Trends in covalent drug discovery: a 2020-23 patent landscape analysis focused on select covalent reacting groups (CRGs) found in fda-approved drugs.

INTRODUCTION: Covalent drugs contain electrophilic groups that can react with nucleophilic amino acids located in the active sites of proteins, particularly enzymes. Recently, there has been considerable interest in using covalent drugs to target non-catalytic amino acids in proteins to modulate difficult targets (i.e. targeted covalent inhibitors). Covalent compounds contain a wide variety of covalent reacting groups (CRGs), but only a few of these CRGs are present in FDA-approved covalent drugs. AREAS COVERED: This review summarizes a 2020-23 patent landscape analysis that examined trends in the field of covalent drug discovery around targets and organizations. The analysis focused on patent applications that were submitted to the World International Patent Organization and selected using a combination of keywords and structural searches based on CRGs present in FDA-approved drugs. EXPERT OPINION: A total of 707 patent applications from > 300 organizations were identified, disclosing compounds that acted at 71 targets. Patent application counts for five targets accounted for ~ 63% of total counts (i.e. BTK, EGFR, FGFR, KRAS, and SARS-CoV-2 Mpro). The organization with the largest number of patent counts was an academic institution (Dana-Farber Cancer Institute). For one target, KRAS G12C, the discovery of new drugs was highly competitive (>100 organizations, 186 patent applications).

Returning from the afterlife? Sotorasib treatment for advanced KRAS mutant lung cancer: A case report.

BACKGROUND: Lung cancer is increasing in incidence worldwide, and targeted therapies are developing at a rapid pace. Furthermore, the KRAS specific gene is strongly associated with non-small cell lung cancer (NSCLC). Adult patients with locally advanced or metastatic NSCLC who have tested positive for the KRAS G12C mutation and have progressed after at least one systemic treatment are treated with sotorasib. CASE SUMMARY: In this study, we report on an advanced NSCLC with a KRAS G12C mutation. The histological diagnosis indicates stage IVB left lung adenocarcinoma with pelvic and bone metastases, identified as cT4N2bM1c. Using circulating tumor DNA analysis, it was possible to determine the mutation abundance of the KRAS gene exon 2, c.34G>Tp.G12C, which was 32.3%. The patient was advised to take sotorasib as part of their treatment. The imaging data were compared before and after treatment. Furthermore, clinical reassessments and regular serial blood testing were conducted. We found that the patient's clinical symptoms significantly improved after receiving sotorasib medication, and there were no notable side effects, such as liver toxicity, during the treatment. CONCLUSION: Sotorasib has shown promising clinical efficacy in patients with the KRAS G12c mutation and has no apparent toxic side effects.

Combining EGFR and KRAS G12C Inhibitors for KRAS G12C Mutated Advanced Colorectal Cancer.

KRAS is a commonly mutated gene in advanced colorectal cancer (CRC). Recently, inhibitors of KRAS G12C were developed and have shown promising efficacy for KRAS G12C mutated non-small cell lung cancer. However, KRAS G12C inhibitor monotherapy has not demonstrated excellent efficacy for KRAS G12C mutated advanced CRC due to multiple resistance mechanisms, especially receptor tyrosine kinase (RTK) signaling activation. To overcome this resistance mechanism, various combinations of epithelial growth factor receptor (EGFR) and KRAS G12C inhibitors, including panitumumab plus sotorasib, have been investigated in clinical trials. The combination of EGFR and KRAS G12C inhibitors for KRAS G12C mutated CRC demonstrated overall response rates ranging from 26% to 62.5% in seven clinical trials of phase I to III, whose data are available so far. The median progression-free survival in these trials ranged from 3.9 to 8.1 months. These efficacy data suggest that KRAS G12C inhibitor combination with EGFR inhibitors is more effective for KRAS G12C mutated advanced CRC than KRAS G12C inhibitor monotherapy. They also showed reasonable safety of the combination regimen. Based on these results, phase III clinical trials are being conducted to investigate EGFR and KRAS G12C inhibitor combinations as a first or second-line treatment for KRAS G12C mutated advanced CRC. Furthermore, other KRAS G12C inhibitors, KRAS G12D inhibitors, and pan-RAS inhibitors are being developed, which could make more patients with advanced CRC eligible for KRAS inhibition.

