Brief Report: Real-World Efficacy and Safety of Sotorasib in U.S. Veterans with KRAS G12C-Mutated NSCLC

Introduction

The KRAS G12C inhibitor sotorasib was approved for treating advanced NSCLC in the second line or later on the basis of the CodeBreaK100 trial. Nevertheless, data on the real-world efficacy and safety of sotorasib, and to its optimal dose, remain limited.

Methods

Patients treated with sotorasib for NSCLC through the Veterans Health Administration were retrospectively identified from the Corporate Data Warehouse. Survival, response, and toxicity data were obtained from chart review.

Results

Among the 128 patients treated with sotorasib through the Veterans Health Administration, objective response rate was 34%, progression-free survival (PFS) six months, and overall survival 12 months. Similar PFS was observed among the 16 patients who received frontline sotorasib without any prior systemic therapy for NSCLC. Toxicity leading to sotorasib interruption or dose reduction occurred in 37% of patients, whereas sotorasib discontinuation for toxicity occurred in 25%. Notably, sotorasib dose reduction was associated with substantially improved PFS and OS.

Conclusions

In this real-world study, the observed efficacy of sotorasib was similar to the results of CodeBreaK100. Patients who received frontline sotorasib had similar PFS to our overall cohort, suggesting that first-line sotorasib monotherapy may benefit patients who are not eligible for chemotherapy. Toxicities leading to sotorasib interruption, dose reduction, or discontinuation were common. Sotorasib dose reduction was associated with improved survival, suggesting that sotorasib dose reduction may not compromise efficacy.

AXL signal mediates adaptive resistance to KRAS G12C inhibitors in KRAS G12C-mutant tumor cells

Recently, novel Kirsten rat sarcoma viral oncogene homolog (KRAS) inhibitors have been clinically developed to treat KRAS G12C-mutated non-small cell lung cancer (NSCLC) patients. However, achieving complete tumor remission is challenging. Therefore, the optimal combined therapeutic intervention with KRAS G12C inhibitors has a potentially crucial role in the clinical outcomes of patients. We investigated the underlying molecular mechanisms of adaptive resistance to KRAS G12C inhibitors in KRAS G12C-mutated NSCLC cells to devise a strategy preventing drug-tolerant cell emergence. We demonstrate that AXL signaling led to the adaptive resistance to KRAS G12C inhibitors in KRAS G12C-mutated NSCLC, activation of which is induced by GAS6 production via YAP. AXL inhibition reduced the viability of AXL-overexpressing KRAS G12C-mutated lung cancer cells by enhancing KRAS G12C inhibition-induced apoptosis. In xenograft models of AXL-overexpressing KRAS G12C-mutated lung cancer treated with KRAS G12C inhibitors, initial combination therapy with AXL inhibitor markedly delayed tumor regrowth compared with KRAS G12C inhibitor alone or with the combination after acquired resistance to KRAS G12C inhibitor. These results indicated pivotal roles for the YAP-GAS6-AXL axis and its inhibition in the intrinsic resistance to KRAS G12C inhibitor.

Sotorasib in KRAS G12C-mutated non-small cell lung cancer: A multicenter real-world experience from the compassionate use program in Germany

BACKGROUND

Sotorasib is a first-in-class KRAS p.G12C-inhibitor that has entered clinical trials in pretreated patients with non-small cell lung cancer (NSCLC) in 2018. First response rates were promising in the CodeBreaK trials. It remains unclear whether response to sotorasib and outcomes differ in a real-world setting when including patients underrepresented in clinical trials.

METHODS

Patients with KRAS p.G12C-mutated advanced or metastatic NSCLC received sotorasib within the German multicenter sotorasib compassionate use program between 2020 to 2022. Data on efficacy, tolerability, and survival were analyzed in the full cohort and in subgroups of special interest such as co-occurring mutations and across PD-L1 expression levels.

RESULTS

We analyzed 163 patients who received sotorasib after a median of two treatment lines (range, 0 to 7). Every fourth patient had a poor performance status and 38% had brain metastases (BM). The objective response rate was 38.7%. The median overall survival was 9.8 months (95% CI, 6.5 to not reached). Median real-world (rw) progression-free survival was 4.8 months (9% CI, 3.9 to 5.9). Dose reductions and permanent discontinuation were necessary in 35 (21.5%) and 7 (4.3%) patients, respectively. Efficacy seems to be influenced by PD-L1 expression and a co-occurring KEAP1 mutation. KEAP1 was associated with an inferior survival. Other factors such as BM, STK11, and TP53 mutations had no impact on response and survival.

CONCLUSION

First results from a real-world population confirm promising efficacy of sotorasib for the treatment of advanced KRAS p.G12C-mutated NSCLC. Patients with co-occurring KEAP1 mutations seem to derive less benefit.

KRAS G12C-mutant driven non-small cell lung cancer (NSCLC)

KRAS G12C mutations in non-small cell lung cancer (NSCLC) partially respond to KRAS G12C covalent inhibitors. However, early adaptive resistance occurs due to rewiring of signaling pathways, activating receptor tyrosine kinases, primarily EGFR, but also MET and ligands. Evidence indicates that treatment with KRAS G12C inhibitors (sotorasib) triggers the MRAS:SHOC2:PP1C trimeric complex. Activation of MRAS occurs from alterations in the Scribble and Hippo-dependent pathways, leading to YAP activation. Other mechanisms that involve STAT3 signaling are intertwined with the activation of MRAS. The high-resolution MRAS:SHOC2:PP1C crystallization structure allows in silico analysis for drug development. Activation of MRAS:SHOC2:PP1C is primarily Scribble-driven and downregulated by HUWE1. The reactivation of the MRAS complex is carried out by valosin containing protein (VCP). Exploring these pathways as therapeutic targets and their impact on different chemotherapeutic agents (carboplatin, paclitaxel) is crucial. Comutations in STK11/LKB1 often co-occur with KRAS G12C, jeopardizing the effect of immune checkpoint (anti-PD1/PDL1) inhibitors.

Computational insights into KRAS G12C inhibition: exploring possible repurposing of Azacitidine and Ribavirin

Kirsten rat sarcoma (KRAS) stands out as the most prevalent mutated oncogene, playing a crucial role in the initiation and progression of various cancer types, including colorectal, lung and pancreatic cancer. The oncogenic modifications of KRAS are intricately linked to tumor development and are identified in 22% of cancer patients. This has spurred the necessity to explore inhibition mechanisms, with the aim of investigating and repurposing existing drugs for diagnosing cancers dependent on KRAS G12C In this investigation, 26 nucleoside-based drugs were collected from literature to assess their effectiveness against KRAS G12C. The study incorporates in-silico molecular simulations and molecular docking examinations of these nucleoside-derived drugs with the KRAS G12C protein using Protein Data Bank (PDB) ID: 5V71. The docking outcomes indicated that two drugs, Azacitidine and Ribavirin, exhibited substantial binding affinities of -8.7 and -8.3 kcal/mol, respectively. These drugs demonstrated stability in binding to the active site of the protein during simulation studies. Root mean square deviation (RMSD) analyses indicated that the complexes closely adhered to an equilibrium RMSD value ranging from 0.17 to 0.2 nm. Additionally, % occupancies, bond angles and the length of hydrogen bonds were calculated. These findings suggest that Azacitidine and Ribavirin may potentially serve as candidates for repurposing in individuals with KRAS-dependent cancers.Communicated by Ramaswamy H. Sarma.

