Predictive Biomarkers Of Therapeutic Response Research Articles

Abstract PO1-18-10: ANNE: A phase II single-arm clinical trial to assess the feasibility and efficacy of neoadjuvant anastrozole in patients with luminal breast cancer and low proliferative index in TNM stages II and III

Abstract Background: Neoadjuvant endocrine therapy (NET) is recommended for the treatment of invasive breast cancer (BC), particularly luminal subtypes, in locally advanced stages. Previous randomized studies have demonstrated the benefits of aromatase inhibitors (AIs) in this context. However, in clinical practice, NET is typically reserved for elderly or frail patients who may not tolerate neoadjuvant chemotherapy. Ideally, after identifying suitable candidates for NET, patients undergo tumor re-biopsy after 2 to 4 weeks of treatment, and only those with Ki67 ≤ 10% proceed with NET. Limitations of this strategy include the standardization of re-biopsy and the reliability of Ki67 immunohistochemical analysis, as treatment decisions are based on these results. Objective: To evaluate the feasibility and efficacy of NET in postmenopausal patients with stage II and III luminal BC and to identify predictive biomarkers of therapeutic response. The efficacy will be measured by the rate of patients with Ki67 ≤ 10% after 4 weeks and Preoperative Endocrine Prognostic Index (PEPI) score 0 on the surgical specimen. The feasibility of the study will be assessed by the acceptance rate of participating in the study (recruitment rate ≥ 50%) and the inclusion rate of >2 patients per month. Methods: This non-randomized phase II clinical trial includes postmenopausal women with invasive breast carcinoma, Scarf-Bloom-Richardson histological grades 1 or 2, Estrogen Receptor positive (Allred ≥ 6), progesterone receptor positive (any value), HER2 negative, Ki-67 antigen < 50% on immunohistochemistry, stages TNM II-III, with palpable tumor ≥ 2 cm, and ECOG 0-2. All eligible patients will receive anastrozole (1 mg/day) continuously until the day before the surgical procedure or exclusion from the study (in case of disease progression during endocrine therapy). After 2 to 4 weeks, a re-biopsy of the breast tumor will be performed. If Ki67 > 10%, endocrine therapy will be suspended, and the patient will be excluded from the study and redirected to neoadjuvant chemotherapy (routine care) or immediate surgery (as per attending clinical oncologist and surgeon). If Ki67 ≤ 10%, the patient will continue to receive NET. Extended NET will be administered for up to 10 months, with monthly physical examinations (using calipers) and bimonthly breast ultrasound. The presence of stable disease on ultrasound at 4, 6, and 8 months indicates scheduling surgery within 2 months thereafter, and disease progression at any time indicates surgery within one month. Patients will complete the EORTC QLQ-C30 and its supplemental module BR45 questionnaires every 2 months. Toxicity will be assessed using CTCAE version 4.0, and patients will respond to 11 specific items extracted from the Brazilian version of PRO-CTCAE. The radiological response will be evaluated by RECIST 1.1. Blood samples for molecular analyses will be collected at baseline and during re-biopsy. MicroRNA profiles will be evaluated using Nanostring, and extracellular vesicles will be examined using ATR-FTIR to identify predictive markers of therapeutic response (Ki67 < 10%) in re-biopsy. All cases will be evaluated using PAM50 at the initial biopsy and at surgery to determine the molecular phenotype (luminal A, B, or other) and molecular response (ROR score difference). Pathologic therapeutic response will be assessed using the PEPI score in all operated cases. The sample size was calculated to be 59 patients. The study was initiated in July 2022, and since then, a total of 26 patients have been enrolled. This study is registered with The Brazilian Registry of Clinical Trials (ReBEC): RBR-5pygzhj. Citation Format: Carlos Paiva, Izabella Oliveira, Vitor Guimarães, Alinne Faria, Domício Lacerda, Anapaula Uema, Nilton Onari, Bianca Paiva, Augusto Antoniazzi, Karina Oikawa, Maria Fernanda Machado, Matheus Godinho, Cristiano Souza, Chrissie Amirati, Gustavo Teixeira, Idam de Oliveira Jr, Márcia Marques, Yara Maia. ANNE: A phase II single-arm clinical trial to assess the feasibility and efficacy of neoadjuvant anastrozole in patients with luminal breast cancer and low proliferative index in TNM stages II and III [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-18-10.

DOP22 Predictive biomarkers of therapeutic response in Inflammatory Bowel Disease: a step towards personalized medicine

