BRAF Kinase Inhibitor Research Articles

Dabrafenib and trametinib for the treatment of non-small cell lung cancer

ABSTRACTIntroduction: BRAFV600E mutations occur in 1–2% of lung adenocarcinomas and act as oncogenic drivers via the mitogen-activated protein kinase (MAPK) pathway. These mutations are mutually exclusive from the more common, epidermal growth factor receptor mutations or anaplastic lymphoma kinase rearrangements and have been associated with poor outcomes and a lower response to platinum-based chemotherapy.Areas covered: Dabrafenib is a potent adenosine-triphosphate-competitive inhibitor of BRAF kinase and is selective for the BRAFV600E mutation in kinase panel screening, cell lines, and xenografts. The efficacy and safety of dabrafenib alone or in combination with the MEK inhibitor trametinib has been demonstrated in a number of clinical trials and herein, we discuss this data and outline the current and future role of BRAF/MEK inhibition in the management of advanced lung cancer.Expert commentary: Responses rates with combination of dabrafenib/trametinib are approximately 63–64% and interestingly occur in both smokers and non-smokers but toxicities require dose reductions in the real world for the majority of patients.

In silico drug screening by using genome-wide association study data repurposed dabrafenib, an anti-melanoma drug, for Parkinson's disease.

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by dopaminergic neuron loss. At present, there are no drugs that stop the progression of PD. As with other multifactorial genetic disorders, genome-wide association studies (GWASs) found multiple risk loci for PD, although their clinical significance remains uncertain. Here, we report the identification of candidate drugs for PD by a method using GWAS data and in silico databases. We identified 57 Food and Drug Administration-approved drug families as candidate neuroprotective drugs for PD. Among them, dabrafenib, which is known as a B-Raf kinase inhibitor and is approved for the treatment of malignant melanoma, showed remarkable cytoprotective effects in neurotoxin-treated SH-SY5Y cells and mice. Dabrafenib was found to inhibit apoptosis, and to enhance the phosphorylation of extracellular signal-regulated kinase (ERK), and inhibit the phosphorylation of c-Jun NH2-terminal kinase. Dabrafenib targets B-Raf, and we confirmed a protein–protein interaction between B-Raf and Rit2, which is coded by RIT2, a PD risk gene in Asians and Caucasians. In RIT2-knockout cells, the phosphorylation of ERK was reduced, and dabrafenib treatment improved the ERK phosphorylation. These data indicated that dabrafenib exerts protective effects against neurotoxicity associated with PD. By using animal model, we confirmed the effectiveness of this in silico screening method. Furthermore, our results suggest that this in silico drug screening system is useful in not only neurodegenerative diseases but also other common diseases such as diabetes mellitus and hypertension.

PO-483 Phenotype switching as an escape mechanism to targeted therapies in melanoma

IntroductionMelanoma is an aggressive skin cancer with increasing incidence worldwide. The development of BRAF kinase inhibitors as targeted treatments for patients with BRAF-mutant tumours and the introduction of immunotherapies contributed profoundly to an improved overall survival of patients with metastatic melanoma. Despite these promising results, the emergence of rapid resistance to these therapeutic approaches remains a serious clinical issue.Material and methodsTo investigate the impact of BRAF inhibitors on miRNomes and transcriptomes, we used in vitro melanoma models consisting of BRAF inhibitor-sensitive and -resistant cell lines generated in our laboratory. Subsequently, miRNA and gene expression analyses were performed in order to identify the underlying mechanisms of resistance.Results and discussionsRegarding miRNome and transcriptome changes, the long-term effects of BRAF inhibition differed in a cell line-specific manner with the two different BRAF inhibitors inducing comparable responses in drug-sensitive melanoma cell lines. Despite this heterogeneity, several miRNAs (e.g. miR-100–5 p) and genes (e.g. AXL) were distinctly differentially expressed in drug-resistant versus -sensitive cell lines. Analyses of co-expressed miRNAs, as well as inversely correlated miRNA-mRNA pairs, revealed a switch from a MITFhigh to an AXLhigh ratio in a subset of drug-resistant melanoma cell lines that might be regulated by miRNAs. Additionally, the inhibition of AXL reduces growth of BRAF inhibitor-resistant melanoma cells, thus the combined inhibition of BRAF and AXL might be beneficial for patients with metastatic melanoma.ConclusionIn this study, promising miRNAs and genes were identified and associated to BRAF inhibitor-mediated resistance in melanoma, and might be considered as prognostic and/or diagnostic resistance biomarkers in melanoma drug resistance.