Association of KRAS G12C Status with Age at Onset of Metastatic Colorectal Cancer

The association of age at the onset of CRC and the prevalence of a KRAS G12C mutation is unclear. A retrospective, multicenter study evaluating metastatic CRC patients from January 2019 to July 2023, treated at the Oncoclinicas units and tested for tissue based KRAS/NRAS and BRAF mutations in a centralized genomics lab. A mismatch repair (MMR) status was retrieved from different labs and electronic medical records, as were patient demographics (age, gender) and tumor sidedness. The chi-square test was used to examine the association between clinical and molecular variables, with p value < 0.05 being statistically significant. A total of 858 cases were included. The median age was 63.7 years (range 22-95) and 17.4% were less than 50 years old at the diagnosis of metastatic CRC. Male patients represented 50.3% of the population. The sidedness distribution was as follows: left side 59.2%, right side 36.8% and not specified 4%. The prevalence of the KRAS mutation was 49.4% and the NRAS mutation was 3.9%. Among KRAS mutated tumors, the most common variants were G12V (27.6%) and G12D (23.5%), while KRAS G12C was less frequent (6.4%), which represented 3.1% of the overall population. The BRAF mutant cases were 7.3% and most commonly V600E. Only five (<1%) non-V600E mutations were detected. MSI-high or dMMR was present in 14 cases (1.6%). In the age-stratified analysis, left-sidedness (p < 0.001) and a KRAS G12C mutation (p = 0.046) were associated with a younger age (<50 years). In the sidedness-stratified analysis, a BRAF mutation (p = 0.001) and MSI-high/dMMR status (p = 0.009) were more common in right-sided tumors. Our data suggest that KRAS G12C mutations are more frequent in early-onset metastatic CRC. To the best of our knowledge, this is the largest cohort in the Latin American population with metastatic CRC reporting RAS, BRAF and MSI/MMR status.

MALDI-TOF Mass Spectrometry-Based Assay for Measuring Covalent Target Engagement of KRAS G12C Inhibitors

MALDI-TOF mass spectrometry enables high-throughput screening of covalent fragment libraries and SAR compound progressions of selective KRAS G12C inhibitors. Using the MALDI-TOF platform instead of the more traditional ESI-MS TOF/orbitrap instrumentation can radically shorten sample acquisition time, allowing up to 384 samples to be screened in 30 min. The typical throughput for a covalent library screen is 1152 samples per 8 h, including processing, calculation, and reporting steps. The throughput can be doubled without any significant assay modification.

KRASG12C inhibition using MRTX1257: a novel radio-sensitizing partner

BACKGROUND

KRAS activating mutations are considered the most frequent oncogenic drivers and are correlated with radio-resistance in multiple cancers including non-small cell lung cancer (NSCLC) and colorectal cancer. Although KRAS was considered undruggable until recently, several KRAS inhibitors have recently reached clinical development. Among them, MRTX849 (Mirati Therapeutics) showed encouraging clinical outcomes for the treatment of selected patients with KRASG12C mutated NSCLC and colorectal cancers. In this work, we explore the ability of MRTX1257, a KRASG12C inhibitor analogous to MRTX849, to radio-sensitize KRASG12C+/+ mutated cell lines and tumors.

METHODS

Both in vitro and in vivo models of radiotherapy (RT) in association with MRTX1257 were used, with different RAS mutational profiles. We assessed in vitro the radio-sensitizing effect of MRTX1257 in CT26 KRASG12C+/+, CT26 WT, LL2 WT and LL2 NRAS KO (LL2 NRAS-/-) cell lines. In vivo, we used syngeneic models of subcutaneous CT26 KRASG12C+/+ tumors in BALB/c mice and T cell deficient athymic nu/nu mice to assess both the radio-sensitizing effect of MRTX1257 and its immunological features.

RESULTS

MRTX1257 was able to radio-sensitize CT26 KRASG12C+/+ cells in vitro in a time and dose dependent manner. Moreover, RT in association with MRTX1257 in BALB/c mice bearing CT26 KRASG12C+/+ subcutaneous tumors resulted in an observable cure rate of 20%. However, no durable response was observed with similar treatment in athymic nude mice. The analysis of the immune microenvironment of CT26 KRASG12C+/+ tumors following RT and MRTX1257 showed an increase in the proportion of various cell subtypes including conventional CD4 + T cells, dendritic cells type 2 (cDC2) and inflammatory monocytes. Furthermore, the expression of PD-L1 was dramatically down-regulated within both tumor and myeloid cells, thus illustrating the polarization of the tumor microenvironment towards a pro-inflammatory and anti-tumor phenotype following the combined treatment.

CONCLUSION

This work is the first to demonstrate in vitro as in vivo the radio-sensitizing effect of MRTX1257, a potent KRASG12C inhibitor compatible with oral administration, in CT26 KRASG12C mutated cell lines and tumors. This is a first step towards the use of new combinatorial strategies using KRAS inhibitors and RT in KRASG12C mutated tumors, which are the most represented in NSCLC with 14% of patients harboring this mutational profile.

Prognostic Role of KRAS G12C Mutation in Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

KRAS G12C mutation (mKRAS G12C) is the most frequent KRAS point mutation in non-small cell lung cancer (NSCLC) and has been proven to be a predictive biomarker for direct KRAS G12C inhibitors in advanced solid cancers. We sought to determine the prognostic significance of mKRAS G12C in patients with NSCLC using the meta-analytic approach. A protocol is registered at the International Prospective Register for systematic reviews (CRD42022345868). PubMed, EMBASE, The Cochrane Library, and Clinicaltrials.gov.in were searched for prospective or retrospective studies reporting survival data for tumors with mKRAS G12C compared with either other KRAS mutations or wild-type KRAS (KRAS-WT). The hazard ratios (HRs) for overall survival (OS) or Disease-free survival (DFS) of tumors were pooled according to fixed or random-effects models. Sixteen studies enrolling 10,153 participants were included in the final analysis. mKRAS G12C tumors had poor OS [HR, 1.42; 95% CI, 1.10-1.84, p = 0.007] but similar DFS [HR 2.36, 95% CI 0.64-8.16] compared to KRAS-WT tumors. Compared to other KRAS mutations, mKRAS G12C tumors had poor DFS [HR, 1.49; 95% CI, 1.07-2.09, p < 0.0001] but similar OS [HR, 1.03; 95% CI, 0.84-1.26]. Compared to other KRAS mutations, high PD-L1 expression (>50%) [OR 1.37 95% CI 1.11-1.70, p = 0.004] was associated with mKRAS G12C tumors. mKRAS G12C is a promising prognostic factor for patients with NSCLC, negatively impacting survival. Prevailing significant heterogeneity and selection bias might reduce the validity of these findings. Concomitant high PD-L1 expression in these tumors opens doors for exciting therapeutic potential.

