anti-EGFR Therapy Research Articles

Abstract 4735: Targeting CDK1/2-driven mechanisms of resistance to BRAF and EGFR inhibition in BRAF(V600E) colorectal cancer restores therapeutic response

Abstract Purpose: Metastatic colorectal cancer (mCRC) is the second leading cause of cancer death worldwide. Roughly 8% of mCRC tumors harbor a BRAF(V600E) mutation, associated with the worst prognosis and limited treatment options. Most CRC research and most clinical trials of targeted therapies have narrowly focused on targeting vertical mechanisms of MAPK re-activation (i.e., EGFR-MAPK), with incremental advances for patients. New approaches are needed to address how therapeutic resistance is mediated by coordinated upregulation of multiple signaling pathways. Methods and Recent Advances: Using an innovative high-throughput kinase-activity mapping (HT-KAM) platform and kinase network resource (PhosphoAtlas), we discovered that SRC kinases drive resistance to BRAF ± anti-EGFR therapy independently of ERK signaling by inducing adaptive transcriptional changes via beta-catenin. This compensatory activation of SRC was mediated by an autocrine PGE2-loop that could be blocked with COX2 inhibitors (COX2i). Using patient-derived xenograft (PDX) models established from pre-treatment biopsies in clinical trial participants, we showed that targeting COX2 in combination with standard of care (SOC) BRAFi + EGFRi is an effective drug repurposing strategy to stabilize tumor growth in vivo. New, Unpublished Findings: Building on our drug discovery pipeline to find and target orthogonal modalities of therapeutic resistance, we leveraged our bank of residual PDX tumors collected after 21-day exposure to SOC therapy, and now report that CDK1 and CDK2 are at the center of a stress response program that enables BRAF(V600E) CRC tumor cells to survive under therapeutic pressure. We used HT-KAM to interrogate the activity of 165 kinases and kinase families, and integrated these profiles using computational methods to model signaling pathways. Out of the reprogrammed kinomes of BRAFi + EGFRi resistant tumors, the CDK1/2 kinases and mechanisms of cell cycle checkpoint emerged as critical dependencies. We validated these findings using multiplex immuno-fluorescence in residual tumors, protein/gene expression profile of tissues and cell lines (e.g., upregulation of Cyclins and CDC25s), and cell viability assay using dinaciclib, a CDK1/2 inhibitor. Considering that COX2i has minimal toxicity, yet improved tumor growth inhibition when added to SOC, we evaluated whether jointly blocking inflammatory pathway (COX2) and cell cycle checkpoints (CDK1/2) could overcome resistance. We found that co-targeting CDK1/2 along with BRAFi + EGFRi ± COX2i is well-tolerated in mice and promotes significant, durable suppression of tumor growth in multiple PDX models, including tumor regression, over 9 weeks of treatment. Conclusion: When tumors progress on SOC BRAFi + EGFRi, a therapeutic window remains open to switch to a CDK1/2i-containing regimen and restore cancer control. Citation Format: Jean-Philippe Coppe, Denise P. Muñoz, Chloe E. Atreya, Yeonjoo Hwang, Mehdi Bouhaddou, Louise E. Heinrich, Mohammad Naser, Ons Zakraoui, Roxana Pirker, Rupa Guha, Christina Moelders, Alessandro Scapozza, Cecilia Schwarzer, Layla Phillips, Changjun Wang, Laura van 't Veer, Veronica Steri, Scott R. VandenBerg. Targeting CDK1/2-driven mechanisms of resistance to BRAF and EGFR inhibition in BRAF(V600E) colorectal cancer restores therapeutic 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 4735.

Abstract 2805: Shotgun sequencing of serial fecal microbiome samples in patients with colorectal cancer reveals distinct bacterial species and metabolic pathways associated with tumor sidedness and age at diagnosis

