Christopher Moy

Activity of the oral MEK inhibitor trametinib in patients with advanced melanoma: a phase 1 dose-escalation trial

BACKGROUND MEK is a member of the MAPK signalling cascade that is commonly activated in melanoma. Direct inhibition of MEK blocks cell proliferation and induces apoptosis. We aimed to analyse safety, efficacy, and genotyping data for the oral, small-molecule MEK inhibitor trametinib in patients with melanoma. METHODS We undertook a multicentre, phase 1 three-part study (dose escalation, cohort expansion, and pharmacodynamic assessment). The main results of this study are reported elsewhere; here we present data relating to patients with melanoma. We obtained tumour samples to assess BRAF mutational status, and available tissues underwent exploratory genotyping analysis. Disease response was measured by Response Evaluation Criteria in Solid Tumors, and adverse events were defined by common toxicity criteria. This study is registered with ClinicalTrials.gov, number NCT00687622. FINDINGS 97 patients with melanoma were enrolled, including 81 with cutaneous or unknown primary melanoma (36 BRAF mutant, 39 BRAF wild-type, six BRAF status unknown), and 16 with uveal melanoma. The most common treatment-related adverse events were rash or dermatitis acneiform (n=80; 82%) and diarrhoea (44; 45%), most of which were grade 2 or lower. No cutaneous squamous-cell carcinomas were recorded. Of 36 patients with BRAF mutations, 30 had not received a BRAF inhibitor before; two complete responses (both confirmed) and ten partial responses (eight confirmed) were noted in this subgroup (confirmed response rate, 33%). Median progression-free survival of this subgroup was 5·7 months (95% CI 4·0-7·4). Of the six patients who had received previous BRAF inhibition, one unconfirmed partial response was recorded. Of 39 patients with BRAF wild-type melanoma, four partial responses were confirmed (confirmed response rate, 10%). INTERPRETATION Our data show substantial clinical activity of trametinib in melanoma and suggest that MEK is a valid therapeutic target. Differences in response rates according to mutations indicate the importance of mutational analyses in the future. FUNDING GlaxoSmithKline.

Comprehensive Predictive Biomarker Analysis for MEK Inhibitor GSK1120212

The MEK1 and MEK2 inhibitor GSK1120212 is currently in phase II/III clinical development. To identify predictive biomarkers, sensitivity to GSK1120212 was profiled for 218 solid tumor cell lines and 81 hematologic malignancy cell lines. For solid tumors, RAF/RAS mutation was a strong predictor of sensitivity. Among RAF/RAS mutant lines, co-occurring PIK3CA/PTEN mutations conferred a cytostatic response instead of a cytotoxic response for colon cancer cells that have the biggest representation of the comutations. Among KRAS mutant cell lines, transcriptomics analysis showed that cell lines with an expression pattern suggestive of epithelial-to-mesenchymal transition were less sensitive to GSK1120212. In addition, a proportion of cell lines from certain tissue types not known to carry frequent RAF/RAS mutations also seemed to be sensitive to GSK1120212. Among these were breast cancer cell lines, with triple negative breast cancer cell lines being more sensitive than cell lines from other breast cancer subtypes. We identified a single gene DUSP6, whose expression was associated with sensitivity to GSK1120212 and lack of expression associated with resistance irrelevant of RAF/RAS status. Among hematologic cell lines, acute myeloid leukemia and chronic myeloid leukemia cell lines were particularly sensitive. Overall, this comprehensive predictive biomarker analysis identified additional efficacy biomarkers for GSK1120212 in RAF/RAS mutant solid tumors and expanded the indication for GSK1120212 to patients who could benefit from this therapy despite the RAF/RAS wild-type status of their tumors. Mol Cancer Ther; 11(3); 720–9. ©2011 AACR.

Sensitivity of Cancer Cells to Plk1 Inhibitor GSK461364A Is Associated with Loss of p53 Function and Chromosome Instability

Polo-like kinases are a family of serine threonine kinases that are critical regulators of cell cycle progression and DNA damage response. Predictive biomarkers for the Plk1-selective inhibitor GSK461364A were identified by comparing the genomics and genetics of a panel of human cancer cell lines with their response to a drug washout followed by an outgrowth assay. In this assay, cell lines that have lost p53 expression or carry mutations in the TP53 gene tended to be more sensitive to GSK461364A. These more sensitive cell lines also had increased levels of chromosome instability, a characteristic associated with loss of p53 function. Further mechanistic studies showed that p53 wild-type (WT) and not mutant cells can activate a postmitotic tetraploidy checkpoint and arrest at pseudo-G1 state after GSK461364A treatment. RNA silencing of WT p53 increased the antiproliferative activity of GSK461364A. Furthermore, silencing of p53 or p21/CDKN1A weakened the tetraploidy checkpoint in cells that survived mitotic arrest and mitotic slippage. As many cancer therapies tend to be more effective in p53 WT patients, the higher sensitivity of p53-deficient tumors toward GSK461364A could potentially offer an opportunity to treat tumors that are refractory to other chemotherapies as well as early line therapy for these genotypes. Mol Cancer Ther; 9(7); 2079–89. ©2010 AACR.