Abstract Background Inflammatory bowel diseases are complex conditions characterized by heterogeneity at clinical, immunological, molecular, genetic, and microbial levels. The most effective approaches to induce clinical remission and control inflammation in these diseases are biologic and JAK-inhibitor therapies. However, a significant proportion of patients do not respond to treatment. Consequently, the identification of predictive biomarkers of clinical response to the different available therapies could improve the selection of patients who may benefit from the most appropriate treatment. Methods A multiomic study (transcriptomic, proteomic, metabolomic and metagenomic) was performed in 53 patients with active Crohn´s disease (CD) and 50 patients with active ulcerative colitis (UC) before and after 14 weeks of treatment (anti-TNFα, ustekinumab, vedolizumab or tofacitinib). Responders and non-responders patients were categorized based on endoscopic findings. Samples (serum, urine, stool and intestinal biopsies) were used for RNA-seq analysis, liquid chromatography-mass spectrometry, nuclear magnetic resonance, and 16S rRNA gene sequencing. Results Our findings revealed multiple mRNAs, proteins and metabolites associated with the response to different treatments (Table 1). Differential gene expression analyses in intestinal tissue showed that the main differences were detected between responders versus non-responders UC patients to anti-TNF, vedolizumab and tofacitinib. Proteomic analysis found numerous differentially expressed proteins between the study groups. Additionally, ROC curves revealed two proteins with good predictive value to discriminate between CD and UC patients responders versus non-responders to anti-TNF treatment (AUC=0.81 and AUC=0.96, respectively). Metabolomics showed up-regulation of 21 lipoproteins in serum from CD patients responders to ustekinumab compared to non-responders. Metabolic analysis pathways identified enrichment in ketone and butyrate metabolism, mitochondrial electron transport chain, carnitine synthesis, and oxidation of chain fatty acids. Regarding metagenomic results, only differences were found in microbial composition in responders versus non-responders UC patients treated with anti-TNF (Figure 1). Conclusion This study provides early insights into shifts in gene and protein expression in intestinal tissue, alterations in serum and urine metabolites, and changes in gut microbiota as potential predictors of response to biologics and JAK-inhibitor treatment. Further research is needed to validate these results and asses their clinical significance in identifying patients most likely to benefit from each therapeutic approach.

Upper airway disease diagnosis as a predictive biomarker of therapeutic response to biologics in severe asthma.

Asthma is a heterogeneous disease sharing airway instability but with different biology, risk factors, and response-to-therapy patterns. Biologics have revolutionized the one-size-fits-to-all approach to personalized medicine in severe asthma (SA), which relies on the identification of biomarkers that define distinct endotypes. Thus, blood eosinophils and, to some extent, exhaled nitric oxide (FeNO) can predict the response to approved anti-type 2 (T2) biologics (anti-IgE, anti-IL-5, and anti-IL-4R alpha), whereas age at onset and comorbidities such as anxiety/depression, obesity, reflux, and upper airway disease (UAD) also influence therapeutic responses in SA. In this article, focusing on the predictive value of biomarkers for the therapeutic response to biologics in SA, we first summarize the level of prediction achieved by T2 biomarkers (blood eosinophils, FeNO) and then review whether data support the predictive value of upper airway diagnosis on such outcomes. Post hoc analysis of most studies with T2 biologics suggests that chronic rhinosinusitis with nasal polyps (CRSwNP) and, to a lower extent, allergic rhinitis may help in predicting clinical response. Considering that T2 biologics are now also approved for the treatment of severe CRSwNP, diagnosis of upper airway disease is a key step in determining eligibility for such therapy.

Usefulness of circulating EPAC1 as biomarkers of therapeutic response to GLP-1 receptor agonists.

The response to Glucagon-like peptide-1 receptor agonists (GLP-1RAs) is highly varia-ble among patients. Thus, the identification of predictive biomarkers of therapeutic response to GLP-1 RA could help us to optimize the use of this class of drugs. GLP-1RAs increase exchange proteins directly activated by cAMP (EPAC). The aim of the present study was to assess whether the increase of EPAC1 after GLP-1RAs treatment could be a biomarker of clinical response. After showing that GLP-1 (10ng/mL) significantly increased the expression of EPAC1 in human endo-thelial vascular cells (HUVEC), a pilot clinical study was planned. For this purpose 49 patients with type 2 diabetes who started treatment with liraglutide were included. EPAC1 concentration was determined by ELISA before and at one month of liraglutide treatment. We found that serum concentration of EPAC1 increased significantly after treatment with liraglutide. Only in those patients in whom EPAC1 increased (64%), a significant decrease in HbA1c, LDL-C, body mass index (BMI), and waist circumference was shown. This pilot study suggests that the increase of circulating EPAC1 after GLP-1RAs treatment could be a useful biomarker to predict clinical GLP1-RAs response.

215 Cutaneous immune-related adverse events predict longer patient survival in advanced cancer patients

Cutaneous immune-related adverse events (cirAEs) are the most common toxicities to occur in the setting of immune checkpoint inhibitor (ICI) therapy. However, their impact on mortality is largely understudied. Here, we investigate the impact of cirAEs on survival among ICI recipients using a robust multi-institutional clinical registry. 3,731 ICI recipients were identified from the Mass General Brigham Healthcare System and the Dana-Farber Cancer Institute, of which 676 developed cirAEs and 3,055 did not. Landmark survival analyses and time-varying Cox proportional hazards modeling were performed, adjusting for demographics, Charlson comorbidity index, cancer type, ICI target, and year of ICI initiation. Overall, patients who developed cirAEs were significantly protected from mortality (HR=0.87, p=0.036), particularly in the setting of melanoma (HR=0.67, p=0.007). Among individual morphologies, lichenoid eruption (HR=0.46, p<0.001), psoriasiform eruption (HR=0.43, p=0.004), vitiligo (HR=0.26, p=0.012), and non-specific rash (HR=0.69, p<0.001) were significantly protective of mortality after multiple comparisons adjustment. Our results demonstrate that CirAE development is associated with a 13% reduction in mortality among all cancers and a 33% reduction in melanoma patients. Furthermore, almost all cirAE morphologies are associated with better survival. Even after excluding vitiligo, cirAE development remains protective among all ICI recipients and melanoma patients. These findings are important as cirAEs tend to occur early after ICI initiation and may serve as predictive biomarkers of therapeutic response.