Abstract Background: The incidence of early onset (EO) colorectal cancer (CRC) (age <50) is rising with a left-sided predominance. Response to chemotherapy and anti-EGFR therapies differ in left- and right-sided colon cancers after accounting for genomic differences. The intestinal microbiome may contribute to CRC pathogenesis and response to therapy; how organisms drive metastasis and treatment resistance is not known. Purpose: To define the microbiome contribution to EO-CRC and response to treatment by analyzing longitudinal samples from previously untreated patients with CRC. Methods: We designed a prospective biospecimen collection platform and selected patients with previously untreated CRC. We collected stool, biopsy or surgical tissue, and peripheral blood mononuclear cells at baseline and serially throughout treatment. Stool samples were analyzed using shotgun sequencing. Alpha diversity was calculated using the inverse Simpson index and compared between groups using the Wilcoxon signed-rank test. Beta diversity was analyzed using the Bray-Curtis dissimilarity matrix and compared using PERMANOVA. Multivariate associations between species abundance, metabolic pathway abundance and clinical covariates were performed using MaAsLin2 R package. Results: We analyzed a total of 132 stool samples from 65 patients with CRC including up to 5 samples from a single patient over time. Mean alpha diversity did not differ significantly by primary site, stage or age at diagnosis. Beta diversity was significantly different between samples from right- compared with left-sided CRC (P=.011) and pre- and post-surgery (P=.001). Beta diversity also differed significantly by diagnosis age (<50 vs. > 50) (P=.001 all samples, P=.032 baseline samples). When CRC baseline samples were examined at the species level, Blautia glucerasea was associated with right-sided primary (P<.001, Q=.1). Considering non-metastatic cases, recurrence was associated with increased Enteroscipio rubneri, Actinomyces oral taxon 448, Bacteroidales sp. and Lancefieldella parvula (P<.01, Q>0.1). We further investigated metabolic pathway associations. The superpathway of L-threonine metabolism was significantly increased in samples from patients with right-sided colon cancer at baseline (P<.001, Q=.03). Considering samples across all time points, right-sided colon cancer was associated with increased abundance of pathways associated with propanoate degradation, L-threonine metabolism, yeast NADPH production, and hydroxyphenylacetate degradation (all P<.001, Q<.05). Conclusions: The functional effects of the intestinal microbiome may underlie the distinct biology of right-sided colon cancer. Composition of the intestinal microbiome differs by age at diagnosis. Updated recurrence data will be presented. Citation Format: Melissa Lumish, Nicholas Waters, Joshua Leinwand, Asha Saxena, Anqi Dai, Teng Fei, Maggie Fox, Andre Chavez, Jonathan Bermeo, Dorina Ismailgeci, Elizabeth Benitez, Christopher Cowley, Julio Garcia-Aguilar, Martin Weiser, Andrea Cercek, Luis A. Diaz, Marcel van den Brink, Jonathan Peled, Karuna Ganesh. Shotgun sequencing of serial fecal microbiome samples in patients with colorectal cancer reveals distinct bacterial species and metabolic pathways associated with tumor sidedness and age at diagnosis [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 2805.

Inhibition of the AURKA/YAP1 axis is a promising therapeutic option for overcoming cetuximab resistance in colorectal cancer stem cells

BackgroundPrimary resistance to anti-EGFR therapies affects 40% of metastatic colorectal cancer patients harbouring wild-type RAS/RAF. YAP1 activation is associated with this resistance, prompting an investigation into AURKA’s role in mediating YAP1 phosphorylation at Ser397, as observed in breast cancer.MethodsWe used transcriptomic analysis along with in vitro and in vivo models of RAS/RAF wild-type CRC to study YAP1 Ser397 phosphorylation as a potential biomarker for cetuximab resistance. We assessed cetuximab efficacy using CCK8 proliferation assays and cell cycle analysis. Additionally, we examined the effects of AURKA inhibition with alisertib and created a dominant-negative YAP1 Ser397 mutant to assess its impact on cancer stem cell features.ResultsThe RAS/RAF wild-type CRC models exhibiting primary resistance to cetuximab prominently displayed elevated YAP1 phosphorylation at Ser397 primarily mediated by AURKA. AURKA-induced YAP1 phosphorylation was identified as a key trigger for cancer stem cell reprogramming. Consequently, we found that AURKA inhibition had the capacity to effectively restore cetuximab sensitivity and concurrently suppress the cancer stem cell phenotype.ConclusionsAURKA inhibition holds promise as a therapeutic approach to overcome cetuximab resistance in RAS/RAF wild-type colorectal cancer, offering a potential means to counter the development of cancer stem cell phenotypes associated with cetuximab resistance.

Targeting epidermal growth factor receptor and its downstream signaling pathways by natural products: A mechanistic insight.

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase (RTK) that maintains normal tissues and cell signaling pathways. EGFR is overactivated and overexpressed in many malignancies, including breast, lung, pancreatic, and kidney. Further, the EGFR gene mutations and protein overexpression activate downstream signaling pathways in cancerous cells, stimulating the growth, survival, resistance to apoptosis, and progression of tumors. Anti-EGFR therapy is the potential approach for treating malignancies and has demonstrated clinical success in treating specific cancers. The recent report suggests most of the clinically used EGFR tyrosine kinase inhibitors developed resistance to the cancer cells. This perspective provides a brief overview of EGFR and its implications in cancer. We have summarized natural products-derived anticancer compounds with the mechanistic basis of tumor inhibition via the EGFR pathway. We propose that developing natural lead molecules into new anticancer agents has a bright future after clinical investigation.