Prognostic Implication of KRAS G12C Mutation in a Real-World KRAS-Mutated Stage IV NSCLC Cohort Treated With Immunotherapy in The Netherlands

Introduction

With the approval of G12C inhibitors as the second line of treatment for KRAS G12C-mutated NSCLC, and the expanding research regarding targeting KRAS, it is key to understand the prognostic implication of KRAS G12C in the current first line of treatment. We compared overall survival (OS) of patients with stage IV KRAS G12C-mutated NSCLC to those with a KRAS non-G12C mutation in a first-line setting of (chemo)immunotherapy.

Methods

This nationwide population-based study used real-world data from The Netherlands Cancer Registry. We selected patients with stage IV KRAS-mutated lung adenocarcinoma diagnosed in 2019 to 2020 who received first-line (chemo-)immunotherapy. Primary outcome was OS.

Results

From 28,120 registered patients with lung cancer, 1185 were selected with a KRAS mutation, of which 494 had a KRAS G12C mutation. Median OS was 15.5 months (95% confidence interval [CI]: 13.6-18.4) for KRAS G12C versus 14.0 months (95% CI:11.2-15.7) for KRAS non-G12C (p = 0.67). In multivariable analysis, KRAS subtype was not associated with OS (hazard ratio = 0.95, 95% CI: 0.82-1.10). For the subgroup with programmed death-ligand 1 at 0% to 49% who received chemoimmunotherapy, median OS was 13.3 months (95% CI: 10.5-15.2) for G12C and 9.8 months (95% CI: 8.6-11.3) for non-G12C (p = 0.48). For the subgroup with programmed death-ligand 1 more than or equal to 50% who received monoimmunotherapy, the median OS was 22.0 months (95% CI: 18.4-27.3) for G12C and 18.9 months (95% CI: 14.9-25.2) for non-G12C (p = 0.36).

Conclusions

There was no influence of KRAS subtype (G12C versus non-G12C) on OS in patients with KRAS-mutated stage IV NSCLC treated with first-line (chemo)immunotherapy.

Reverse vaccinology and immunoinformatics approaches to design multi-epitope based vaccine against oncogenic KRAS

Mutant KRAS-induced tumorigenesis is highly involved in the progression of pancreatic, lung, and breast cancer. Comparatively, KRAS G12D and KRAS G12C are the most frequent mutations that promote cancer progression and aggressiveness. Although KRAS mutant inhibitors exhibit significant therapeutic potential, day by day, they are becoming resistant among patients. Multi-epitope based cancer vaccines are a promising alternative strategy that induces an immune response against tumor antigens. In the present study, we have designed, constructed, and validated a novel multi-epitope vaccine construct against KRAS G12D and G12C mutants using reverse vaccinology and immunoinformatics approaches. In addition, the vaccine construct was structurally refined and showed significant physiochemical properties, and could induce an immune response. Furthermore, the optimized vaccine construct was cloned into a pET‑28a (+) expression vector through in silico cloning. Conclusively, the multi-epitope vaccine construct is structurally stable, soluble, antigenic, non‑allergic, and non‑toxic. Further, it has to be studied in in vitro and in vivo to evaluate its therapeutic efficacy against KRAS-mutated cancers in the near future.

Canadian Consensus Recommendations on the Management of KRAS G12C-Mutated NSCLC

Activating mutations in Kirsten rat sarcoma viral oncogene homologue (KRAS), in particular, a point mutation leading to a glycine-to-cysteine substitution at codon 12 (G12C), are among the most frequent genomic alterations in non-small cell lung cancer (NSCLC). Several agents targeting KRAS G12C have recently entered clinical development. Sotorasib, a first-in-class specific small molecule that irreversibly inhibits KRAS G12C, has since obtained Health Canada approval. The emergence of novel KRAS-targeted therapies warrants the development of evidence-based consensus recommendations to help clinicians better understand and contextualize the available data. A Canadian expert panel was convened to define the key clinical questions, review recent evidence, and discuss and agree on recommendations for the treatment of advanced KRAS G12C-mutated NSCLC. The panel agreed that testing for KRAS G12C should be performed as part of a comprehensive panel that includes current standard-of-care biomarkers. Sotorasib, the only approved KRAS G12C inhibitor in Canada, is recommended for patients with advanced KRAS G12C-mutated NSCLC who progressed on guideline-recommended first-line standard of care for advanced NSCLC without driver alterations (immune-checkpoint inhibitor(s) [ICIs] +/- chemotherapy). Sotorasib could also be offered as second-line therapy to patients who progressed on ICI monotherapy that are not candidates for a platinum doublet and those that received first-line chemotherapy with a contraindication to ICIs. Preliminary data indicate the activity of KRAS G12C inhibitors in brain metastases; however, the evidence is insufficient to make specific recommendations. Regular liver function monitoring is recommended when patients are prescribed KRAS G12C inhibitors due to risk of hepatotoxicity.

Survival of patients with KRAS G12C mutated stage IV non-small cell lung cancer with and without brain metastases treated with immune checkpoint inhibitors

INTRODUCTION

Few data is available on whether brain metastases (BM) influence survival in patients with stage IV KRAS G12C mutated (KRAS G12C+ ) non-small cell lung cancer (NSCLC) treated with first-line immune checkpoint inhibitor (ICI) +/- chemotherapy ([chemo]-ICI).

METHODS

Data was retrospectively collected from the population-based Netherlands Cancer Registry. The cumulative incidence of intracranial progression, overall survival (OS) and progression free survival (PFS) was determined for patients with KRAS G12C+ stage IV NSCLC diagnosed January 1 - June 30, 2019, treated with first-line (chemo)-ICI. OS and PFS were estimated using Kaplan-Meier methods and BM+ and BM- groups were compared using log-rank tests.

RESULTS

Of 2489 patients with stage IV NSCLC, 153 patients had KRAS G12C+ and received first-line (chemo)-ICI. Of those patients, 35% (54/153) underwent brain imaging (CT and/or MRI), of which 85% (46/54) MRI. Half of the patients with brain imaging (56%; 30/54) had BM, concerning one-fifth (20%; 30/153) of all patients, of which 67% was symptomatic. Compared to BM-, patients with BM+ were younger and had more organs affected with metastasis. Around one-third (30%) of patients with BM+ had ≥5 BM at diagnosis. Three quarters of patients with BM+ received cranial radiotherapy prior to start of (chemo)-ICI. The 1-year cumulative incidence of intracranial progression was 33% for patients with known baseline BM and 7% for those without (p = 0.0001). Median PFS was 6.6 (95% CI 3.0-15.9) and 6.7 (95% CI 5.1-8.5) months for BM+ and BM- (p = 0.80), respectively. Median OS was 15.7 (95% CI 6.2-27.3) and 17.8 (95% CI 13.4-22.0) months for BM+ and BM- (p = 0.77), respectively.

CONCLUSION

Baseline BM are common in patients with metastatic KRAS G12C+ NSCLC. During (chemo)-ICI treatment, intracranial progression was more frequent in patients with known baseline BM, justifying regular imaging during treatment. In our study, presence of known baseline BM did not influence OS or PFS.

