D-1553 (Garsorasib), a Potent and Selective Inhibitor of KRASG12C in Patients With NSCLC: Phase 1 Study Results

Divarasib in the Evolving Landscape of KRAS G12C Inhibitors for NSCLC

Kristen Rat Sarcoma viral oncogene (KRAS) mutations are one of the most common oncogenic drivers found in 12-14% of non-small cell lung cancer (NSCLC) and 4% of colorectal cancer tumors. Although previously difficult to target, sotorasib and adagrasib are now approved for previously treated NSCLC patients with KRAS G12C mutations. In preclinical studies, divarasib was 5 to 20 times as potent and up to 50 times as selective as sotorasib and adagrasib. While sotorasib met its primary endpoint in the phase III second line study against docetaxel, the progression-free survival (PFS) benefit was small and no overall survival (OS) benefit was observed. Adagrasib has demonstrated clinical benefit in the phase I/II KRYSTAL-1 study setting, however, 44.8% of patients reported grade 3 or higher toxicities. Divarasib has been studied in a phase I dose expansion cohort with promising efficacy [objective response (ORR) 53.4% and PFS 13.1 months]. Although most patients reported toxicities, the majority were low-grade and manageable with supportive care. Here we discuss these results in the context of the evolving KRAS G12C landscape.

Management of sotorasib-related adverse events and hepatotoxicities following anti-PD-(L)1 therapy: Experience with sotorasib in two French anti-cancer centers and practical guidance proposal

INTRODUCTION

Sotorasib is a first-in-class KRASG12C inhibitor that showed significant clinical activity in KRASG12C-mutated non-small cell lung cancer (NSCLC). The most frequent grade 3 or 4 sotorasib-related adverse events (AEs) were diarrhea (4-12 %) and hepatotoxicity (10.1-15.1 %). Data is lacking about the management of these AEs, especially in patients receiving sequential anti-PD-(L)1 and sotorasib therapy. Our aim was to report the management of grade ≥ 2 sotorasib-related AEs in real-world setting and to propose practical guidance for the management of grade ≥ 2 sotorasib-related AEs and more generally KRASG12C inhibitors-related AEs.

MATERIALS AND METHODS

Records from all consecutive patients who initiated sotorasib through expanded access program in two French anti-cancer centers from January 1st 2021 to April 1st 2023 were reviewed to identify and grade sotorasib-related AEs, according to NCI-CTCAE v5.0., and to collect AEs management data. Patients were included in the analysis if they presented a grade ≥ 2 sotorasib-related AE.

RESULTS

From 57 patients identified, 21 met inclusion criteria including eighteen (86 %) who received sequential anti-PD-(L)1 and sotorasib therapy. Hepatotoxicity (76 %) and diarrhea (24 %) were the most common grade ≥ 2 sotorasib-related AEs. Among the 16 patients with a grade ≥ 2 hepatotoxicity, 12 (75 %) definitely discontinued sotorasib, among which 9 (56 %) after dose reductions and rechallenge, and five (32 %) received corticosteroids, allowing only one patient to resume sotorasib. Diarrhea and nausea were usually manageable and not associated with sotorasib discontinuation. We propose a step-by-step management practical guidance for sotorasib-related hepatotoxicity based on dose-reduction and careful monitoring. Liver biopsy is strongly encouraged for grade 3 and 4 hepatotoxicity to assess candidates for corticosteroids.

DISCUSSION

The experience with sotorasib might help better prevent, screen and manage sotorasib-related and other KRASG12C inhibitors-related AEs, particularly hepatotoxicity.

The golden key to open mystery boxes of SMARCA4-deficient undifferentiated thoracic tumor: focusing immunotherapy, tumor microenvironment and epigenetic regulation

SMARCA4-deficient undifferentiated thoracic tumor is extremely invasive. This tumor with poor prognosis is easily confused with SMARCA4-deficent non-small cell lung cancer or sarcoma. Standard and efficient treatment has not been established. In this review, we summarized the etiology, pathogenesis and diagnosis, reviewed current and proposed innovative strategies for treatment and improving prognosis. Immunotherapy, targeting tumor microenvironment and epigenetic regulator have improved the prognosis of cancer patients. We summarized clinicopathological features and immunotherapy strategies and analyzed the progression-free survival (PFS) and overall survival (OS) of patients with SMARCA4-UT who received immune checkpoint inhibitors (ICIs). In addition, we proposed the feasibility of epigenetic regulation in the treatment of SMARCA4-UT. To our knowledge, this is the first review that aims to explore innovative strategies for targeting tumor microenvironment and epigenetic regulation and identify potential benefit population for immunotherapy to improve the prognosis.

