An overview of experimental and investigational multikinase inhibitors for the treatment of metastatic colorectal cancer

Predicting drug response and toxicity in metastatic colorectal cancer: the role of germline markers

INTRODUCTION

Despite the introduction of targeted agents leading to therapeutic advances, clinical management of patients with metastatic colorectal cancer (mCRC) is still challenged by significant interindividual variability in treatment outcomes, both in terms of toxicity and therapy efficacy. The study of germline genetic variants could help to personalize and optimize therapeutic approaches in mCRC.

AREAS COVERED

A systematic review of pharmacogenetic studies in mCRC patients published on PubMed between 2011 and 2021, evaluating the role of germline variants as predictive markers of toxicity and efficacy of drugs currently approved for treatment of mCRC, was perfomed.

EXPERT OPINION

Despite the large amount of pharmacogenetic data published to date, only a few genetic markers (i.e., DPYD and UGT1A1 variants) reached the clinical practice, mainly to prevent the toxic effects of chemotherapy. The large heterogeneity of available studies represents the major limitation in comparing results and identifying potential markers for clinical use, the role of which remains exploratory in most cases. However, the available published findings are an important starting point for future investigations. They highlighted new promising pharmacogenetic markers within the network of inflammatory and immune response signaling. In addition, the emerging role of previously overlooked rare variants has been pointed out.

Cocrystals of regorafenib with dicarboxylic acids: synthesis, characterization and property evaluation

Three cocrystals of regorafenib were synthesized, and two of them demonstrate significantly improved solubility and tabletability without compromising physicochemical stability.

Genetic Markers of the Host to Predict the Efficacy of Colorectal Cancer Targeted Therapy

The introduction of anti-EGFR (cetuximab and panitumumab) and antiangiogenic (bevacizumab, regorafeninb, ramucirumab, and aflibercept) agents in the therapeutic armamentarium of the metastatic colorectal cancer (CRC) has significantly improved the therapeutic efficacy and patients survival. However, despite the great improvements achieved in the patients life expectation, the high inter-individual heterogeneity in the response to the targeted agents still represent an issue for the management of advanced CRC patients. Even if the role of tumor genetic mutations as predictive markers of drug efficacy has been well-established, the contribution of the host genetic markers is still controversial. Promising results regard the germ-line immune-profile, inflammation and tumor microenvironment. Inherent variations in KRAS 3'UTR region as well as EGF/ EGFR genes were investigated as markers of cetuximab effectiveness. More recently interesting data in the field of anti- EGFR agents were generated also for germ-line variants in genes involved in inflammation (e.g. COX-2, LIFR, IGF1 signaling), immune system (e.g., FCGRs, IL-1RA), and other players of the RAS signaling, including the Hippo pathway related genes (e.g. Rassf, YAP, TAZ). Host genetic variants in VEGF-dependent (i.e., EGF, IGF-1, HIF1α, eNOS, iNOS) and -independent (i.e., EMT cascade, EGFL7) pathways, with specific attention on inflammation and immune system-related factors (e.g., IL-8, CXCR-1/2, CXCR4-CXCL12 axis, TLRs, GADD34, PPP1R15A, ANXA11, MKNK1), were investigated as predictive markers of bevacizumab outcome, generating some promising results. In this review, we aimed to summarize the most recent literature data regarding the potential role of common and rare inhered variants in predicting which CRC patients will benefit more from a specifically targeted drug administration.

Pharmacogenomics of Targeted Agents for Personalization of Colorectal Cancer Treatment

The use of targeted agents in the treatment of metastatic colorectal cancer (CRC) has improved patient outcomes. Anti-epidermal growth factor receptor (anti-EGFR) agents (cetuximab and panitumumab) and antiangiogenic molecules (bevacizumab, regorafeninb, ramucirumab, and aflibercept) have been successfully integrated into clinical practice. Other drugs have been designed to target additional deregulated pathways in CRC, such as MAPK (mitogen-activated protein kinase)/PI3K-AKT (phosphatidylinositol-3-kinase-AKT serine/threonine kinase)/mTOR (mammalian target of rapamycin), HER-2 and 3 ( human epidermal growth factor receptor-2 and -3), and BRAF. A major issue with targeted treatment is early identification of patients with primary or secondary drug resistance. Pharmacogenomic research has demonstrated its value in this field, highlighting some tumor mutations that could discriminate responders from non-responders. The tumor genetic profile of the RAS/RAF pathway is needed before treatment with anti-EGFR agents; mutations in EGFR pathway genes have also been explored in relation to antiangiogenic molecules although further data are required prior to their integration into clinical practice. The introduction of immunotherapy has paved the way for a new generation of predictive markers, including genome-wide assessment of the tumor landscape. Furthermore, the development of next generation sequencing technology and non-invasive approaches to analyze circulating tumor DNA will make real-time monitoring of the tumor pharmacogenomic markers possible in the clinical routine, rendering precision medicine available to every patient.

Receptor tyrosine kinase inhibition by regorafenib/sorafenib inhibits growth and invasion of meningioma cells

Systemic chemotherapeutic treatment for unresectable and/or aggressive meningiomas is still unsatisfying. PDGF receptor (PDGFR)-mediated activation of mitogenic signalling has been shown to be active in meningiomas. Therefore, we evaluate in vitro and in vivo the effects of inhibiting PDGFR using the clinically well-characterised tyrosine kinase inhibitors sorafenib or regorafenib in meningioma models. IOMM-Lee meningioma cells were used to assess cytotoxic effects, inhibition of proliferation, induction of apoptosis, as well as inhibition of migration and motility by sorafenib and regorafenib. Using an orthotopic mouse xenograft model, growth inhibition as monitored by magnetic resonance imaging, and overall survival of sorafenib- or regorafenib-treated mice compared with control animals was determined. Treatment of malignant IOMM-Lee cells resulted in significantly reduced cell survival and induction of apoptosis following regorafenib and sorafenib treatment. Western blots showed that both drugs target phosphorylation of p44/42 ERK via downregulation of the PDGFR. Both drugs additionally showed significant inhibition of cell motility and invasion. In vivo, mice with orthotopic meningioma xenografts showed a reduced volume (n.s.) of signal enhancement in MRI (mainly tumour) following sorafenib and regorafenib treatment. This was translated in a significantly increased overall survival time (p ≤ 0.05) for regorafenib-treated mice. Analyses of in vivo-grown tumours demonstrated again reduced PDGFR expression and expression/phosphorylation of p44/42. Sorafenib and regorafenib show antitumour activity in vitro and in vivo by targeting PDGFR and p44/42 ERK signalling.