KRASG12C Inhibitors in Non-Small Cell Lung Cancer: A Review.

Rat sarcoma virus (RAS) GTPase is one of the most important drivers of non-small cell lung cancer (NSCLC). RAS has three different isoforms (Harvey rat sarcoma viral oncogene homolog [HRAS], Kirsten rat sarcoma viral oncogene homolog [KRAS] and Neuroblastoma ras viral oncogene homolog [NRAS]), of which KRAS is most commonly mutated in NSCLC. The mutated KRAS protein was historically thought to be "undruggable" until the development of KRASG12C inhibitors. In this review, from the aspect of brain metastasis, we aim to provide an overview of the advances in therapies that target KRASG12C, the limitations of the current treatments, and future prospects in patients with KRAS p.G12C mutant NSCLC.

Efficacy and Safety of KRASG12C Inhibitor IBI351 Monotherapy in Patients With Advanced NSCLC: Results From a Phase 2 Pivotal Study.

INTRODUCTION: KRAS glycine-to-cysteine substitution at codon 12 (G12C) mutation is a well-recognized and increasingly promising therapeutic target with huge unmet clinical needs in NSCLC patients. IBI351 is a potent covalent and irreversible inhibitor of KRAS G12C. Here, we present the efficacy and safety of IBI351 from an open-label, single-arm, phase 2 pivotal study. METHODS: Eligible patients with NSCLC with KRAS G12C who failed standard therapy were enrolled. IBI351 was orally administered at a dose of 600 mg twice daily. The primary endpoint was confirmed objective response rate assessed by an independent radiological review committee (IRRC) as per Response Evaluation Criteria in Solid Tumors v1.1. Other endpoints were safety, IRRC-confirmed disease control rate, duration of response, progression-free survival (PFS), and overall survival. RESULTS: As of December 13, 2023, 116 patients were enrolled (Eastern Cooperative Oncology Group Performance Status 1: 91.4%; brain metastasis: 30.2%; prior treatments with both anti-PD-1 or anti-PD-L1 inhibitors and platinum-based chemotherapy: 84.5%). As per the IRRC assessment, the confirmed objective response rate was 49.1% (95% confidence interval [CI]: 39.7-58.6), and the disease control rate was 90.5% (95% CI: 83.7-95.2). The median duration of response was not reached whereas disease progression or death events occurred in 22 patients (38.6%), and the median PFS was 9.7 months (95% CI: 5.6-11.0). overall survival data was immature. Treatment-related adverse events (TRAEs) occurred in 107 patients (92.2%) whereas 48 patients (41.4%) had equal to or higher than grade three TRAEs. Common TRAEs were anemia (44.8%), increased alanine aminotransferase (28.4%), increased aspartate aminotransferase (27.6%), asthenia (26.7%) and presence of protein in urine (25.0%). TRAEs leading to treatment discontinuation occurred in nine patients (7.8%). In biomarker evaluable patients (n = 95), all patients had positive KRAS G12C in tissue whereas 72 patients were blood-positive and 23 were blood-negative for KRAS G12C. Patients with KRAS G12C in both blood and tissue had higher tumor burden at baseline (p < 0.05) and worse PFS (p < 0.05). Tumor mutation profiling identified tumor protein p53 (45.3%), serine/threonine kinase 11 (STK11) (30.5%), and kelch-like ECH-associated protein 1 (21.1%) as the most common genes co-mutated with KRAS G12C. Among 13 genes with mutation frequency equal to or higher than 5%, mutations of six genes (STK11, kelch-like ECH-associated protein 1, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit gamma, DNA polymerase epsilon, SMAD family member 4, and BMP/retinoic acid-inducible neural-specific protein 3) were significantly associated with worse PFS (p < 0.05). Mutation in STK11 was also found to have a significant association with higher tumor burden at baseline and lower response rate (p < 0.05). CONCLUSIONS: IBI351 monotherapy demonstrated promising and sustained efficacy with manageable safety, supporting its potential as a new treatment option for KRAS G12C-mutant NSCLC.