Novel pyrrol-2(3H)-ones and pyridazin-3(2H)-ones carrying quinoline scaffold as anti-proliferative tubulin polymerization inhibitors

A novel quinolinyl pyrrolone and quinolinyl pyridazinone derivatives has been synthesized and characterized using different spectroscopic and elemental analysis techniques. Most of the target compounds displayed promising antiproliferative activity; In general, the pyrrolone derivatives 4a-f exhibited higher antiproliferative activity than their corresponding pyridazinone. The pyrrolone 4f showed outstanding antiproliferative activity with moderate selectivity against CNS and renal cancer with selectivity ratio of 3.49 and 3.56, respectively. Compound 4e and 5d experienced tubulin polymerization inhibitory activity comparable to that of vincristine while 4c, 4e and 4d showed good BRAF kinase inhibition compared to Erlotinib. Docking of compound 4e into colchicine binding site and biological assay results revealed that these compounds act mainly through tubulin polymerization inhibitory mechanism and can exhibit pre G1 apoptosis and cell cycle arrest at G2/M phase.

Surgical rescue of adrenal metastasis by melanoma following treatment with vemurafenib

We report the case of a patient presenting with a single melanoma metastasis in the adrenal gland, who underwent systemic treatment with vemurafenib (BRAF kinase inhibitor) in the first instance and then underwent surgery. Current literature recommends surgical treatment of melanoma metastases and supports the use of inhibitors in patients with a BRAF kinase mutation since they may improve disease control in a more sustained manner over time. Although for many years surgery was the only therapy for stage IV disease, with modern drug therapies, the situation has become more complex; this has created the challenge of determining the optimal combination and appropriate sequence of therapies; in this sense we consider it fundamental that cases such as the one presented here are discussed in tumor committee meetings.

Targeting the MAPK Pathway in RAS Mutant Cancers.

Despite decades of extensive drug discovery efforts, there are currently no targeted therapies approved to treat KRAS mutant cancers. In this review, we highlight the challenges and opportunities in targeting KRAS mutant tumors through inhibition of mitogen-activated protein kinase (MAPK) signaling with conformation-specific kinase inhibitors. Through structural analysis and mechanistic studies with BRAF and mitogen-activated protein kinase (MEK) inhibitors, we describe how kinase-dependent and -independent functions of MAPK signaling components regulate KRAS-driven tumorigenesis and how these insights can be used to treat RAS mutant cancers with small molecule kinase inhibitors.

Assessment of Growth Inhibitory, Cell Cycle Arrest, and Apoptosis Inducing Potential of RAS-MAPK Inhibitors in Gemcitabine-Sensitive Pancreatic Cancer Cells