Tumor location matters, next generation sequencing mutation profiling of left-sided, rectal, and right-sided colorectal tumors in 552 patients

Despite the introduction of new molecular classifications, advanced colorectal cancer (CRC) is treated with chemotherapy supplemented with anti-EGFR and anti-VEGF targeted therapy. In this study, 552 CRC cases with different primary tumor locations (250 left side, 190 rectum, and 112 right side) were retrospectively analyzed by next generation sequencing for mutations in 50 genes. The most frequently mutated genes were TP53 in left-sided tumors compared to right-sided tumors and BRAF in right-sided tumors compared to left-sided tumors. Mutations in KRAS, NRAS, and BRAF were not detected in 45% of patients with left-sided tumors and in 28.6% of patients with right-sided tumors. Liver metastases were more common in patients with left-sided tumors. Tumors on the right side were larger at diagnosis and had a higher grade (G3) than tumors on the left. Rectal tumors exhibit distinctive biological characteristics when compared to left-sided tumors, including a higher absence rate of KRAS, NRAS, and BRAF mutations (47.4% in rectal versus 42.8% in left-sided tumors). These rectal tumors are also unique in their primary metastasis site, which is predominantly the lungs, and they have varying mutation rates, particularly in genes such as BRAF, FBXW7, and TP53, that distinguish them from tumors found in other locations. Primary tumor location has implications for the potential treatment of CRC with anti-EGFR therapy.

Fruquintinib (Fruzaqla) for metastatic colorectal cancer.

Fruquintinib (Fruzaqla – Takeda), an oral kinase inhibitor, has been approved by the FDA for treatment of adults with metastatic colorectal cancer (mCRC) who received prior fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy, anti-VEGF therapy, and, in patients with RAS wild-type mutations, anti-EGFR therapy. The drug can be used in patients with mCRC regardless of biomarker status. Fruquintinib is the first drug to become available in the US for treatment of mCRC that targets 3 VEGF receptor kinases.

Guanylate binding protein 4 shapes an inflamed tumor microenvironment and identifies immuno-hot tumors

PurposeGuanylate binding protein 4 (GBP4) is induced by interferons and various cytokines and has been recognized as functionally relevant in numerous types of human cancers. While the role of GBP4 in cancer has been preliminarily summarized, its correlation with antitumor immunity remains unclear and requires further research.MethodsFirst, a comprehensive pan-cancer analysis was conducted, focusing on GBP4’s expression patterns and immunological functions. Subsequently, we explored the correlations between GBP4 and immunological features within the tumor microenvironment (TME) in non-small cell lung cancer (NSCLC) patients. Additionally, we examined the relationships between GBP4 and emerging immunobiomarkers, such as N6-methyladenosine (m6A) genes. Moreover, we assessed the utility of GBP4 in predicting the clinical characteristics and treatment responses of patients with NSCLC.ResultsPan-cancer analysis revealed that GBP4 plays a positive role in most cancer types via the majority of immunomodulators. Furthermore, GBP4 demonstrated positive associations with immunomodulatory factors, tumor-infiltrating immune cells (TIICs) and inhibitory immune checkpoints. Remarkably, the expression of GBP4 was found to be a predictor of significantly enhanced responsiveness to anti-EGFR therapy and immunotherapy.ConclusionsGBP4 expression profiles offer a promising avenue for identifying highly immunogenic tumors across a wide spectrum of cancers. GBP4 holds potential as a robust pan-cancer biomarker for assessing the immunological characteristics of tumors, with particular relevance to its ability to predict therapeutic responses, notably in the context of anti-EGFR therapy and immunotherapy.

Prospective observational study investigating the impact of treatment sequence using regorafenib and FTD/TPI for metastatic colorectal cancer on overall survival (OSERO study).

103 Background: Regorafenib (REG) and trifluridine/tipiracil (FTD/TPI) with or without bevacizumab (BEV) are widely used as a later-line treatment for patients (pts) with metastatic colorectal cancer (mCRC). It is still unclear which is the preferable treatment strategy to start with, either REG, FTD/TPI, or FTD/TPI + BEV in clinical practice. Methods: We conducted a non–intervention, prospective, observational study in pts with mCRC at 41 sites. The key eligibility criteria were ECOG performance status (PS) 0 or 1, pts refractory to or intolerant of fluoropyrimidine, oxaliplatin, irinotecan, anti–angiogenesis, and anti–EGFR therapy if RAS status were wild type, and pts who plan to receive sequential treatment with REG and FTD/TPI BEV. Pts who starts with REG are enrolled in cohort A, FTD/TPI in cohort B, or FTD/TPI plus BEV in cohort C. The primary endpoint is overall survival (OS) of each group. Results: Between September 2020 and December 2022, a total of 501 pts were enrolled and 455 were identified as full analysis set. Pts’ characteristics of cohort A (149 pts) / B (80 pts) /C (226 pts) were as follows: median age 64.0 / 65.5 / 67.0 years, male 53.0 / 52.5 / 55.3%, ECOG PS 0 52.3 / 31.3 / 48.7%, tumor location right–sided 33.6 / 27.5 / 20.4%, RAS wild type 35.6 / 41.3 / 43.4%, and BRAF V600E mutant type 6.7 / 7.5 / 4.0 %. Pts who received subsequent with FTD/TPI BEV in cohort A / REG in cohort B / REG in cohort C were 62.4 / 37.5 / 62.8%. The median OS of cohort A / B / C was 11.8 / 7.1 / 10.2 months. Cox hazard model revealed hazard ratio (HR) 1.40 (95% confidence interval [CI] 1.01–1.94; p = 0.043) for cohort B, and HR 1.04 (95% CI 0.80–1.34; p = 0.784) for cohort C compared with cohort A. After adjusting age, ECOG PS, tumor location, the number of metastatic sites, the adjusted HR were 1.29 (95% confidence interval [CI] 0.87–1.91; p = 0.213) for cohort B, and 1.00 (95% CI 0.75–1.34; p = 0.998) for cohort C compared with cohort A. Conclusions: This study demonstrates that the OS are comparable regardless of whether REG, FTD/TPI, or FTD/TPI + BEV is administered first. Clinical trial information: UMIN000040586 .

