p.G12C KRAS mutation prevalence in non-small cell lung cancer: Contribution from interregional variability and population substructures among Hispanics

KRAS-mutant non-small cell lung cancer (NSCLC) therapy based on tepotinib and omeprazole combination

BACKGROUND

KRAS-mutant non-small cell lung cancer (NSCLC) shows a relatively low response rate to chemotherapy, immunotherapy and KRAS-G12C selective inhibitors, leading to short median progression-free survival, and overall survival. The MET receptor tyrosine kinase (c-MET), the cognate receptor of hepatocyte growth factor (HGF), was reported to be overexpressed in KRAS-mutant lung cancer cells leading to tumor-growth in anchorage-independent conditions.

METHODS

Cell viability assay and synergy analysis were carried out in native, sotorasib and trametinib-resistant KRAS-mutant NSCLC cell lines. Colony formation assays and Western blot analysis were also performed. RNA isolation from tumors of KRAS-mutant NSCLC patients was performed and KRAS and MET mRNA expression was determined by real-time RT-qPCR. In vivo studies were conducted in NSCLC (NCI-H358) cell-derived tumor xenograft model.

RESULTS

Our research has shown promising activity of omeprazole, a V-ATPase-driven proton pump inhibitor with potential anti-cancer properties, in combination with the MET inhibitor tepotinib in KRAS-mutant G12C and non-G12C NSCLC cell lines, as well as in G12C inhibitor (AMG510, sotorasib) and MEK inhibitor (trametinib)-resistant cell lines. Moreover, in a xenograft mouse model, combination of omeprazole plus tepotinib caused tumor growth regression. We observed that the combination of these two drugs downregulates phosphorylation of the glycolytic enzyme enolase 1 (ENO1) and the low-density lipoprotein receptor-related protein (LRP) 5/6 in the H358 KRAS G12C cell line, but not in the H358 sotorasib resistant, indicating that the effect of the combination could be independent of ENO1. In addition, we examined the probability of recurrence-free survival and overall survival in 40 early lung adenocarcinoma patients with KRAS G12C mutation stratified by KRAS and MET mRNA levels. Significant differences were observed in recurrence-free survival according to high levels of KRAS mRNA expression. Hazard ratio (HR) of recurrence-free survival was 7.291 (p = 0.014) for high levels of KRAS mRNA expression and 3.742 (p = 0.052) for high MET mRNA expression.

CONCLUSIONS

We posit that the combination of the V-ATPase inhibitor omeprazole plus tepotinib warrants further assessment in KRAS-mutant G12C and non G12C cell lines, including those resistant to the covalent KRAS G12C inhibitors.

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.

Prevalence of oncogenic driver mutations in Hispanics/Latin patients with lung cancer. A systematic review and meta-analysis

INTRODUCTION

The frequency of actionable mutations varies between races, and Hispanic/Latino (H/L) people are a population with different proportions of ancestry. Our purpose was to establish prevalence of actionable mutations in the H/L population with NSCLC.

METHODS

EMBASE, LILACS, MEDLINE, and Virtual Health Library were searched for studies published up to April 2023 that evaluated the prevalence of ALK, BRAF, EGFR, HER-2, KRAS, MET, NTRK, RET, ROS1 in H/L patients. Meta-analyses were done to determine prevalence using a random effects model.

RESULTS

Fifty-five articles were included. EGFR and KRAS were the most prevalent genes with high heterogeneity across the countries. The overall mutation frequency for EGFR was 22%. The most frequent mutations in the EGFR gene were del19 (10%) and L858R (7%). The mean of KRAS mutation was a 14% prevalence. KRASG12C was the most frequent mutation with a 7% prevalence in an entire population. The overall frequency of ALK rearrangement was 5%. The mean frequency of ROS-1 rearrangement was 2%, and the frequencies of HER-2, MET, BRAF, RET, NTRK molecular alterations were 4%, 3%, 2%, 2%, and 1% respectively. Almost half of the cases were male, and 65.8% had a history of tobacco exposure. The most common clinical stage was IV.