SHP2 Contributes to Resistance of KRAS p.G12C-Driven Lung Cancer Cells to MRTX849 by Regulating β-catenin/c-MYC Axis

OBJECTIVE

SHP2 has been promulgated to be involved in chemoresistance in a variety of cancers. However, its relationship with MRTX849-resistance in KRAS G12C mutant lung cancer has not been revealed.

METHODS

Lung cancer cell lines resistant to MRTX849 were first constructed by repeated dosing over 10 months, and the parental and drug-resistant strains were evaluated for SHP2 expression at different time points (2, 4, 6, 8, 10 months). We further analyzed whether SHP2 knockdown affects the sensitivity of MRTX849-resistant cells to MRTX849, and overexpression of SHP2 in the parental cell line to assess its effect on MRTX849 resistance, mainly by CCK-8, clonogenic assay, TUNEL staining and Western blotting to assess cell viability, proliferation, apoptosis, as well as β-catenin/c-MYC pathway protein expression.

RESULTS

SHP2 expression remained largely unchanged in the parental cell line, whereas they were gradually upregulated in a time-dependent manner in the resistant cell line. SHP2 knockdown enhanced the sensitivity of MRTX849-resistant cell lines to MRTX849 and encouraged the killing of lung cancer cells by MRTX849, as indicated by a more significant decrease in cell viability and proliferation after knockdown of SHP2 in the presence of MRTX849 compared with MRTX849 untreated, while apoptosis was more significantly enhanced. Additionally, SHP2 overexpression enhanced the resistance of MRTX849 to lung cancer cells. Eventually, we confirmed that the MRTX849-resistance effect of SHP2 on lung cancer cells was through the activation of the β-catenin/c-MYC pathway.

CONCLUSION

SHP2 contributes to resistance of KRAS G12C-driven lung cancer cells to MRTX849 by regulating β-catenin/c-MYC axis.

Establishing the Role of Iridoids as Potential Kirsten Rat Sarcoma Viral Oncogene Homolog G12C Inhibitors Using Molecular Docking; Molecular Docking Simulation; Molecular Mechanics Poisson-Boltzmann Surface Area; Frontier Molecular Orbital Theory; Molecular Electrostatic Potential; and Absorption, Distribution, Metabolism, Excretion, and Toxicity Analysis

The RAS gene family is one of the most frequently mutated oncogenes in human cancers. In KRAS, mutations of G12D and G12C are common. Here, 52 iridoids were selected and docked against 8AFB (KRAS G12C receptor) using Sotorasib as the standard. As per the docking interaction data, 6-O-trans-p-coumaroyl-8-O-acetylshanzhiside methyl ester (dock score: -9.9 kcal/mol), 6'-O-trans-para-coumaroyl geniposidic acid (dock score: -9.6 kcal/mol), 6-O-trans-cinnamoyl-secologanoside (dock score: -9.5 kcal/mol), Loganic acid 6'-O-beta-d-glucoside (dock score: -9.5 kcal/mol), 10-O-succinoylgeniposide (dock score: -9.4), Loganic acid (dock score: -9.4 kcal/mol), and Amphicoside (dock score: -9.2 kcal/mol) showed higher dock scores than standard Sotorasib (dock score: -9.1 kcal/mol). These common amino acid residues between iridoids and complexed ligands confirmed that all the iridoids perfectly docked within the receptor's active site. The 100 ns MD simulation data showed that RMSD, RMSF, radius of gyration, and SASA values were within range, with greater numbers of hydrogen bond donors and acceptors. MM/PBSA analysis showed maximum binding energy values of -7309 kJ/mol for 6-O-trans-p-coumaroyl-8-O-acetylshanzhiside methyl ester. FMO analysis showed that 6-O-trans-p-coumaroyl-8-O-acetylshanzhiside methyl ester was the most likely chemically reactive molecule. MEP analysis data highlighted the possible electrophilic and nucleophilic attack regions of the best-docked iridoids. Of all the best-docked iridoids, Loganic acid passed Lipinski, Pfizer, and GSK filters with a similar toxicity profile to Sotorasib. Thus, if we consider these iridoids to be KRAS G12C inhibitors, they will be a boon to mankind.

Overall survival in patients with advanced non-small cell lung cancer with KRAS G12C mutation with or without STK11 and/or KEAP1 mutations in a real-world setting

BACKGROUND

KRAS mutations occur frequently in advanced non-small cell lung cancer (aNSCLC); the G12C mutation is the most prevalent. Alterations in STK11 or KEAP1 commonly co-occur with KRAS mutations in aNSCLC. Using real-world data, we assessed the effect of KRAS G12C mutation with or without STK11 and/or KEAP1 mutations on overall survival (OS) in patients with aNSCLC receiving cancer immunotherapy (CIT), chemotherapy, or both in first line (1L) and second line (2L).

METHODS

Patients diagnosed with aNSCLC between January 2011 and March 2020 in a clinico-genomic database were included. Cox proportional hazards models adjusted for left truncation, baseline demographics and clinical characteristics were used to analyze the effect of STK11 and/or KEAP1 co-mutational status on OS in patients with KRAS wild-type (WT) or G12C mutation.

RESULTS

Of 2715 patients with aNSCLC without other actionable driver mutations, 1344 (49.5%) had KRAS WT cancer, and 454 (16.7%) had KRAS G12C-positive cancer. At 1L treatment start, significantly more patients with KRAS G12C-positive cancer were female, smokers, and had non-squamous histology, a higher prevalence of metastasis and programmed death-ligand 1 positivity than those with KRAS WT cancer. Median OS was comparable between patients with KRAS G12C-positive and KRAS WT cancer when receiving chemotherapy or combination CIT and chemotherapy in the 1L or 2L. Median OS was numerically longer in patients with KRAS G12C vs KRAS WT cancer treated with 1L CIT (30.2 vs 10.6 months, respectively) or 2L CIT (11.3 vs 7.6 months, respectively). Co-mutation of STK11 and KEAP1 was associated with significantly shorter OS in patients receiving any type of 1L therapy, regardless of KRAS G12C mutational status.

CONCLUSIONS

This real-world study showed that patients with KRAS G12C-positive or KRAS WT cancer have similar OS in the 1L or 2L when treated with chemotherapy or combination CIT and chemotherapy. In contrast to aNSCLC patients with EGFR or ALK driver mutations, patients with KRAS G12C-positive cancer may benefit from CIT monotherapy. Co-mutation of STK11 and KEAP1 was associated with significantly shorter survival, independent of KRAS G12C mutational status, reflecting the poor prognosis and high unmet need in this patient population.

Multiple initiatives to conquer KRAS G12C inhibitor resistance from the perspective of clinical therapy

INTRODUCTION

KRAS G12C targeted covalent inhibitors for cancer therapy are revolutionary. However, resistance to KRAS G12C inhibitors in clinical trials is a proven fact.

AREAS COVERED

The authors focus on providing coverage and emphasizing the strategy of conquering KRAS G12C inhibitor resistance from the perspective of clinical therapy. The authors also provide the readers with their expert perspectives for future development.