Event Abstract Back to Event Assessment of growth inhibitory, cell cycle arrest and apoptosis inducing potential of RAS-MAPK inhibitors in gemcitabine-sensitive pancreatic cancer cells Nityaa Selvarajoo1 and Johnson Stanslas1* 1 Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Malaysia Background Pancreatic cancer is an aggressive disease. Although its occurrence rate remains low in Malaysia, it is the third leading cause of cancer-related death in the United States of America because of limited treatment options. Gemcitabine is a standard chemotherapy for pancreatic cancer. Most pancreatic cancers harbour K-Ras mutations that lead to constitutive activation of mitogen-activated protein kinase (MAPK) signalling pathway. The aim of this study was to determine the cell cycle and apoptosis inducing potential of RAS-MAPK inhibitors such as B-Raf kinase inhibitor (vemurafenib), a Mek1/2 kinase inhibitor (selumetinib) and Erk1/2 kinase inhibitor (ulixertinib) in gemcitabine-sensitive pancreatic cancer cell lines. Methods 3-(4,5-Dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used in assessing in vitro growth inhibition of RAS-MAPK inhibitors against pancreatic cancer cell lines (Panc-1 - mutated KRAS, wild-type BRAF, MEK, and ERK; Colo-357 - mutated KRAS and BRAF, wild-type MEK and ERK; Capan-2 - mutated KRAS, wild-type BRAF, MEK, and ERK); Miapaca-2 - mutated KRAS, wild-type BRAF, MEK, and ERK); BxPC-3- wild-type KRAS, BRAF, MEK and ERK). Cells were treated with 0.1-100 µM of RAS-MAPK inhibitors alone or with gemcitabine and the 50% cell viability- inhibition values were obtained from dose-response curves at 96 hours time-point. Subsequently, flow cytometry was utilised to analyse cell cycle arrest, while Muse® Annexin V & Dead Cell Kit (Merck) was performed to determine apoptosis. Results Ulixertinib exhibited strongest inhibitory effect on Capan-2 with an IC50 value of 0.64 µM, while it showed moderate activity (3.2 µM – 7.25 µM) in other pancreatic cancer cell lines. Vemurafenib and selumetinib were less active against all cell lines. Ulixertinib at 1 µM induced G1 cell cycle arrest in Capan-2. In apoptosis assay, treatment with 1 µM induced 29% and 20.3% of early and late apoptotic cells population, respectively. Conclusion The results suggested that Ulixertinib inhibited growth of Capan-2 cells by inducing G1 arrest and apoptosis. It is presented itself as the most active RAS-MAPK inhibitor against the molecularly selected pancreatic cancer cell lines. Keywords: RAS-MAPK inhibitors, gemcitabine, Apoptosis, Pancreatic Cancer, Cell Cycle Conference: International Conference on Drug Discovery and Translational Medicine 2018 (ICDDTM '18) “Seizing Opportunities and Addressing Challenges of Precision Medicine”, Putrajaya, Malaysia, 3 Dec - 5 Feb, 2019. Presentation Type: Poster Presentation Topic: Cancer Citation: Selvarajoo N and Stanslas J (2019). Assessment of growth inhibitory, cell cycle arrest and apoptosis inducing potential of RAS-MAPK inhibitors in gemcitabine-sensitive pancreatic cancer cells. Front. Pharmacol. Conference Abstract: International Conference on Drug Discovery and Translational Medicine 2018 (ICDDTM '18) “Seizing Opportunities and Addressing Challenges of Precision Medicine”. doi: 10.3389/conf.fphar.2018.63.00145 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Sep 2018; Published Online: 17 Jan 2019. * Correspondence: Prof. Johnson Stanslas, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia, rcxjs@upm.edu.my Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Nityaa Selvarajoo Johnson Stanslas Google Nityaa Selvarajoo Johnson Stanslas Google Scholar Nityaa Selvarajoo Johnson Stanslas PubMed Nityaa Selvarajoo Johnson Stanslas Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

7-Azaindole: A Versatile Scaffold for Developing Kinase Inhibitors.

The majority of kinase inhibitors have been developed as ATP competitors to interact with a hinge region in ATP binding sites of kinases. 7-Azaindole has been found as an excellent hinge binding motif by making two hydrogen bonds with the kinase hinge region. Vemurafenib, a B-RAF kinase (serine-threonine kinase [STK]) inhibitor approved by the U.S. Food and Drug Administration (FDA) for the treatment of melanoma, was created from this simple 7-azaindole fragment by successful use of structure-based drug design techniques. The huge potential of 7-azaindole as a hinge-binding motif has encouraged many researchers to employ it as a kinase privileged fragment. This paper will review recent examples of 7-azaindole-based kinase inhibitors, and discusses their binding interactions with the kinase hinge regions.

Dabrafenib plus trametinib for compassionate use in metastatic melanoma: A STROBE-compliant retrospective observational postauthorization study.