CONCLUSIONS

The prevalence of driver mutations such as EGFR and KRAS in LA populations differs from what is reported in Asians and Europeans. In the present article, countries with a high proportion of Amerindian ancestry show a greater prevalence of EGFR in contrast to countries with a high proportion of Caucasians. Lack of information on some countries or studies with a small sample size affects the real prevalence data for the region.

KRAS G12C in advanced NSCLC: Prevalence, co-mutations, and testing

KRAS is the most commonly mutated oncogene in advanced, non-squamous, non-small cell lung cancer (NSCLC) in Western countries. Of the various KRAS mutants, KRAS G12C is the most common variant (~40%), representing 10-13% of advanced non-squamous NSCLC. Recent regulatory approvals of the KRASG12C-selective inhibitors sotorasib and adagrasib for patients with advanced or metastatic NSCLC harboring KRASG12C have transformed KRAS into a druggable target. In this review, we explore the evolving role of KRAS from a prognostic to a predictive biomarker in advanced NSCLC, discussing KRAS G12C biology, real-world prevalence, clinical relevance of co-mutations, and approaches to molecular testing. Real-world evidence demonstrates significant geographic differences in KRAS G12C prevalence (8.9-19.5% in the US, 9.3-18.4% in Europe, 6.9-9.0% in Latin America, and 1.4-4.3% in Asia) in advanced NSCLC. Additionally, the body of clinical data pertaining to KRAS G12C co-mutations such as STK11, KEAP1, and TP53 is increasing. In real-world evidence, KRAS G12C-mutant NSCLC was associated with STK11, KEAP1, and TP53 co-mutations in 10.3-28.0%, 6.3-23.0%, and 17.8-50.0% of patients, respectively. Whilst sotorasib and adagrasib are currently approved for use in the second-line setting and beyond for patients with advanced/metastatic NSCLC, testing and reporting of the KRAS G12C variant should be included in routine biomarker testing prior to first-line therapy. KRAS G12C test results should be clearly documented in patients' health records for actionability at progression. Where available, next-generation sequencing is recommended to facilitate simultaneous testing of potentially actionable biomarkers in a single run to conserve tissue. Results from molecular testing should inform clinical decisions in treating patients with KRAS G12C-mutated advanced NSCLC.

Biological insights in non-small cell lung cancer

Lung oncogenesis relies on intracellular cysteine to overcome oxidative stress. Several tumor types, including non-small cell lung cancer (NSCLC), upregulate the system xc- cystine/glutamate antiporter (xCT) through overexpression of the cystine transporter SLC7A11, thus sustaining intracellular cysteine levels to support glutathione synthesis. Nuclear factor erythroid 2-related factor 2 (NRF2) serves as a master regulator of oxidative stress resistance by regulating SLC7A11, whereas Kelch-like ECH-associated protein (KEAP1) acts as a cytoplasmic repressor of the oxidative responsive transcription factor NRF2. Mutations in KEAP1/NRF2 and p53 induce SLC7A11 activation in NSCLC. Extracellular cystine is crucial in supplying the intracellular cysteine levels necessary to combat oxidative stress. Disruptions in cystine availability lead to iron-dependent lipid peroxidation, thus resulting in a type of cell death called ferroptosis. Pharmacologic inhibitors of xCT (either SLC7A11 or GPX4) induce ferroptosis of NSCLC cells and other tumor types. When cystine uptake is impaired, the intracellular cysteine pool can be sustained by the transsulfuration pathway, which is catalyzed by cystathionine-B-synthase (CBS) and cystathionine g-lyase (CSE). The involvement of exogenous cysteine/cystine and the transsulfuration pathway in the cysteine pool and downstream metabolites results in compromised CD8+ T cell function and evasion of immunotherapy, diminishing immune response and potentially reducing the effectiveness of immunotherapeutic interventions. Pyroptosis is a previously unrecognized form of regulated cell death. In NSCLCs driven by EGFR, ALK, or KRAS, selective inhibitors induce pyroptotic cell death as well as apoptosis. After targeted therapy, the mitochondrial intrinsic apoptotic pathway is activated, thus leading to the cleavage and activation of caspase-3. Consequently, gasdermin E is activated, thus leading to permeabilization of the cytoplasmic membrane and cell-lytic pyroptosis (indicated by characteristic cell membrane ballooning). Breakthroughs in KRAS G12C allele-specific inhibitors and potential mechanisms of resistance are also discussed herein.

