda, Marvin Au, Damian Trujillo, Michael Chisamore, Denise de Almeida Nagata, Mohsen S. Ghomi, Dirk G. Brockstedt, Paul D. Kassner, George Katibah. A combined mregDC and Treg signature associates with antitumor efficacy of CCR4 antagonist tivumecirnon FLX475 [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 2485.

Abstract 2112: Identification of biomarkers associated with sensitivity to a novel PCNA inhibitor (AOH1996) by CRISPRi screening

Abstract Proliferating cell nuclear antigen (PCNA) plays an essential role in regulating DNA synthesis and repair and is essential for cancer cell growth and survival. We discovered a cancer-associated isoform of PCNA (caPCNA), which is ubiquitously and highly expressed in a broad range of cancer cells and tumor tissues but is not significantly expressed in non-malignant cells. Further studies of this novel caPCNA isoform as an anti-cancer drug target led to the identification of a cancer distinct region of PCNA which is partly delineated by the L126-Y133 peptide sequence and the discovery of a small molecule (AOH1996), which binds to this cancer distinct region as shown by crystallization studies. By targeting caPCNA, AOH1996 selectively kills cancer cells by interfering with the resolution of transcription-replication conflicts (TRC). Importantly, it causes no discernable toxicity at 6 times of its effective dose in mice. AOH1996 is currently in a phase 1 clinical trial for adult solid tumors at City of Hope (IND 138273). To identify genes that may be used as biomarkers for patient selection or potential targets for combination therapies, we screened a CRISPR interference (CRISPRi) library, which targets genes that are involved in cell signaling and cell cycle regulation. After culturing transduced cells in the presence of DMSO or 250 nM AOH1996 (corresponding to IC20) in triplicates for 14 generations, we measured the relative abundance of each guide RNA (gRNA) construct. Significant changes in the abundance of the gRNA constructs in AOH1996-treated cells relative to that in DMSO-treated cells were determined by the MAGeCK method. The target genes of the depleted or enriched gRNAs are predominantly involved in DNA repair, cell cycle regulation, and transcription regulation, which is consistent with the action mechanism of AOH1996. We validated the effect of these genes on sensitivity to AOH1996 and identified a panel of target proteins whose up or down-regulation is associated with sensitivity to AOH1996. Some of these proteins are targets of known chemotherapeutic drugs, which may be used in combination with AOH1996 in the clinic. Citation Format: Long Gu, Ming li, Chun-Wei Chen, Robert J. Hickey, Linda H. Malkas. Identification of biomarkers associated with sensitivity to a novel PCNA inhibitor (AOH1996) by CRISPRi screening [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 2112.

Abstract 2866: NAPRTsilencing in rhabdomyosarcoma confers therapeutic vulnerabilities to NAD+depletion

Abstract Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma among children, and new treatments are needed to improve survival. Cells primarily synthesize nicotinamide adenine dinucleotide (NAD) through the Preiss-Handler and Salvage pathways driven by nicotinic acid phosphoribosyltransferase (NAPRT) and nicotinamide phosphoribosyltransferase (NAMPT), respectively. NAMPT inhibitors (NAMPTi) have been tested in clinical trials, but their efficacy has been limited by (a) lack of appropriate biomarkers for patient selection, and (b) significant dose-limiting toxicities (DLTs), including myelosuppression and retinal toxicity, although the latter has been described only in preclinical studies. Previous work from our group indicates that loss of NAPRT expression by tumor-specific promoter CpG island methylation may provide a novel biomarker for sensitivity to NAMPTi in a variety of tumors. Here, we sought to determine if RMS harbors NAPRT silencing that confers a synthetic lethal interaction with NAMPTi. We probed methylation data within the Cancer Dependency Map (DepMap) and found a high frequency of NAPRT gene promoter hypermethylation in RMS models. Predicted NAPRT silencing was confirmed at the protein level by western blot in a panel of RMS cell lines. In vitro growth delay assays demonstrated that NAPRT-silenced cells are exquisitely sensitive to NAMPTi even in the presence of nicotinic acid (NA) supplementation, while NAPRT-expressing cells were completely rescued. This sensitivity to NAMPTi was further mirrored by changes in NAD levels. In vivo, NAMPTi induced significant tumor regression in a NAPRT-silenced RMS xenograft model. To further establish the translational relevance, NAPRT protein expression in a TMA of 51 human RMS tumors was assessed via IHC staining using a newly validated NAPRT monoclonal antibody (4A5D7). Based on a semi-quantitative scoring system accounting for the percentage of positive tumor cells and staining intensity, 28% of RMS samples demonstrated loss of NAPRT protein expression. Overall, these data suggest that NAPRT loss may serve as a therapeutic target in RMS by inducing a synthetic lethal interaction with NAD+ depleting agents. Future studies in patient-derived xenograft (PDX) models will determine the optimal cut-off of NAPRT expression that portends NAMPTi sensitivity, paving the way for the development of biomarker-driven clinical trials in RMS. Ongoing studies will also evaluate the efficacy of combining NAMPTi with existing cytotoxic and DNA damaging chemotherapy in these difficult-to-treat tumors. Citation Format: Sophia J. Zhao, Katelyn J. Noronha, Prateek Bhardwaj, Karlie N. Lucas, Ranjini K. Sundaram, Collin D. Heer, Raffaella Morotti, Josh Spurrier, Mitch Raponi, Ranjit S. Bindra, Juan C. Vasquez. NAPRTsilencing in rhabdomyosarcoma confers therapeutic vulnerabilities to NAD+depletion [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 2866.