Amivantamab monotherapy in relapsed/refractory metastatic colorectal cancer: OrigAMI-1, an open-label, phase 1b/2 study.

135 Background: Amivantamab (ami), an EGFR-MET bispecific antibody with immune cell-directing activity, has shown preclinical activity in colorectal cancer (CRC) models. MET amplification is implicated in driving resistance to anti-EGFR therapies in metastatic CRC (mCRC). We hypothesize that dual, co-inhibition of EGFR and MET with ami could improve outcomes in relapsed/refractory mCRC. Methods: OrigAMI-1 (NCT05379595) is assessing the safety and efficacy of ami as monotherapy in patients (pts) with refractory mCRC in 3 separate cohorts (Table). Eligible pts were wild-type for KRAS, NRAS, BRAF, and EGFR ectodomain by ctDNA testing, without ERBB2/ HER2 amplification. Cohorts A and B included pts with left-sided mCRC without/with prior exposure to anti-EGFR monoclonal antibodies, respectively, and cohort C included pts with right-sided mCRC. Safety population included all pts receiving the recommended phase 2 dose (RP2D; 1050 mg [1400 mg, ≥80kg]). Investigator-assessed response per RECIST v1.1 is reported for evaluable pts with post-baseline disease assessment(s) or who discontinued for any reason. Ami plus FOLFOX or FOLFIRI is being explored in additional cohorts. Results: As of September 4, 2023, 93 pts were treated at RP2D; 89 were response evaluable (median follow-up: 4.4 mo). Median age was 60 years, 66% were male, and median prior lines of therapy were 2, with 94% receiving prior bevacizumab and 69% prior anti-EGFR therapy. Best timepoint responses were: Cohort A: 7/17, 41.2%; Cohort B: 13/54, 24.1%; Cohort C: 1/18, 5.6%. Disease control rates (DCR) were 88.2%, 72.2%, and 77.8% for Cohorts A, B, and C, respectively. Median duration of response (mDoR) for confirmed responders was 7.5 and 7.4 mo for Cohorts A and B, respectively. Treatment is ongoing for the responder in Cohort C. 10/13 responders (77%) remain on treatment. Preliminary biomarker data suggest ami may be active in alterations associated with anti-EGFR antibody resistance (eg, EML4-ALK fusion, PTEN). The most frequent treatment-emergent adverse events were rash (84%) and infusion-related reactions (53%). No new safety signals were observed. Updated results will be presented at the meeting. Conclusions: Ami monotherapy demonstrated promising, durable antitumor activity in refractory mCRC, including pts treated with prior anti-EGFR therapy and pts with right-sided disease. The safety profile of ami in mCRC is manageable and consistent with prior NSCLC experience. Clinical trial information: NCT05379595 . [Table: see text]

Clinical utility of serial circulating tumor DNA (ctDNA) to identify acquired resistance to anti-EGFR antibodies in metastatic colorectal cancer (mCRC).

158 Background: Real-world evidence informing on the value of incorporating serial ctDNA into clinical practice is lacking. We aimed to explore the utility of serial ctDNA for identifying mechanisms of resistance and new targets for patients (pts) receiving anti-EGFR therapy for mCRC. Methods: We retrospectively reviewed 2801 pts with mCRC who had ≥1 alteration detected on a Guardant360 assay (Guardant Health) and subsequently had serial ctDNA assessments with known intervening therapies. We compared detection of new MAPK pathway alterations ( RAS/EGFR/BRAFV600 SNV or indel, MET or ERBB2 amplification) among patients who initially lacked these alterations by whether patients received anti-EGFR antibody alone (panitumumab or cetuximab), in combination with chemotherapy, or if they had never received an anti-EGFR antibody between ctDNA assays. Patients with a subsequent ctDNA assay after therapy initiation were included for analysis of acquired alterations. Results: Of 2801 pts, 1308 (47%) harbored ≥1 MAPK alteration in their first ctDNA timepoint and were excluded from analysis. Of the remaining 1493 without a MAPK alteration prior to therapy, 588 (39.4%) had a MAPK alteration detected in a subsequent ctDNA timepoint. Among 447 of 1493 pts (31.8%) with subsequent exposure to anti-EGFR antibodies, acquisition of a MAPK alteration occurred in 229/447 (51.2%). This was more common (OR 2.01. 95% CI 1.61-2.51, P<0.0001) than in patients without exposure to anti-EGFR antibodies (359/1046 [34.3%]). Acquired MAPK alterations were more common among those receiving single agent antibodies (42/66, 63.6%) than anti-EGFR plus chemotherapy (187/381, 49.1%) (OR 1.82, 95% CI 1.05-3.08, P=0.030). Patients with anti-EGFR antibody exposure were found to have higher blood TMB scores in the first assay after treatment compared to patients treated with chemotherapy alone (11.5 vs. 8.8 mut/MB, respectively; P=0.001), with no significant blood TMB difference between those receiving single agent anti-EGFR versus anti-EGFR plus chemotherapy (median 12.4 vs. 11.5 mut/MB; P=0.52). Patients who acquired MAPK alterations after anti-EGFR therapy had higher blood TMB scores compared to patients who did not acquire MAPK alterations (median 14.3 vs 8.6 mut/MB, respectively; p<0.0001). Conclusions: In this large cohort of pts with mCRC and treatment information, we demonstrate serial ctDNA identified a large proportion of patients acquiring resistance alterations that may impact response to future therapies. These results suggest serial ctDNA analysis may provide additional molecular insights for patients receiving anti-EGFR therapy and inform future anti-EGFR rechallenge strategies.