Mitogen-activated protein kinase (MEK/ERK) inhibition sensitizes cancer cells to centromere-associated protein E inhibition

Inhibition of centromere‐associated protein‐E (CENP‐E) has demonstrated preclinical anti‐tumor activity in a number of tumor types including neuroblastoma. A potent small molecule inhibitor of the kinesin motor activity of CENP‐E has recently been developed (GSK923295). To identify an effective drug combination strategy for GSK923295 in neuroblastoma, we performed a screen of siRNAs targeting a prioritized set of genes that function in therapeutically tractable signaling pathways. We found that siRNAs targeted to extracellular signal‐related kinase 1 (ERK1) significantly sensitized neuroblastoma cells to GSK923295‐induced growth inhibition (p = 0.01). Inhibition of ERK1 activity using pharmacologic inhibitors of mitogen‐activated ERK kinase (MEK1/2) showed significant synergistic growth inhibitory activity when combined with GSK923295 in neuroblastoma, lung, pancreatic and colon carcinoma cell lines. Synergistic growth inhibitory activity of combined MEK/ERK and CENP‐E inhibition was a result of increased mitotic arrest and apoptosis. There was a significant correlation between ERK1/2 phosphorylation status in neuroblastoma cell lines and GSK923295 growth inhibitory activity (r = 0.823, p = 0.0006). Consistent with this result we found that lung cancer cell lines harboring RAS mutations, which leads to oncogenic activation of MEK/ERK signaling, were significantly more resistant than cell lines with wild‐type RAS to GSK923295‐induced growth inhibition (p = 0.047). Here we have identified (MEK/ERK) activity as a potential biomarker of relative GSK923295 sensitivity and have shown the synergistic effect of combinatorial MEK/ERK pathway and CENP‐E inhibition across different cancer cell types including neuroblastoma.

High chromosome number in hematological cancer cell lines is a negative predictor of response to the inhibition of Aurora B and C by GSK1070916.

BackgroundAurora kinases play critical roles in mitosis and are being evaluated as therapeutic targets in cancer. GSK1070916 is a potent, selective, ATP competitive inhibitor of Aurora kinase B and C. Translation of predictive biomarkers to the clinic can benefit patients by identifying the tumors that are more likely to respond to therapies, especially novel inhibitors such as GSK1070916.Methods59 Hematological cancer-derived cell lines were used as models for response where in vitro sensitivity to GSK1070916 was based on both time and degree of cell death. The response data was analyzed along with karyotype, transcriptomics and somatic mutation profiles to determine predictors of response.Results20 cell lines were sensitive and 39 were resistant to treatment with GSK1070916. High chromosome number was more prevalent in resistant cell lines (p-value = 0.0098, Fisher Exact Test). Greater resistance was also found in cell lines harboring polyploid subpopulations (p-value = 0.00014, Unpaired t-test). A review of NOTCH1 mutations in T-ALL cell lines showed an association between NOTCH1 mutation status and chromosome number (p-value = 0.0066, Fisher Exact Test).ConclusionsHigh chromosome number associated with resistance to the inhibition of Aurora B and C suggests cells with a mechanism to bypass the high ploidy checkpoint are resistant to GSK1070916. High chromosome number, a hallmark trait of many late stage hematological malignancies, varies in prevalence among hematological malignancy subtypes. The high frequency and relative ease of measurement make high chromosome number a viable negative predictive marker for GSK1070916.

Mutation and copy number detection in human cancers using a custom genotyping assay

Identification of biomarkers for positive and negative predictors of response to cancer therapeutics can help direct clinical strategies. However, challenges with tissue availability and costs are significant limiting factors for diagnostic assays. To address these challenges, we have customized a high-throughput single nucleotide polymorphism genotyping assay with the objective of simultaneously surveying known somatic mutations and copy number alterations for translational studies in cancer. As constructed, this assay can interrogate 376 known somatic mutations and quantify copy number alterations of genes commonly implicated in tumorigenesis or progression. Validation of this assay on a panel of 321 cell lines demonstrates sensitivity to accurately detect mutations, robust accuracy in the presence of infiltrating normal tissue, and the ability to detect both DNA copy number amplifications and deletions. This technology, with its high sensitivity, small DNA requirements, and low costs is an attractive platform for biomarker exploration in cancer.