EXPERT OPINION

It is essential to improve the therapeutic effect and achieve long-term disease control through accumulating rapid exploration of drug resistance mechanisms in preclinical trials and developing rational combination dosing approaches from clinical practice. Our presentation of the perspective provides insights into drug resistance in this groundbreaking area of research.

Large-scale clinico-genomic profile of non-small cell lung cancer with KRAS G12C: Results from LC-SCRUM-Asia study

INTRODUCTION

KRAS G12C is an oncogenic driver mutation, accounting for approximately 14% of Caucasian patients with non-small cell lung cancer (NSCLC). Recently, several KRAS G12C-targeted drugs have been developed; however, the clinico-genomic characteristics of NSCLC patients with KRAS G12C remain unclear.

MATERIALS AND METHODS

Based on the large-scale prospective lung cancer genomic screening project (LC-SCRUM-Asia) database, the clinico-genomic characteristics and therapeutic outcomes of NSCLC patients with KRAS G12C were evaluated.

RESULTS

From March 2015 to March 2021, 10,023 NSCLC patients were enrolled in LC-SCRUM-Asia. KRAS mutations were detected in 1258 patients (14 %), including G12C in 376 (4.0 %), G12D in 289 (3.1 %) and G12V in 251 (2.7 %). The proportions of males and smokers were higher in patients with KRAS G12C than in those with KRAS non-G12C mutations (males: 73 % vs 63 %, p < 0.001; smokers: 89 % vs 76 %, p < 0.001). KRAS G12C-positive tumors showed a higher tumor mutation burden (TMB) (mean, 8.1 mut/Mb, p < 0.001) and a higher percentage of tumors with programmed cell death ligand-1 (PD-L1) expression ≥50 % (52 %, p = 0.08). The overall survival in patients with KRAS G12C (median, 24.6 months) was not different between patients with other mutation subtypes (G12V: 18.2 months, p = 0.23; G12D: 20.6 months, p = 0.65; other KRAS mutations: 18.3 months, p = 0.20). Among KRAS-mutated patients who received immune checkpoint inhibitors (ICIs), the progression-free survival in G12C-positive patients (median, 3.4 months) was similar to that in G12V-positive patients (4.2 months, p = 0.90), but significantly longer than that in G12D- (2.0 months, p = 0.02) and other KRAS mutation-positive patients (2.5 months, p = 0.02).

CONCLUSIONS

The frequencies of KRAS G12C were lower in Asian than in Caucasian NSCLC patients. Among the KRAS-mutated NSCLC patients, G12C-positive tumors showed increased immunogenicity, such as high TMB and high PD-L1 expression, and potential sensitivity to ICIs.

Efficacy of immune checkpoint inhibitors in patients with KRAS-mutant advanced non-small cell lung cancer: A retrospective analysis

The efficacy of immune checkpoint inhibitors (ICIs) on KRAS-mutant advanced non-small cell lung cancer (NSCLC) remains controversial. This retrospective study compared the effects of ICIs treatment and chemotherapy on the prognosis of patients with KRAS-mutant advanced NSCLC and different mutant subtypes in the real world. The study included 95 patients with KRAS-mutant advanced NSCLC. Patients treated with first-line ICIs plus platinum-containing chemotherapy had better progression-free survival (PFS) (7.4 vs 4.5 months, P = 0.035) and overall survival (OS) (24.1 vs 13.2 months, P = 0.007) than those receiving platinum-containing chemotherapy alone, and second-line ICI monotherapy was associated with better PFS (4.8 vs 3.0 months, P = 0.043) and OS (18.0 vs 13.8 months, P = 0.013) than chemotherapy monotherapy. There was no significant difference in PFS (5.267 vs 6.734 months, P = 0.969) and OS (19.933 vs 20.933 months, P = 0.808) between patients with KRAS-mutant and KRAS-wild-type NSCLC treated with ICIs or between KRAS G12C and KRAS non-G12C patients (PFS: 8.1 vs 4.8 months, P = 0.307; OS: 21.3 vs 21.8 months, P = 0.434). In summary, patients with advanced NSCLC with KRAS mutations can benefit from ICIs, but no difference between KRAS mutant subtypes was observed.

Targeting KRASp.G12C Mutation in Advanced Non-Small Cell Lung Cancer: a New Era Has Begun

OPINION STATEMENT

KRASp.G12C mutation occurs in 12% of newly diagnosed advanced NSCLC and has recently emerged as a positive predictive biomarker for the selection of advanced NSCLC patients who may respond to novel KRASp.G12C inhibitors. The recent discovery of a new binding pocket under the effector region of KRAS G12C oncoprotein has made direct pharmacological inhibition of the KRASp.G12 mutation possible, leading to the clinical development of a new series of direct selective inhibitors, with a potential major impact on patients' survival and quality of life. Promising efficacy and tolerability data emerging from the early phase CodeBreak trial have already supported the regulatory approval of sotorasib as first in class targeted treatment for the second-line treatment of KRASp.G12C-positive NSCLC population, following immunotherapy-based first-line therapies, while the randomized phase III CodeBreak 200 clinical study has recently confirmed a significant superiority of sotorasib over docetaxel in terms of progression-free survival and quality of life. However, KRAS mutant NSCLC is a high heterogeneous disease characterized by a high rate of co-mutations, most frequently involving P53, STK11, and KEAP1 genes, which significantly modulate the composition of the tumor microenvironment and consequently affect clinical responses to both immunotherapy and targeted inhibitors now available in clinical practice. Both pre-clinical and clinical translational series have recently revealed a wide spectrum of resistance mechanisms occurring under selective KRASG12C inhibitors, including both on-target and off-target molecular alterations as well as morphological switching, negatively affecting the antitumor activity of these drugs when used as single agent therapies. The understanding of such biological background along with the emergence of pre-clinical data provided a strong rational to investigate different combination strategies, including the inhibition of SHP2, SOS1, and KRAS G12C downstream effectors, as well as the addition of immunotherapy and/or chemotherapy to targeted therapy. The preliminary results of these trials have recently suggested a promising activity of SHP2 inhibitors in the front-line setting, while toxicity issues limited the concurrent administration of immune-checkpoint inhibitors and sotorasib. The identification of predictive genomic/immunological biomarkers will be crucial to understand how to optimally sequencing/combining different drugs and ultimately personalize treatment strategies under clinical investigation, to definitively increase the survival outcomes of KRASp.G12C mutant advanced NSCLC patients.

KRAS G12D targeted therapies for pancreatic cancer: Has the fortress been conquered?

KRAS mutations are among the most commonly occurring mutations in cancer. After being deemed undruggable for decades, KRAS G12C specific inhibitors showed that small molecule inhibitors can be developed against this notorious target. At the same time, there is still no agent that could target KRAS G12D which is the most common KRAS mutation and is found in the majority of KRAS-mutated pancreatic tumors. Nevertheless, significant progress is now being made in the G12D space with the development of several compounds that can bind to and inhibit KRAS G12D, most notably MRTX1133. Exciting advances in this field also include an immunotherapeutic approach that uses adoptive T-cell transfer to specifically target G12D in pancreatic cancer. In this mini-review, we discuss recent advances in KRAS G12D targeting and the potential for further clinical development of the various approaches.