Targeting KRASG12C in Non-Small-Cell Lung Cancer: Current Standards and Developments

Among the most common molecular alterations detected in non-small-cell lung cancer (NSCLC) are mutations in Kristen Rat Sarcoma viral oncogene homolog (KRAS). KRAS mutant NSCLC is a heterogenous group of diseases, different from other oncogene-driven tumors in terms of biology and response to therapies. Despite efforts to develop drugs aimed at inhibiting KRAS or its signaling pathways, KRAS had remained undruggable for decades. The discovery of a small pocket in the binding switch II region of KRASG12C has revolutionized the treatment of KRASG12C-mutated NSCLC patients. Sotorasib and adagrasib, direct KRASG12C inhibitors, have been approved by the US Food and Drug Administration (FDA) and other regulatory agencies for patients with previously treated KRASG12C-mutated NSCLC, and these advances have become practice changing. However, first-line treatment in KRASG12C-mutated NSCLC does not differ from NSCLC without actionable driver genomic alterations. Treatment with KRASG12C inhibitors is not curative and patients develop progressive disease, so understanding associated mechanisms of drug resistance is key. New KRASG12C inhibitors and several combination therapy strategies, including with immune checkpoint inhibitors, are being studied in clinical trials. The aim of this review is to explore the clinical impact of KRAS, and outline different treatment approaches, focusing on the novel treatment of KRASG12C-mutated NSCLC.

Targeting KRAS in cancer

RAS family variants-most of which involve KRAS-are the most commonly occurring hotspot mutations in human cancers and are associated with a poor prognosis. For almost four decades, KRAS has been considered undruggable, in part due to its structure, which lacks small-molecule binding sites. But recent developments in bioengineering, organic chemistry and related fields have provided the infrastructure to make direct KRAS targeting possible. The first successes occurred with allele-specific targeting of KRAS p.Gly12Cys (G12C) in non-small cell lung cancer, resulting in regulatory approval of two agents-sotorasib and adagrasib. Inhibitors targeting other variants beyond G12C have shown preliminary antitumor activity in highly refractory malignancies such as pancreatic cancer. Herein, we outline RAS pathobiology with a focus on KRAS, illustrate therapeutic approaches across a variety of malignancies, including emphasis on the 'on' and 'off' switch allele-specific and 'pan' RAS inhibitors, and review immunotherapeutic and other key combination RAS targeting strategies. We summarize mechanistic understanding of de novo and acquired resistance, review combination approaches, emerging technologies and drug development paradigms and outline a blueprint for the future of KRAS therapeutics with anticipated profound clinical impact.

From bench to bedside: current development and emerging trend of KRAS-targeted therapy

Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) is the most frequently mutated oncogene in human cancers with mutations predominantly occurring in codon 12. These mutations disrupt the normal function of KRAS by interfering with GTP hydrolysis and nucleotide exchange activity, making it prone to the GTP-bound active state, thus leading to sustained activation of downstream pathways. Despite decades of research, there has been no progress in the KRAS drug discovery until the groundbreaking discovery of covalently targeting the KRASG12C mutation in 2013, which led to revolutionary changes in KRAS-targeted therapy. So far, two small molecule inhibitors sotorasib and adagrasib targeting KRASG12C have received accelerated approval for the treatment of non-small cell lung cancer (NSCLC) harboring KRASG12C mutations. In recent years, rapid progress has been achieved in the KRAS-targeted therapy field, especially the exploration of KRASG12C covalent inhibitors in other KRASG12C-positive malignancies, novel KRAS inhibitors beyond KRASG12C mutation or pan-KRAS inhibitors, and approaches to indirectly targeting KRAS. In this review, we provide a comprehensive overview of the molecular and mutational characteristics of KRAS and summarize the development and current status of covalent inhibitors targeting the KRASG12C mutation. We also discuss emerging promising KRAS-targeted therapeutic strategies, with a focus on mutation-specific and direct pan-KRAS inhibitors and indirect KRAS inhibitors through targeting the RAS activation-associated proteins Src homology-2 domain-containing phosphatase 2 (SHP2) and son of sevenless homolog 1 (SOS1), and shed light on current challenges and opportunities for drug discovery in this field.

Recent advances of anti-angiogenic inhibitors targeting VEGF/VEGFR axis

Vascular endothelial growth factors (VEGF), Vascular endothelial growth factor receptors (VEGFR) and their downstream signaling pathways are promising targets in anti-angiogenic therapy. They constitute a crucial system to regulate physiological and pathological angiogenesis. In the last 20 years, many anti-angiogenic drugs have been developed based on VEGF/VEGFR system to treat diverse cancers and retinopathies, and new drugs with improved properties continue to emerge at a fast rate. They consist of different molecular structures and characteristics, which enable them to inhibit the interaction of VEGF/VEGFR, to inhibit the activity of VEGFR tyrosine kinase (TK), or to inhibit VEGFR downstream signaling. In this paper, we reviewed the development of marketed anti-angiogenic drugs involved in the VEGF/VEGFR axis, as well as some important drug candidates in clinical trials. We discuss their mode of action, their clinical benefits, and the current challenges that will need to be addressed by the next-generation of anti-angiogenic drugs. We focus on the molecular structures and characteristics of each drug, including those approved only in China.