Insights into EGFR Mutations and Oncogenic KRAS Mutations in Non-Small-Cell Lung Cancer

Genetic mutations can activate different sets of proto-oncogenes and tumor suppressors genes [...].

Overall survival and role of programmed death ligand 1 expression in patients with metastatic non-small-cell lung cancer and immunotherapy: an observational study from central Switzerland

BACKGROUND

In clinical trials, therapy with immune checkpoint inhibitors has improved the survival of patients with metastatic non-small-cell lung cancer (NSCLC). These trials were important for drug approval and for defining new treatment standards but the effect of checkpoint inhibitors in patients treated outside of clinical trials is not well known. The goal of this study was to assess the effect of immunotherapy on the overall survival of patients with metastatic NSCLC in the region of central Switzerland.

MATERIALS AND METHODS

The study included 274 patients with histologically confirmed metastatic (stage IV) NSCLC in central Switzerland in the years 2015 to 2018. Patients with NSCLC and actionable driver mutations were excluded. Patients with checkpoint inhibitor treatment (immuno-oncology [IO] group, n = 122) were compared with patients without checkpoint inhibitor treatment (no-IO group, n = 152). Baseline demographics, disease characteristics and therapies applied were collected retrospectively. The primary endpoint was median overall survival calculated either from diagnosis or from the start of checkpoint inhibitor therapy to death or data cut-off (21 July 2021). We used the Kaplan-Meier method and an adjusted Cox proportional-hazards regression model. The expression of programmed-death ligand 1 (PD-L1) on tumour cells was used for exploratory analysis.

RESULTS

Patients had a median age of 68.4 years, most were male (61.7%) and more than half were current or former smokers (65%). A test for PD-L1 expression was available for 55.8% of the tumours. Patients in the IO group were younger than patients in the no-IO group. Among the 122 patients in the IO group, the median overall survival was 15 months (95% confidence interval [CI] 12-20). In the no-IO group, the median overall survival was 4 months (95% CI 3-7) with chemotherapy and 2 months (95% CI 1-2) with best supportive care. Patients with high (≥50%) PD-L1 expression and checkpoint inhibitor therapy had a slightly longer overall survival than patients with low PD-L1 and checkpoint inhibitor therapy.

CONCLUSION

These results suggest that treatment with checkpoint inhibitors improves overall survival in patients with metastatic NSCLC and that PD-L1 expression could have a predictive value in patients treated outside of clinical trials. Further studies are needed to study the magnitude of the benefit of checkpoint inhibitors according to molecular NSCLC subtype.

Survival Outcomes of Metastatic Non-small Cell Lung Cancer Patients With Limited Access to Immunotherapy and Targeted Therapy in a Cancer Center of a Low- and Middle-Income Country

OBJECTIVE

To describe the survival outcomes of metastatic non-small cell lung cancer patients with limited access to immunotherapy and targeted therapy in a cancer reference center in Colombia.

METHODS

A retrospective analysis of metastatic non-small cell lung cancer patients treated between 2013 and 2018 was performed, majority diagnosed with adenocarcinoma. It was carried out in a public cancer reference center that provides care to patients of low and middle socioeconomic status. Overall survival and progression-free survival were evaluated by Kaplan-Meier analysis and log-rank test. A Cox regression model was performed for univariate and multivariate analysis.

RESULTS

209 patients were included with majority of adenocarcinoma (79.5%). First-line treatment was cytotoxic chemotherapy (50.2%), EGFR-targeted therapy (14.8%), chemoimmunotherapy (1.9%), and ALK-targeted therapy (1.4%). 31.6% received best supportive care. Median time of follow-up was 13 months, median overall survival was 11.2 months (95% CI, 7.9-14.4), 13 months for adenocarcinoma (95% CI, 8.1-17.9), and 2.5 months for squamous cell carcinoma (95% CI, 0.6-4.4) (P < .001). Median progression-free survival was 9.3 months (95% CI, 7.9-10.7) without differences according to the type of first-line therapy. Median time-to-treatment was 55 days and only 54% of patients with a tested actionable mutation in EGFR received an EGFR-targeted therapy as the first-line treatment. Multivariate analysis showed that squamous cell carcinoma histology and receiving best supportive care were independent factors for worse overall survival ((HR:1.8, 95% CI, 1.076-3.082, P=.026) and (HR:14.6, 95% CI, 8.921-24.049, P < .001), respectively). Meanwhile, squamous cell carcinoma histology was an independent factor for worse progression-free survival (HR:3.4, 95% CI, 1.540-7.464, P=.002).