Predictive Biomarkers in the Management of Bladder Cancer: Perspectives in an Evolving Therapeutic Landscape

Bladder cancer (BC) is a heterogeneous disease with prognosis and therapeutic strategies highly dependent on tumor grade and stage. Predictive biomarkers of therapeutic response have been studied to guide selection of intravesical and/or systemic therapy. A predictive biomarker is measured before the start of treatment and provides information on the likelihood of response to a specific therapy. Many candidate predictive biomarkers for BC have been identified, but few have been rigorously validated or distinguished from simply having treatment-agnostic prognostic capacity. Identifying predictive biomarkers tailored to therapeutic mechanism of action has considerable implications for the sequencing of therapies, as well as bladder preservation strategies in advanced disease states. We evaluate predictive tissue-based, urine-based, and serum-based biomarkers across the spectrum of non–muscle-invasive and muscle-invasive BC and preview predictive biomarkers for emerging targeted therapies.

Inflammatory Bowel Disease Treatments and Predictive Biomarkers of Therapeutic Response.

Inflammatory bowel disease (IBD) is a chronic immune-mediated inflammation of the gastrointestinal tract with a highly heterogeneous presentation. It has a relapsing and remitting clinical course that necessitates lifelong monitoring and treatment. Although the availability of a variety of effective therapeutic options including immunomodulators and biologics (such as TNF, CAM inhibitors) has led to a paradigm shift in the treatment outcomes and clinical management of IBD patients, some patients still either fail to respond or lose their responsiveness to therapy over time. Therefore, according to the recent Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE-II) recommendations, continuous disease monitoring from symptomatic relief to endoscopic healing along with short- and long-term therapeutic responses are critical for providing IBD patients with a tailored therapy algorithm. Moreover, considering the high unmet need for novel therapeutic approaches for IBD patients, various new modulators of cytokine signaling events (for example, JAK/TYK inhibitors), inhibitors of cytokines (for example IL-12/IL-23, IL-22, IL-36, and IL-6 inhibitors), anti-adhesion and migration strategies (for example, β7 integrin, sphingosine 1-phosphate receptors, and stem cells), as well as microbial-based therapeutics to decolonize the bed buds (for example, fecal microbiota transplantation and bacterial inhibitors) are currently being evaluated in different phases of controlled clinical trials. This review aims to offer a comprehensive overview of available treatment options and emerging therapeutic approaches for IBD patients. Furthermore, predictive biomarkers for monitoring the therapeutic response to different IBD therapies are also discussed.

Talimogene Laherparepvec: Moving From First-In-Class to Best-In-Class.

Talimogene laherparepvec (T-VEC) is a modified oncolytic herpes Simplex virus, type 1 (HSV-1) encoding granulocyte-macrophage colony stimulating factor (GM-CSF). T-VEC is adapted for selective replication in melanoma cells and GM-CSF was expressed to augment host anti-tumor immunity. T-VEC is indicated for the local treatment of melanoma recurrent after primary surgery and is the first-in-class oncolytic virus to achieve approval by the FDA in 2015. This review will describe the progress made in advancing T-VEC to the most appropriate melanoma patients, expansion to patients with non-melanoma cancers and clinical trial results of T-VEC combination studies. Further, strategies to identify predictive biomarkers of therapeutic response to T-VEC will be discussed. Finally, a brief outline of high-priority future directions for investigation of T-VEC and other promising oncolytic viruses will set the stage for a best-in-class oncolytic virus to bring the maximum benefit of this emerging class of anti-cancer agents to patients with cancer.

Abstract P2-07-13: High-dimensional, single-cell analysis and transcriptional profiling reveal novel correlatives of response to PARP inhibition plus PD-1 blockade in triple-negative breast cancer

