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Background The bromodomain and extraterminal protein (BET) inhibitor trotabresib has demonstrated antitumor activity in patients with advanced solid tumors, including high-grade gliomas. CC-90010-GBM-001 (NCT04047303) is a phase I study investigating the pharmacokinetics, pharmacodynamics, and CNS penetration of trotabresib in patients with recurrent high-grade gliomas scheduled for salvage resection. Methods Patients received trotabresib 30 mg/day on days 1–4 before surgery, followed by maintenance trotabresib 45 mg/day 4 days on/24 days off after surgery. Primary endpoints were plasma pharmacokinetics and trotabresib concentrations in resected tissue. Secondary and exploratory endpoints included safety, pharmacodynamics, and antitumor activity. Results Twenty patients received preoperative trotabresib and underwent resection with no delays or cancelations of surgery; 16 patients received maintenance trotabresib after recovery from surgery. Trotabresib plasma pharmacokinetics were consistent with previous data. Mean trotabresib brain tumor tissue:plasma ratio was 0.84 (estimated unbound partition coefficient [KPUU] 0.37), and modulation of pharmacodynamic markers was observed in blood and brain tumor tissue. Trotabresib was well tolerated; the most frequent grade 3/4 treatment-related adverse event during maintenance treatment was thrombocytopenia (5/16 patients). Six-month progression-free survival was 12%. Two patients remain on treatment with stable disease at cycles 25 and 30. Conclusions Trotabresib penetrates the blood–brain-tumor barrier in patients with recurrent high-grade glioma and demonstrates target engagement in resected tumor tissue. Plasma pharmacokinetics, blood pharmacodynamics, and safety were comparable with previous results for trotabresib in patients with advanced solid tumors. Investigation of adjuvant trotabresib + temozolomide and concomitant trotabresib + temozolomide + radiotherapy in patients with newly diagnosed glioblastoma is ongoing (NCT04324840).

Author(s): Munster, Pamela; Mita, Monica; Mahipal, Amit; Nemunaitis, John; Massard, Christophe; Mikkelsen, Tom; Cruz, Cristina; Paz-Ares, Luis; Hidalgo, Manuel; Rathkopf, Dana; Blumenschein, George; Smith, David C; Eichhorst, Barbara; Cloughesy, Tim; Filvaroff, Ellen H; Li, Shaoyi; Raymon, Heather; de Haan, Hans; Hege, Kristen; Bendell, Johanna C | Abstract: PurposeThis first-in-human Phase I study investigated the safety, pharmacokinetics (PK), pharmacodynamic profile, and preliminary efficacy of CC-115, a dual inhibitor of mammalian target of rapamycin (mTOR) kinase and DNA-dependent protein kinase.Patients and methodsPatients with advanced solid or hematologic malignancies were enrolled in dose-finding and cohort expansion phases. In dose-finding, once-daily or twice-daily (BID) ascending oral doses of CC-115 (range: 0.5-40 mg/day) in 28-day continuous cycles identified the maximum-tolerated dose for cohort expansion in 5 specified tumor types. Twelve additional patients with mixed solid tumors participated in a bioavailability substudy.ResultsForty-four patients were enrolled in the dose-finding cohort. Dose-limiting toxicity included thrombocytopenia, stomatitis, hyperglycemia, asthenia/fatigue, and increased transaminases. CC-115 10 mg BID was selected for cohort expansion (n=74) in which fatigue, nausea, and decreased appetite were the most frequent toxicities. Dose-proportional PK was found. CC-115 distributed to glioblastoma tissue (mean tumor/plasma concentration ratio: 0.713). Total exposure of CC-115 was similar under fasting and fed conditions. A patient with endometrial carcinoma remained in complete remission g4 years. Partial response (PR; n=2) and stable disease (SD; n=4) were reported in the bioavailability substudy; SD was reached in 53%, 22%, 21%, and 64% of patients with head and neck squamous cell carcinoma, Ewing sarcoma, glioblastoma multiforme, and castration-resistant prostate cancer, respectively. Chronic lymphocytic leukemia/small lymphocytic lymphoma showed 38% PR and 25% SD.ConclusionCC-115 was well-tolerated, with toxicities consistent with mTOR inhibitors. Together with biomarker inhibition and preliminary efficacy, oral CC-115 10 mg BID is a promising novel anticancer treatment.Clinical trial registrationNCT01353625.