CONCLUSIONS

Despite advances in precision medicine, during the study period, cytotoxic chemotherapy was the most used treatment in our patients. Furthermore, about a third of them received best supportive care. The use of targeted therapies has been restricted by access to molecular diagnosis and remained low until 2018. Access to immunotherapy should be prioritized.

Sotorasib in KRASG12C mutated lung cancer: Can we rule out cracking KRAS led to worse overall survival?

The KRAS oncogene is present in up to 25% of solid tumors and for decades had been undruggable. Sotorasib was the first-in-class KRAS inhibitor to reach the US and European market, and its pharmacological inhibition is restricted to the KRAS p.G12C mutation. Sotorasib showed activity (tumor shrinkage) in patients with non-small cell lung cancer harboring this specific mutation, and efficacy was tested in the CodeBreaK 200, open-label, phase 3 trial (NCT04303780). The results were presented in the ESMO 2022 meeting. CodeBreaK 200 found an improvement in the primary endpoint of progression-free survival (PFS), but overall survival, a key secondary endpoint, was not improved. However, critical questions about the trial's design may limit inferences regarding the reported results. The control arm treatment was inferior to the best standard of care. A late protocol modification (which lowered the sample size and allowed a problematic crossover) prohibited the trial from making a determination regarding overall survival. Imbalance in censoring rates, with potential informative censoring, makes PFS estimates unreliable. Quality-of-life data were also limited. Ultimately, CodeBreaK 200 does not clarify how this therapy should be used in practice, and while we maintain cautious enthusiasm for this and other Ras inhibitors, we await more informative trials.

RNA-based next generation sequencing in non-small-cell lung cancer in a routine setting: an experience from an Italian referral center

Aim: ALK, ROS1, NTRK and RET gene fusions and MET exon 14 skipping alterations represent novel predictive biomarkers for advanced non-small-cell lung cancer (NSCLC). Therefore, testing patients for these genetic variants is crucial for choosing the best selective treatment. Over the last couple of decades, next generation sequencing (NGS) platforms have emerged as an extremely useful tool for detecting these variants. Materials & methods: In the present study, we report our NGS molecular records produced during a year of diagnostic activity. Results: Overall, our in-house developed NGS workflow successfully analyzed n = 116/131 (88.5%) NSCLC samples. Of these, eight (6.8%) and five (4.3%) out of 116 patients harbored ALK and RET gene rearrangements, respectively: one case harbored ROS1 gene fusion (0.7%). Conclusion: Our results highlight that an RNA-based NGS analysis can reliably detect gene fusion alterations, thereby playing a pivotal role in the management of NSCLC patients.

Uniting Latin America Through Research: How Regional Research Can Strengthen Local Policies, Networking, and Outcomes for Patients With Lung Cancer

Lung cancer represents a considerable global health threat, leading the list in terms of cancer-related deaths worldwide. An important proportion of lung cancer cases occur within Latin America, and current projections show that over the next decade, the number of deaths due to lung cancer will double in the region, underscoring the need to implement evidence-based interventions to improve outcomes. Several challenges have limited the progress in lung cancer research in Latin America for many years, though recently the surge of multidisciplinary, transnational, and transcultural research groups have overcome many of these limitations. The increase in region-specific knowledge has improved cancer care in the area, providing clinicians with a specific demographic and molecular profile for Hispanic patients with lung cancer; as a result, the implementation of precision oncology has benefited from a profound knowledge of the patient profile. Nonetheless, there are still challenges to improve research in Latin America, including stabilizing funding sources to continue independent research, supporting mentoring programs and an early immersion in clinical research for early career fellows, and overcoming barriers for publishing.