Abstract 5181: Early activity and biomarker evaluation of NT219 in combination with cetuximab in a Phase 1/2 study of recurrent/metastatic squamous cell carcinoma of the head and neck (R/M SCCHN)

Abstract Background. NT219 is a novel small molecule, dual inhibitor, that uniquely triggers the degradation of Insulin Receptor Substrates 1/2 (IRS) and the dephosphorylation and suppression of STAT3. These two major oncogenic targets in the tumor and tumor microenvironment (TME) play a key role in drug resistance, particularly to EGFR inhibitors. Previously, we demonstrated synergistic effect of NT219 and cetuximab in multiple SCCHN patient-derived xenograft (PDX) models. HPV-negative R/M SCCHN patients have poor survival and demonstrate IGF1R/IRS and STAT3 upregulation. We report biomarker results from dose escalation of NT219 in combination with cetuximab in patients (pts) with immunotherapy-refractory R/M SCCHN (NCT04474470). Method. Biopsies from 11 enrolled SCCHN patients treated with different dose levels of NT219 (6, 12, 24 and 50 mg/kg) were obtained and evaluated using Immunohistochemistry and pathological analysis. Evaluation of potential biomarkers included measurements of IRS1/2 levels, as well as IGF1R and STAT3 phosphorylation (pIGF1R, pSTAT3) in tissue biopsies, and H-score was defined for tumor cells, infiltrating immune cells, and fibroblasts in the TME. Membrane completeness (mc) parameter was included in pIGF1R scoring. Results. NT219 Cmax and AUC demonstrated a dose dependent increase, with 50mg/kg dose mean human AUC reaching Human Equivalent Dose efficacy of animal models. Indeed, at this dose, anti-tumor activity in humans was also demonstrated with 2 confirmed partial responses (PR) reported. At the 50 mg/kg NT219 dose, out of 4 SCCHN pts, for whom pre-treatment biopsies were available, 3 were HPV negative and 2 of them achieved PR. Pretreatment biopsies of these 2 pts demonstrated high activated IGF1R membranal staining (Avg. mcH-score: 285, p-value:) and high activated STAT3 nuclear staining (Avg. H-score: 285), in contrast to the non-responding SCCHN pts (30 and 33, with p-value 0.017, 0.004 respectively). Inhibition of intratumoral IGF1R/IRS and STAT3 was demonstrated in on-treatment biopsies. Analysis will be presented at the conference. Conclusion. NT219 in combination with cetuximab demonstrated safety and early activity with 2 confirmed PRs at 50mg/kg dose level in R/M SCCHN pts. This dose level was the first dose at which the observed NT219 exposure was within the range of the efficacious dose levels in pre-clinical models. Detection of activated IGF1R and STAT3 in responding pts, compared to the non-responding pts, suggests a potential use of these targets as biomarkers for future patient selection. This notion is further substantiated by the demonstration of NT219 on-target effects in on-treatment tumor biopsies. Upregulation of NT219 targets, IGF1R and STAT3, in HPV-negative SCCHN pts and their response to the NT219+cetuximab treatment, support further evaluation of this patient population. Citation Format: Ari J. Rosenberg, Shumei Kato, Daniel Johnson, Aron Popovtzer, Vi K. Chiu, Ravit Geva, Hava Ben-David, Tomer Meirson, Michael Schickler, Hadas Reuveni. Early activity and biomarker evaluation of NT219 in combination with cetuximab in a Phase 1/2 study of recurrent/metastatic squamous cell carcinoma of the head and neck (R/M SCCHN) [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 5181.

Abstract 903: AURIGIN: A comprehensive single-cell OMICs atlas of human development and an AI/ML framework to classify and identify the drivers of tumor plasticity and altered cellular state