The main objective of the study was to evaluate the efficacy and safety of dabrafenib alone or combined with trametinib for compassionate use in patients with metastatic melanoma.This retrospective, observational study involved 135 patients with unresectable stage IIIC or stage IV melanoma from an expanded-access program at 30 Spanish centers.Forty-eight patients received dabrafenib monotherapy and 87 received combination dabrafenib and trametinib; 4.4% and 95.6% of the patients had stage IIIC and IV melanoma, respectively. All patients showed BRAF mutations in their primary or metastatic lesions; 3 were positive for V600K while the remainder had V600E or V600+. A positive response to treatment was reported in 89.3% of the patients. Overall survival rates at 12 and 24 months were 59.6% (95% confidence interval [CI], 52.5–68.9%) and 36.4% (95% CI, 27.8–45%), respectively. Progression-free survival rates at 12 and 24 months were 39.3% (95% CI, 31.1–47.5%) and 21.6% (95% CI, 14.5–28.7%), respectively. Fifty-seven patients (42.2%) reported cutaneous toxicity of any type, mainly hyperkeratosis (14.8%) and rash (11.9%). The most frequent adverse events were pyrexia (27.4%), asthenia (19.3%), arthralgia (16.9%), and diarrhoea (13.2%).Our results suggest that both dabrafenib alone or in combination with trametinib are effective for compassionate use in terms of response and/or survival rates. However, differences in patients’ prognostic features ought to be considered. No new findings were revealed regarding the safety profiles of either regimen. This is the first study to evaluate the efficacy of these 2 selective BRAF and mitogen-activated extracellular signal-regulated kinase inhibitors in a real-world setting in Spain.

Virtual screening of B-Raf kinase inhibitors: A combination of pharmacophore modelling, molecular docking, 3D-QSAR model and binding free energy calculation studies

B-Raf kinase has been identified as an important target in recent cancer treatment. In order to discover structurally diverse and novel B-Raf inhibitors (BRIs), a virtual screening of BRIs against ZINC database was performed by using a combination of pharmacophore modelling, molecular docking, 3D-QSAR model and binding free energy (ΔGbind) calculation studies in this work. After the virtual screening, six promising hit compounds were obtained, which were then tested for inhibitory activities of A375 cell lines. In the result, five hit compounds show good biological activities (IC50<50μM). The present method of virtual screening can be applied to find structurally diverse inhibitors, and the obtained five structurally diverse compounds are expected to develop novel BRIs.

Abstract 158: ASN003, a highly selective inhibitor of B-Raf and PI3 kinases, shows strong antitumor activity in B-Raf inhibitor resistant patient-derived xenograft models

Abstract The RAS-RAF-MEK and PI3K-AKT-mTOR pathways are two major signaling pathways involved in human cancer. Components of these two pathways are frequently mutated in a wide variety of solid tumors. Concurrent double mutations in the two pathways are also observed quite often in a broad range of tumor types. Additionally, inhibition of one of these pathways often leads to the upregulation of the other pathway and development of resistance. In preclinical models, combined inhibition of both pathways has been shown to impart greater efficacy as compared to inhibition of either pathway alone. ASN003 is a novel, highly selective, small-molecule inhibitor of both RAS-RAF and PI3K pathways, discovered using a rational design approach. ASN003 shows potent inhibitory activity against B-RAF and PI3K kinases (low nM IC50). Within the PI3K family, ASN003 has high selectivity for inhibition of PI3Kα and PI3Kδ over PI3Kβ. In a panel of 292 kinases, ASN003 showed high selectivity for inhibiting B-RAF and PI3 kinases, and associated mutant kinases. In cell-based mechanistic studies, ASN003 inhibited phosphorylation of ERK, AKT and S6, and showed strong antiproliferative activity (IC50 = 60-300 nM) in cell lines with B-RAF and PI3K pathway mutations as well as in vemurafenib-resistant cell lines. In pharmacodynamic studies in multiple tumor models, ASN003 showed strong inhibition of the phosphorylation of downstream targets of B-RAF and PI3K, confirming appropriate target engagement. In in vivo efficacy studies, ASN003 showed strong tumor growth inhibition or regression in multiple tumor xenograft models, including A375 (B-Raf V600E mutation), RKO (B-Raf V600E and PIK3CA mutations), and A2058 (B-Raf V600E mutation and PTEN loss). We now report that ASN003 also showed strong tumor growth inhibition (&amp;gt;80%) in a patient-derived xenograft (PDX) model established from a relapsed patient with progressive B-Raf mutant melanoma who showed initial response to vemurafenib. Sequencing analysis showed that the vemurafenib resistant tumor acquired a concurrent PIK3CA mutation. Dual targeting of the B-RAF and PI3K pathways with ASN003 has the potential to treat and/or prevent the acquired resistance to selective B-RAF inhibitors, and may also treat a broader patient population and provide greater efficacy and survival benefit than selective B-RAF inhibitors or selective PI3K pathway inhibitors alone. ASN003 is currently in Phase I clinical development in patients with advanced solid tumors, including tumors with B-Raf V600 mutation, PI3 kinase pathway alterations or PTEN loss. Citation Format: Scott K. Thompson, Roger A. Smith, Niranjan Rao, Michael J. Wick, Sanjeeva P. Reddy. ASN003, a highly selective inhibitor of B-Raf and PI3 kinases, shows strong antitumor activity in B-Raf inhibitor resistant patient-derived xenograft models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 158. doi:10.1158/1538-7445.AM2017-158