An evaluation of sotorasib for the treatment of patients with non-small cell lung cancer with KRAS G12C mutations

INTRODUCTION

Improving the clinical outcomes of patients with KRAS^G12C-mutated non-small cell lung cancer (NSCLC), the majority of whom are current or former smokers, has been a barrier to improving population-level outcomes in NSCLC. Novel, effective KRAS^G12C inhibitors are emerging and sotorasib is the first member of that class to achieve commercial availability.

AREAS COVERED

In this review, we survey the epidemiology of KRAS^G12C-mutated NSCLC, as well as sotorasib's chemistry, pharmacology, and clinical trial data.

EXPERT OPINION

While sotorasib's development has been unique and exciting, questions persist regarding its intracranial penetrance, optimal dose, and efficacy relative to standard-of-care therapy. Improvements in the clinical activity of KRAS inhibition will hinge on better understanding of resistance mechanisms, the development of broad-spectrum inhibitors with activity beyond G12C mutations, and combination therapy targeting multiple mediators of KRAS signaling and alternative pathways. From a regulatory perspective, sotorasib's development may, in time, prove to be an instructive example for early-phase clinical trialists and regulators focused on dose optimization.

The treatment of advanced non-small cell lung cancer harboring KRAS mutation: a new class of drugs for an old target-a narrative review

Background and Objective

The genetic nature of cancer provides the rationale to support the need for molecular diagnosis and patient selection for individualised antineoplastic treatments that are the best in both tolerability and efficacy for each cancer patient, including non-small cell lung cancer (NSCLC) patients. Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations represent the prevalent oncogenic driver in NSCLC, being detected in roughly one-third of cases and KRAS G12C is the most frequent mutation found in approximately 13% of patients.

Methods

This paper gives an overview of the numerous scientific efforts in recent decades aimed at KRAS inhibition.

Key Content and Findings

Sotorasib is the first approved KRAS G12C inhibitor that has been shown to provide a durable clinical benefit in patients with pre-treated NSCLC with KRAS G12C mutation. Together with the development of new targeted drugs, the development of strategies to control resistance mechanisms is one of the major drivers of research that is exploring the use of KRAS inhibitors not only alone, but also in combination with other targeted therapies, chemotherapy and immunotherapy.

Conclusions

This review will describe the major therapeutic developments in KRAS mutation-dependent NSCLC and will analyse future perspectives to maximise benefits for this group of patients.

Inhibitor of the Nuclear Transport Protein XPO1 Enhances the Anticancer Efficacy of KRAS G12C Inhibitors in Preclinical Models of KRAS G12C-Mutant Cancers

The identification of molecules that can bind covalently to KRAS G12C and lock it in an inactive GDP-bound conformation has opened the door to targeting KRAS G12C selectively. These agents have shown promise in preclinical tumor models and clinical trials. FDA has recently granted approval to sotorasib for KRAS G12C mutated non-small cell lung cancer (NSCLC). However, patients receiving these agents as monotherapy generally develop drug resistance over time. This necessitates the development of multi-targeted approaches that can potentially sensitize tumors to KRAS inhibitors. We generated KRAS G12C inhibitor-resistant cell lines and observed that they exhibit sensitivity toward selinexor, a selective inhibitor of nuclear export protein exportin1 (XPO1), as a single agent. KRAS G12C inhibitors in combination with selinexor suppressed the proliferation of KRAS G12C mutant cancer cell lines in a synergistic manner. Moreover, combined treatment of selinexor with KRAS G12C inhibitors resulted in enhanced spheroid disintegration, reduction in the number and size of colonies formed by G12C mutant cancer cells. Mechanistically, the combination of selinexor with KRAS G12C inhibitors suppressed cell growth signaling and downregulated the expression of cell cycle markers, KRAS and NF-kB as well as increased nuclear accumulation of tumor suppressor protein Rb. In an in vivo KRAS G12C cell-derived xenograft model, oral administration of a combination of selinexor and sotorasib was demonstrated to reduce tumor burden and enhance survival. In conclusion, we have shown that the nuclear transport protein XPO1 inhibitor can enhance the anticancer activity of KRAS G12C inhibitors in preclinical cancer models.

Significance

In this study, combining nuclear transport inhibitor selinexor with KRAS G12C inhibitors has resulted in potent antitumor effects in preclinical cancer models. This can be an effective combination therapy for cancer patients that do not respond or develop resistance to KRAS G12C inhibitor treatment.

BRAF V600E and previously unidentified KRAS G12C mutations in odontogenic tumors may affect MAPK activation differently depending on tumor type

Although several types of odontogenic tumors share the same mutations in MAPK pathway genes, their effects on MAPK activation remain unclarified. This study aimed to evaluate the associations between these mutations and ERK phosphorylation in ameloblastoma and mixed odontogenic tumors (MOTs) and to analyze the expression pattern of phosphorylated ERK (p-ERK) for determining the involvement of MAPK activation in the development and progression of odontogenic tumors. Forty-three odontogenic tumors consisting of 18 ameloblastomas and 25 MOTs were analyzed for BRAF, KRAS, and NRAS mutations by Sanger sequencing. The expressions of BRAF^V600E protein and p-ERK were detected by immunohistochemistry. The associations of mutation status and p-ERK expression were statistically analyzed. In ameloblastoma cells, the effect of BRAF^V600E inhibition on MAPK activation was investigated. In benign MOTs, BRAF^V600E mutations were neither expressed at the protein level nor associated with p-ERK expression. In contrast, BRAF^V600E -mutant ameloblastic fibrosarcoma showed co-expression of BRAF V600E protein and p-ERK, especially in the sarcomatous component. In ameloblastoma, p-ERK was predominantly expressed in the tumor periphery showing a significant correlation with BRAF^V600E mutations, and in vitro BRAF^V600E inhibition decreased ERK phosphorylation. KRAS^G12C mutations, previously unidentified in odontogenic tumors, were detected in one case each of benign MOT and ameloblastoma; only the latter was high-p-ERK. In conclusion, unlike in benign MOTs, BRAF^V600E and KRAS^G12C mutations lead to MAPK activation in ameloblastoma, suggesting their role as therapeutic targets. p-ERK intratumoral heterogeneity indicates that MAPK pathway activation may be associated with sarcomatous proliferation of ameloblastic fibrosarcoma and infiltrative behavior of ameloblastoma. This article is protected by copyright. All rights reserved.

Targeting KRAS Mutant in Non-Small Cell Lung Cancer: Novel Insights Into Therapeutic Strategies

Although KRAS-activating mutations represent the most common oncogenic driver in non-small cell lung cancer (NSCLC), various attempts to inhibit KRAS failed in the past decade. KRAS mutations are associated with a poor prognosis and a poor response to standard therapeutic regimen. The recent development of new therapeutic agents (i.e., adagrasib, sotorasib) that target specifically KRAS G12C in its GDP-bound state has evidenced an unprecedented success in the treatment of this subgroup of patients. Despite providing pre-clinical and clinical efficacy, several mechanisms of acquired resistance to KRAS G12C inhibitors have been reported. In this setting, combined therapeutic strategies including inhibition of either SHP2, SOS1 or downstream effectors of KRAS G12C seem particularly interesting to overcome acquired resistance. In this review, we will discuss the novel therapeutic strategies targeting KRAS G12C and promising approaches of combined therapy to overcome acquired resistance to KRAS G12C inhibitors.

