Abstract 3598: A first-in-class tri-complex KRASG13C(ON) inhibitor validates therapeutic targeting of KRASG13Cand drives tumor regressions in preclinical models

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.

Targeting KRAS-Mutated Gastrointestinal Malignancies with Small-Molecule Inhibitors: A New Generation of Breakthrough Therapies

Kirsten rat sarcoma virus (KRAS) is one of the most important and frequently mutated oncogenes in cancer and the mutational prevalence is especially high in many gastrointestinal malignancies, including colorectal cancer and pancreatic ductal adenocarcinoma. The KRAS protein is a small GTPase that functions as an "on/off" switch to activate downstream signaling, mainly through the mitogen-activated protein kinase pathway. KRAS was previously considered undruggable because of biochemical constraints; however, recent breakthroughs have enabled the development of small-molecule inhibitors of KRAS G12C. These drugs were initially approved in lung cancer and have now shown substantial clinical activity in KRAS G12C-mutated pancreatic ductal adenocarcinoma as well as colorectal cancer when combined with anti-EGFR monoclonal antibodies. Early data are encouraging for other gastrointestinal cancers as well and many other combination strategies are being investigated. Several new KRAS G12C inhibitors and novel inhibitors of other KRAS alterations have recently entered the clinic. These molecules employ a variety of innovative mechanisms and have generated intense interest. These novel drugs are especially important as KRAS G12C is rare in gastrointestinal malignancies compared with other KRAS alterations, representing potentially groundbreaking advances. Soon, the rapidly evolving landscape of novel KRAS inhibitors may substantially shift the therapeutic landscape for gastrointestinal cancers and offer meaningful survival improvements.

Annual review of KRAS inhibitors in 2022

Kirsten rat sarcoma viral (KRAS) oncogene is the most commonly mutated isoform of RAS, accounting for 85% of RAS-driven human cancers. KRAS functioning as a signaling hub participates in multiple cellular signaling pathways and regulates a variety of critical processes such as cell proliferation, differentiation, growth, metabolism and migration. Over the past decades, KRAS oncoprotein has been considered as an "undruggable" target due to its smooth surface and high GTP/GDP affinity. The breakthrough in directly targeting G12C mutated-KRAS and recently approved covalent KRAS^G12C inhibitors sotorasib and adagrasib broke the myth of KRAS undruggable and confirmed the directly targeting KRAS as one of the most promising strategies for the treatment of cancers. Targeting KRAS^G12C successfully enriched the understanding of KRAS and brought opportunities for the development of inhibitors to directly target other KRAS mutations. With the stage now set for a new era in the treatment of KRAS-driven cancers, the development of KRAS inhibitors also enters a booming epoch. In this review, we overviewed the research progress of KRAS inhibitors with the potential to treat cancers covering articles published in 2022. The design strategies, discovery processes, structure-activity relationship (SAR) studies, cocrystal structure analysis as well as in vitro and in vivo activity were highlighted with the aim of providing updated sight to accelerate the further development of more potent inhibitors targeting various mutated-KRAS with favorable drug-like properties.

Drugging KRAS: current perspectives and state-of-art review

After decades of efforts, we have recently made progress into targeting KRAS mutations in several malignancies. Known as the ‘holy grail’ of targeted cancer therapies, KRAS is the most frequently mutated oncogene in human malignancies. Under normal conditions, KRAS shuttles between the GDP-bound ‘off’ state and the GTP-bound ‘on’ state. Mutant KRAS is constitutively activated and leads to persistent downstream signaling and oncogenesis. In 2013, improved understanding of KRAS biology and newer drug designing technologies led to the crucial discovery of a cysteine drug-binding pocket in GDP-bound mutant KRAS G12C protein. Covalent inhibitors that block mutant KRAS G12C were successfully developed and sotorasib was the first KRAS G12C inhibitor to be approved, with several more in the pipeline. Simultaneously, effects of KRAS mutations on tumour microenvironment were also discovered, partly owing to the universal use of immune checkpoint inhibitors. In this review, we discuss the discovery, biology, and function of KRAS in human malignancies. We also discuss the relationship between KRAS mutations and the tumour microenvironment, and therapeutic strategies to target KRAS. Finally, we review the current clinical evidence and ongoing clinical trials of novel agents targeting KRAS and shine light on resistance pathways known so far.