Trifluridine/tipiracil (TAS-102) in combination with anti-EGFR re-challenge versus TAS-102 plus anti-VEGF in patients with mCRC who experienced first-line anti-EGFR-based chemotherapy.

120 Background: TAS-102 is one of the standard treatments for refractory metastatic colorectal cancer (mCRC). Add-on bevacizumab to TAS-102 has been proved to improve progression-free survival (PFS) and overall survival (OS). However, the two strategies of combination with anti-EGFR or anti-VEGF in RAS/RAF wild-type mCRC patients have not been compared. Methods: We retrospectively collected mCRC patients who received TAS-102 treatment from December 2018 to March 2023 at National Taiwan University Hospital. The key inclusion criteria included RAS/RAF wild-type, first-line treatment with anti-EGFR therapy, and TAS-102 in combination with anti-EGFR re-challenge, or with anti-VEGF therapy. Concurrent use of other chemotherapies was allowed. The patients with combination duration less than 4 weeks were excluded. Results: A total of 30 patients were enrolled. There were 20 patients who received TAS-102 plus anti-EGFR re-challenge, and 10 were treated with TAS-102 plus anti-VEGF. The median treatment line of TAS-102 combined with targeted therapies was 5 (Range 3-11). There was no significant difference in baseline characteristics between the two groups (Table). For TAS-102 plus anti-EGFR vs VEGF, the ORR was 30.0% vs 0%, and the DCR was 70.0% vs 30.0%, respectively. The median PFS was 4.0 vs 2.3 (p=0.389) months, respectively. The median OS was 12.67 vs 9.93 (p=0.722) months, respectively. Conclusions: TAS-102 plus anti-EGFR re-challenge showed a higher ORR than TAS-102 plus anti-VEGF. The PFS and OS were comparable in both arm and numerically longer in the TAS-102 plus anti-EGFR re-challenge group.[Table: see text]

Genome-wide DNA methylation status to predict the efficacy of modified (m)-FOLFOXIRI plus cetuximab as initial treatment for RAS wild-type metastatic colorectal cancer: A biomarker study of the DEEPER trial (JACCRO CC-13AR).

152 Background: Genome-wide DNA methylation status (GWMS) has been shown to be a predictor of therapeutic response to anti-EGFR antibody therapies. This study investigated the association between GWMS and clinical outcomes of first-line chemotherapy with anti-EGFR or anti-VEGF antibody agents for metastatic colorectal cancer (mCRC). Methods: Tumor tissues of mCRC patients registered in the JACCRO CC-13AR (clinical trial number: UMIN000018412) were analyzed for GWMS and were classified into low-methylated colorectal cancer (LMCC) and high-methylated colorectal cancer (HMCC). Clinical data were obtained from the randomized phase II trial, DEEPER trial (JACCRO CC-13) [NCT02515734], in which patients were randomly assigned to m-FOLFOXIRI plus cetuximab (CET) arm and m-FOLFOXIRI plus bevacizumab (BEV) arm for treatment. Progression-free survival (PFS), overall survival (OS), depth of response (DpR), and response rate (RR) were analyzed according to GWMS for each treatment arm. Results: One hundred thirty-seven out of 227 patients enrolled in the JACCRO CC-13AR were analyzed. Of these, 122 (89.1%) and 15 (10.9%) were classified in the LMCC and HMCC, respectively; 66 were assigned to the CET arm including 7 HMCCs, and 54 were assigned to the BEV arm including 8 HMCCs. In the CET arm, PFS and OS of the LMCC were significantly longer than those of the HMCC (median PFS 14.3 vs. 4.0 months, hazard ratio [HR] 0.11, 95% CI: 0.05–0.29, P<0.01; median OS 42.7 vs. 13.6 months, HR 0.04, 95% CI: 0.01–0.13, P<0.01). There were no differences in DpR and RR between the LMCC and the HMCC (median DpR 58.1% vs. 46.7%, P=0.45), although RR of the LMCC was numerically higher than that of the HMCC (71.2% vs. 42.9%, P=0.13). In contrast, in the BEV arm, there were no differences in PFS, DpR, and RR between the two groups (median PFS 16.1 vs. 12.2 months, P=0.08; median DpR 48.3% vs. 53.9%, P=0.99; RR 73.0% vs. 75.0%, P=0.91). However, OS of the LMCC was significantly longer than that of the HMCC (median OS 48.9 vs. 24.2 months, HR 0.39, 95% CI: 0.16–0.95, P=0.03). Conclusions: This study showed that GWMS may be a prognostic marker for initial treatment in RAS wild-type mCRC. Also, GWMS correlates to the survival outcomes of m-FOLFOXIRI plus CET as initial treatment for RAS wild-type mCRC. Clinical trial information: 000018412 .

