Common KRAS Mutations Research Articles

Exploring the molecular profile of localized colon cancer: insights from the AIO Colopredict Plus registry.

Understanding the mutational landscape of colon cancer (CC) is crucial for targeted therapy development. Microsatellite instability (MSI-H), rat sarcoma (RAS), and B-Raf proto-oncogene, serine/threonine kinase (BRAF) mutations (MT) are pivotal markers. Further investigation into clinicopathological features of RAS and BRAF MT in microsatellite stable (MSS) and MSI-H tumors is warranted. A retrospective analysis of 4883 localized CC patients (pts.) was conducted. Molecular profiling assessed MSI, KRAS, NRAS, and BRAF MT. Correlation with clinicopathological data employed ANOVA and Chi-square tests. Disease-free survival (DFS) and overall survival (OS) were analyzed adjusting for age, gender, sidedness, UICC stage, Charlson Comorbidity Index (CCI). A Cox model incorporated all variables as covariates. This analysis included 4883 pts. (2302 female/2572 male, 3865 (79.2%) MSS, 1018 (20.8%) MSI-H). MSS pts. had more All-Wild Type (WT), KRAS MT, and NRAS MT tumors vs. MSI-H pts. (42.1% vs. 21.1%; 39.8% vs. 15.4%; 3.6% vs. 0.7%; p<0.001 for each). BRAF MT tumors (95.5% BRAF V600E MT) were more prevalent in MSI-H individuals (62.8% vs. 8.1%, p<0.001). KRAS and BRAF MT tumors were more frequently right-sided, while BRAF MT tumors were associated with female gender, advanced disease stage, lymph node positivity, and poorer differentiation in the MSS subset (p<0.001). Common KRAS mutations included p.G12D (30.44%) and p.G12V (21.3%) in MSS and p.G13D (28.9%) and p.G12D (22.37%) in MSI-H. NRAS MT tumors were dominated by codon 61 mutations (51.7%). Survival analysis revealed worst prognosis in BRAF MT MSS tumors (DFS: HR 1.74 (95% CI 1.15-2.62, p=0.009; OS: HR 1.61 (95% CI 0.99-2.6), p=0.055). The 3-years DFS and 5-years OS rates were lowest in this subset (61.6% and 57.7% respectively). These findings highlight the complex interplay between molecular subtypes, clinicopathological features, and survival outcomes in early CC. Further research is needed to elucidate underlying mechanisms and develop personalized treatment strategies.

Abstract PR012: A first-in-class EGFR-directed KRAS G12V selective inhibitor

Abstract The KRAS proto-oncogene encodes a small GTPase that is crucial for the activation of intracellular signaling pathways that control cell proliferation, survival and differentiation. KRAS is frequently mutated in cancer resulting in its constitutive activation and dysregulation of downstream signaling pathways that drive oncogenic transformation. KRAS G12V is the second most common KRAS mutation in cancer, and occurs frequently in lung, colon and pancreatic cancers. However, while significant advancements have been made in developing KRAS G12C, G12D and pan-KRAS inhibitors, there remain no direct KRAS G12V inhibitors in the clinic. Due to challenges targeting oncogenes with traditional small molecule approaches, RNA interference (RNAi) has become an attractive therapeutic approach for many oncogenes. RNAi has faced many obstacles as an effective cancer therapeutics, including the lack of cancer- specific tissue targeting, rapid oligonucleotide nuclease degradation and clearance from circulation, the need for endosomal escape, and unwanted immune stimulation. However, recently, the use of targetable ligands conjugated to chemically modified siRNAs have shown promise in circumventing these barriers. Here, we describe the development of EFTX-G12V, a fully-modified, mutant-selective siRNA conjugated to an EGFR ligand that shows improved tumor delivery and significant anti-tumor activity in lung and colon cancer models. We used a structure-activity relationship screening approach to identify a highly mutant-selective fully chemically modified siRNA that inhibits KRAS G12V expression at both the mRNA and protein level while completely sparing KRAS WT. Furthermore, this siRNA inhibited cancer cell growth in vitro and showed no off-target effects. To address the issue of tumor-specific delivery, we conjugated a non-mitogenic EGFR ligand to the siRNA and found enhanced delivery to tumors with varying levels of EGFR expression. EFTX-G12V significantly inhibited KRAS G12V mRNA and protein in vivo and showed significant anti-tumor activity in lung and colon xenograft models. Importantly, EFTX-G12V showed no off-target effects on WT KRAS in somatic tissues including kidney, skin and bladder. Unexpectedly, we found that mutant-selective targeting showed improved efficacy in comparison to a pan-KRAS siRNA. EFTX-G12V significantly inhibited tumor angiogenesis while pan-KRAS targeting had inconsistent effects suggesting that mutant-selective targeting has advantages within the tumor microenvironment. Together our findings represent a technologic advance in ligand-directed, mutant-selective oncogene targeting using RNAi and reveal new biologic insights in KRAS targeting that may have broader implications with regards to safety and efficacy. Citation Format: Lyla Stanland, Hayden Huggins, Alessandro Porrello, Yogitha Chareddy, Salma Azam, Jillian Perry, Pradeep Pallan, Kristina Whately, Lincy Edatt, Matthew Fleming, Jonah Im, Christina Gutierrez-Ford, Imani Simmons, Vandanaa Jayaprakash, Rani Sellers, Gabriela de la Cruz, Albert Wielgus, Martin Egli, Albert Bowers, Chad Pecot. A first-in-class EGFR-directed KRAS G12V selective inhibitor [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr PR012.

Targeted Genetic Sequencing Analysis of 223 Cases of Pseudomyxoma Peritonei Treated by Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy Shows Survival Related to GNAS and KRAS Status.