Abstract Altered cellular state and plasticity have been increasingly identified as drivers of poor prognosis and treatment-resistance in cancer. Identifying therapeutics that correct altered cellular state and plasticity meets a broad need in the field of oncology, particularly in tumors resistant to standard-of-care therapy. Tumor plasticity and altered cellular states encompass many potential configurations, including dedifferentiated and transdifferentiated tumors, so classifying tumors based on their specific cell state profile is critical to identifying the gene drivers that are specific to that altered state. For that reason, we have developed AURIGIN - a platform that combines a comprehensive single-cell OMICs atlas of human development with an AI/ML framework that can classify cell state plasticity and identify the genes and pathways that drive those specific altered cellular states. AURIGIN is more comprehensive than previously disclosed single cell atlases in that it focuses and enriches the diverse stem, progenitor, and developmental states commonly involved in plastic cell states of cancer. The platform standardizes and integrates these states with multiple atlases of differentiated adult tissues to create a unified atlas of human development. In addition, the AI/ML paradigm of AURIGIN is embedded with developmental biology models that enable it to deconvolute state heterogeneity within tumor indications for precise identification of the most relevant gene targets for novel therapies. AURIGIN also unifies classified plasticity across tissue types by identifying altered cellular states that span multiple indications. Furthermore, we present the implementation of AURIGINDRIVE ML models that integrate pathway information, physical interaction datasets, and regulatory annotations to accurately predict the gene targets at the top of hierarchy of control of tumor plasticity. AURIGIN also enables and accelerates target validation by identifying models that map to the relevant classified plastic states. Similarly, AURIGIN defines clinically relevant patient selection and treatment efficacy biomarkers that are specifically defined from the classified plastic cellular state. We demonstrate the success of AURIGIN for therapeutic discovery. In sum, AURIGIN amplifies the value of multiOMIC tumor data in cellular state and plasticity target discovery by mapping the data into a developmental biology-informed ML framework. Citation Format: Joseph DeBartolo, Henry Wilson, Kimberly S. Straley, Maulasri Bhatta, Sambad Sharma, Sara Sinicropi-Yao, James Neef, Betty Chan, Andrew McRiner, Mark Bittinger, Laura Antipov, Katharine E. Yen, Thomas G. Graeber, David S. Millan. AURIGIN: A comprehensive single-cell OMICs atlas of human development and an AI/ML framework to classify and identify the drivers of tumor plasticity and altered cellular state [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 903.

Abstract 7176: Optimization of T cell co-stimulatory agonists: A semi-mechanistic PKPD model integrating drug properties and tumor-immune interactions

Abstract Background: Despite the success of some immune checkpoint inhibitors in the treatment of cancer, T-cell co-stimulation has faced limited clinical success due to the intricacies around the optimal engagement of agonistic antibodies to co-stimulatory receptors, and the absence of biomarkers for patient selection. Understanding agonist-binding characteristics, pharmacokinetics, T cell subpopulation activation and differentiation kinetics, T cell life span in the tumor microenvironment, and the impact of T cell/tumor interactions on tumor growth kinetics is crucial for the positive clinical outcomes of T cell agonists. Currently there is not a suitable model to describe these complex interactions. Methods: We investigated the pharmacokinetic (PK), pharmacodynamics (PD), and anti-tumor efficacy of an anti-TNFR2 agonist, HFB3-1, and an anti-OX40 agonist, HFB10-1, in syngeneic tumor models. Flow cytometry was employed to profile post-treatment tumor infiltrating lymphocytes (TILs) in dissociated tumor tissues. In vitro binding affinity was determined using Biolayer Interferometry. A semi-mechanistic model, integrating PK, tumor growth, and immune interaction networks (interactions among Teff, Treg, and tumor cells), was developed in Berkeley Madonna (version 10.5.1). This was subsequently adapted to a human tumor growth model with T cell interaction networks to assess the impact of doses and dosing regimens on tumor growth inhibition. Results: A semi-mechanistic PKPD model was successfully developed incorporating drug properties including binding affinity, agonistic effect, ADCC activity, and pharmacokinetics, and tumor growth characteristics including tumor growth kinetics, TIL composition, interaction, proliferation, and turnover. This model was applied to investigate the effect of FcγR, dose, and dosing frequency on in vivo efficacy. Following incorporation of human PK and human tumor microenvironment properties into the model, tumor growth characteristics were simulated under varying human dosing regimens. Simulation results indicated that lower and less frequent doses optimize T cell co-stimulation for optimal anti-tumor activity. Conclusion: Our semi-mechanistic PKPD model elucidates the intricate interactions between T cell co-stimulatory agonists and the tumor-immune cells in the tumor microenvironment. The model advocates for pulsatile agonism as the optimal anti-tumor activity for T cell co-stimulation agents. This model serves as a valuable tool for guiding dose and dose regimen optimization for T cell co-stimulatory agonists in clinical development. Citation Format: Jinping Gan, William Hedrich, Yun-Yueh Lu, Wenhua Xu, Robert H. Andtbacka, Francisco Adrian, Liang Schweizer. Optimization of T cell co-stimulatory agonists: A semi-mechanistic PKPD model integrating drug properties and tumor-immune interactions [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 7176.

Abstract 5139: PD1-PDL1 interaction as a superior predictor for response to immune checkpoint therapy in NSCLC patients