Abstract Background: TOPACIO was a phase I/II study evaluating the PARP inhibitor (PARPi) niraparib in combination with the anti-PD-1 antibody pembrolizumab in patients with locally advanced and metastatic triple-negative breast cancer (TNBC, n=55) and ovarian cancer irrespective of BRCA mutation status. In the efficacy-evaluable population (n=47) the objective response rate (ORR) was 21% and disease control rate (DCR) 49%. Although activity was greater in patients with BRCA mutations (7/15, ORR=47% and 12/15, DCR=80%), durable clinical benefit was seen in patients with wild-type BRCA tumors (3/27, ORR=11% and 9/27, DCR=33%). In a limited cohort of 20 patients with durable clinical benefit, there were 8 BRCA wildtype patients, four of whom had mutations in genes associated with the homologous recombination repair and other DNA damage repair pathways. Pre-treatment tissues were collected and evaluated for tumor PD-L1 status. Patients with PD-L1 positive tumors (28/47, 60%) had a higher response rate (9/28, ORR=32%) than those with PD-L1 negative tumors (1/13, ORR=8%; 6 tumors had unknown PD-L1 status). It remains unstudied whether the tumor’s gene expression profile or immune status in baseline biospecimens is predictive of treatment response. In this study we conducted exploratory biomarker analyses to test the hypothesis that gene expression patterns and immune status are associated with treatment response. Methods: Transcriptional profiling of baseline samples was performed using the BC360 (n=41) and PanCancer IO360 (n=42) panels (Nanostring) and multigene signatures were used to measure tumor and immune activities as well as relative immune cell abundance. Transcriptional analysis was paired with high-dimensional, single-cell cyclic immunofluorescence (CyCIF) of samples that had adequate tissue for analysis (n=19) to characterize the composition and topology of the immune microenvironment at single-cell resolution. Results: Nanostring transcriptional analysis revealed that PAM50 genes stratified tumor samples into 4 subgroups with distinct histology as determined by CyCIF. Each subgroup was capable of responding to niraparib plus pembrolizumab. Multiple genes involved in WNT signaling (WNT5B, TANKS1, TANKS2, PARP4, and NET02) were associated with favorable clinical responses. Low neuropilin and tolloid-like protein 2 (NETO2) gene expression was strongly correlated with favorable progression free survival (PFS; R=-0.61, p=0.0008, Spearman’s correlation), suggesting it may be a predictive biomarker of therapeutic response. Nanostring gene expression signatures for tumor inflammation, apoptosis, and inflammatory chemokines also distinguished responders from non-responders (p&amp;lt;0.05). CyCIF analysis performed on whole tissue sections accounting for 2.97 million single cells revealed 43 distinct cell-states comprising the tumor microenvironment. PD1+CD4+ T cells were significantly correlated with extended PFS (R=0.65, p=0.006, Spearman’s correlation). However, PD1+CD4+ T cells were less abundant in patients who continue to respond to the therapy (2.7-fold reduced, p=0.004), suggesting two groups of responders. Conclusion: WNT signaling, NETO2 and PD1+CD4 T cells are candidate biomarkers for predicting response to niraparib plus pembrolizumab. Further studies are underway to characterize the biological underpinnings of these correlative findings. Citation Format: Jennifer L Guerriero, Gregory J Baker, Jia-Ren Lin, Yu-An Chen, Ricardo Pastorello, Tuulia Vallius, Janae Davis, Clarence Yapp, Sarah E Church, Eric Miller, Anniina Färkkilä, Shaveta Vinayak, Melinda L Telli, Giulia Fulci, Alan D'Andrea, Geoffrey I Shapiro, Sara M Tolaney, Sandro Santagata, Peter K Sorger, Elizabeth A Mittendorf. High-dimensional, single-cell analysis and transcriptional profiling reveal novel correlatives of response to PARP inhibition plus PD-1 blockade in triple-negative breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-07-13.

CTNI-14. EVALUATING METABOLIC ALTERATIONS IN PATIENTS WITH EGFR ACTIVATED RECURRENT GLIOBLASTOMA (RGBM) BY INHIBITING EGFR WITH OSIMERTINIB

Abstract BACKGROUND EGFR activated GBM is highly metabolically active and effective targeting with EGFR TKis in human-tumor models rapidly attenuates glucose metabolism engaging apoptotic machinery. Rapid changes in glucose uptake using 18F-FDG-PET is an effective predictive biomarker of therapeutic response in these models. Clinical 18F-FDG-PET may allow investigators to obtain early readout on EGFR TKi in this patient population. We explore this approach using osimertinib in EGFRamp/p53wt rGBM. METHODS EGFRamp/p53wt rGBM patients were treated with oral osimertinib 240mg for three days followed by 160mg/day until progression. F18-FDG-PET scan was obtained as a double baseline, 24 hours apart, prior to dosing with osimertinib. Third scan was obtained after 3 doses of 240mg. Primary objective defines test-retest variance of tumor FDG uptake before osimertinib and to evaluate if osimertinib significantly decreases glucose utilization after three doses. Study-drug and funding provided by AstraZeneca. RESULTS 12 pts were evaluated, 10 female, median age 57.5 years (44-61). Volumetric mRANO showed no responses, 6 SD, 5 PD, and one NE. Median PFS was 31 days, no patient achieved 6-month-PFS and median OS was 5.5 months. No new adverse event signal appeared. Double baseline PET SUV mean was 0.97 (normalized to whole cerebellum) with upward trend from first to second scan with mean percent change of 2.8 and 95% CI(0.7,5.1). Change in PET from 2nd to 3rd showed mean percent change -3.2 with 95% CI (-11.1,4.8). Preclinical models suggest 15-20% attenuation is needed to predict improved outcomes in patients treated with EGFR-TKi. CONCLUSION F18-FDG-PET has little variance with test-retest showing upward trend with second scan. Post osimertinib F18-FDG-PET shows limited attenuation of tumor FDG uptake. No clinical signal was seen in study. Deeper attenuation of FDG uptake may be needed to show clinical effect from EGFR inhibitors. F18-FDG-PET can be used to evaluate change in tumor glucose utilization.