Abstract DDT02-04: A novel PRMT5 inhibitor with potent in vitro and in vivo activity in preclinical lung cancer models

PRMT5 is a type II methyltransferase that specifically adds methyl groups to arginine as a long-lasting post-translational modification. The PRMT5/MEP50 complex regulates a plethora of cellular processes, such as epigenetics and splicing, which are notable events involved in tumorigenesis. Although not frequently mutated or amplified in tumors, elevated PRMT5 protein levels in lung and hematologic cancers are correlated with poorer survival. The PRMT5 inhibitor JNJ-64619178 has been selected as a clinical candidate based on its high selectivity and potency (subnanomolar range) under different in vitro and cellular conditions, paired with favorable pharmacokinetics and safety properties. JNJ-64619178 binds into the SAM binding pocket and reaches the substrate binding pocket to inhibit PRMT5/MEP50 function in a time-dependent manner. Broad cell line panel profiling of JNJ-64619178 revealed a wide range of sensitivity, which is indicative of a genomic dependency instead of a general cytotoxic on-target consequence of PRMT5 inhibition. Further investigations indicate a synthetic lethal correlation between PRMT5 inhibition and key cancer driver pathways. JNJ-64619178, dosed orally (10 mg/kg, every day), showed selective and efficient blockage of the methylation of SMD1/3 proteins, which are crucial components of the spliceosome and substrates of PRMT5/MEP50. JNJ-64619178 also demonstrated tumor regression in a biomarker-driven human small cell lung cancer xenograft model (NCI-H1048) and prolonged tumor growth inhibition after dosing cessation. In rodent and nonrodent toxicology studies, a tolerated dose of JNJ-64619178 has been identified, with the observed toxicity consistent with on-target activity. In summary, JNJ-64619178 has a favorable preclinical package that supports clinical testing in patients diagnosed with lung cancer and hematologic malignancies. Citation Format: Dirk Brehmer, Tongfei Wu, Geert Mannens, Lijs Beke, Petra Vinken, Dana Gaffney, Weimei Sun, Vineet Pande, Jan-Willem Thuring, Hillary Millar, Italo Poggesi, Ivan Somers, An Boeckx, Marc Parade, Erika van Heerde, Thomas Nys, Carol Yanovich, Barbara Herkert, Tinne Verhulst, Marc Du Jardin, Lieven Meerpoel, Christopher Moy, Gaston Diels, Marcel Viellevoye, Wim Schepens, Alain Poncelet, Joannes T. Linders, Edward C. Lawson, James P. Edwards, Dushen Chetty, Sylvie Laquerre, Matthew V. Lorenzi. A novel PRMT5 inhibitor with potent in vitro and in vivo activity in preclinical lung cancer 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 DDT02-04. doi:10.1158/1538-7445.AM2017-DDT02-04

Abstract 895: Genomic characterization of premalignant lung squamous cell carcinoma lesions

Background: Lung squamous cell carcinoma (SqCC) arises in the epithelial layer of the bronchial airways and is often preceded by the development of premalignant lesions. However, not all premalignant lesions will progress to lung SqCC and many of these lesions will regress without therapeutic intervention. Understanding the molecular events that contribute to progression of premalignant lesions in the airway will allow us to identify biomarkers for early detection and develop therapeutic strategies for early intervention. Methods: Bronchial brushings and biopsies were obtained from high-risk smokers undergoing lung cancer screening by auto-fluorescence bronchoscopy and CT at the Roswell Park Cancer Institute. For each subject (n = 30), both premalignant lesions (PMLs) and the cytologically normal mainstem bronchus were sampled repeatedly over time (n = 288 samples). DNA and RNA were isolated from a total of 197 bronchial biopsies of PML (average of 5 per subject) and 91 bronchial brushings. DNA was also isolated from the blood to serve as a matched normal. Exome capture was performed using the Agilent SureSelect Human All Exon+UTR 70MB kit and sequenced to a mean depth of coverage of 75x (n = 85 samples from 22 subjects). RNA libraries were prepared with Illumina TruSeq (mRNA-Seq: n = 288 samples from 30 subjects and miRNA-Seq: n = 183 samples from 26 subjects). Results: We identified gene and miRNA expression changes associated with histological grade as well as progressive/stable disease. The Hippo pathway, Wnt signaling, p53 signaling, and immune-related pathways are modulated with histological grade and disease progression. Genes associated with histological grade in the cytologically normal airway and in the biopsies were significantly concordantly enriched (FDR 3/Mb) were taken from adjacent sites over two time points in the same individual with a history of lung squamous cell carcinoma. These lesions had a significantly overlapping set of mutations (p = 2.2 × 10 −17 ) indicating a common evolutionary ancestor, and contained mutations in CREBBP and FAT1, suggesting they are at increased risk for progressing to frank malignancy. Conclusions: We performed genomic profiling of PMLs in the airways of high-risk smokers. The gene expression and somatic alterations that were observed in known cancer genes may be among the earliest events in cancer development. Citation Format: Joshua D. Campbell, Catalina Perdomo, Sarah Mazzilli, Yaron Geshalter, Samjot S. Dhillon, Gang Liu, Sherry Zhang, Hangqio Lin, Jessica Vick, Christopher Moy, Evan Johnson, Matthew Meyerson, Suso Platero, Marc Lenburg, Mary Reid, Avrum Spira, Jennifer Beane. Genomic characterization of premalignant lung squamous cell carcinoma lesions. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 895.