Early onset metastatic colorectal cancer: Clinical-prognostic characteristics and correlation to molecular profile.

195 Background: Despite a reduction of both incidence and mortality of CRC in the elderly population, several studies published in the last decade have shown an increase in the incidence of early-onset CRC (EO-CRC). Clinical and prognostic data on this setting are limited and conflicting. The aim of our study was to evaluate the clinical, prognostic, and molecular differences in a large group of patients (pts) with early onset mCRC. Methods: We collected data from 589 metastatic EO-CRC from 4 different Italian Institutions. A historical control group of 316 pts > 50 year old was also included in the analysis. All pts had one or more metastatic sites, molecular profiling available (including RAS, BRAF, and MSI status), and underwent at least one line of treatment. The main objective of the study was to evaluate clinical outcome in terms of median overall survival for the global population of EO-CRC pts and in different molecular subgroups according to RAS and BRAF status. Results: In the EO-CRC group median age was 44 (±6) and 67 (±11) in the historical control group. M/F ratios were 2:1 and 1:1, respectively. In the overall population mOS was 34,1 in EO-CRC pts vs 42,0 months (mo) (p = 0,0006) in the control group. In the RAS/BRAF mutated subgroup mOS in EO-CRC pts was 28,6 vs 36,0 mo in the control group (p = 0,0065). In RAS/BRAF wild type subgroup mOS in EO-CRC pts was 44,1 vs 49 mo (p = 0,13). Finally, in the BRAF V600E mutated subgroup EO-CRC pts showed a 16 mo mOS vs 26 mo (p = 0,04). In the overall population mPFS was 12,0 in EO-CRC pts vs 10,0 mo (p = 0,02) in the control group. Furthermore, the overall response rate (ORR) was 53% in EO-CRC and 69% in LO-CRC. Conclusions: Our work including a large population of EO-CRC pts indicates a general worse prognosis for pts with early onset colorectal cancer compared to late onsets. Interestingly this seems to occur regardless of the molecular status. On the other hand findings in the RAS/BRAF wild type population might also suggest a less unfavourable impact of EO-CRC on prognosis possibly related to anti-EGFR therapy. Subsequent investigations will be needed to further understand the specific clinical and molecular characteristics of this growing group of pts to better define the more appropriate treatment strategy.

Targeting IL-6/STAT3 signaling abrogates EGFR-TKI resistance through inhibiting Beclin-1 dependent autophagy in HNSCC

Head and neck squamous cell carcinoma (HNSCC) is featured by notorious EGFR tyrosine kinase inhibitor (TKI) resistance attributable to activation of parallel pathways. The numerous phase I/II trials have rarely shown encouraging clinical outcomes of EGFR-TKIs during treatment in HNSCC patients with advanced tumors. A unique IL-6/STAT3 signaling axis is reported to regulate multiple cancer-related pathways, but whether this signaling is correlated with reduced EGFR-TKI responsiveness is unclear. Here, we found that STAT3 signaling is compensatorily upregulated after EGFR-TKI exposure and confers anti-EGFR therapy resistance during HNSCC therapy. Targeting STAT3 using small molecule inhibitors promotes complete recovery or sustained elimination of HNSCC tumors through combination with EGFR-TKIs both in vitro and in diverse animal models. Mechanistically, phosphorylated STAT3 was proven to enhance oncogenic autophagic flux, protecting cancer cells and preventing EGFR-TKI-induced tumor apoptosis. Thus, blockade of STAT3 signaling simultaneously disrupts several key interactions during tumor progression and remodels the autophagic degradation system, thereby rendering advanced HNSCC eradicable through combination with EGFR-TKI therapy. These findings provide a clinically actionable strategy and suggest STAT3 as a predictive biomarker with therapeutic potential for EGFR-TKI resistant HNSCC patients.