Therapeutic strategies targeting the epidermal growth factor receptor signaling pathway in metastatic colorectal cancer.

More than 1.9 million new colorectal cancer (CRC) cases and 935000 deaths were estimated to occur worldwide in 2020, representing about one in ten cancer cases and deaths. Overall, colorectal ranks third in incidence, but second in mortality. More than half of the patients are in advanced stages at diagnosis. Treatment options are complex because of the heterogeneity of the patient population, including different molecular subtypes. Treatments have included conventional fluorouracil-based chemotherapy, targeted therapy, immunotherapy, etc. In recent years, with the development of genetic testing technology, more and more targeted drugs have been applied to the treatment of CRC, which has further prolonged the survival of metastatic CRC patients.

Treatment patterns and outcomes in KRASG12C-positive advanced NSCLC patients previously treated with immune checkpoint inhibitors: A Canada-wide real-world, multi-center, retrospective cohort study.

OBJECTIVES: KRAS mutations, particularly KRASG12C, are prevalent in non-small cell lung cancer (NSCLC). Immune checkpoint inhibitors (ICIs) have been a frontline treatment, but recently developed KRASG12C-selective inhibitors, such as sotorasib, present new therapeutic options. We conducted a multi-center retrospective cohort study to gain insights into real-world treatment patterns and outcomes in patients with KRASG12C-positive advanced NSCLC receiving systemic therapy post-ICI treatment. METHODS: From the CAnadian CAncers With Rare Molecular Alterations-Basket Real-world Observational Study (CARMA-BROS), a cohort of 102 patients with KRASG12C-positive advanced NSCLC across 9 Canadian centers diagnosed between 2015 and 2021 was analyzed. Clinico-demographic and treatment data were obtained from electronic health records. Survival outcomes were assessed using Kaplan-Meier curves and Cox proportional hazards models. RESULTS: The patients (median age 66 years; 58 % female; 99 % current/former tobacco exposure; 59 % PD-L1 ≥ 50 %), exhibited heterogeneous treatment patterns post-ICI. Most patients received ICIs as a first-line therapy, with varying subsequent lines including chemotherapy and targeted therapy. In patients receiving systemic therapy post-ICI, median overall survival was 12.6 months, and real-world progression-free survival was 4.7 months. KRASG12C-selective targeted therapy post-ICI (n = 20) showed longer real-world progression-free survival compared to single-agent chemotherapy (aHR = 0.39, p = 0.012). CONCLUSION: This study contributes valuable real-world data on KRASG12C-positive advanced NSCLC post-ICI treatment. The absence of a standard treatment sequencing post-ICI underscores the need for further investigation and consensus-building in the evolving landscape of KRASG12C-targeted therapies.

Assessment of KRASG12C inhibitors for colorectal cancer.

Colorectal cancer (CRC) is a highly prevalent and lethal cancer worldwide. Approximately 45% of CRC patients harbor a gain-in-function mutation in KRAS. KRAS is the most frequently mutated oncogene accounting for approximately 25% of all human cancers. Gene mutations in KRAS cause constitutive activation of the KRAS protein and MAPK/AKT signaling, resulting in unregulated proliferation and survival of cancer cells and other aspects of malignant transformation, progression, and metastasis. While KRAS has long been considered undruggable, the FDA recently approved two direct acting KRAS inhibitors, Sotorasib and Adagrasib, that covalently bind and inactivate KRASG12C. Both drugs showed efficacy for patients with non-small cell lung cancer (NSCLC) diagnosed with a KRASG12C mutation, but for reasons not well understood, were considerably less efficacious for CRC patients diagnosed with the same mutation. Thus, it is imperative to understand the basis for resistance to KRASG12C inhibitors, which will likely be the same limitations for other mutant specific KRAS inhibitors in development. This review provides an update on clinical trials involving CRC patients treated with KRASG12C inhibitors as a monotherapy or combined with other drugs. Mechanisms that contribute to resistance to KRASG12C inhibitors and the development of novel RAS inhibitors with potential to escape such mechanisms of resistance are also discussed.