Abstract Background: Immune checkpoint therapies (ICT) are now widely introduced in clinical oncology and most often guided by PDL1 expression in diagnostic biopsies. However, the predictive value of this testing is only modest, leading to over- and undertreatment. Conceptually, the prevention of binding of ligand PDL1 to PD1 receptor is decisive for the efficacy of ICT. Therefore, directly detecting the spatial PD1-PDL1 interaction would provide more predictive information. Methods: A second-generation in situ proximity ligation assay (isPLA; Navinci Diagnostics) was established to detect PD1-PD-L1 interactions in diagnostic patient samples and linked to an automated analysis pipeline (QuPath). For basic validation, we used pan-cancer tissue microarrays (TMA) including 16 solid tumor types, and a non-small cell lung cancer (NSCLC) TMA (359 ICT-naïve surgically treated patients). In addition, we analyzed diagnostic tissue biopsies from 75 advanced NSCLC patients treated with anti-PD1-PDL1 regiments. Results: The pan-cancer analysis revealed varying levels of PD1-PDL1 interaction among the solid cancer types, with the lowest levels detected in liver cancer and the highest in testicular cancer. A general positive association was observed between the literature-reported objective ICT response rate (ORR) per tumor type and its corresponding PD1-PDL1 interaction status. Conventional immunohistochemical analysis of the ICT-naïve, surgically treated NSCLC cohort revealed variable protein expression level for both, PDL1 and PD1, for 200 cases, but only 108 (54%) of them demonstrated a detectable PD1-PDL1 interaction with our isPLA assay. EGFR mutated cases showed generally lower PD1-PDL1 interaction scores (p=0.01). PD1-PDL1 interaction was not associated with survival (p=0.46). A subsequent analysis of the ICT-NSCLC cohort revealed a significant positive association between PD1-PDL1 interaction status and prolonged overall survival upon ICT (median survival 14.8 vs 32.3 months; p=0.022). The standard tumor proportional score (TPS) of membranous PDL1 expression did not correlate with ICT-specific survival (p=0.40). Conclusions: The second generation isPLA successfully distinguishes a previously difficult-to-define patient subset with positive PD1-PDL1 interaction status. Our data suggest that the PD1-PDL1 interaction is a superior clinical biomarker for patient selection for ICT in NSCLC. The interaction analysis is applicable to sections from minute diagnostics biopsies and accessible by light microscopy either semi-quantitatively by a pathologist or by an automated image analysis program. Thus, the assay holds great potential to be integrated into routine clinical pathological workflow to stratify cancer patients for ICT. Citation Format: Patrick Micke, Amanda Lindberg, Rebecca Artursson, Louise Hellberg, Hui Yu, Max Backman, Johan Botling, Hans Brunnström, Artur Mezheyeuski, Johan Isaksson, Carina Strell. PD1-PDL1 interaction as a superior predictor for response to immune checkpoint therapy in NSCLC 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 5139.

Abstract 6404: GRB2 stabilizes RAD51 at reversed replication forks restricting genomic instability and associated innate immune response

Abstract Growth factor receptor-bound protein 2 (GRB2) is a cytoplasmic adapter for tyrosine kinase signaling and a nuclear adaptor for homology-directed-DNA repair. Here we find nuclear GRB2 protects DNA at stalled replication forks from MRE11-mediated degradation in the BRCA2 replication fork protection axis. Mechanistically, GRB2 binds and inhibits RAD51 ATPase activity to stabilize RAD51 on stalled replication forks. In GRB2-depleted cells, PARP inhibitor (PARPi) treatment releases DNA fragments from stalled forks into the cytoplasm that activate the cGAS-STING pathway to trigger pro-inflammatory cytokine production. Moreover in a syngeneic mouse metastatic ovarian cancer model, GRB2 depletion in the context of PARPi treatment reduced tumor burden and enabled high survival consistent with immune suppression of cancer growth. Collective findings unveil GRB2 function and mechanism for fork protection in the BRCA2-RAD51-MRE11 axis and suggest GRB2 as a potential therapeutic target and an enabling predictive biomarker for patient selection for PARPi and immunotherapy combination. Citation Format: Zamal Ahmed, Zu Ye, Shengfeng Xu, Yin Shi, Xueqian Cheng, Yuan Zhang, Sunetra Roy, Sarita Namjoshi, Michael A. Longo, Todd Link, Katharina Schlacher, Guang Peng, Dihua Yu, Bin Wang, John Tainer. GRB2 stabilizes RAD51 at reversed replication forks restricting genomic instability and associated innate immune response [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 6404.

Abstract 5203: Identification of prognostic and predictive biomarkers for palbociclib add-on therapy using cancer panel sequencing of cell-free DNA in patients with HR-positive HER2-negative advanced and metastatic breast cancer with fulvestrant resistance