Pseudomyxoma peritonei (PMP) is an unusual condition with unique behaviour caused by a mucinous neoplasm, usually arising from the appendix. The aim of this study was to evaluate the prevalence of genomic alterations in clinical specimens of PMP using a targeted assay and correlate the findings with clinical, pathological and outcome data. Sequencing data from 223 patients were analysed. The median follow-up interval was 48 months. The primary neoplasm was appendiceal in 216 patients, ovarian in 4, urachal in 2 and renal in one. We confirmed common mutations in GNAS and KRAS (42% each) with significant co-occurrence of variants in these genes. TP53 mutations were found in 8%. Other mutations were rare but included novel mutations in BAP1 and ERBB4. Of 17 patients with acellular peritoneal mucin, 6 (35%) were positive for DNA mutations. The non-appendiceal cases generally showed a similar mutational landscape to the appendiceal lesions with GNAS and KRAS commonly mutated, although one urachal lesion showed multi-hit TP53 mutation without variants in either GNAS or KRAS. Survival was significantly associated with the grade of the primary neoplasm, the grade of the peritoneal disease, the completeness of cytoreduction score and with mutation in either GNAS, KRAS or both. The hazard ratio (HR) associated with mutation in GNAS and/or KRAS was 1.87 (p = 0.004). Survival outcome was more closely associated with the grade of the peritoneal disease than with the grade of the primary neoplasm. Our findings support the developing concept that mutational analysis may provide prognostic information in patients with PMP.

Tumor Cell Spatial Organization Directs EGFR/RAS/RAF Pathway Primary Therapy Resistance through YAP Signaling.

Non-small cell lung cancers (NSCLC) harboring common mutations in EGFR and KRAS characteristically respond transiently to targeted therapies against those mutations, but invariably, tumors recur and progress. Resistance often emerges through mutations in the therapeutic target or activation of alternative signaling pathways. Mechanisms of acute tumor cell resistance to initial EGFR (EGFRi) or KRASG12C (G12Ci) pathway inhibition remain poorly understood. Our study reveals that acute response to EGFR/RAS/RAF-pathway inhibition is spatial and culture context specific. In vivo, EGFR mutant tumor xenografts shrink by > 90% following acute EGFRi therapy, and residual tumor cells are associated with dense stroma and have increased nuclear YAP. Interestingly, in vitro EGFRi induced cell cycle arrest in NSCLC cells grown in monolayer, while 3D spheroids preferentially die upon inhibitor treatment. We find differential YAP nuclear localization and activity, driven by the distinct culture conditions, as a common resistance mechanism for selective EGFR/KRAS/BRAF pathway therapies. Forced expression of the YAPS127A mutant partially protects cells from EGFR-mediated cell death in spheroid culture. These studies identify YAP activation in monolayer culture as a non-genetic mechanism of acute EGFR/KRAS/BRAF therapy resistance, highlighting that monolayer vs spheroid cell culture systems can model distinct stages of patient cancer progression.

Abstract C168: Developing lung adenocarcinoma cell lines to mitigate lung cancer health disparities

Abstract Lung cancer continues to be the number one cause of cancer-related deaths worldwide and remains a prominent source of cancer health disparities. Black/African American (B/AA) males exhibit a 12% higher lung cancer incidence rate and a 15% higher lung cancer death rate when compared to white males. Lung adenocarcinoma (LUAD) is the most common histological subtype of lung cancer in all ethnic/racial groups, including B/AAs. To further examine this phenomenon, we want to create a collection of lung cancer cell lines that would be useful for molecular studies of lung cancer development, progression, development of new targeted therapies, and pre-clinical drug testing. After reviewing the literature (Leon et al. 2023, Frontiers in Oncology, Vol. 13, p. 1187585, 2023), we identified only 30 unique B/AA cell lines out of ∼800, the majority of which are derived from White and Asian patients. Moreover, only 6 of the 30 cell lines are derived from patients with LUAD. We are in the process of deriving more LUAD cell lines from B/AA patients as well as alveolar epithelial cell lines in order to study the development of LUAD. In addition, we are creating a collection of multiple independent isogenic cell line variants from an existing lung cancer cell line NCI-H23. NCI-H23 was derived from a B/AA male LUAD patient and harbors a KRASG12C heterozygous mutation. G12C is the most common KRAS mutation in LUAD (∼40% of KRAS mutations) followed by G12V (∼20%), G12D (∼15%), G12A (∼10%), and G13C (∼6%). We used CRISPR/Cas-9 genome- based editing to replace the KRASG12C mutation with KRASG12V, KRASG12D, KRASG12A, and KRASG13C. We have derived multiple independent cell lines for most mutations. We are in the process of performing whole genome sequencing of these cell lines to exclude any off-target effects that may have arisen from the CRISPR/Cas-9 engineering. In addition, we will carry out whole genome RNA sequencing to assess the effect of the engineering and/or KRAS mutation switching. As a control, we are also sequencing the genomes and transcriptomes of three monoclonal cell lines we derived from NCI-H23 cells, to determine what variability ensues with the derivation of monoclonal lines, since that is required to obtain the CRISPR/Cas9-edited cells. We will use this collection of cell lines to study the efficacy of polyisoprenylated cysteinyl amide inhibitors (PCAIs) and other drugs on cell lines bearing these KRAS mutations. PCAIs were developed to target cells carrying mutant KRAS. Our efforts will provide new cell lines to study lung adenocarcinoma in B/AA subjects, addressing a key shortcoming and disparity in the lung cancer research toolkit. Citation Format: Sofia A. Lugo, Christopher Leon, Matthew A. Gladstone, Chunli Yan, Daniel J. Mullen, Pablo E. Puente, Kweku Ofosu-Asante, Justin K. Mensah-Mamfo, Kyle R. Phillips, Yong Huang, Nazarius S. Lamango, Ite A. Offringa. Developing lung adenocarcinoma cell lines to mitigate lung cancer health disparities [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C168.