A case of hepatoid adenocarcinoma of the lung harboring KRAS G12C responded favorably to sotorasib.

Hepatoid adenocarcinoma of the lung is a rare variant of adenocarcinoma. We describe a case of hepatoid adenocarcinoma of the lung that harbored KRAS G12C and responded favorably to sotorasib. A man in his 70s was found to have an abnormality on his chest X-ray. He underwent right middle lobectomy, and a pathological examination of the surgical specimen showed conventional invasive adenocarcinoma with highly focal hepatoid adenocarcinoma. He received chemoradiotherapy and concurrent radiation, followed by durvalumab for postoperative recurrence. After three doses of durvalumab, he reported feeling short of breath. A computed tomography scan showed emerging broad consolidation in the right lower lobe. Transbronchial lung biopsy specimens from the consolidation showed hepatoid adenocarcinoma harboring KRAS G12C mutation. Therefore, he was started on sotorasib 960 mg daily. Eight days later, a computed tomography scan showed that the area of consolidation had reduced in size. Progressive disease was detected after 42 days of treatment with sotorasib. The patient died 1 month after cessation of sotorasib and 3 months after postoperative recurrence. We have encountered what we believe to be the first case of hepatoid adenocarcinoma of the lung with KRAS G12C mutation that responded favorably to treatment with sotorasib.

The Target Therapy Hyperbole: "KRAS (p.G12C)"-The Simplification of a Complex Biological Problem.

Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) gene variations are linked to the development of numerous cancers, including non-small cell lung cancer (NSCLC), colorectal cancer (CRC), and pancreatic ductal adenocarcinoma (PDAC). The lack of typical drug-binding sites has long hampered the discovery of therapeutic drugs targeting KRAS. Since "CodeBreaK 100" demonstrated Sotorasib's early safety and efficacy and led to its approval, especially in the treatment of non-small cell lung cancer (NSCLC), the subsequent identification of specific inhibitors for the p.G12C mutation has offered hope. However, the CodeBreaK 200 study found no significant difference in overall survival (OS) between patients treated with Docetaxel and Sotorasib (AMG 510), adding another degree of complexity to this ongoing challenge. The current study compares the three-dimensional structures of the two major KRAS isoforms, KRAS4A and KRAS4B. It also investigates the probable structural changes caused by the three major mutations (p.G12C, p.G12D, and p.G12V) within Sotorasib's pocket domain. The computational analysis demonstrates that the wild-type and mutant isoforms have distinct aggregation propensities, resulting in the creation of alternate oligomeric configurations. This study highlights the increased complexity of the biological issue of using KRAS as a therapeutic target. The present study stresses the need for a better understanding of the structural dynamics of KRAS and its mutations to design more effective therapeutic approaches. It also emphasizes the potential of computational approaches to shed light on the complicated molecular pathways that drive KRAS-mediated oncogenesis. This study adds to the ongoing efforts to address the therapeutic hurdles presented by KRAS in cancer treatment.

Brain metastases in clinical trial participants with KRAS-mutated advanced non-small cell lung cancer receiving docetaxel: Pooled data analysis.