Abstract Purpose: The combination of cyclin-dependent kinase 4/6 inhibitors with endocrine therapies has shown promise for improving the survival of patients with hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative advanced and metastatic breast cancer (ABC/MBC). The FUTURE trial (UMIN000029294) demonstrated that adding palbociclib after acquiring fulvestrant resistance is potentially safe and effective. To further identify biomarkers for patient selection, this preplanned translational sub-study aims to use cancer panel sequencing of cell-free DNA (cfDNA) to discover prognostic and predictive biomarkers for additional palbociclib treatment after acquiring fulvestrant resistance in patents with HR-positive/HER2-negative ABC/MBC. Methods: Herein, we utilized 149 cfDNA samples from 61 patients with disease progression after fulvestrant monotherapy and who subsequently received fulvestrant and palbociclib. Circulating cfDNA was analyzed at the time of palbociclib addition after fulvestrant resistance, on day 15 of cycle one (D15), and at the end of treatment (EOT) using the ThruPLEX ctDNA Assay, which can identify single or multi nucleotide variants, DNA insertions, and deletions in up to 34 cancer-associated genes. Results: The genetic landscape of patients with BC undergoing palbociclib treatment was dynamic and changed over the course of treatment. Regarding progression-free survival, alterations in NRAS (Hazard Ratio (HR): 11.97, P < 0.005)), MAP3K1 (HR: 6.86, P < 0.005), and TP53 (HR: 3.6, P = 0.02) were identified in cfDNA on D15 and were linked to poor prognoses. Alterations in CBFB at baseline (HR: 5.15, P = 0.01), in BRCA2 (HR: 7.17, P < 0.005) and NRAS (HR: 5.32, P < 0.005) at D15, and ESR1 (HR: 4.37, P = 0.01) at EOT were also linked to poor prognosis, whereas alterations in WEE1 (HR: -5.84, P = 0.02) at EOT were associated with a favorable prognosis. Alterations in ESR1, WEE1, CBFB, and BRCA2 were prognostic factors at peak frequencies during treatment. Moreover, our research uncovered a novel observation that as treatment progressed, the relationship between prognostic factors focused on alterations in ESR1 and TP53 tended to weaken. Conclusion: Cancer panel testing for cfDNA identified prognostic and predictive biomarkers for palbociclib add-on therapy after acquiring fulvestrant resistance in patients with HR-positive/HER2-negative ABC/MBC. These findings have important implications for patient selection and personalized treatment strategies in such patients. Citation Format: Takashi Takeshita, Takayuki Iwamoto, Naoki Niikura, Kenichi Watanabe, Yuichiro Kikawa, Kokoro Kobayashi, Nobutaka Iwakuma, Takuho Okamura, Hiroshi Tada, Shinji Ozaki, Toshitaka Okuno, Uhi Toh, Yutaka Yamamoto, Michiko Tsuneizumi, Hiroshi Ishiguro, Norikazu Masuda, Shigehira Saji. Identification of prognostic and predictive biomarkers for palbociclib add-on therapy using cancer panel sequencing of cell-free DNA in patients with HR-positive HER2-negative advanced and metastatic breast cancer with fulvestrant resistance [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 5203.

Abstract 5903: MASTL small-molecule inhibition to target mitosis for cancer therapy

Abstract Cell cycle/tumor repressors can be pharmacologically activated to repress uncontrollable proliferation of cancer cells. However, targeting cell cycle regulators of G2/M and mitotic checkpoints to achieve maximum therapeutic benefit remains a challenge due to a limited therapeutic index. Here, we identified highly potent and selective oral bioavailable clinical candidate inhibitors to the first-in-class oncology target Microtubule Associated Serine/Threonine Kinase-Like (MASTL) aimed at expanding therapeutic control of the cell cycle for cancer therapy. Breath of efficacy screening in multiple tumor indications in vitro followed by computational analyses identified the regulatory subunit PPP2R2A as a potential patient selection biomarker that strongly correlates to MASTL inhibitor response irrespective of cancer genetic alterations. Functional genetics studies confirmed that sensitivity to MASTL inhibition is defined by PPP2R2A expression. To identify genetic mediators of MASTL inhibitor resistance, a whole genome CRISPR knockout screen with the MASTL inhibitor was performed and further established that the MASTL inhibitor response is dependent on PPP2R2A containing PP2A complexes. Mechanistic studies (proteomics, resistance, functional genetics, and time-lapse microscopy) demonstrated that MASTL inhibition disrupts mitosis by activating the tumor suppressor PP2A, leading to a switch from CDK1 activity to CDK1 inactivity, mitotic defects, and cancer cell death. MASTL inhibition treatment in tumor models in vivo and in patient-derived organoid models results in potent tumor growth inhibition. Our results demonstrate that the first identified highly selective MASTL clinical candidate inhibitors represent a potential new cancer therapeutic strategy to target mitosis and mitotic exit by activating the tumor repressor PP2A to counter CDK1 activity. All procedures performed on animals were in accordance with regulations and established guidelines and were reviewed and approved by an Institutional Animal Care and Use Committee or through an ethical review process. Citation Format: Chad M. Toledo, Koleen J. Eisele, Dong Hyun Kim, Xinmeng Mu, Sonja Brun, Carl Davis, Eric C. Greenwald, Fion Hui, Meilan He, Yanling Yang, Ana Flores-Bojorquez, Yuxin Li, Penney L. Khamphavong, Joseph H. Lee, Jian Li, Dana J. Ramms, Greg Jones, Marin Auth, Cory L. Painter, Andrew Nager, Jon Oyer, Sergei L. Timofeevski, William E. Pierceall, Anwar Murtaza, Jonathan R. Heyen, Rebecca Gallego, Casey Quinlan, Indrawan McAlpine, Todd L. VanArsdale. MASTL small-molecule inhibition to target mitosis for cancer 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 5903.