Targeting KRAS G12C mutation in lung adenocarcinoma

Lung cancer continues to be a major cause of cancer related death globally. Therapies targeting driver mutations have significantly extended the survival of patients whose lung cancer cells harbor these mutations. Patients with KRAS mutations, however, lacked specific targeted therapy until the recent FDA approval of sotorasib, a specific inhibitor of KRAS G12C mutant protein. We will discuss the efficacy and toxicities of the novel KRAS G12C inhibitors as well as other indirect strategies for targeting oncogenic KRAS mutations. We will review the limited literature on acquired resistance to these inhibitors and the novel combinatorial treatment strategies that are being tested currently in clinical trials.

Mutational profiles of primary pulmonary adenocarcinoma and paired brain metastases disclose the importance of KRAS mutations

BACKGROUND

Brain metastases present a significant complication in lung cancer with an unmet therapeutic need.

METHODS

In this single-centre, retrospective study, we genotyped a clinico-pathologically well-annotated cohort of consecutively resected brain metastases of lung adenocarcinomas and paired primary tumours, diagnosed from 2000 to 2015, using the Ion Torrent Oncomine Comprehensive Cancer Panel v3.

RESULTS

Among 444 consecutive brain metastases, 210 (49%) originated from lung cancer. Analysis was successful in 111 samples, including 54 pairs of brain metastasis and primary tumour. Most driver alterations were preserved in brain metastases. Private alterations exclusive to primary tumours, brain metastases or both sites (intersecting cases) were present in 22%, 26% and 26% of cases, respectively. Seven percent had no shared mutations. KRAS mutations were more frequent in primary tumours metastasised to the brain (32/55, 58%) compared to TCGA (33%, p < 0.005) and own data from routine diagnostics, independent from clinical or pathological characteristics. Fourteen cases showed alterations in the EGFR signalling pathway including additional KRAS alterations that were private to brain metastases. KRAS G12C was detected most frequently (26% of patients) and KRAS G12C and G13C variants were significantly enriched in brain metastases. Synchronous and metachronous cases had a similar mutation profile.

CONCLUSIONS

Our results suggest an important role of KRAS alterations in the pathobiology of brain metastases from lung adenocarcinomas. This has direct therapeutic implications as inhibitors selectively targeting KRAS G12C are entering the clinics.

Discovery of KRas G12C-IN-3 and Pomalidomide-based PROTACs as degraders of endogenous KRAS G12C with potent anticancer activity

A series of KRAS G12C-targeting PROTACs (PROteolysis TArgeting Chimeras) were designed and synthesized based on KRas G12C-IN-3 (a KRAS G12C inhibitor) and pomalidomide as degraders of KRAS G12C with a molecular weight of < 900. Among them, compound KP-14 (m.w. = 852.16; tPSA = 174.53) showed the highest KRAS G12C-degrading capability in NCI-H358 cancer cells (DC₅₀≈1.25 μM). KP-14 bound to KRAS G12C through the acrylamide warhead and recruited the E3 ligase CRBN, causing rapid and sustained KRAS G12C degradation which led to suppression of MAPK signaling pathway in NCI-H358 cells. In addition, KP-14 selectively induced the degradation of KRAS G12C but not other KRAS isoforms such as G13D via PROTAC mechanism. Furthermore, KP-14 exhibited potent antiproliferative activity against NCI-H358 cancer cells and was able to suppress the formation of NCI-H358 tumor colonies. Collectively, this work suggests that KP-14 may serve as a tool compound for exploring the degradation of KRAS G12C by PROTAC strategy and deserve further investigation as a potential anticancer agent.

Severe Immune Checkpoint Inhibitor Hepatitis in KRAS G12C-Mutant NSCLC Potentially Triggered by Sotorasib: Case Report

Sotorasib is a first-in-class small molecule that irreversibly inhibits KRAS G12C, locking it in an inactive state, inhibiting oncogenic signaling, and inducing a proinflammatory microenvironment. Here, we report the first case of life-threatening hepatitis in a patient with NSCLC shortly after commencing sotorasib, in which biopsy result was consistent with checkpoint inhibitor (CPI) immune-related adverse event, implicating sotorasib as being able to trigger CPI immune hepatitis. Given the large proportion of patients potentially treatable with sequential sotorasib after CPI, coupled with limited trial data, sotorasib-triggered CPI immune-related hepatitis should be considered in patients with sotorasib hepatotoxicity.

The Prognostic Effect of KRAS Mutations in Non-Small Cell Lung Carcinoma Revisited: A Norwegian Multicentre Study

BACKGROUND

due to emerging therapeutics targeting KRAS G12C and previous reports with conflicting results regarding the prognostic impact of KRAS and KRAS G12C in non-small cell lung cancer (NSCLC), we aimed to investigate the frequency of KRAS mutations and their associations with clinical characteristics and outcome. Since mutation subtypes have different preferences for downstream pathways, we also aimed to investigate whether there were differences in outcome according to mutation preference for the Raf, PI3K/Akt, or RalGDS/Ral pathways.

METHODS

retrospectively, clinicopathological data from 1233 stage I-IV non-squamous NSCLC patients with known KRAS status were reviewed. KRAS' associations with clinical characteristics were analysed. Progression free survival (PFS) and overall survival (OS) were assessed for the following groups: KRAS wild type (wt) versus mutated, KRAS wt versus KRAS G12C versus KRAS non-G12C, among KRAS mutation subtypes and among mutation subtypes grouped according to preference for downstream pathways.

RESULTS

a total of 1117 patients were included; 38% had KRAS mutated tumours, 17% had G12C. Among KRAS mutated, G12C was the most frequent mutation in former/current smokers (45%) and G12D in never smokers (46%). There were no significant differences in survival according to KRAS status, G12C status, among KRAS mutation subtypes or mutation preference for downstream pathways.

CONCLUSION

KRAS status or KRAS mutation subtype did not have any significant influence on PFS or OS.

Focal Adhesion Kinase (FAK) Inhibition Synergizes with KRAS G12C Inhibitors in Treating Cancer through the Regulation of the FAK-YAP Signaling

KRAS mutation is one of the most prevalent genetic drivers of cancer development, yet KRAS mutations are until very recently considered undruggable. There are ongoing trials of drugs that target the KRAS G12C mutation, yet acquired drug resistance from the extended use has already become a major concern. Here, it is demonstrated that KRAS G12C inhibition induces sustained activation of focal adhesive kinase (FAK) and show that a combination therapy comprising KRAS G12C inhibition and a FAK inhibitor (IN10018) achieves synergistic anticancer effects. It can simultaneously reduce the extent of drug resistance. Diverse CDX and PDX models of KRAS G12C mutant cancer are examined and synergistic benefits from the combination therapy are consistently observed. Mechanistically, it is found that both aberrant FAK-YAP signaling and FAK-related fibrogenesis impact on the development of KRAS G12C inhibitor resistance. This study thus illustrates the mechanism of resistance of cancer to the treatment of KRAS G12C inhibitor, as well as an innovative combination therapy to improve treatment outcomes for KRAS G12C mutant cancers.