18F-FMISO PET Imaging Identifies Hypoxia and Immunosuppressive Tumor Microenvironments and Guides Targeted Evofosfamide Therapy in Tumors Refractory to PD-1 and CTLA-4 Inhibition.

Hypoxia is a common characteristic of many tumor microenvironments, and it has been shown to promote suppression of antitumor immunity. Despite strong biological rationale, longitudinal correlation of hypoxia and response to immunotherapy has not been investigated. In this study, we probed the tumor and its surrounding microenvironment with 18F-FMISO PET imaging to noninvasively quantify tumor hypoxia in vivo prior to and during PD-1 and CTLA-4 checkpoint blockade in preclinical models of breast and colon cancer. Longitudinal imaging identified hypoxia as an early predictive biomarker of therapeutic response (prior to anatomic changes in tumor volume) with a decreasing standard uptake value (SUV) ratio in tumors that effectively respond to therapy. PET signal correlated with ex vivo markers of tumor immune response including cytokines (IFNγ, GZMB, and TNF), damage-associated molecular pattern receptors (TLR2/4), and immune cell populations (macrophages, dendritic cells, and cytotoxic T cells). Responding tumors were marked by increased inflammation that were spatially distinct from hypoxic regions, providing a mechanistic understanding of the immune signaling pathways activated. To exploit image-guided combination therapy, hypoxia signal from PET imaging was used to guide the addition of a hypoxia targeted treatment to nonresponsive tumors, which ultimately provided therapeutic synergy and rescued response as determined by longitudinal changes in tumor volume. The results generated from this work provide an immediately translatable paradigm for measuring and targeting hypoxia to increase response to immune checkpoint therapy and using hypoxia imaging to guide combinatory therapies.

Mutations in the KRAS gene as a predictive biomarker of therapeutic response in patients with colorectal cancer

Abstract Introduction: Despite the important role of general KRAS mutational status in the selection of an adequate therapeutic protocol in patients with colorectal cancer (CRC), studies that focus on its specific mutations and their significance on progression of disease are scarce. This study aimed to determine the significance of specific KRAS mutations in response to standard chemotherapy protocols with oxaliplatin-based (FOLFOX 4, OXFL) in the first-line and irinotecan-based chemotherapy (FOLFIRI, IFL) in the second-line therapy, and to evaluate the correlation between these mutations and clinicopathological characteristics of CRC patients. Methods: Genomic DNA was extracted from the FFPE tumour tissue sections while the KRAS mutation test was performed by using PCR methods. Results: Prevalence of KRAS gene mutations in CRC patients was 45%. Mutated KRAS was more frequent in later stages of tumor infiltrations (P =0.0017), on the right side of the colon (P= 0.0044), and in patients who developed metastases in the first 6 months after CRC diagnosis than in patients who developed metastases after 24 months (P=0.0083). In a group of patients with a poor therapeutic response to standard chemotherapy the most frequent mutations in KRAS gene were G12D and G12V (63.88%), while in a group of patients with a good response to therapeutic protocols the most prevalent mutation was G12A (66.66%). Conclusion: Our results indicate that there was a significant difference in biological behaviour between tumours harboring different mutations in KRAS gene. Overall, mutation G12A could be a novel prognostic biomarker for CRC patients treated with standard chemotherapy.

Identification of a predictive metabolic signature of response to immune checkpoint inhibitors in non-small cell lung cancer: METABO-ICI clinical study protocol

BackgroundImmune checkpoints inhibitors (ICI) are becoming new standards of care for the treatment of non-small cell lung cancer (NSCLC), both as first (alone or in association with chemotherapy) and second line. However, no powerful predictive biomarker of therapeutic response to ICI has been found to date. It has been recently shown that microbiota composition could influence the ability of patients to respond to ICI. Indeed, the microbiota produces circulating metabolites that will subsequently act on immune system, the investigators hypothesized that plasma metabolic signature, reflecting a global microbiota function, could represent a predictive biomarker of response to ICI. MethodsMonocentric prospective study. Primary objective is to identify baseline metabolic signature (metabolomics analysis by mass spectrometry) associated to ICI response. Secondary objectives are to link metabolic signature with microbiota composition (metagenomics analysis RNA 16S) and immune profile, and altogether with clinic response to ICI. The study will include 60 NSCLC patients treated by ICI in 1st, 2nd or 3rd line of treatment at the Grenoble Alpes University hospital (CHUGA) in 18 months. Patients that have received antibiotic or steroid treatment, 2 or 4 weeks before ICI initiation, respectively, will be excluded. Blood and feces will be collected prior to, at 2 months after ICI treatment initiation, and at 6 months or at progression. Expected resultsWe expect to highlight a metabolic profile predictive of response to ICI. By identifying factors associated with early progression, we could avoid to treat potential non-responding patients. Moreover, by restoring a favorable microbiota, patients’ ability to respond to these treatments might be restored.