Abstract C012: Overcoming Cell Subtype-Specific Adaptive Resistance to KRAS G12D Inhibition in KRAS G12D-Mutant Pancreatic Cancer

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) has a 5-year survival rate of only 12%, with limited treatment options. Oncogenic KRAS mutations drive PDAC tumor progression, which occur in the majority of PDAC tumors. KRAS G12D is the most common KRAS mutation, found in 36% of PDAC cases, which is associated with the worst clinical outcomes. Mutant-selective KRAS G12D inhibitors (KRASi G12D), such as MRTX1133, have recently demonstrated initial responses in KRAS G12D-mutant preclinical models. However, mechanisms of adaptive resistance to KRAS G12D inhibition are largely under-investigated and novel therapeutic strategies to overcome drug resistance are urgently needed. Results: Adaptive RAS signaling reactivation was found to dampen KRAS G12D inhibition in a library of KRAS G12D PDAC cell lines, thereby minimizing drug efficacy. Quantitative downstream analyses of drug combination screening using a KRAS G12D cell line library further identified this adaption to KRAS inhibition was cell subtype specific. Fibroblast growth factor receptor (FGFRs) drove adaptive RAS reactivation specifically in mesenchymal PDAC cells, which are aggressive, and intrinsically resistant to KRASi. In contrast, epithelial growth factor receptor (EGFR) reactivated RAS G12D signaling in epithelial cells, which are sensitive to KRASi G12D. Genetic and pharmacological inhibition of FGFR1 or FGFR2 improved drug efficacy by decreasing FGFR-mediated RAS reactivation specifically in mesenchymal PDAC lines. Pharmacological blockade of EGFR enhanced drug efficacy by inhibiting EGFR-mediated RAS reactivation specifically in epithelial PDAC lines. Furthermore, low-concentration of a novel pan- RAS inhibitor, which inhibits both wild-type and mutant RAS, completely abrogated MAPK signaling and significantly improved efficacy, when combined with KRASi G12D, suggesting a pro-survival dependency on wild-type RAS as a compensatory mechanism in response to KRAS G12D inhibition. Conclusion: Upstream RTK-mediated adaptive RAS signaling re-activation in response to KRAS inhibition in PDAC is cell subtype specific. Complete inhibition of RAS signaling by overcoming adaptive RAS rebound improves efficacy of KRASi G12D. Citation Format: Qingxiang (Nick) Lin, Alvin Morales, Haley Barnes, Ryan Bruce Corcoran. Overcoming Cell Subtype-Specific Adaptive Resistance to KRAS G12D Inhibition in KRAS G12D-Mutant Pancreatic Cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C012.

The histopathological spectrum and molecular changes associated with KRAS G12C mutation in non-small cell lung carcinoma

KRAS G12C is the most common KRAS mutation in non-small cell lung carcinoma (NSCLC), for which targeted therapy has recently been developed. From the 732 cases of NSCLC that underwent next-generation sequencing at the Department of Anatomical Pathology, Liverpool Hospital, between July 2021 and May 2023, we retrieved 83 (11%) consecutive cases of KRAS G12C mutated NSCLC, and analysed their clinical, pathological, and molecular features. Of the 83 cases of KRAS G12C mutated NSCLC, there were 46 (55%) men and 37 (45%) women, with mean age of 72 years. Of the 49 cases with known clinical information, 94% were current or ex-smokers, and 49% were stage IV at diagnosis with median survival of 12 months. Sixty-three percent were histology cases and the remainder were cytology cases. Eighty-two percent were non-mucinous adenocarcinomas, with conventional histology including lepidic, acinar, solid, single cells and micropapillary patterns, and 62% were poorly differentiated. There were five (6%) cases of mucinous adenocarcinoma, one case of pleomorphic carcinoma and one case of high-grade fetal adenocarcinoma. TTF1 was positive in the majority (89%) of cases. Nineteen (23%) cases had TP53 co-mutation, and these cases had trends towards higher PD-L1 expression, poor differentiation, and presentation as stage IV disease, but the differences were not statistically significant. KRAS G12C mutated NSCLCs almost exclusively occurred in smokers and were mostly non-mucinous adenocarcinomas with conventional histological patterns which ranged from well to poorly differentiated. Around a quarter had TP53 co-mutation, the histological impacts and immune profile of which need to be assessed in a larger study.

Concurrent inhibition of oncogenic and wild-type RAS-GTP for cancer therapy.

RAS oncogenes (collectively NRAS, HRAS and especially KRAS) are among the most frequently mutated genes in cancer, with common driver mutations occurring at codons 12, 13 and 611. Small molecule inhibitors of the KRAS(G12C) oncoprotein have demonstrated clinical efficacy in patients with multiple cancer types and have led to regulatory approvals for the treatment of non-small cell lung cancer2,3. Nevertheless, KRASG12C mutations account for only around 15% of KRAS-mutated cancers4,5, and there are no approved KRAS inhibitors for the majority of patients with tumours containing other common KRAS mutations. Here we describe RMC-7977, a reversible, tri-complex RAS inhibitor with broad-spectrum activity for the active state of both mutant and wild-type KRAS, NRAS and HRAS variants (a RAS(ON) multi-selectiveinhibitor). Preclinically, RMC-7977 demonstrated potent activity against RAS-addicted tumours carrying various RAS genotypes, particularly against cancer models with KRAS codon 12 mutations (KRASG12X). Treatment with RMC-7977 led to tumour regression and was well tolerated in diverse RAS-addicted preclinical cancer models. Additionally, RMC-7977 inhibited the growth of KRASG12C cancer models that are resistant to KRAS(G12C) inhibitors owing to restoration of RAS pathway signalling. Thus, RAS(ON) multi-selectiveinhibitors can target multiple oncogenic and wild-type RAS isoforms and have the potential to treat a wide range of RAS-addicted cancers with high unmet clinical need. A related RAS(ON) multi-selectiveinhibitor, RMC-6236, is currently under clinical evaluation in patients with KRAS-mutant solid tumours (ClinicalTrials.gov identifier: NCT05379985).