The Importance of Screening for EGFR Mutation in Lung Cancer

Lung cancer is one of the cancers with the most cases occurring in both men and women. It was found that a number of patients with lung cancer had mutations in the epidermal growth factor receptor (EGFR). The EGFR mutation is a somatic mutation associated with non-small cell lung cancer (NSCLC), which can be identified using real-time PCR or Next Generation Sequencing (NGS) in a sample obtained from formalin-fixed paraffin-embedded tissue. The presence of EGFR mutation in lung cancer tissue has revealed an opportunity to treat this disease with anti-EGFR therapy. First-generation EGFR inhibitors work by reversibly inhibiting the EGFR tyrosine kinase. However, it does not work with the T790M mutation which needs a third-generation EGFR inhibitor that can irreversibly inhibit both active and inactive variants of EGFR. Screening of EGFR mutation in NSCLC has been mandatory to reveal an opportunity for treating with EGFR inhibitor.

Detection of KRAS Mutations in Triple-negative Breast Cancers by Polymerase Chain Reaction

Abstract Background: Recently, it has been proven that KRAS gene mutation analysis is an additional in vitro diagnostic method for determining colorectal cancer patients who will not respond to anti-epidermal growth factor receptor (EGFR) therapy. KRAS mutation status assessment may be important in other EGFR-overexpressed cancers, such as breast cancer tumors. Only 5% of breast tumors are KRAS-mutated, yet 60% of triple-negative breast tumors express EGFR, making them potential targets for EGFR inhibitors. To provide a biological foundation for assessing anti-EGFR therapy, we aimed to examine the frequency of KRAS mutations in triple-negative breast cancer (TNBC). Materials and Methods: Forty breast cancer cases were evaluated. These 40 cases have undergone immunohistochemistry for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 markers which exhibited a negative reaction and were ascertained as triple negative. The mutation status of KRAS was determined by real-time polymerase chain reaction (RT-PCR) to detect wild or mutant types of KRAS. Results: In our study, we observed that, out of the total 40 cases of TNBCs, 14 (35%) cases were of wild type and 26 (65%) cases were mutant type detected by RT-PCR. Conclusion: According to our study, KRAS mutations were detected in TNBCs, and EGFR inhibitors may be effective in the treatment of these tumors, which overexpress EGFR in around 65% of cases.

Synergistic anti-tumor activity, reduced pERK, and immuno-stimulatory cytokine profiles with 5-FU or ONC212 plus KRAS G12D inhibitor MRTX1133 in CRC and pancreatic cancer cells independent of G12D mutation.

KRAS mutations occur in ~40-50% of mCRC and are associated with aggressive disease that is refractory to anti-EGFR therapies. Pancreatic cancer harbors ~90% KRAS driver gene mutation frequency. Small molecules targeting KRAS G12C gained FDA approval for KRAS G12C-mutated NSCLC. ONC212, a fluorinated imipridone with nM anti-cancer activity has preclinical efficacy against pancreatic cancer and other malignancies. MRTX1133, identified as a noncovalent selective KRAS G12D inhibitor that suppresses G12D signaling by binding to the switch II pocket thereby inhibiting protein-protein interactions. We investigated cell viability, drug synergies, pERK suppression and cytokine, chemokine or growth factor alterations following treatment with 5-Fluorouracil (5-FU) or ONC212 plus MRTX1133 in 6 human CRC and 4 human pancreatic cancer cell lines. IC50 sensitivities ranged from 7 to 12 µM for 5-FU, 0.2-0.8 µM for ONC212, and > 100 nM to > 5,000 nM for MRTX1133 (G12D N = 4: LS513 > 100, HPAF-II > 1,000, SNUC2B > 5,000, PANC-1 > 5,000). For non-G12D, the range of IC50 for MRTX1133 was > 1,000 to > 5,000 nM for CRC lines with G12V, G13D, or WT KRAS (N = 7). Synergies between MRTX1133 plus 5-FU or ONC212 were observed regardless of KRAS G12D mutation with combination indices of < 0.5 indicating strong synergy. Observed synergies were greater with MRTX1133 plus ONC212 compared to MRTX1133 plus 5-FU. pERK was suppressed with mutant but not wild-type KRAS at nM MRTX1133 doses. Immunostimulatory profiles included reduction in IL8/CXCL8, MICA, Angiopoietin 2, VEGF and TNF-alpha and increase in IL-18/IL-1F4 with MRTX treatments and combinations. Our studies reveal preclinical activity of MRTX1133 alone or synergies when combined with 5-FU or ONC212 against mCRC and pancreatic cancer cells regardless of KRAS G12D mutation. The results suggest that KRAS G12V and KRAS G13D should be further considered in clinical trials including combination therapies involving MRTX1133 and 5-FU or ONC212.