LAMC2 promotes cancer progression and gemcitabine resistance through modulation of EMT and ATP-binding cassette transporters in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with poor prognosis. Gemcitabine remains an effective option for the majority of PDAC patients. Unfortunately, currently no reliable prognostic and predictive biomarkers of therapeutic response are available for the patients with PDAC. Laminin γ2 (LAMC2) is overexpressed in several cancers, and its high expression facilitates cancer development and chemoresistance. However, its functional role in PDAC remains unclear, and a better understanding of this will likely help improve the prognosis of PDAC patients. This study aimed to elucidate the clinical and biological role of LAMC2 in PDAC. We first analyzed the expression levels of LAMC2 by real-time reverse transcription PCR in a cohort of 114 PDAC patients. Interestingly, higher expression of LAMC2 significantly correlated with poor survival in PDAC cohort. In addition, elevated LAMC2 expression served as a potential prognostic marker for survival. Subsequently, functional characterization for the role of LAMC2 in PDAC was performed by small interfering RNA knockdown in pancreatic cancer (PC) cell lines. Interestingly, inhibition of LAMC2 in PC cells enhanced the gemcitabine sensitivity and induction of apoptosis. Moreover, it inhibited colony formation ability, migration and invasion potential. Furthermore, LAMC2 regulated the expression of epithelial-mesenchymal transition (EMT) phenotype. In addition, LAMC2 significantly correlated with genes associated with the expression of ATP-binding cassette (ABC) transporters in PC cells and PDAC patients. In conclusion, these results suggest that LAMC2 regulates gemcitabine sensitivity through EMT and ABC transporters in PDAC and may be a novel therapeutic target in PDAC patients.

Exosomes and extracellular vesicles as liquid biopsy biomarkers in diffuse large B-cell lymphoma: Current state of the art and unmet clinical needs.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma, and it constitutes biologically heterogeneous entities. Standard first-line therapies cure ~60% of patients, the rest being either refractory or experiencing relapse. Currently, there are no robust predictive biomarkers of therapeutic response. Heterogeneity of DLBCL is partly explained by the cell of origin (COO), ie, germinal centre B cell or activated B cell, with the latter exhibiting worse prognosis. While gene expression profiling (GEP) is the gold standard for determining COO, surrogate immunohistochemical algorithms are used clinically, but show significant discordance with GEP. Recently, additional genetic subgroups with different prognoses have been reported. However, the tools/expertise required for analysis prohibit widespread deployment. Liquid biopsy-based assays show promise in providing clinically actionable information, are noninvasive and facilitate serial sampling to assess mechanisms of therapy resistance. Circulating, cell-free DNA analysis has shown enhanced sensitivity for detecting molecular alterations, but this modality cannot determine alterations of the tumor proteome or on signalling pathways. Exosomes are endosomally derived vesicles, are found in high abundance in body fluids and are readily isolated using a variety of methods. Tumour-derived exosomes can yield data regarding genetic, transcriptional, and proteomic changes useful for diagnosis, prognosis, and therapy of DLBCL. At present, standardized techniques for isolating exosomes are lacking and discriminating between exosomes from neoplastic and normal B cells is challenging. Refinements in isolation procedures are required to realize their full potential as precision medicine tools to provide comprehensive information on disease subtypes, identify prognostic factors, allow real-time monitoring of therapy response and delineate novel drug targets.

Recurrent ZNF83-E293V Mutation Promotes Bladder Cancer Progression through the NF-κB Pathway via Transcriptional Dysregulation of S100A8

Urothelial carcinoma (UC) is the predominant form of bladder cancer. Significant molecular heterogeneity caused by diverse molecular alterations brings about large variations in the response to treatment in UC. An improved understanding of the genetic mechanisms underlying the development and progression of UC is essential. Through deep analysis of next-generation sequencing data of 99 UC patients, we found that 18% of cases had recurrent somatic mutations in zinc finger protein gene zinc finger protein 83 (ZNF83). ZNF83 mutations were correlated with poor prognosis of UC. We also found a hotspot mutation, p.E293V, in the evolutionarily well-conserved region of ZNF83. ZNF83-E293V increased tumor growth and reduced the apoptosis of UC cells compared to wild-type ZNF83 both in vitro and in mice xenografted tumors. ZNF83-E293V activated nuclear factor κB (NF-κB) more potently than did the wild-type protein owing to its decreased transcriptional repression for S100A8. The NF-κB inhibitors could pharmacologically block the tumor growth in mice engrafted with ZNF83-E293V-transfected UC cells. These findings provide a mechanistic insight and a potential therapeutic strategy for UC, which established a foundation for using the ZNF83-E293V mutation as a predictive biomarker of therapeutic response from NF-κB inhibitors.