Abstract 1943: Discovery and characterization of potential drivers of resistance to the KRAS G12D inhibitor, MRTX1133, in cancer cell line models

Abstract Introduction: KRASG12D is the most common KRAS mutation and is present in approximately 34% of pancreatic cancer, 10-12% of colorectal cancer, 4% of lung adenocarcinoma and in a number of other cancer types. We previously identified MRTX1133, a potent, selective, and non-covalent KRASG12D inhibitor. The advancement of MRTX1133 to clinical trials warrants continued study of the role of the KRASG12D mutation in cancer pathogenesis and progression. Methods: Previous pharmacodynamic and pharmacogenomic profiling in sensitive and partially resistant models identified mechanisms implicated in limiting the anti-tumor response including signaling pathways that induce feedback reactivation and/or bypass KRAS dependence. Thus, cell lines (GP2D and SNU-1033, colorectal cancer; HPAC and AsPC-1, pancreatic cancer) were utilized to study acquired resistance to MRTX1133 following continuous treatment at increasing concentrations over time. These cell lines were confirmed to be stably resistant as determined by evaluation of response to MRTX1133 in vitro and in vivo. These cell lines were extensively profiled to determine underlying mechanisms of resistance utilizing molecular profiling strategies as well as drug combination screens to interrogate pathways that could circumvent resistance. Results: In one of the four generated cell lines with acquired resistance, evidence of secondary KRAS mutations Y96N and H95Q were confirmed by RNAseq and are likely drivers of resistance in this cell line and are consistent with known mechanisms of KRASG12C inhibitor resistance. The three other MRTX1133 resistant cell lines did not show evidence of secondary KRAS mutations and were further evaluated for mechanisms that bypass KRAS dependence. Combinations of MRTX1133 with therapies that target pathways including upstream RTK signaling, mTOR, or AKT broadly enhanced the anti-tumor activity of MRTX1133 in both in vitro cell viability and in vivo efficacy studies in the resistant cell lines. Conclusion: Collectively, these data provide early insight onto potential mechanisms of resistance to selective KRASG12D inhibitors and demonstrate the importance of developing rational combination strategies designed to address drug resistance. In addition, these studies provide a catalogue of potentially druggable vulnerabilities that complement KRAS blockade. Citation Format: Xousaen M. Helu, Ellie Griffiths, Andrew Calinisan, Allan Hebbert, Larry Yan, Natalie Hoffman, David Trinh, Laura Hover, Julio Fernandez-Banet, David M. Briere, Ella Lifset, Peter Olson, James G. Christensen, Jill Hallin. Discovery and characterization of potential drivers of resistance to the KRAS G12D inhibitor, MRTX1133, in cancer cell line models [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 1943.

Abstract 1932: Overcoming acquired resistance to KRAS(G12D) inhibition using a KRAS-HSP90 hetero-bifunctional small molecule therapeutic agent

Abstract KRAS mutations are highly prevalent across many different cancer types. Recent advancements in KRAS-targeted drugs, such as the FDA-approved KRAS(G12C) inhibitors sotorasib and adagrasib for NSCLC patients, have shown great promise in the clinic. Nonetheless, these new agents fail to address other mutations, such as KRAS(G12D), which overall is the most common KRAS mutation in cancers, being found in 37% of pancreatic ductal adenocarcinomas, 12.5% of colorectal cancers and 4.9% of lung adenocarcinomas. Recently, MRTX1133 has been described as a selective, non-covalent inhibitor of KRAS(G12D) that shows promising preclinical efficacy and is undergoing clinical testing. However, based on prior clinical experience with sotorasib and adagrasib, acquired resistance to MRTX1133 may reasonably be anticipated. In fact, we find that KRAS(G12D)-mutated cell lines and a patient-derived organoid model exhibit varying degrees of inherent resistance to MRTX1133. To examine the consequences of blocking KRAS signaling, we employed a KRAS(G12D)-specific PROTAC, which simulated the effects of KRAS deletion. This demonstrated that receptor tyrosine kinase (RTK) activation could compensate for loss of KRAS signaling and was a key de novo resistance mechanism. This suggests that combination therapies may need to be individually tailored to treat patients resistant to KRAS(G12D)-targeted therapies. Additionally, we developed MRTX1133 resistant cells by culturing sensitive AsPC-1 pancreatic cancer cells in gradually increasing concentrations of the inhibitor. The resulting resistant cells displayed a complex RTK activation profile compared to parental cells. To counteract this, we employed KRAS(G12D)-CHAMP RNK08179, a hetero-bifunctional small molecule agent that simultaneously targets both KRAS(G12D) and HSP90, an RTK-regulating chaperone protein. RNK08179 effectively suppressed both KRAS signaling and RTK activation in MRTX1133-resistant cancer models, overcoming the compensatory resistance mechanisms observed with MRTX1133 alone. These findings highlight the potential of KRAS-CHAMPs as a novel, effective treatment strategy for KRAS-driven cancers, particularly those resistant to KRAS(G12D) inhibitors. Citation Format: Ines Pulido Endrino, Laura gunder, Qiyue Luan, Chenghao Ying, Zimo Yang, Jinhua Li, Yaya Wang, Yuetong Sun, Chuhe Liu, Yan Dai, Haoxin Zhou, Malek Massad, Ian Papautsky, Thomas L. Prince, Guoqiang Wang, Kevin P. Foley, Weiwen Ying. Overcoming acquired resistance to KRAS(G12D) inhibition using a KRAS-HSP90 hetero-bifunctional small molecule therapeutic agent [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 1932.