Overcoming resistance to targeted therapy with immunotherapy and combination therapy for metastatic melanoma.

Resistance to targeted therapy is an ongoing problem for the successful treatment of Stage IV metastatic melanoma. For many patients, the use of targeted therapies, such as BRAF kinase inhibitors, were initially promising yet resistance inevitably occurred. Even after combining BRAF kinase inhibitors with MEK pathway inhibitors to offset re-activation of the MAP kinase pathway, resistance is still documented. Similarly, outcomes with immune checkpoint inhibitors as monotherapy were optimistic for some patients without relapse or progression, yet the majority of patients undergoing monotherapy have progressive disease. Will immunotherapy and combination therapy trials overcome resistance in metastatic melanoma? In an effort to treat resistant disease, new clinical trials evaluating the combination of immunotherapy with other therapies, such as kinase inhibitors, adoptive cell therapy, chimeric CD40 ligand to boost costimulation, or a tumor-specific oncolytic virus enhancing granulocyte macrophage colony-stimulating factor (GM-CSF) expression, are currently underway. Updated studies on the mechanisms of resistance, immune escape and options to reinvigorate immune cells support the continued discovery of new and improved forms of therapy.

ROS production induced by BRAF inhibitor treatment rewires metabolic processes affecting cell growth of melanoma cells

BackgroundMost melanoma patients with BRAFV600E positive tumors respond well to a combination of BRAF kinase and MEK inhibitors. However, some patients are intrinsically resistant while the majority of patients eventually develop drug resistance to the treatment. For patients insufficiently responding to BRAF and MEK inhibitors, there is an ongoing need for new treatment targets. Cellular metabolism is such a promising new target line: mutant BRAFV600E has been shown to affect the metabolism.MethodsTime course experiments and a series of western blots were performed in a panel of BRAFV600E and BRAFWT/NRASmut human melanoma cells, which were incubated with BRAF and MEK1 kinase inhibitors. siRNA approaches were used to investigate the metabolic players involved. Reactive oxygen species (ROS) were measured by confocal microscopy and AZD7545, an inhibitor targeting PDKs (pyruvate dehydrogenase kinase) was tested.ResultsWe show that inhibition of the RAS/RAF/MEK/ERK pathway induces phosphorylation of the pyruvate dehydrogenase PDH-E1α subunit in BRAFV600E and in BRAFWT/NRASmut harboring cells. Inhibition of BRAF, MEK1 and siRNA knock-down of ERK1/2 mediated phosphorylation of PDH. siRNA-mediated knock-down of all PDKs or the use of DCA (a pan-PDK inhibitor) abolished PDH-E1α phosphorylation. BRAF inhibitor treatment also induced the upregulation of ROS, concomitantly with the induction of PDH phosphorylation. Suppression of ROS by MitoQ suppressed PDH-E1α phosphorylation, strongly suggesting that ROS mediate the activation of PDKs. Interestingly, the inhibition of PDK1 with AZD7545 specifically suppressed growth of BRAF-mutant and BRAF inhibitor resistant melanoma cells.ConclusionsIn BRAFV600E and BRAFWT/NRASmut melanoma cells, the increased production of ROS upon inhibition of the RAS/RAF/MEK/ERK pathway, is responsible for activating PDKs, which in turn phosphorylate and inactivate PDH. As part of a possible salvage pathway, the tricarboxylic acid cycle is inhibited leading to reduced oxidative metabolism and reduced ROS levels. We show that inhibition of PDKs by AZD7545 leads to growth suppression of BRAF-mutated and -inhibitor resistant melanoma cells. Thus small molecule PDK inhibitors such as AZD7545, might be promising drugs for combination treatment in melanoma patients with activating RAS/RAF/MEK/ERK pathway mutations (50% BRAF, 25% NRASmut, 11.9% NF1mut).