Predicting Complete Response to Itacitinib and Corticosteroids in Acute Graft Versus Host Disease

<h3>Background</h3> Acute graft versus host disease (aGVHD) represents a serious and potentially life threatening condition in patients receiving hematopoietic stem cell transplantation (HSCT). aGVHD is characterized by increased levels of inflammatory mediators and activated T cells in circulation leading to tissue and organ damage. In a parallel-cohort phase 1 trial (NCT02614612) that evaluated the combination of corticosteroids and itacitinib, a potent and highly selective JAK1 inhibitor, we utilized broad proteomic analysis to identify potentially predictive biomarkers of therapeutic response to the combination treatment. <h3>Methods</h3> Plasma was collected from 25 patients enrolled in the clinical trial prior to and at designated times following treatment. Proteomic analysis on plasma was conducted by OLINK Proteomics using a proximity extension assay. Statistical differences were identified using unpaired T tests and one-way ANOVA. Significance was conferred when p<0.05. All participants provided written consent. <h3>Results</h3> Patients were stratified based on their overall response to treatment with itacitinib and corticosteroid at day 28 (based on CIBMTR). Patients included 10 complete responders (CR), 1 very good partial responder (VGPR), 8 partial responders (PR) and 6 patients with progressive disease and/or death (PD/death) prior to day 28. Biomarkers were identified and associated with therapeutic response by comparing the levels of approximately 1000 proteins in the CR (N=10) and PD/Death (N=6) cohorts specifically. Initial analysis identified 55 proteins significantly upregulated (P<0.05) and 75 proteins significantly downregulated (P<0.05) at baseline in the CR cohort and the PD/Death cohort. Potential biomarkers were further screened based on correlation to known aGVHD biomarkers, degree of separation between the populations, as well as reliable and consistent testing (ie, coefficient of variation <20%). Novel biomarkers identified include macrophage chemotactic protein 3 (MCP3/CCL7), stem cell factor (SCF/KIT-L), interleukin 8 (IL8), paraoxonase 3 (PON3), calcitonin (CALCA), and tumor necrosis factor receptor super family 6B (TNFRSF6B). (Table 1). Each of these biomarkers demonstrated a significant (P<.05) difference between CR and PD/death cohorts, with intermediate levels detected in patients with an intermediate (VGPR/PR) response to treatment. <h3>Conclusion</h3> Biomarkers identified in this study may be useful in predicting complete responses to treatment with a combination of corticosteroids and itacitinib in patients with aGVHD post HSCT.

Analysis of Molecular Pretreated Tumor Profiles as Predictive Biomarkers of Therapeutic Response and Survival Outcomes after Neoadjuvant Therapy for Rectal Cancer in Moroccan Population.

Pathologic features depending on tumor response to preoperative chemoradiotherapy are important to determine the outcomes in patients with rectal cancer. Evaluating the potential predictive roles of biomarker expression and their prognostic impact is a promising challenge. We reported here the immunohistochemical staining of a panel marker of mismatch repair protein (MMR), Ki67, HER-2, and p53. Additionally, identification of somatic mutations of KRAS, NRAS, and BRAF genes were performed by direct sequencing and pyrosequencing in pretreated biopsy tissues from 57 patients diagnosed for rectal cancer. Clinical features and pathological criteria for postneoadjuvant treatment surgical resection specimen's data were collected. Immunohistochemical expression and mutational status were correlated with therapeutic response, overall survival, and disease progression. The mean age of patients was 56 years. Seven (12.3%) out of 57 patients had a complete therapeutic response. Our analysis showed that when using complete therapeutic response (Dworak 4) and incomplete therapeutic response (Dworak 3, 2, and 1) as grouping factor, high p53 expression at the pretreatment biopsy was significantly associated to an incomplete response (p = 0.002). For 20 and 2 out of 57, KRAS and NRAS mutations were detected, respectively. The majority of these mutations affected codon 12. KRAS mutations detected at codon 146 (A146T, A146V) was associated with the appearance of recurrence and distant metastasis (p = 0.019). A high expression of HER-2 corresponding to score 3+ was observed in 3 pretreatment biopsy specimens. This class was significantly associated with a short relapse-free survival (p = 0.002). Furthermore, the high expression of Ki67 was moderately correlated with an older age (p = 0.016, r = 0.319). In addition, this shows that high p53 expression in the pretreatment biopsy was associated with an incomplete response in surgical resection specimens after neoadjuvant treatment, and a HER-2 score 3+ can be a predictive factor of distant metastasis and local recurrence. Larger, prospective, and more studies are needed.

A Biomarker Signature to Predict Complete Response to Itacitinib and Corticosteroids in Acute Graft Versus Host Disease