Abstract 2504: Determining tumour homologous recombination repair status in PDX and clinical samples using automated RAD51 scoring

Abstract PARP inhibitors (PARPi) as monotherapy are approved in a wide variety of cancers that show genetic alterations that result in homologous recombination repair (HRR) deficiency. Current genomic scar tests for HRR deficiency (HRD) are predictive of response to PARPi on a population scale but they may fail to provide a real-time functional status of HRR in an individual. RAD51 is a critical DNA repair factor that functions in HRR to safeguard the integrity of the genome and could be a useful patient selection biomarker for PARPi response.During HRR, RAD51 forms filamentous structures to facilitate repair, which can be visualised by direct immunofluorescence (IF) as nuclear foci. Quantification of these RAD51 foci has been shown to be a functional readout of HRR status, however current manual counting of foci is challenging and can result in high inter-observer variability. In order to standardise RAD51 quantification, we aimed to develop an image analysis solution.Tumour samples from patient derived xenograft (PDX) studies and human tissues from commercial sources and clinical trials were co-stained with IF for RAD51 and geminin, as a marker of cells in S/G2 phase of the cell cycle. Manual scoring was performed as reported previously. Visiopharm was used to create and image analysis pipeline in allowing delineate tumour epithelial areas, detection of the geminin positive nuclei and RAD51 foci within these and the quantification of the foci.We have successfully developed an image analysis solution to select geminin positive proliferating tumour cells from PDX and clinical material, then quantify the RAD51 foci within these cells. There is a good correlation with manual scores with a similar accuracy to the manual inter-observer variability (PDX: R2 = 0.76, F1 = 0.95 [n=34]; breast cancer samples: R2 = 0.72, F1 = 0.92 [n=33]). Developing and image analysis solution has challenges due to several factors such as pan-nuclear staining of non-focus forming RAD51 being variable across samples, manual scoring using a wider Z-plane, susceptibility of RAD51 to pre-analytical factors and the fact that a duplex IF stain with geminin is required to mark actively replicating cells.The frequent inactivation of HRR is known to sensitise cancer cells to PARP inhibitors, we demonstrate a quantitative functional readout of HRR competency using RAD51 foci staining and an image analysis algorithm. This solution may enable the use of RAD51 foci as a patient selection biomarker for PARP inhibitors by providing an objective, robust and reproducible algorithm for scoring. Citation Format: Jack Robertson, Jack Ashton, Gemma N. Jones, Gordon Mills, Tugba Y. Ozmen, Matthew J. Rames, Soonyoung Park, Paul Waring, Natalia Lukashchuk, Elizabeth Harrington. Determining tumour homologous recombination repair status in PDX and clinical samples using automated RAD51 scoring [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 2504.

Abstract 3301: Translational research of CDK12/13 inhibitor, CTX-439, informing clinical trial strategy

Abstract Gene dysregulation is a hallmark of cancer, arising from genetic alterations that invariably lead to dysregulated transcriptional programs. This dysregulation renders cancer cells highly dependent on certain gene expression regulators, leading to a potential for novel therapeutic strategies. Consequently, ongoing research aims to develop small molecules targeting RNA transcriptional processes. Cyclin-dependent kinase 12/13 (CDK12/13) is a member of the cyclin-dependent kinase family of serine/threonine protein kinases. CDK12/13 regulates the RNA transcription elongation by phosphorylating RNA polymerase II and promotes the elongation of transcripts, specifically those involved in DNA damage responses, such as BRCA1/2. The inhibition of CDK12/13 is expected to exert a synergistic effect when combined with PARP inhibitors and chemotherapeutic reagents. Therefore, we developed a novel small molecule inhibitor, CTX-439 (former name: CRD-1835439). Additionally, we demonstrated that CTX-439 exhibits a preclinical efficacy in vitro and in vivo [Cancer Res. (2022) 82 (12_Supplement): 5485]. To identify potential strategies for a clinical trial of CTX-439, in the current study, we conducted translational research to elucidate (1) pharmacodynamics (PD) markers to monitor the suppression of CDK12/13 in humans, (2) patient selection biomarkers to determine sensitivity to CTX-439, and (3) combination strategies with other key medications. Firstly, to identify PD markers of CTX-439, we performed a comprehensive analysis employing RNA-seq, Pol II-ChIP-seq, and Poly(A)-seq. We confirmed that CTX-439 induced the usage of intronic polyadenylation sites by inhibiting CDK12, resulting in the production of shortened mRNA. Of these transcripts, PCF11 emerged as a potential PD marker for clinical trials, which was confirmed using qPCR analysis of human blood. Secondly, to clarify the indication of CTX-439, we performed an in vitro survey involving 400 cell lines and 100 PDX-derived organoids (PDXOs) to identify biomarkers displaying sensitivity and insensitivity to CTX-439. Furthermore, a significant anti-tumor effect of CTX-439 was revealed in PDX models that showed sensitivity in the survey. CTX-439 exhibited a synergistic effect in combination with PARP inhibitors both in vitro and in vivo, highlighting its potential for use in combination strategies. Additionally, CTX-439 showed an anti-tumor effect when combined with other chemotherapy and molecular-targeted drugs. Collectively, the results from these translational research studies provide a foundation for developing a clinical trial by clearly defining PD monitoring, patient stratification biomarkers, and combination strategies. These findings highlight the therapeutic potential of CTX-439 as a single-agent and in combination with inhibitors, such as PARP, for the treatment of cancers characterized by transcriptional addiction. Citation Format: Hiroko Yamakawa, Shunsuke Ebara, Akio Mizutani, Misaki Yoshida, Midori Sugiyama, Koji Yamamoto, Daisuke Komura, Miwako Kakiuchi, Shumpei Ishikawa, Kosuke Yusa, Daisuke Morishita. Translational research of CDK12/13 inhibitor, CTX-439, informing clinical trial strategy [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 3301.