Limitations in the management of colorectal cancer in sub-Saharan Africa

Colorectal cancer (CRC) was regarded as a rare disease in native West Africans. It is now accepted as an established disease with a rising incidence. The CRC is now known to be a complex tumour with different aetiopathological pathways. With all cancers early detection is important if one aims to cure the patient. A summary of the clinical features include: Unexplained ill-health and anaemia in patients with cancer of the caecum and ascending colon; palpable abdominal mass for colon cancer; rectal bleeding and tenesmus for carcinoma of the rectum; palpable mass on digital rectal examination in at least 75% of cases. The current complete management of this disease involves extirpative surgery and adjuvant treatment with a combination of cytotoxic chemotherapy and tailored therapy. This presentation will look at ways in which seamless management of CRC in this environment is hampered. The ‘PATIENT’ factor: Ignorance (which leads to unfavourable health-seeking behaviour) Poverty (goes for all developing countries) Gullibility (under which falls religion and alternative treatment) Cultural taboos (which lead to refusal of colostomy-based treatments) Aversion of the sequelae of rectal cancer treatment especially in males where up to 30% of patients are under the age of 40 years. Late presentation (effect of 1–5) The ‘COUNTRY’ factor: Politics: inadequate budget for health Workers not enough; current brain drain of doctors, major cancer centres are stretched. Infra-structure: There is a glaring lack of any population screening programme, a lack of public enlightenment messages for awareness and only two government centres have functioning radiotherapy machines. Staplers and cytotoxic drugs have to be imported, thus are expensive and out of reach of the common man. The ‘GENETICS’ factor: The biology of CRC in the native African is different from that of Caucasians and more aggressive. Carcinomatosis peritonei is frequent. There’s also the emergence of unusual metastases to the lungs and spine, bypassing the liver. A summary of the findings by Nigerian researchers on the molecular biology of native Nigerian CRC showed MSI (Not otherwise stated) occurred in 23–53% of Nigerian CRC, MSI-H seen in 28.1–43%. KRAS in 21% while BRAF was seen in 4.5%. The significance of these results may mean that we might not be administering the right combination chemotherapy in over 50% of our patients. Some studies have shown that patients with MSI-H CRC appear to have ineffectual or even detrimental responses to 5FU-based adjuvant chemotherapy. We all know that 5FU is the cornerstone of most of the combination chemotherapy we administer to patients (FOLFOX, FOLFIRI, CapeOX, XelOX). In addition, the 2012 study on BRAF and KRAS in Nigerians by Abdulkareem et al. also suggests that Nigerian patients may benefit more from anti-EGFR therapy (Cetuximab, Panitumumab) than Caucasians. However, cost implications will make prescribing these drugs a mere academic exercise in most Nigerian patients.

Targeted Mass Spectrometry Analyses of Somatic Mutations in Colorectal Cancer Specimens Using Differential Ion Mobility.

Identification of K-Ras and B-Raf mutations in colorectal cancer (CRC) is essential to predict patients' response to anti-EGFR therapy and formulate appropriate therapeutic strategies to improve prognosis and survival. Here, we combined parallel reaction monitoring (PRM) with high-field asymmetric waveform ion mobility (FAIMS) to enhance mass spectrometry sensitivity and improve the identification of low-abundance K-Ras and B-Raf mutations in biological samples without immunoaffinity enrichment. In targeted LC-MS/MS analyses, FAIMS reduced the occurrence of interfering ions and enhanced precursor ion purity, resulting in a 3-fold improvement in the detection limit for K-Ras and B-Raf mutated peptides. In addition, the ion mobility separation of isomeric peptides using FAIMS facilitated the unambiguous identification of K-Ras G12D and G13D peptides. The application of targeted LC-MS/MS analyses using FAIMS is demonstrated for the detection and quantitation of B-Raf V600E, K-Ras G12D, G13D, and G12V in CRC cell lines and primary specimens.

Intragenic EGFR::EGFR.E1E8 Fusion (EGFRvIII) in 4331 Solid Tumors.

Epidermal growth factor receptor variant III (EGFRvIII, the deletion of exons 2-7) is a recurrent intragenic EGFR::EGFR.E1E8 fusion that occurs in high-grade gliomas. The presence of EGFRvIII in other solid tumors has not been well characterized. We retrospectively reviewed advanced malignant solid tumor cases tested by a custom hybrid capture 610-gene next-generation sequencing platform from 2021 to 2022. EGFRvIII was identified in 17 of 4331 (0.4%) cases, including 16 of 238 (7%) brain tumors and 1/301 (0.3%) breast tumors. EGFRvIII-positive brain tumors were all glioblastoma IDH-wildtype, most with concurrent TERT promoter mutation (14 of 16), EGFR amplification (13 of 16), and EGFR mutation (8 of 16). The only EGFRvIII-positive breast lesion was a sarcomatoid neoplasm in a young female patient. A separate breast case tested outside our institution with reported EGFRvIII was noted in a young female patient with a malignant phyllodes tumor with stromal overgrowth. Microscopically, both EGFRvIII-positive breast tumors showed high-grade sarcomatoid morphology with brisk mitotic activity. In summary, EGFRvIII is rare, occurring primarily in glioblastoma and rarely in breast sarcomatoid neoplasm, with no instances identified in other tumor types in our series. This select group of patients may benefit from chemotherapy and/or targeted anti-EGFR therapy.