Prognostic value of KRAS G12V mutation in lung adenocarcinoma stratified by stages and radiological features

ObjectiveKRAS G12V is one of the most common KRAS mutation variants in lung adenocarcinoma (LUAD), and yet its prognostic value is still unrevealed. In this study, we investigated the clinicopathologic characteristics and prognostic value of the KRAS G12V mutation in LUAD. MethodsData of 3829 patients who underwent LUAD resection between 2008 and 2020 were collected. Mutations were classified as wild-type, G12V, or non-G12V. The clinicopathologic characteristics, postoperative outcomes, and recurrence pattern were analyzed among groups. ResultsIn total, 3554 patients were wild-type and 275 patients harbored a KRAS mutation: 60 patients with G12V (22.2%) and 215 patients with non-G12V (77.8%). The KRAS G12V mutation was more frequent in male patients, older patients (≥60 years), former/current smokers, those patients with radiologic solid nodules, and those with highly invasive histologic subtypes. Tumors carrying KRAS G12V mutation exhibited elevated programmed death-ligand 1 expression in comparison with wild-type tumors. KRAS G12V was more prevalent in older patients and had less lymphovascular invasion compared with other mutation types. FGF3, RET, and KDR co-mutations occurred more frequently in the KRAS G12V group. Multivariate analysis demonstrated that the KRAS G12V mutation was an independent prognostic factor in stage Ⅰ tumors, whereas the KRAS non-G12V mutation was not. KRAS G12V was associated with early recurrence and locoregional recurrence. ConclusionsThe KRAS G12V mutation was associated with aggressive clinical-pathologic phenotype and early recurrence. To note, this mutation exhibited a significantly worse prognosis in patients with part-solid and stage Ⅰ lung adenocarcinoma. Meanwhile, the prognostic significance of KRAS G12C and G12V variants was comparable.

Clinical impact of KRAS mutations in metastatic pancreatic ductal adenocarcinoma (PDAC).

619 Background: Mutations in the KRAS oncogene occur in most PDAC and lead to the activation of the KRAS protein. Little is known about the differential impact of KRAS mutations on the outcomes of patients receiving standard of care cytotoxic treatments for metastatic disease. KRAS inhibitors are emerging as promising options for this disease and understanding the impact of distinct KRAS mutations in patient outcomes is needed. Methods: This study used the nationwide Flatiron Health electronic health record (EHR)-derived de-identified database from 5,369 patients. Adult patients with diagnosis of metastatic PDAC who received at least one line of systemic therapy and had sufficient data available were included in this analysis. Median time to next treatment (TTNT) and overall survival (OS) time were calculated for three common first-line treatments and KRAS mutations. TTNT and OS were calculated for each permutation of treatment and each KRAS mutation. Hazard ratios (HR) were generated for each KRAS mutation and treatment, accounting for potentially confounding variables. Results: Of the 5,369 patients, 2,472 met the inclusion/exclusion criteria. G12C had the shortest median OS (7.5 mo) and G12R had the longest (9.1 mo). Overall, KRAS mutation-positive patients had a median OS of 8.6 mo, compared to 11.7 mo for KRAS Wild Type (WT) patients. A Cox Proportional Hazard analysis of OS across KRAS mutation status found that G12C, G12V, G12D, and Other Non G12/13 KRAS had significantly higher HR than KRAS WT. A comparison of the three common first-line interventions for metastatic PDAC showed that FOLFIRINOX had the longest median TTNT (5.3 mo) and the longest OS (10.2 mo), while Gemcitabine had the shortest TTNT (2.6 mo) and OS (5.9 mo). A Cox Proportional Hazard analysis of OS across all patients found that Gemcitabine and Gemcitabine with Nabpaclitaxel had significantly higher HR than FOLFIRINOX. FOLFIRINOX had the longest TTNT in the G12C, G12V, G12D, G12R, and other non-G12/G13 KRAS groups (see table). Conclusions: Our data suggest that FOLFIRINOX has a longer TTNT than other first-line regimens for KRAS G12C, G12V, G12D, and G12R. KRAS G12C was associated with the shortest OS among common KRAS mutations.[Table: see text]

Association of KRAS G12C status with age at onset of metastatic colorectal cancer in the Brazilian population: A multicenter analysis of a molecular profile database (RAS, BRAF and MSI status).

173 Background: Precision oncology has changed clinical practice in metastatic colorectal cancer (mCRC). However, there is little data about molecular epidemiology of mCRC in Brazil. Our study aims to create a nation-wide database to develop future projects in the Oncoclinicas Group. Methods: This was an observational, retrospective, and multicenter study. Anonymized medical records of adult patients (18 years or older) with mCRC from January 2019 to July 2023 were reviewed. All specimens were centrally reviewed in our laboratory (all tissue-based analysis). Demographic data included age, gender, region of origin and sidedness. Molecular data included RAS, BRAF and MMR status. Descriptive statistics, frequencies and percentages were used for categorical variables, while mean and medians for numerical variables. The correlation between variables was analyzed through Chi-square and T-test (when applicable). Significance for all results was established as a p value of &lt; 0.05. The statistical software used was SPSS. Results: A total of 858 cases were included. Median age was 63.7 y/o (range 22-95) and 11.9% were &lt; 45 y/o. Male patients represented 50.3% of the population and 76.1% were from the Southeast region. Left-sided tumors comprised 59.2% of the cases, 36.8% were right-sided and 4% were not specified. Wild-type KRAS corresponded to 46.7% of the total cases, while 49.4% were KRAS mutant and 3.9% NRAS mutant. The most common KRAS mutations were G12V (27.6%) and G12D (23.5%). KRAS G12C mutation was found in 6.4% of all KRAS mutant tumors. The most common NRAS mutation was the Q61K (24.2%). Only 7.3% of cases were BRAF mutated, most of them V600E, only 5 non-V600E mutations were detected. MSI-high was present in 14 cases only (1.6%). In the age-stratified analysis, left-sidedness (p=0.001) and KRAS G12C mutation (p=0.016) were associated with younger age (&lt;45 y/o). In the sidedness-stratified analysis, younger age (p=0.001), BRAF mutation (p=0.001) and MSI-high status (p=0.009), were more common in right-sided tumors. Conclusions: In our Brazilian cohort of mCRC patients, frequencies of RAS and BRAF mutations were similar to worldwide data. However, we found lower than expected frequency of MSI-high tumors. KRAS G12C mutation was associated with early-onset mCRC, an emergent population in which KRAS G12C inhibitors might be particulary useful. To the best of our knowledge, this is the largest cohort in the Brazilian population with mCRC reporting RAS, BRAF and MSI status. Larger studies are needed to confirm these findings.