Trametinib for patients with advanced melanoma – Authors' reply

Gerald Falchook and colleagues show clinical activity of the MEK inhibitor trametinib in patients with either BRAF-mutant or wild-type melanoma. Recently, two essential topics for melanoma have been reported: hepatocyte growth factor (HGF)-dependent resistance to therapy and new driver mutations in melanoma. Stroma-mediated resistance to treatment of BRAF-mutant melanoma is common and HGF secretion from stromal cells seems to be responsible for this drug resistance. Analysis of biopsy samples from patients with BRAF-mutant melanoma suggests that patients with abundant HGF from stromal cells have poor responses to treatment. Furthermore, an inverse relation has been reported between plasma HGF concentration and response to treatment in patients with BRAF-mutant melanoma. HGF secretion leads to activation of the HGF receptor MET, and dual inhibition of RAF and either HGF or MET results in reversal of drug resistance in BRAFmutant melanoma. In Falchook and colleagues’ study, examination by immuno histochemistry of whether HGF expression in melanoma sections correlated with poor responses to the MEK inhibitor trametinib would have been informative, not only in patients with the BRAF mutation, but also in patients with wild-type BRAF. These results would clarify the possibility that a combination of the MEK inhibitor and MET inhibitors have a synergistic eff ect. Moreover, although EGF is less able than HGF to reactivate ERK in most melanoma cell lines, EGF and EGFR mediated resistance might be of interest in melanoma and in colon cancers. For driver mutations, six genes related to melanoma have been newly identifi ed (PPP6C, RAC1, SNX31, TACC1, STK19, and ARID2), with RAC1 mutations also reported. The Illumina platform was used in Falchook and colleagues’ study to analyse the mutational and copy number status of 78 diff erent genes commonly implicated in tumorigenesis. Within these data, is there any information about the six new melanoma genes? If these driver mutations are present, examination of whether they correlate with reduced responses to therapy with trametinib would be interesting, because such examination would not only contribute to drug response predictions but also might help select other treatment options, including combination therapies. Furthermore, data on amplifi cation of BRAF, either with or without mutations, could provide information on whether copy number of this gene plays a role in response to therapy? In the context of treatment with the MEK inhibitor trametinib, an integrated examination including HGF secretion and other gene mutations would open up the possibility of prediction of drug response and combination therapy.

Abstract B173: Synergistic interaction between CENP‐E inhibitor GSK923295 and MEK inhibitor GSK1120212

Centromere protein‐E (CENP‐E) is a mitotic kinesin that is required during mitosis for metaphase chromosome alignment. GSK923295 (′295) is a potent and specific inhibitor of human CENP‐E currently being developed as a next generation antimitotic drug for the treatment of cancer. It has shown a broad spectrum of anti‐cancer activity in vitro and in vivo. A siRNA library screen targeting the ‘druggable genome’ identified multiple MAPK pathway genes as sensitizers to ′295, including BRAF and ERK1. Since the MEK protein plays an important role in the MAPK pathway, combination studies between GSK MEK inhibitor GSK1120212 (′212) and ′295 were performed in cancer cell lines from different tissue origins, and the combination effect was evaluated based on three different criteria: Excess over Single Highest Agent (EOHSA), Bliss, and Combination Index (CI).. Synergistic response was observed in 5/6 colon cancer cell lines, 5/15 lung cancer cell lines, and 6/8 pancreas cancer cell lines. Additionally, the combination of ′212 and ′295 treatment induced a much stronger apoptotic response than either drug alone in two colon cancer cell lines. These data suggest that combining MEK and CENP‐E inhibitors might improve clinical efficacy over either as a single agent in selected tumors. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B173.