BACKGROUND: Acute graft versus host disease (aGVHD) represents a serious and potentially life-threatening condition in patients receiving hematopoietic stem cell transplantation (HSCT). Development of aGVHD is characterized by increased levels of inflammatory mediators and activated T cells in circulation, leading to tissue and organ damage. Previously, we demonstrated that a panel measuring ST2, REG3A, and TNFR1 poorly predicted response to the combination of corticosteroids and itacitinib, a potent and highly selective JAK1 inhibitor, in a parallel-cohort phase 1 trial (NCT02614612). In this study, we utilized broad proteomic analysis to identify potentially predictive biomarkers of therapeutic response to the combination treatment. METHODS: Plasma samples were collected from 25 patients enrolled in the Phase 1 clinical trial prior to and at designated times following treatment. Broad proteomic analysis was conducted by OLINK Proteomics using a proximity extension assay. Selected biomarkers were quantitated by the same method based on standard curves generated using recombinant proteins. Statistical differences were identified using unpaired T tests and significance conferred when p&lt;0.05. All participants provided written consent before enrollment. RESULTS: The 25 patients in this study were stratified based on overall response to treatment with itacitinib and corticosteroid at day 28 (based on CIBMTR). Patients included 10 complete responders (CR), 1 very good partial responder (VGPR), 8 partial responders (PR) and 6 patients with progressive disease and/or death (PD/death) prior to day 28. Novel biomarkers were identified and associated with therapeutic response by comparing the levels of approximately 1000 proteins in the CR (N=10) and PD/Death (N=6) cohorts specifically. The initial analysis identified 50 proteins significantly upregulated (P&lt;.05) and 52 proteins significantly down-regulated (P&lt;.05) in the CR cohort at baseline compared with the PD/Death cohort. The list of candidates were further screened based on correlation to known aGVHD biomarkers, degree of separation between the populations, as well as reliable and consistent testing (ie, coefficient of variation &lt;20%). From these analyses, candidate biomarkers were identified and representative examples are shown in table 1. Novel biomarkers include macrophage chemotactic protein 3 (MCP3/CCL7), stem cell factor (SCF/KIT-L), interleukin 8 (IL8), and tumor necrosis factor receptor super family 6B (TNFRSF6B). Each of these candidate biomarkers demonstrated a significant (P&lt;.05) difference between CR and PD/death cohorts, with intermediate levels detected in patients with an intermediate (VGPR/PR) response to treatment. Because MCP3, IL8, and TNFRSF6B presumably associate with inflammation, elevation of these biomarkers in the PD/Death cohort that poorly respond to a JAK inhibitor (JAKi) is not surprising. In addition, elevation of SCF in responders to JAKi is consistent with supporting hematopoiesis. CONCLUSION: Potentially novel biomarkers may be useful in predicting complete responses to treatment with a combination of corticosteroids and itacitinib in patients with aGVHD post HSCT. Disclosures Pratta: Incyte Research Institute: Employment. Liu:Incyte: Employment, Equity Ownership. Owens:Incyte Corporation: Employment, Equity Ownership. Yan:Incyte Corporation: Employment. Arbushites:Incyte: Employment. Howell:Incyte: Employment.

Abstract 4012: Small RNA-sequencing identifies a microRNA signature predictive of response to FOLFOX-based adjuvant therapy in stage II and III colorectal cancer

Abstract Purpose: Current NCCN guidelines for identifying high-risk stage II/III colorectal cancer (CRC) who may benefit from FOLFOX-based adjuvant chemotherapy remain inadequate. While stage III CRC patients often receive six months of oxaliplatin-based therapy following radical surgery, such treatments are frequently toxic and do not benefit all patients. The use of adjuvant chemotherapy in stage II CRC patients is even more controversial. Hence, identification of high-risk CRC patients with the highest likelihood to benefit from such treatments is of paramount clinical importance. Since microRNAs (miRNAs) have emerged as key functional players and important disease biomarkers, using genomewide miRNA expression profiling, we explored their potential as predictive biomarkers of therapeutic response in CRC. Experimental design: Small RNA-sequencing was performed in a cohort of stage II/III CRC patients who received, at least 6 months of FOLFOX-based therapy (n=71; 30 with recurrence, and 41 without recurrence). Identification of differentially expressed miRNAs was done using DESeq2, and biomarker prioritization using LASSO-Cox's proportional hazards model and AUC (area under the curve) analysis, using recurrence-free survival (RFS) as an outcome. The miRNA-signature was validated by using miRCURY LNA miRNA assays in three, independent patient cohorts of tissue (fresh frozen and FFPE) and serum specimens obtained from stage II/III CRC patients (n=91, 77 and 82, respectively). Univariate and multivariate Cox proportional hazard models were used to evaluate the performance of the miRNA classifier, in conjunction with known clinicopathological risk factors and the microsatellite instability (MSI) status. Results: The small RNA-expression profiling led to the identification of a 13-gene miRNA classifier that significantly predicted recurrence free survival (HR: 2.72, 95% CI: 1.96-3.76, p&amp;lt;0.0001) with an AUC of 0.90 (95% CI: 0.83-0.97). This classifier was successfully validated in two tissue cohorts, with impressive AUCs of 0.78 (95% CI: 0.64-0.90, fresh frozen cohort) and 0.86 (95% CI: 0.69-1.00, FFPE cohort), respectively. Importantly, our miRNA signature yielded an impressive AUC of 0.73 (95% CI: 0.60-0.88), even in the preoperative serum specimens from CRC patients. Multivariate analyses revealed that our miRNA classifier was the only independent predictor of response to FOLFOX-based treatment in stage II and III CRC patients. Conclusions: We report a novel miRNA-based classifier, which robustly predicts response to FOLFOX-based adjuvant chemotherapy in stage II/III CRC patients. Validation of this classifier in pre-operative serum provides an attractive opportunity to explore its potential for disease monitoring during the longitudinal follow-up in CRC patients. Citation Format: Raju Kandimalla, Uthra Balaji, Jinghua Gu, Marta Mendiola, Francesc Balaguer, Luis Bujanda, Joan Maurel, Jaime Feliu, Ajay Goel. Small RNA-sequencing identifies a microRNA signature predictive of response to FOLFOX-based adjuvant therapy in stage II and III colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4012.