Association of candidate alterations with primary resistance to KRAS G12D targeting in colorectal cancer.

170 Background: KRAS-mutant colorectal cancer (CRC) has a worse prognosis and greater resistance to therapy, attracting tremendous efforts to develop both allele-specific and pan-KRAS targeting agents including KRAS G12C and G12D inhibitors. CRC has demonstrated both primary and acquired resistance to KRAS G12C inhibitors, which can be better evaluated by circulating tumor DNA (ctDNA)-based next generation sequencing (NGS) methods without tissue sampling bias. Here, we utilized clinical ctDNA data to delineate the landscape of candidate alterations associated with primary resistance to KRAS G12D targeting in CRC. Methods: Samples from advanced CRC patients with Guardant360 data in 2021 were categorized into a KRAS G12D group and comparator groups of KRAS G12C and KRAS not detected (ND) according to KRAS mutation status. Demographics, MSI-H status, and blood tumor mutational burden (bTMB) were summarized and compared between groups using t-test for continuous variables and Fisher’s exact test for categorical variables. Co-occurrence patterns of alterations between KRAS and other genes were assessed. Primary resistance mutations were inferred by acquired resistance findings to KRAS G12C inhibitors reported by Awad et al. N Engl J Med. 2021 and Tanaka et al. Cancer Discov. 2021. Results: Among approximately 2500 samples, 16.8% had KRAS G12D, the most common KRAS mutation in CRC. The mean allele frequency of KRAS G12D (11.4%) is comparable to that of KRAS G12C (10.9%). Mean age (61.6 years), MSI-H frequency (3.8%), and mean bTMB (14.2 Mut/Mb) of KRAS G12D group is comparable to those of KRAS ND group. This contrasts with KRAS G12C with significantly lower mean age (60.2 years, p=0.01), lower MSI-H frequency (0.56%, p=0.03), and higher mean bTMB (16.3 Mut/Mb, p=0.02) compared to KRAS ND. Both KRAS G12D and G12C significantly co-occur with APC, PIK3CA, and SMAD4 alterations. FBXW7, AR, and KEAP1 alterations were unique co-occurrences to KRAS G12D, while KIT was unique to KRAS G12C. Candidate alterations associated with primary resistance in KRAS G12D CRC included simultaneously present mutations of KRAS Q61H (14.1%), G12V (6.4%), G12C (5.9%), G13D (3.6%), BRAF V600E (2.7%) and others, amplification of MET (2%), MYC (1.6%), and KRAS (1.4%), and FGFR3-TACC3 translocation (Table). Conclusions: KRAS G12D is associated with unique co-occurring molecular alterations compared to KRAS G12C in CRC. ctDNA-based NGS platforms can survey candidate alterations associated with primary resistance to KRAS G12D targeting in CRC. Further validation in preclinical models is needed. [Table: see text]

The impact of Wnt pathway alterations including RNF43, GNAS, CTNNB1, and APC on prognosis and potential therapeutic vulnerability in pancreatic adenocarcinoma (PDAC).

698 Background: Several Wnt pathway genes (RNF43, GNAS, CTNNB1, APC) are mutated in PDAC but their clinical implications remain unclear. Both RNF43, a membrane E3 ubiquitin ligase that negatively regulates Wnt via FZD, and GNAS, a mediator of GPCR signaling, are enriched in IPMN-associated PDAC whereas CTNNB1 is a hallmark of solid pseudopapillary neoplasms. Here, we retrospectively analyzed progression-free survival (PFS) and overall survival (OS) in a PDAC cohort to understand potential therapeutic and prognostic differences between tumors with (MUT) or without (WT) Wnt pathway mutations. Methods: We analyzed longitudinal outcomes across 774 patients (pts) with NGS results from Perthera’s Real-World Evidence database who received at least 1 line of therapy in the advanced setting for PDAC. PFS was evaluated from initiation of 1st line for advanced disease until discontinuation due to disease progression. Hazard ratios and p-values were computed via Cox regression when comparing PFS within subsets that received either 1st line FOLFIRINOX (FFX) or 1st line gemcitabine/nab-paclitaxel (GA). Differences in frequencies of genomic alterations outside the Wnt pathway were analyzed by Fisher’s exact test. Results: Within the analysis cohort (N = 774), Wnt pathway alterations were present in 72 (9.3%) of PDAC tumors based on mutations in either RNF43 (4%), GNAS (3%), CTNNB1 (&lt;1%), or APC (2%). Median OS (relative to advanced diagnosis) was significantly longer in the MUT subgroup compared to WT (Table). Median PFS on 1st line GA was significantly longer in MUT pts, and a similar insignificant trend was noted for PFS on 1st line FFX (Table). MSI-high and PIK3CA mutations were enriched for co-occurrence with Wnt pathway alterations whereas common PDAC mutations in KRAS and TP53 were less frequent in MUT pts (Table). Gene-specific trends and potential confounders will be discussed in the context of multivariate OS/PFS analyses. Conclusions: The presence of Wnt pathway alterations identifies a subgroup of advanced PDAC with improved PFS and OS.[Table: see text]

Abstract B060: Enhancing models of pancreatic cancer: Integrating patient-derived models with tissue engineering to investigate clinical responses to therapy