GRB2 stabilizes RAD51 at reversed replication forks suppressing genomic instability and innate immunity against cancer

Growth factor receptor-bound protein 2 (GRB2) is a cytoplasmic adapter for tyrosine kinase signaling and a nuclear adapter for homology-directed-DNA repair. Here we find nuclear GRB2 protects DNA at stalled replication forks from MRE11-mediated degradation in the BRCA2 replication fork protection axis. Mechanistically, GRB2 binds and inhibits RAD51 ATPase activity to stabilize RAD51 on stalled replication forks. In GRB2-depleted cells, PARP inhibitor (PARPi) treatment releases DNA fragments from stalled forks into the cytoplasm that activate the cGAS–STING pathway to trigger pro-inflammatory cytokine production. Moreover in a syngeneic mouse metastatic ovarian cancer model, GRB2 depletion in the context of PARPi treatment reduced tumor burden and enabled high survival consistent with immune suppression of cancer growth. Collective findings unveil GRB2 function and mechanism for fork protection in the BRCA2-RAD51-MRE11 axis and suggest GRB2 as a potential therapeutic target and an enabling predictive biomarker for patient selection for PARPi and immunotherapy combination.

Bibliometric Analysis of the Highly Cited Articles on Biomarker Discovery for Irritable Bowel Syndrome from 1985 to 2023.

With an increasing number of patients with irritable bowel syndrome (IBS) and availability of many pharmacological treatment options, there is an urgent need to develop and validate IBS biomarkers for prognostication and selection of patients for treatment and monitoring. The usage of investigations is limited because of its invasive nature, poor patient acceptability, and sampling variability. The bibliometric analysis of biomarker discovery of IBS articles will help in understanding current research trends of biomarkers study of IBS. To study the most highly cited articles from literature search on the biomarker for IBS to provide simple educational source. A bibliometric literature review-the electronic search by terms and keywords were searched in PubMed databases. The commonly cited article was searched from 1985 to 2023. The total citation number was received from knowledge search engines like Google Scholar. Articles were classified according to number of citations, year of publication, journal name, authors, publications from continents of countries of origin, research hotspots, and article title. The articles written in English and other languages were included in the analysis. Total number of articles found was 1,449. The mean number of citations per article was 177. The citation count ranged from 24 to 1,191. The articles with citations >30 were included in the study. The majority of articles (n = 175) were published between 2016 and 2023. Among the highly cited articles, the most prevalent topic of interest was biomarker discovery. Most of the articles were original articles. The continent of origin for most of the articles was the United States of America (n = 163), Europe (n = 145), United Kingdom (n = 23), Asia (n = 23), Australia (n = 14), etc. Conclusion: The analysis of articles on biomarker discovery for IBS will help in understanding the requirement for unmet need for the discovery of biomarker for IBS. The current bibliometric study has highlighted the work of authors with advanced knowledge about discovery of the biomarker for IBS. This study will help to identify the current trends in the biomarker discovery for IBS and help for the further evolution of the field.

TRIM29 modulates proteins involved in PTEN/AKT/mTOR and JAK2/STAT3 signaling pathway and suppresses the progression of hepatocellular carcinoma.

Tripartite motif-containing 29 (TRIM29), also known as the ataxia telangiectasia group D-complementing (ATDC) gene, has been reported to play an oncogenic or tumor suppressive role in developing different tumors. So far, its expression and biological functions in hepatocellular carcinoma (HCC) remain unclear. We investigated TRIM29 expression pattern in human HCC samples using quantitative RT-PCR and immunohistochemistry. Relationships between TRIM29 expression level, clinical prognostic indicators, overall survival (OS), and disease-free survival (DFS) were evaluated by Kaplan-Meier analysis and Cox proportional hazards model. A series of in vitro experiments and a xenograft tumor model were conducted to detect the functions of TRIM29 in HCC cells. RNA sequencing, western blotting, and immunochemical staining were performed to assess the molecular regulation of TRIM29 in HCC. We found that the mRNA and protein levels of TRIM29 were significantly reduced in HCC samples, compared with adjacent noncancerous tissues, and were negatively correlated with poor differentiation of HCC tissues. Survival analysis confirmed that lower TRIM29 expression significantly correlated with shorter OS and DFS of HCC patients. TRIM29 overexpression remarkably inhibited cell proliferation, migration, and EMT in HCC cells, whereas knockdown of TRIM29 reversed these effects. Moreover, deactivation of the PTEN/AKT/mTOR and JAK2/STAT3 pathways might be involved in the tumor suppressive role of TRIM29 in HCC. Our findings indicate that TRIM29 in HCC exerts its tumor suppressive effects through inhibition of the PTEN/AKT/mTOR and JAK2/STAT3 signaling pathways and may be used as a potential biomarker for survival in patients with HCC.

A novel stratification scheme combined with internal arteries in CT imaging for guiding postoperative adjuvant transarterial chemoembolization in hepatocellular carcinoma: a retrospective cohort study.

