Abstract CT019: A phase I trial of the combination of the dual RAF-MEK inhibitor VS-6766 and the FAK inhibitor defactinib: Evaluation of efficacy in KRAS mutated NSCLC

Epithelial-mesenchymal transition status is a remarkable biomarker for the combination treatment with avutometinib and defactinib in KRAS-mutated non-small cell lung cancer

BACKGROUND

Recent therapeutic strategies for KRAS-mutated cancers that inhibit the MAPK pathway have attracted considerable attention. The RAF/MEK clamp avutometinib (VS-6766/CH5126766/RO5126766/CKI27) is promising for patients with KRAS-mutated cancers. Although avutometinib monotherapy has shown clinical activity in patients with KRAS-mutated cancers, effective combination strategies will be important to develop.

METHODS

Using a phosphorylation kinase array kit, we explored the feedback mechanism of avutometinib in KRAS-mutated NSCLC cells, and investigated the efficacy of combining avutometinib with inhibitors of the feedback signal using in vitro and in vivo experiments. Moreover, we searched for a biomarker for the efficacy of combination therapy through an in vitro study and analysis using the The Cancer Genome Atlas Programme dataset.

RESULTS

Focal adhesion kinase (FAK) phosphorylation/activation was increased after avutometinib treatment and synergy between avutometinib and FAK inhibitor, defactinib, was observed in KRAS-mutated NSCLC cells with an epithelial rather than mesenchymal phenotype. Combination therapy with avutometinib and defactinib induced apoptosis with upregulation of Bim in cancer cells with an epithelial phenotype in an in vitro and in vivo study.

CONCLUSIONS

These results demonstrate that the epithelial-mesenchymal transition status may be a promising biomarker for the efficacy of combination therapy with avutometinib and defactinib in KRAS-mutated NSCLC.

Emerging Targeted Therapies in Advanced Non-Small-Cell Lung Cancer

Lung cancer remains the leading cause of cancer-related mortality worldwide. Non-small-cell lung cancer (NSCLC) is the most common type and is still incurable for most patients at the advanced stage. Targeted therapy is an effective treatment that has significantly improved survival in NSCLC patients with actionable mutations. However, therapy resistance occurs widely among patients leading to disease progression. In addition, many oncogenic driver mutations in NSCLC still lack targeted agents. New drugs are being developed and tested in clinical trials to overcome these challenges. This review aims to summarize emerging targeted therapy that have been conducted or initiated through first-in-human clinical trials in the past year.

Development of Combination Strategies for Focal Adhesion Kinase Inhibition in Diffuse Gastric Cancer

PURPOSE

Diffuse gastric cancer (DGC) is an aggressive and frequently lethal subtype of gastric cancer. Because DGC often lacks genomic aberrations that indicate clear candidate therapeutic targets, it has been challenging to develop targeted therapies for this gastric cancer subtype. Our previous study highlighted the contribution of focal adhesion kinase (FAK) in the tumorigenesis of DGC and the potential efficacy of small-molecule FAK inhibitors. However, drug resistance to monotherapy often hinders the efficacy of treatment.

EXPERIMENTAL DESIGN

We generated a genome-scale library of open reading frames (ORF) in the DGC model of Cdh1-/-RHOAY42C/+ organoids to identify candidate mechanisms of resistance to FAK inhibition. Compensatory activated pathways were also detected following treatment with FAK inhibitors. Candidates were investigated by cotargeting in vitro and in vivo experiments using DGC.

RESULTS

We found that cyclin-dependent kinase 6 (CDK6) promoted FAK inhibitor resistance in ORF screen. In addition, FAK inhibitor treatment in DGC models led to compensatory MAPK pathway activation. Small-molecule CDK4/6 inhibitors or MAPK inhibitors effectively enhanced FAK inhibitor efficacy in vitro and in vivo.

CONCLUSIONS

Our data suggest that FAK inhibitors combined with MAPK inhibitors or CDK4/6 inhibitors warrant further testing in clinical trials for DGC.

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.

Single agent VS-6766 or VS-6766 plus defactinib in KRAS-mutant non-small-cell lung cancer: the RAMP-202 phase II trial

KRAS mutations occur in approximately 30% of lung adenocarcinomas, mainly in codon 12 (83% of cases), p.G12C being the prevalent one (40%), followed by p.G12V and p.G12D (22 and 16%, respectively). Treatment options for advanced KRAS mutant non-small-cell lung cancer (KRAS-MT NSCLC) are limited to chemotherapy and immune checkpoint inhibitors (CPIs). However, clinical trials exploring specific targeted agents are expected to change the treatment landscape of this disease. Here, we describe the design and scientific rationale of the randomized, phase II, open label, RAMP-202 study, which will evaluate the efficacy and safety of VS-6766 versus VS-6766 in combination with defactinib in advanced KRAS-MT NSCLC patients after failure of prior platinum-based chemotherapy and CPI.