A phase Ib/II dose-escalation study evaluating triple combination therapy with a BRAF (encorafenib), MEK (binimetinib), and CDK 4/6 (ribociclib) inhibitor in patients (Pts) with BRAF V600-mutant solid tumors and melanoma.

9518 Background: The benefits of BRAF + MEK inhibition (dual combo) in pts with BRAF V600-mutant ( BRAFV600) melanoma are known. Preclinical data supports inhibiting CDK 4/6 and BRAF + MEK (triple combo) to improve antitumor activity. We report safety and preliminary efficacy from a phase 1b/2 study (NCT01543698) of encorafenib (ENCO; a selective BRAF kinase inhibitor), binimetinib (BINI; a MEK inhibitor), and ribociclib (RIBO; a CDK 4/6 inhibitor). Methods: Phase 1b of this open-label, multicenter study enrolled pts with confirmed BRAFV600advanced solid tumors. Escalating doses of RIBO 100 mg-600 mg QD for 3 wk on/1 wk off were administered with ENCO 200 mg QD + BINI 45 mg BID in successive cohorts (6 pts each) until the maximum tolerated or recommended phase 2 dose (RP2D) was reached. Due to potential pharmacokinetic interactions with RIBO, the ENCO dose was lower than the dual combo RP2D (450 mg QD). Dose escalations followed an adaptive Bayesian model. In phase 2, the triple combo was tested in pts with BRAFV600melanoma naïve to prior BRAF inhibitor treatment; the primary endpoint was objective response rate (ORR) per RECIST v1.1. Results: In phase 1b (n = 21), no dose-limiting toxicities were reported and the triple combo RP2D was ENCO 200 mg QD + BINI 45 mg BID + RIBO 600 mg QD. ENCO AUC was slightly lower than at the dual combo RP2D. In phase 2 (n = 42), 59.5% pts had an ECOG PS of 0 and 43% of pts had elevated lactate dehydrogenase. The most common (≥5%) grade 3/4 toxicities were neutropenia (26.2%), increased alanine transaminase (14.3%), diarrhea (7.1%), and anemia (7.1%). Ten pts (23.8%) discontinued treatment due to an AE, of which 4 were increased transaminases. The confirmed ORR was 52.4%, including 4 complete responses, 18 partial responses, and 15 pts with stable disease. Median duration of exposure in phase 2 was 9.1 mo (range, 0.0-21.6). Median progression-free survival was 9.0 mo (95% confidence interval, 7.0-11.1). Conclusions: Triple therapy with ENCO + BINI + RIBO in this small trial of pts with high disease burden was associated with responses in over half of pts and some evidence of increased toxicity. Clinical trial information: NCT01543698.

BEACON CRC (binimetinib [BINI], encorafenib [ENCO], and cetuximab [CTX] combined to treat BRAF-mutant metastatic colorectal cancer [mCRC]): A multicenter, randomized, open-label, three-arm phase III study of ENCO plus CTX plus or minus BINI vs irinotecan (IRI)/CTX or infusional 5-fluorouracil/folinic acid/IRI (FOLFIRI)/CTX with a safety lead-in of ENCO + BINI + CTX in patients (Pts) with BRAFV600E mCRC.