KRAS G12C Mutations in NSCLC: From Target to Resistance

Lung cancer represents the most common form of cancer, accounting for 1.8 million deaths globally in 2020. Over the last decade the treatment for advanced and metastatic non-small cell lung cancer have dramatically improved largely thanks to the emergence of two therapeutic breakthroughs: the discovery of immune checkpoint inhibitors and targeting of oncogenic driver alterations. While these therapies hold great promise, they face the same limitation as other inhibitors: the emergence of resistant mechanisms. One such alteration in non-small cell lung cancer is the Kirsten Rat Sarcoma (KRAS) oncogene. KRAS mutations are the most common oncogenic driver in NSCLC, representing roughly 20-25% of cases. The mutation is almost exclusively detected in adenocarcinoma and is found among smokers 90% of the time. Along with the development of new drugs that have been showing promising activity, resistance mechanisms have begun to be clarified. The aim of this review is to unwrap the biology of KRAS in NSCLC with a specific focus on primary and secondary resistance mechanisms and their possible clinical implications.

Discovery of novel quinazoline-based covalent inhibitors of KRAS G12C with various cysteine-targeting warheads as potential anticancer agents

A series of novel quinazoline analogs with a variety of cysteine-targeting warheads (electrophiles) were designed and synthesized based on ARS-1620 as covalent KRAS G12C inhibitors. Among them, compounds LLK10 and LLK14 exhibited similar or better antiproliferative activity than ARS-1620. LLK10 was used for subsequent biological studies due to the higher selectivity towards KRAS G12C-mutated cells than LLK14. LLK10 maintained the mechanism of action by forming a covalent bond with KRAS G12C protein, thus decreasing the level of phosphorylated Mek and Erk, and leading to tumor cell apoptosis. In addition, LLK10 was able to suppress the formation of H358 tumor colonies. Molecular modeling study indicated that LLK10 binds with high affinity to the SWII binding site in KRAS G12C and overlaps well with ARS-1620. The high binding affinity of LLK10 was further confirmed by the isothermal titration calorimetry (ITC) assay in which LLK10 exhibited a K_D of 115 nM for binding to KRAS G12C. These results suggest that the novel covalent inhibitors of KRAS G12C with different warheads deserve further investigation as potential anticancer agents.

Allosteric SHP2 inhibitors in cancer: Targeting the intersection of RAS, resistance, and the immune microenvironment

The nonreceptor protein tyrosine phosphatase SHP2 (encoded by PTPN11) integrates growth and differentiation signals from receptor tyrosine kinases (RTKs) into the RAS/mitogen-activated protein kinase (MAPK) cascade. Considered 'undruggable' over three decades, SHP2 is now a potentially druggable target with the advent of allosteric SHP2 inhibitors. These agents hold promise for improving patient outcomes, showing efficacy in preclinical cancer models, where SHP2 is critical for either oncogenic signaling or resistance to current targeted agents. SHP2 inhibition may also produce immunomodulatory effects in certain tumor microenvironment cells to help cultivate antitumor immune responses. The first generation of allosteric SHP2 inhibitors is under clinical evaluation to determine safety, appropriate tolerability management, and antitumor efficacy, investigations that will dictate future clinical applications.

Functional dissection of the KRAS G12C mutation by comparison among multiple oncogenic driver mutations in a lung cancer cell line model

The development of molecular targeted therapy has improved clinical outcomes in patients with life-threatening advanced lung cancers with driver oncogenes. However, selective treatment for KRAS-mutant lung cancer remains underdeveloped. We have successfully characterised specific molecular and pathological features of KRAS-mutant lung cancer utilising newly developed cell line models that can elucidate the differences in driver oncogenes among tissues with identical genetic backgrounds. Among these KRAS-mutation-associated specific features, we focused on the IGF2-IGF1R pathway, which has been implicated in the drug resistance mechanisms to AMG 510, a recently developed selective inhibitor of KRAS G12C lung cancer. Experimental data derived from our cell line model can be used as a tool for clinical treatment strategy development through understanding of the biology of lung cancer. The model developed in this paper may help understand the mechanism of anticancer drug resistance in KRAS-mutated lung cancer and help develop new targeted therapies to treat patients with this disease.

KRAS G12C mutations in Asia: a landscape analysis of 11,951 Chinese tumor samples

Background

Kirsten rat sarcoma vial oncogene (KRAS) is one of the most prevalent oncogenes in multiple cancer types, but the incidence is different between the Asian and non-Asian populations. The recent development of KRAS G12C targeting drug has shown great promise. It is thus important to understand the genomic landscape of KRAS G12C in a specific population.

Methods

Sequencing data of 11,951 tumor samples collected from 11/2016 to 7/2019 from multiple centres in China were analyzed for KRAS mutation status. Concomitant genomic aberrations were further analyzed in tumors with KRAS G12C mutations, which were sequenced with comprehensive cancer panel including over 450 cancer-related genes. Smoking status and its correlation with KRAS were analyzed in 2,235 lung cancer cases within this cohort.

Results

KRAS mutations were identified in 1978 (16.6%) patient samples. Specifically, KRAS G12C accounted for 14.5% (n=286) of all KRAS mutations. G12C was most commonly seen in lung cancer (4.3%), followed by colorectal cancer (2.5%) and biliary cancer (2.3%). Almost all patients (99.6%) with G12C mutations had concomitant genomic aberrations. These were most commonly associated with the RAS/RTK pathway including BRAF and PI3KCA mutations. Moreover, KRAS mutation was positively correlated with smoking status in lung adenocarcinomas.

Conclusions

The overall incidence of KRAS G12C mutations remains low in the Chinese population. The most common tumor types harboring KRAS G12C mutations are in patients suffering from lung, colorectal and biliary cancers.

Covalent Guanosine Mimetic Inhibitors of G12C KRAS

Ras proteins are members of a large family of GTPase enzymes that are commonly mutated in cancer where they act as dominant oncogenes. We previously developed an irreversible guanosine-derived inhibitor, SML-8-73-1, of mutant G12C RAS that forms a covalent bond with cysteine 12. Here we report exploration of the structure-activity relationships (SAR) of hydrolytically stable analogues of SML-8-73-1 as covalent G12C KRAS inhibitors. We report the discovery of difluoromethylene bisphosphonate analogues such as compound 11, which, despite exhibiting reduced efficiency as covalent G12C KRAS inhibitors, remove the liability of the hydrolytic instability of the diphosphate moiety present in SML-8-73-1 and provide the foundation for development of prodrugs to facilitate cellular uptake. The SAR and crystallographic results reaffirm the exquisite molecular recognition that exists in the diphosphate region of RAS for guanosine nucleotides which must be considered in the design of nucleotide-competitive inhibitors.