OBJECTIVES: Limited data are available on central nervous system (CNS) efficacy with standard-of-care therapies for KRAS-mutated (KRASmut) advanced non-small cell lung cancer (NSCLC). The objective of this study was to investigate the incidence and progression of brain metastases in KRASmut advanced NSCLC treated with docetaxel using pooled data from historical clinical trials. MATERIALS AND METHODS: Data from phase 2/3 trials of docetaxel-containing regimens in advanced NSCLC were sourced from the Medidata platform. Analysis was restricted to stage IIIB-IV KRASmut NSCLC with disease progression after ≥ 1 systemic anticancer therapy. Participants with asymptomatic, treated, and stable brain metastases were included. Endpoints included 12-month CNS disease control rate (CNS-DCR) and CNS progression per Response Evaluation Criteria in Solid Tumors; progression-free survival (PFS); and overall survival (OS). Data were pooled and analyses stratified by baseline brain metastases status. RESULTS: A total of 595 participants were included in the analysis (62 [10%] with baseline brain metastases and 533 [90 %] without). Among participants with brain metastases, 17 (27.4 %) had CNS progression during docetaxel treatment and 12-month CNS-DCR was 75.8 %; 45 (8.4 %) participants without baseline brain metastases developed brain metastases during treatment. In an analysis restricted to patients with metastatic disease, outcomes with and without baseline brain metastases included: median PFS, 3.3 and 4.9 months (p < 0.005); 12-month PFS, 5 % and 16 %; median OS, 6.9 and 10.4 months (p < 0.005); and 12-month OS, 20 % and 44 %, respectively. CONCLUSION: These findings establish CNS progression rates with docetaxel in previously treated KRASmut advanced NSCLC and facilitate interpretation of data from ongoing randomized clinical trials of novel KRAS-targeted therapeutic strategies vs. docetaxel.

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.

KRAS G12C Inhibitors in the Treatment of Metastatic Colorectal Cancer.

KRAS mutations contribute substantially to the overall colorectal cancer burden and have long been a focus of drug development efforts. After a lengthy preclinical road, KRAS inhibition via the G12C allele has finally become a therapeutic reality. Unlike in NSCLC, early studies of KRAS inhibitors in CRC struggled to demonstrate single agent activity. Investigation into these tissue-specific treatment differences has led to a deeper understanding of the complexities of MAPK signaling and the diverse adaptive feedback responses to KRAS inhibition. EGFR reactivation has emerged as a principal resistance mechanism to KRAS inhibitor monotherapy. Thus, the field has pivoted to dual EGFR/KRAS blockade with promising efficacy. Despite significant strides in the treatment of KRAS G12C mutated CRC, new challenges are on the horizon. Alternative RTK reactivation and countless acquired molecular resistance mechanisms have shifted the treatment goalpost. This review focuses on the historical and contemporary clinical strategies of targeting KRAS G12C alterations in CRC and highlights future directions to overcome treatment challenges.

Structural perspectives on recent breakthrough efforts toward direct drugging of RAS and acquired resistance.

The Kirsten rat sarcoma viral oncoprotein homolog (KRAS) is currently a primary focus of oncologists and translational scientists, driven by exciting results with KRAS-targeted therapies for non-small cell lung cancer (NSCLC) patients. While KRAS mutations continue to drive high cancer diagnosis and death, researchers have developed unique strategies to target KRAS variations. Having been investigated over the past 40 years and considered "undruggable" due to the lack of pharmacological binding pockets, recent breakthroughs and accelerated FDA approval of the first covalent inhibitors targeting KRASG12C, have largely sparked further drug development. Small molecule development has targeted the previously identified primary location alterations such as G12, G13, Q61, and expanded to address the emerging secondary mutations and acquired resistance. Of interest, the non-covalent KRASG12D targeting inhibitor MRTX-1133 has shown promising results in humanized pancreatic cancer mouse models and is seemingly making its way from bench to bedside. While this manuscript was under review a novel class of first covalent inhibitors specific for G12D was published, These so-called malolactones can crosslink both GDP and GTP bound forms of G12D. Inhibition of the latter state suppressed downstream signaling and cancer cell proliferation in vitro and in mouse xenografts. Moreover, a non-covalent pan-KRAS inhibitor, BI-2865, reduced tumor proliferation in cell lines and mouse models. Finally, the next generation of KRAS mutant-specific and pan-RAS tri-complex inhibitors have revolutionized RAS drug discovery. This review will give a structural biology perspective on the current generation of KRAS inhibitors through the lens of emerging secondary mutations and acquired resistance.