Abstract Cancer modeling systems can be advantageous in enabling personalized medicine through rapid testing of therapeutic responsiveness. However, modeling systems often fail in these efforts due to 1) inadequately replicating unique patient genetics, 2) inadequately modeling the patient tumor microenvironment (TME), and 3) lack of internal validation references when isolated from clinical drug response data. We have developed a patient-derived models of cancer (PDMC) program for pancreatic cancer that addresses these challenges. By integrating patient cancer modeling and tissue engineering efforts with clinical trial protocols that perform serial tissue biopsies and analyses during treatment, we can make direct assessments of how different modeling systems replicate actual patient outcomes. Clinical trial protocols include tissue biopsies pre- and post- treatment using targeted therapeutics including MEK and PARP inhibitors. The modeling program, meanwhile, includes collecting metadata from pre- and post- treatment biopsies, the banking of patient tissues, cell line and xenograft generation from each biopsy, multiomic comparisons of models to patient tissue, comparisons of therapeutic responsiveness in models, and ultimately tissue re-engineering through bioprinting of tumor cells along with TME components. Whole exome sequencing is used to confirm that genetic alterations are preserved in each model, and we have established models representing a range of human PDAC genomic profiles. This includes common KRAS and TP53 mutations, as well as rare BRCA mutations and KRAS-wild-type tumors with BRAF mutations. Many cancer-associated fibroblast (CAF) lines have also been established through this program. Including patient derived cell lines, CAD lines, endothelial cells, and PBMCs into 3D bioprinted tumors allows us to better model the TME. Assays performed upon bioprinted tissues can then be directly compared to the same assays performed on the patient tumor to assess similarities as well as further obstacles. Ongoing efforts include building a resource of precise and validated PDMCs for diverse pancreatic cancers, and establishing a path forward for improved cancer modeling for the actualization of personalized medicine in PDAC treatment. Citation Format: Alexander C. Smith, John Muschler, Mike Munks, Rosalie C. Sears, Jonathan Brody. Enhancing models of pancreatic cancer: Integrating patient-derived models with tissue engineering to investigate clinical responses to therapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B060.

Comprehensive characterization of genomic features and clinical outcomes following targeted therapy and secondary cytoreductive surgery in OCCC: a single center experience.

Ovarian clear cell carcinoma (OCCC) is associated with chemoresistance. Limited data exists regarding the efficacy of targeted therapies such as immune checkpoint inhibitors (ICI) and bevacizumab, and the role of secondary cytoreductive surgery (SCS). We retrospectively analyzed genomic features and treatment outcomes of 172 OCCC patients treated at our institution from January 2000 to May 2022. Next-generation sequencing (NGS) was performed where sufficient archival tissue was available. 64.0% of patients were diagnosed at an early stage, and 36.0% at an advanced stage. Patients with advanced/relapsed OCCC who received platinum-based chemotherapy plus bevacizumab followed by maintenance bevacizumab had a median first-line progression-free survival (PFS) of 12.2 months, compared with 9.3 months for chemotherapy alone (hazard ratio=0.69; 95% confidence interval [CI]=0.33, 1.45). In 27 patients who received an ICI, the overall response rate was 18.5% and median duration of response was 7.4 months (95% CI=6.5, 8.3). In 17 carefully selected patients with fewer than 3 sites of relapse, median PFS was 35 months (95% CI=0, 73.5) and median overall survival was 96.8 months (95% CI=44.6, 149.0) after SCS. NGS on 58 tumors revealed common mutations in ARID1A (48.3%), PIK3CA (46.6%), and KRAS (20.7%). Pathogenic alterations in PIK3CA, FGFR2, and NBN were associated with worse survival outcomes. Median tumor mutational burden was 3.78 (range, 0-16). All 26 patients with available loss of heterozygosity (LOH) scores had LOH <16%. Our study demonstrates encouraging outcomes with bevacizumab and ICI, and SCS in select relapsed OCCC patients. Prospective trials are warranted.

Abstract C063: Frequency and spectrum of KRAS mutations in lung adenocarcinoma from Black/African American and White/European patients

Abstract Lung cancer is the most common cause of cancer death in the United States and a major source of cancer health disparity. Lung cancer incidence and mortality rates are higher in Black/African American (B/AA) men than in men from other racial/ethnic groups. Lung adenocarcinoma, arising in the alveoli or air sacs of the lung, is the most common subtype of lung cancer in all ethnic/racial groups. Genetic driver mutations can differ among racial/ethnic groups, in the identity of the mutated genes, their mutation frequencies, and the spectrum of mutations for each given gene. In addition, the same mutation could have different effects depending on an individual patient’s genetic background, resulting in differential responses to therapies. Therefore, it is important to identify the frequency and spectrum of driver mutations in different population groups. Protooncogenes from the RAS family, KRAS, NRAS, and HRAS, play a crucial role in cell growth regulation, cell proliferation, and survival. KRAS is frequently mutated in numerous cancer types, including lung adenocarcinoma, and has been reported to be the driver gene in ~30% of lung adenocarcinomas from White/European (W/E) patients. Due to the much lower number of lung cancer samples analyzed from B/AA patients, it has been unclear if the KRAS mutational frequency and spectrum in B/AA lung adenocarcinoma patients differs from that in W/E patients. Here we collected available existing data sets with mutational information on KRAS muations in lung adenocarcinoma from B/AA and W/E patients. We obtained data for 1555 B/AA and 13840 White lung adenocarcinoma patients. While B/AA lung adenocarcinoma patients had a lower prevalence of KRAS mutations (27% vs. 35%) than W/E patients, (χ2 p-value= 5.877e-10), KRAS was still the most frequently mutated cancer driver gene in both groups. The most common KRAS mutations in both B/AA and W/E patients were alterations of glycine 12 to cysteine (G12C), valine (G12V), aspartic acid (G12D), and alanine (G12A), as well as glutamine 61 to histidine (Q61H) and glycine 13 to cysteine (G13C). Given that a substantial proportion of lung adenocarcinoma patients carry a mutated KRAS gene, investigating new potential KRAS-targeting therapies remains especially urgent. To this end, we are investigating polyisoprenylated cysteinyl amide inhibitors (PCAIs), a group of potential cancer therapy agents designed to specifically disrupt and suppress hyperactive G-protein signaling, as caused by mutated RAS proteins. We are testing PCAI efficiacy on B/AA and W/E lung adenocarcinoma cell lines carrying various KRAS mutations. Citation Format: Daniel J. Mullen, Pablo E. Puente, Christopher Leon, Diana I. Romero, Kweku Ofosu-Asante, Yong Huang, Nazarius S. Lamango, Ite A. Offringa. Frequency and spectrum of KRAS mutations in lung adenocarcinoma from Black/African American and White/European patients [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C063.