Nucleic Acid-Based Approaches to Tackle KRAS Mutant Cancers

Activating mutations in KRAS are highly relevant to various cancers, driving persistent efforts toward the development of drugs that can effectively inhibit KRAS activity. Previously, KRAS was considered 'undruggable'; however, the recent advances in our understanding of RNA and nucleic acid chemistry and delivery formulations have sparked a paradigm shift in the approach to KRAS inhibition. We are currently witnessing a large wave of next-generation drugs for KRAS mutant cancers-nucleic acid-based therapeutics. In this review, we discuss the current progress in targeting KRAS mutant tumors and outline significant developments in nucleic acid-based strategies. We delve into their mechanisms of action, address existing challenges, and offer insights into the current clinical trial status of these approaches. We aim to provide a thorough understanding of the potential of nucleic acid-based strategies in the field of KRAS mutant cancer therapeutics.

The current landscape of using direct inhibitors to target KRASG12C-mutated NSCLC

Mutation in KRAS protooncogene represents one of the most common genetic alterations in NSCLC and has posed a great therapeutic challenge over the past ~ 40 years since its discovery. However, the pioneer work from Shokat's lab in 2013 has led to a recent wave of direct KRASG12C inhibitors that utilize the switch II pocket identified. Notably, two of the inhibitors have recently received US FDA approval for their use in the treatment of KRASG12C mutant NSCLC. Despite this success, there remains the challenge of combating the resistance that cell lines, xenografts, and patients have exhibited while treated with KRASG12C inhibitors. This review discusses the varying mechanisms of resistance that limit long-lasting effective treatment of those direct inhibitors and highlights several novel therapeutic approaches including a new class of KRASG12C (ON) inhibitors, combinational therapies across the same and different pathways, and combination with immunotherapy/chemotherapy as possible solutions to the pressing question of adaptive resistance.

Stratification of patients with KRAS-mutated advanced non-small cell lung cancer: improving prognostics

INTRODUCTION

KRAS is the most frequently mutated oncogene in cancer and encodes a key signaling protein in tumors. Due to its high affinity for GTP and the lack of a large binding pocket that allosteric inhibitors can occupy, KRAS has long been considered 'non-druggable.' Finding effective treatment measures for patients with KRAS mutations is our top priority.

AREAS COVERED

In this article, we will provide an overview of the KRAS pathway and review the current state of therapeutic strategies for targeting oncogenic KRAS, as well as their potential to improve outcomes in patients with KRAS-mutant malignancies. We will also discuss the development of these strategies and gave an outlook on prospects.

EXPERT OPINION

KRAS mutations have posed a significant challenge in the treatment of advanced non-small cell lung cancer (NSCLC) over the past few decades. However, the emergence of immunotherapy and KRAS inhibitors, such as Sotorasib (AMG 510) and Adagrasib (MRTX849), has marked a new era in cancer therapy. As more research and clinical trials continue, we anticipate the development of more effective treatment strategies and better options for lung cancer patients.

Efficacy and toxicity of drugs targeting KRASG12C mutation in non-small cell lung cancer: a meta-analysis

OBJECTIVE

To systematically analyze the efficacy and toxicity of drugs targeting KRASG12C mutation in non-small cell lung cancer (NSCLC).

METHODS

The candidate studies were identified in PubMed, Embase, Cochrane Library, CNKI, and Wanfang databases up to 1 June 2023. Data on efficacy, prognosis, and adverse events (AEs) were extracted and calculated by meta-analysis.

RESULTS

Six eligible prospective studies were included in this meta-analysis, including 563 patients with advanced or metastatic NSCLC. For patients with NSCLC, the objective response rate (ORR) of drugs targeting KRASG12C mutation was 37% (95%CI 31-43), median duration of response (DOR) was 8.89 months (95%CI 7.96-9.83), and median progression-free survival (PFS) was 6.40 months (95%CI 5.86-6.93). The overall incidence of AEs was 88% (95%CI 79-96) and the incidence of grade ≥3 AEs was 44% (95%CI 24-64). The most common AEs were diarrhea, nausea, fatigue, and vomiting. The most common grade ≥3 AEs were Alaninetransaminase (ALT) or Aspartatetransaminase (AST) increased and diarrhea.

CONCLUSION

Sotorasib, Adagrasib, and Garsorasib as the drugs of choice for patients with KRASG12C mutation NSCLC, have definite efficacy and acceptable safety, especially for patients with advanced or metastatic disease and within posterior line therapy.