Targeting WEE1 enhances the antitumor effect of KRAS-mutated non-small cell lung cancer harboring TP53 mutations.

The clinical development of Kirsten rat sarcoma virus (KRAS)-G12C inhibitors for the treatment of KRAS-mutant lung cancer is limited by the presence of co-mutations, intrinsic resistance, and the emergence of acquired resistance. Therefore, innovative strategies for enhancing apoptosis in KRAS-mutated non-small cell lung cancer (NSCLC) are urgently needed. Through CRISPR-Cas9 knockout screening using a library of 746 crRNAs and drug screening with a custom library of 432 compounds, we discover that WEE1 kinase inhibitors are potent enhancers of apoptosis, particularly in KRAS-mutant NSCLC cells harboring TP53 mutations. Mechanistically, WEE1 inhibition promotes G2/M transition and reduces checkpoint kinase 2 (CHK2) and Rad51 expression in the DNA damage response (DDR) pathway, which is associated with apoptosis and the repair of DNA double-strand breaks, leading to mitotic catastrophe. Notably, the combined inhibition of KRAS-G12C and WEE1 consistently suppresses tumor growth. Our results suggest targeting WEE1 as a promising therapeutic strategy for KRAS-mutated NSCLC with TP53 mutations.

Sotorasib as first-line therapy in patients with advanced non-small cell lung cancer with KRAS gene mutations combined with brain metastases: a case report.

Background: Non-small cell lung cancer (NSCLC) has a high incidence of lung cancer, with a 30% incidence of KRAS mutations and a low 5-year survival rate. Until the Food and Drug Administration (FDA) approved sotorasib in May 2021, no therapies targeted mutated KRAS in cancer. Sotorasib, a new KRAS inhibitor, is currently recognized as the newest clinically targeted agent with apparent clinical efficacy in NSCLC patients with KRAS G12C mutations. FDA approval is required for patients with advanced or metastatic NSCLC undergoing at least one chemotherapy regimen. Case Description: In our study, we report a patient with advanced NSCLC combined with brain metastases, clinical stage IV (c.T3N0M1b), KRAS G12C (+) detected by next-generation sequencing (NGS) technology, direct use of sotorasib, an inhibitor of KRAS G12C, as first-line therapy. The patient was treated with 4 months of oral therapy, had significant partial remission (PR), and remained in stable disease (SD) for nearly 9 months of follow-up, with no other side effects. Further extension of the follow-up period is needed to assess the impact of sotorasib as first-line therapy on patient survival. A series of clinical trials in phase 3 is ongoing, covering the first-line usage widespread. Conclusions: Based on the literature review, this is the first domestic report in China where sotorasib was used directly as first-line treatment in patients with advanced combined brain metastasis from NSCLC. It needs a longer follow-up to evaluate the efficacy of sotorasib further as a first-line.

ABCB1 attenuates brain exposure to the KRASG12C inhibitor opnurasib whereas binding to mouse carboxylesterase 1c influences its plasma exposure.