Although postoperative adjuvant transarterial chemoembolization (PA-TACE) improves survival outcomes in a subset of patients with resected hepatocellular carcinoma (HCC), the lack of reliable biomarkers for patient selection remains a significant challenge. The present study aimed to evaluate whether computed tomography imaging can provide more value for predicting benefits from PA-TACE and to establish a new scheme for guiding PA-TACE benefits. In this retrospective study, patients with HCC who had undergone preoperative contrast-enhanced computed tomography and curative hepatectomy were evaluated. Inverse probability of treatment weight was performed to balance the difference of baseline characteristics. Cox models were used to test the interaction among PA-TACE, imaging features, and pathological indicators. An HCC imaging and pathological classification (HIPC) scheme incorporating these imaging and pathological indicators was established. This study included 1488 patients [median age, 52 years (IQR, 45-61 years); 1309 male]. Microvascular invasion (MVI) positive, and diameter >5cm tumors achieved a higher recurrence-free survival (RFS), and overall survival (OS) benefit, respectively, from PA-TACE than MVI negative, and diameter ≤5cm tumors. Patients with internal arteries (IA) positive benefited more than those with IA-negative in terms of RFS ( P =0.016) and OS ( P =0.018). PA-TACE achieved significant RFS and OS improvements in HIPC3 (IA present and diameter >5 cm, or two or three tumors) patients but not in HIPC1 (diameter ≤5cm, MVI negative) and HIPC2 (other single tumor) patients. Our scheme may decrease the number of patients receiving PA-TACE by ~36.5% compared to the previous suggestion. IA can provide more value for predicting the benefit of PA-TACE treatment. The proposed HIPC scheme can be used to stratify patients with and without survival benefits from PA-TACE.

A phase 1, first-in-human, dose-escalation and expansion study of FX-909 in patients with advanced solid malignancies, including advanced urothelial carcinoma.

TPS709 Background: High Expression of Peroxisome proliferator-activated receptor gamma (PPARG), a nuclear receptor-family transcription factor, drives the initiation and development of UC in luminal molecular subtype tumors. Genetic profiling of UC has identified recurrent oncogenic alterations in the PPARG transcriptional complex, including focal amplification, missense mutations, and fusions in the heterodimeric partner of PPARG, the retinoid X receptor alpha (RXRA). High levels of PPARG expression and recurrent oncogenic alterations are observed in other solid malignancies including colorectal, gastroesophageal, pancreatic and lung cancers. FX-909 is an oral, first-in-class, new molecular agent that specifically, potently, and covalently modifies PPARG to mediate basal and ligand-activated transcription. Treatment of genetically defined UC xenografts with FX-909 has shown an 84% tumor growth inhibition (TGI) at a dose expected to be equivalent to 50 mg dose in humans, which is the starting dose in this clinical study. Methods: FX-909-CLINPRO-1 (NCT05929235) is a first-in-human, multicenter, open-label Phase 1 study to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary clinical activity of FX-909 given orally in patients with advanced solid malignancies. Patients enrolled in the trial must have ECOG performance status ≤2 and must be ≥ 18 years of age. Initially, FX-909 will be given once daily to patients with any advanced solid malignancy in a dose-escalation phase (Part A) utilizing a 3+3 design. Five dose cohorts of 3 to 6 patients are planned. At the time of submission, three patients are enrolled in Part A- cohort one, 50mg. Additional patients will be allowed to backfill to previously cleared dose levels that demonstrate therapeutically relevant exposures or evidence of clinical activity. Once a RP2D has been determined, a monotherapy expansion phase (Part B) will proceed in a Simon 2-stage design in patients with locally advanced (unresectable) or metastatic UC with measurable disease and tumors harboring defined genetic alterations in PPARG, RXRA and FGFR3 (Motley et al, 2022). In stage 1, up to 19 evaluable patients will be enrolled. If ≥4 objective responses are observed, enrollment will continue into Stage 2 with an additional 14 evaluable patients. One treatment cycle is 28 days. Dose expansion will evaluate the safety, PK/PD profile, and antitumor activity of FX-909 at the RP2D. Exploratory objectives include the evaluation patient selection biomarkers from tissue and blood samples. FX-909 clinical activity will be assessed using RECIST v1.1 criteria. The study is currently enrolling patients in the US. Clinical trial information: NCT05929235 .

Identification of protein biomarkers for prediction of response to platinum-based treatment regimens in patients with non-small cell lung cancer.

The majority of patients with resected stage II-IIIA non-small cell lung cancer (NSCLC) are treated with platinum-based adjuvant chemotherapy (ACT) in a one-size-fits-all approach. However, a significant number of patients do not derive clinical benefit, and no predictive patient selection biomarker is currently available. Using mass spectrometry-based proteomics, we have profiled tumour resection material of 2 independent, multi-centre cohorts of in total 67 patients with NSCLC who underwent ACT. Unsupervised cluster analysis of both cohorts revealed a poor response/survival sub-cluster composed of ~ 25% of the patients, that displayed a strong epithelial-mesenchymal transition signature and stromal phenotype. Beyond this stromal sub-population, we identified and validated platinum response prediction biomarker candidates involved in pathways relevant to the mechanism of action of platinum drugs, such as DNA damage repair, as well as less anticipated processes such as those related to the regulation of actin cytoskeleton. Integration with pre-clinical proteomics data supported a role for several of these candidate proteins in platinum response prediction. Validation of one of the candidates (HMGB1) in a third independent patient cohort using immunohistochemistry highlights the potential of translating these proteomics results to clinical practice.