TPS3622 Background: BRAF mutations are found in ≈10% of mCRC cases. Pts with BRAFV600E mCRC have a poor prognosis, with shorter progression-free survival (PFS) and overall survival (OS) than pts with BRAFwt mCRC (Van Cutsem et al 2011; Modest et al 2012; Sorbye et al 2015). The benefits of combined BRAF + EGFR inhibition in mCRC have been demonstrated in vitro (Corcoran et al 2012; Prahallad et al 2012; Yang et al 2012), and preclinical evidence suggests that adding MEK signaling inhibition improves antitumor activity. Early clinical data indicate that BRAF + EGFR + MEK inhibition has greater activity than BRAF + EGFR inhibition in pts with BRAFV600E mCRC (Van Cutsem et al 2016). Our study will examine the combination of BINI (a MEK inhibitor) + ENCO (a selective BRAF kinase inhibitor) + CTX (an anti-EGFR antibody) and of ENCO + CTX in pts with BRAFV600E mCRC. Methods: BEACON CRC (NCT02928224) is enrolling pts with BRAFV600E mCRC whose disease has progressed after 1 or 2 prior regimens in the metastatic setting. A safety lead-in phase (≈30 pts) will determine the safety and tolerability of oral ENCO 300 mg QD + oral BINI 45 mg BID + intravenous CTX 400 mg/m2 followed by 250 mg/m2 QW. In the phase 3 portion, ≈615 pts will be randomized 1:1:1 to triplet (ENCO + BINI + CTX), doublet (ENCO + CTX), or control (investigator’s choice of IRI/CTX or FOLFIRI/CTX) arms. Pts will be treated in 28-day cycles until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, or death. The primary endpoint is OS (triplet vs control). Secondary endpoints include OS (doublet vs control), confirmed investigator-assessed objective response rate according to RECIST version 1.1 (triplet or doublet vs control; triplet vs doublet), PFS (triplet or doublet vs control), duration of response, time to response, pharmacokinetics, and pt-reported outcomes. Safety will be summarized using standard adverse event reporting. Clinical trial information: NCT02928224.

Open-label, multicentre safety study of vemurafenib in 3219 patients with BRAFV600 mutation-positive metastatic melanoma: 2-year follow-up data and long-term responders' analysis

BackgroundThe orally available BRAF kinase inhibitor vemurafenib is an effective and tolerable treatment option for patients with metastatic melanoma harbouring BRAFV600 mutations. We assessed the safety of vemurafenib in a large population of patients with few alternative treatment options; we report updated 2-year safety. MethodsThis was an open-label, multicentre study of vemurafenib (960 mg bid) in patients with previously treated or untreated BRAF mutation-positive metastatic melanoma (cobas® 4800 BRAF V600 Mutation Test). The primary end-point was safety; efficacy end-points were secondary. An exploratory analysis was performed to assess safety outcomes in patients with long duration of response (DOR) (≥12 or ≥24 months). ResultsAfter a median follow-up of 32.2 months (95% CI, 31.1–33.2 months), 3079/3219 patients (96%) had discontinued treatment. Adverse events (AEs) were largely consistent with previous reports; the most common all-grade treatment-related AEs were arthralgia (37%), alopecia (25%) and hyperkeratosis (23%); the most common grade 3/4 treatment-related AEs were squamous cell carcinoma of the skin (8%) and keratoacanthoma (8%). In the exploratory analysis, patients with DOR ≥12 months (n = 287) or ≥24 months (n = 133) were more likely to experience grade 3/4 AEs than the overall population. No new specific safety signals were observed with longer vemurafenib exposure. ConclusionsAfter 2 years' follow-up, safety was maintained in this large group of patients with BRAFV600 mutation-positive metastatic melanoma who are more representative of routine clinical practice than typical clinical trial populations. These data suggest that long-term vemurafenib treatment is effective and tolerable without the development of new safety signals.

Impact of BRAF kinase inhibitors on the miRNomes and transcriptomes of melanoma cells

BackgroundMelanoma is an aggressive skin cancer with increasing incidence worldwide. The development of BRAF kinase inhibitors as targeted treatments for patients with BRAF-mutant tumours contributed profoundly to an improved overall survival of patients with metastatic melanoma. Despite these promising results, the emergence of rapid resistance to targeted therapy remains a serious clinical issue. MethodsTo investigate the impact of BRAF inhibitors on miRNomes and transcriptomes, we used in vitro melanoma models consisting of BRAF inhibitor-sensitive and -resistant cell lines generated in our laboratory. Subsequently, microarray analyses were performed followed by RT-qPCR validations. ResultsRegarding miRNome and transcriptome changes, the long-term effects of BRAF inhibition differed in a cell line-specific manner with the two different BRAF inhibitors inducing comparable responses in three melanoma cell lines. Despite this heterogeneity, several miRNAs (e.g. miR-92a-1-5p, miR-708-5p) and genes (e.g. DOK5, PCSK2) were distinctly differentially expressed in drug-resistant versus -sensitive cell lines. Analyses of coexpressed miRNAs, as well as inversely correlated miRNA-mRNA pairs, revealed a low MITF/AXL ratio in two drug-resistant cell lines that might be regulated by miRNAs. ConclusionSeveral genes and miRNAs were differentially regulated in the drug-resistant and -sensitive cell lines and might be considered as prognostic and/or diagnostic resistance biomarkers in melanoma drug resistance. General significanceThus far, only little information is available on the significance and role of miRNAs with respect to kinase inhibitor treatments and emergence of drug resistance. In this study, promising miRNAs and genes were identified and associated to BRAF inhibitor-mediated resistance in melanoma. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O’Donoghue.