Abstract B093: Treating KRAS(G12D) inhibitor resistance using a KRAS- and HSP90 chaperone-targeted hetero-bispecific small molecule agent

Abstract KRAS is the most frequently mutated oncoprotein in human cancers. Although long considered “undruggable”, recent breakthroughs in medicinal chemistry have led to FDA-approval of the KRAS(G12C) mutation-specific inhibitors sotorasib and adagrasib for the treatment of KRAS(G12C)-positive non-small cell lung cancer. However, illustrating the need to develop additional novel agents targeting mutated KRAS, the 5-year relative survival rate for pancreatic cancer, which is commonly associated with a variety of different KRAS mutations, is only 12% (all SEER stages) due to poor early detection and a lack of effective treatments. In particular, KRAS(G12D) is the most common KRAS mutation, being found in 37% of pancreatic ductal adenocarcinomas (PDACs), as well as in 12.5% of colorectal cancer and 4.9% of lung adenocarcinoma (LUAD) patients. MRTX1133 is a highly-selective, non-covalent KRAS(G12D) inhibitor that has recently entered a phase 1 clinical trial. However, here we show that exposure of KRAS(G12D)-mutated PDAC (PANC-1 and AsPC-1) and LUAD (SK-LU-1) cell lines and a patient-derived organoid (PDO) PDAC model (RPAN001) to MRTX1133 resulted in varying degrees of in vitro efficacy. Decreased downstream KRAS signaling in the form of reduced phospho-ERK1/2 levels was observed to rapidly recover within 24 hours of treatment with 500 nM MRTX1133. Moreover, this rebound coincided with increased expression of KRAS, NRAS andHRAS mRNAs. Concurrently, activation of the receptor tyrosine kinases (RTKs) EGFR and MET was observed in PANC-1 and SK-LU-1 cells that displayed innate resistance to MRTX1133, while the sensitive AsPC-1 cells showed no such RTK activation. These results suggest that targeting of both KRAS(G12D) and RTKs may be needed to treat KRAS(G12D) inhibitor-resistant cancers. To address this, we employed a novel hetero-bispecific CHAMP molecule, RNK08179, that simultaneously targets both KRAS(G12D) and HSP90, an RTK-regulating chaperone protein. RNK08179 treatment demonstrated a striking reduction in phospho-ERK1/2 levels, RTK activation and cell viability in MRTX1133-resistant PANC-1 and SK-LU-1 cells. Furthermore, similar efficacy was observed in the MRTX1133-resistant RPAN001 PDO model. In summary, RNK08179 displayed promising efficacy in cancer models harboring KRAS(G12D) by suppressing both mutated KRAS and HSP90-supported RTK signaling. Citation Format: Ines Pulido, Qiyue Luan, Chenghao Yin, Zimo Yang, Jinhua Lin, Yaya Wang, Yuetong Sun, Chuche Liu, Haoxin Zhou, Marek Massad, Ian Papautsky, Thomas L. Prince, Guoqiang Wang, Kevin P. Foley, Weiwen Ying, Takeshi Shimamura. Treating KRAS(G12D) inhibitor resistance using a KRAS- and HSP90 chaperone-targeted hetero-bispecific small molecule agent [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B093.

Clinical outcomes of KRAS-mutant non-small cell lung cancer under untargeted therapeutic regimes in the real world: a retrospective observational study.

Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation seemingly suffered less effective therapeutic regimens in the absence of widely-accepted targeted drugs compared with other mutation types in non-small cell lung cancer (NSCLC). However, whether these non-selective therapy schedules for KRAS mutation matters is still under debate. Correspondingly, we aimed to compare the long term expectancy of indicated therapeutic regimes and further explore the optimal schemes of KRAS mutated NSCLC in the absence of targeted drugs in this retrospective study cohort. We conducted a single-center retrospective analysis among 66 patients diagnosed with KRAS-mutant advanced NSCLC from November 2018 to December 2020. These enrolled cases were divided into different subgroups in light of mutant isotypes, pathological characteristics, and therapeutic regimes to uncover indicated long-term survival benefits. Additionally, clinical outcomes of treatment schedules and interventional lines to KRAS-mutant NSCLC were described in detail. This cohort enrolled 8 patients with stage IIIB (12.1%) and 58 patients with stage IV (87.9%) with the median age 62 years, ranging from 32 to 91 years old. Genetically, G12C conducted as the most common KRAS mutation type, accounting for 30.3%. Pemetrexed combined with platinum chemotherapy seemed to be a priority (72.7%), and chemotherapy combined with immunotherapy became an alternative (15.2%) in clinic. Performing further analysis of long-term survival of patients receiving different treatment methods indicated that the median overall survival (mOS) in first-line therapy with antiangiogenesis or untreated was 13 and 12 months, respectively (P=0.79). In the first-line regimen, median survival was 17 months for patients who received combined immune checkpoint inhibitors and 12 months for those who did not (P=0.34). The mOS was 20 months for those who had used immune checkpoint inhibitors and 12 months for those who had not (P=0.11). Survival analysis results of NSCLC patients with different KRAS mutation types showed the median survival time of patients with G12C mutation type and patients without with nonG12C mutation type was 19 and 12 months, respectively (P=0.37). In the absence of KRAS targeted drugs, available treatment plans failed to benefit KRAS mutant sufferers regardless of isotypes, making the KRAS-targeted drugs urgent.