Opnurasib (JDQ443) is a newly developed oral KRASG12C inhibitor, with a binding mechanism distinct from the registered KRASG12C inhibitors sotorasib and adagrasib. Phase I and II clinical trials for opnurasib in NSCLC are ongoing. We evaluated the pharmacokinetic roles of the ABCB1 (P-gp/MDR1) and ABCG2 (BCRP) efflux and OATP1 influx transporters, and of the metabolizing enzymes CYP3A and CES1 in plasma and tissue disposition of oral opnurasib, using genetically modified cell lines and mouse models. In vitro, opnurasib was potently transported by human (h)ABCB1 and slightly by mouse (m)Abcg2. In Abcb1a/b- and Abcb1a/b;Abcg2-deficient mice, a significant ∼100-fold increase in brain-to-plasma ratios was observed. Brain penetration was unchanged in Abcg2-/- mice. ABCB1 activity in the blood-brain barrier may therefore potentially limit the efficacy of opnurasib against brain metastases. The Abcb1a/b transporter activity could be almost completely reversed by co-administration of elacridar, a dual ABCB1/ABCG2 inhibitor, increasing the brain penetration without any behavioral or postural signs of acute CNS-related toxicity. No significant pharmacokinetic roles of the OATP1 transporters were observed. Transgenic human CYP3A4 did not substantially affect the plasma exposure of opnurasib, indicating that opnurasib is likely not a sensitive CYP3A4 substrate. Interestingly, Ces1-/- mice showed a 4-fold lower opnurasib plasma exposure compared to wild-type mice, whereas no strong effect was seen on the tissue distribution. Plasma Ces1c therefore likely binds opnurasib, increasing its retention in plasma. The obtained pharmacokinetic insights may be useful for further optimization of the clinical efficacy and safety of opnurasib, and might reveal potential drug-drug interaction risks.

Discovery of novel coumarin-based KRAS-G12C inhibitors from virtual screening and Rational structural optimization.

KRAS-G12C inhibitors has been made significant progress in the treatment of KRAS-G12C mutant cancers, but their clinical application is limited due to the adaptive resistance, motivating development of novel structural inhibitors. Herein, series of coumarin derivatives as KRAS-G12C inhibitors were found through virtual screening and rational structural optimization. Especially, K45 exhibited strong antiproliferative potency on NCI-H23 and NCI-H358 cancer cells harboring KRAS-G12C with the IC50 values of 0.77 µM and 1.50 µM, which was 15 and 11 times as potent as positive drug ARS1620, respectively. Furthermore, K45 reduced the phosphorylation of KRAS downstream effectors ERK and AKT by reducing the active form of KRAS (KRAS GTP) in NCI-H23 cells. In addition, K45 induced cell apoptosis by increasing the expression of anti-apoptotic protein BAD and BAX in NCI-H23 cells. Docking studies displayed that the 3-naphthylmethoxy moiety of K45 extended into the cryptic pocket formed by the residues Gln99 and Val9, which enhanced the interaction with the KRAS-G12C protein. These results indicated that K45 was a potent KRAS-G12C inhibitor worthy of further study.

KRAS G12C inhibitor combination therapies: current evidence and challenge.

Although KRAS G12C inhibitors have proven that KRAS is a "druggable" target of cancer, KRAS G12C inhibitor monotherapies have demonstrated limited clinical efficacy due to primary and acquired resistance mechanisms. Multiple combinations of KRAS G12C inhibitors with other targeted therapies, such as RTK, SHP2, and MEK inhibitors, have been investigated in clinical trials to overcome the resistance. They have demonstrated promising efficacy especially by combining KRAS G12C and EGFR inhibitors for KRAS G12C-mutated colorectal cancer. Many clinical trials of combinations of KRAS G12C inhibitors with other targeted therapies, such as SOS1, ERK, CDK4/6, and wild-type RAS, are ongoing. Furthermore, preclinical data have suggested additional promising KRAS G12C combinations with YAP/TAZ-TEAD inhibitors, FAK inhibitors, and farnesyltransferase inhibitors. The combinations of KRAS G12C inhibitors with immunotherapies and chemotherapies have also been investigated, and the preliminary results were reported. More recently, KRAS-targeted therapies not limited to KRAS G12C are being developed, potentially broadening the treatment landscape of KRAS-mutated cancers. Rationally combining KRAS inhibitors with other therapeutics is likely to play a significant role in future treatment for KRAS-mutated solid tumors.

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.