Metastatic BRAF K601E-mutated melanoma reaches complete response to MEK inhibitor trametinib administered for over 36\xa0months

BackgroundThe BRAF K601E mutation occurs in 5% of patients with melanoma, and is the third most common type of BRAF mutation. However, treatment with BRAF and mitogen-activated extracellular signal-regulated kinase (MEK) inhibitors is only approved in patients with BRAF V600-positive melanoma, and patients with K601E-mutated melanoma do not have access to such drugs.Case presentationA female patient was diagnosed with high tumor burden metastatic melanoma harboring the BRAF K601E mutation. After chemotherapy failure, she underwent compassionate treatment with trametinib. Trametinib showed good activity and efficacy, with 48% shrinkage of a metastatic lymphadenopathy after 4 months’ treatment. However, the patient reported treatment-related skin toxicity that required dosage reduction and a personalized intermittent trametinib dosing schedule. After over 36 months from the first trametinib administration, and resection of a metastatic lymphadenopathy, the patient experienced complete response.ConclusionsThis case report shows that trametinib could be a valid therapeutic option in patients with metastatic melanoma harboring the rare BRAF K601E mutation.

Clinical Pharmacokinetics of Vemurafenib.

Vemurafenib is an orally administered small-molecule inhibitor of the oncogenic BRAF kinase that is indicated for the treatment of patients with unresectable or metastatic melanoma harbouring BRAF V600 mutations. Vemurafenib is absorbed rapidly after a single oral dose of 960mg, reaching maximum drug concentration approximately 4h after administration. Extensive accumulation occurs after multiple dosing at 960mg twice daily. Steady state is achieved after approximately 15-21days and exposure at steady state is relatively constant. Population pharmacokinetic analysis identified a vemurafenib half-life of ≈57h and elimination appears to be predominantly via the hepatic route. Pharmacokinetic parameters are generally consistent regardless of age, sex or race. No dose adjustments are necessary for patients with mild or moderate hepatic or renal impairment, but the effects of severe hepatic or renal impairment on vemurafenib pharmacokinetics are uncertain. Vemurafenib appears to be a substrate and inducer of cytochrome P450 (CYP) 3A4, a moderate inhibitor of CYP1A2 and both a substrate and inhibitor of the drug efflux transporters P-glycoprotein and breast cancer resistance protein. The relationship between plasma vemurafenib concentrations and response remains to be clarified.

Oncolytic virotherapy including Rigvir and standard therapies in malignant melanoma.

The treatment of metastatic melanoma has evolved from an era where interferon and chemotherapy were the mainstay of treatments to an era where immunotherapy has become the frontline. Ipilimumab (IgG1 CTLA-4 inhibitor), nivolumab (IgG4 PD-1 inhibitor), pembrolizumab (IgG4 PD-1 inhibitor) and nivolumab combined with ipilimumab have become first-line therapies in patients with metastatic melanoma. In addition, the high prevalence of BRAF mutations in melanoma has led to the discovery and approval of targeted molecules, such as vemurafenib (BRAF kinase inhibitor) and trametinib (MEK inhibitor), as they yielded improved responses and survival in malignant melanoma patients. This is certainly a burgeoning time in immunotherapy drug development, and the aforementioned efforts along with the recent US Food and Drug Administration approval of talimogene laherparepvec (T-VEC), a recombinant oncolytic herpes virus, have paved the way to exploring the role of additional oncolytic viruses, such as the echovirus Rigvir, as new and innovative treatment modalities in patients with melanoma. Herein, we discuss the current standard of care treatment in melanoma with an emphasis on immunotherapy and oncolytic viruses in development.