Purpose: Protein kinases are known to play a prominent role in oncogenic progression across multiple cancer subtypes, yet their role in prostate cancer progression remains underexplored. The purpose of this study was to identify kinases that drive prostate cancer progression. Experimental Design: To discover kinases that drive prostate cancer progression, we investigated the association between gene expression of all known kinases and long-term clinical outcomes in tumor samples from 545 patients with high-risk disease. We evaluated the impact of genetic and pharmacologic inhibition of the most significant kinase associated with metastatic progression in vitro and in vivo. Results: DNA-dependent protein kinase (DNAPK) was identified as the most significant kinase associated with metastatic progression in high-risk prostate cancer. Inhibition of DNAPK suppressed the growth of both AR-dependent and AR-independent prostate cancer cells. Gene set enrichment analysis nominated Wnt as the top pathway associated with DNAPK. We found that DNAPK interacts with the Wnt transcription factor LEF1 and is critical for LEF1-mediated transcription. Conclusions: Our data show that DNAPK drives prostate cancer progression through transcriptional regulation of Wnt signaling and is an attractive therapeutic target in aggressive prostate cancer.

Trotabresib, a novel bromodomain and extraterminal protein inhibitor, has demonstrated antitumor activity and blood–brain barrier penetration in patients with high-grade gliomas, and enhanced the antiproliferative effects of temozolomide in preclinical models. CC-90010-GBM-002 (NCT04324840) is a phase 1b/2 study investigating the addition of trotabresib to standard-of-care (SOC) concomitant temozolomide plus radiotherapy and adjuvant temozolomide, followed by maintenance trotabresib, in patients with newly diagnosed glioblastoma. The design of the dose escalation (part A) has been described previously (Vieito M, et al. SNO 2021. Abstract CTNI-51). Primary objectives of part A were to establish the safety, tolerability, and maximum tolerated dose/recommended phase 2 dose (RP2D) of trotabresib. In part A, addition of trotabresib to SOC was safe and well tolerated in the concomitant (N = 14) and adjuvant (N = 18) cohorts; the most frequent grade 3/4 treatment-related adverse event was thrombocytopenia (7/14 and 9/18 patients, respectively). The RP2D for trotabresib was 30 mg/day 4 days on/24 days off in both settings. At data cutoff (February 20, 2022), median duration of treatment was 34 weeks (concomitant cohort) and 33 weeks (adjuvant cohort); progression-free survival data are not yet mature. Trotabresib plasma pharmacokinetics and pharmacodynamics were consistent with monotherapy. At last follow-up, 6 and 5 patients remained on treatment in the concomitant and adjuvant dose-escalation cohorts, respectively, including 1 patient in cycle 20 with ongoing complete response. The ongoing randomized phase 2 dose expansion (part B; planned N = 162) is comparing concomitant trotabresib at the RP2D + SOC followed by adjuvant trotabresib at the RP2D + SOC, followed by maintenance trotabresib 45 mg/day 4 days on/24 days off, versus SOC alone in patients with newly diagnosed IDH–wild-type glioblastoma. Key objectives are to compare progression-free and overall survival, safety, and tolerability. Longer follow-up from part A and the first disclosure of data from part B will be presented.

CC-91516 (also called CC0776314), a selective and potent inhibitor of ERK1/2 and NLK, was discovered via a phenotypic screen of a kinase-focused library for compounds that synergize with mTOR kinase inhibitor CC-223 to induce apoptosis in combination with CC-223. Broad kinase selectivity profiling identified ERK1/2 and NLK as targets of CC-91516. Crystal structure of CC-91516 in complex with ERK2 reveals that its 2, 4, 6-trichlorophenyl moiety binds to a unique back pocket of the adenosine-5′-triphosphate (ATP) binding site of ERK2, which is not accessible to other ERK inhibitors such as BVD-523 and GDC-0994. This unique binding mode of CC-91516 leads to a slow off-rate for its ERK binding with long residence time disrupting both the active and inactive ERK forms. Consequentially, CC-91516 causes sustained inhibition of the MAPK pathway in BRAF mutant colorectal cancer cells. In addition, CC-91516 also regulates Wnt/β-catenin and YAP pathways in multiple cancer cell lines. CC-91516 shows potent yet selective anti-proliferative activity against a large panel of cancer cell lines. Activating mutations in BRAF or CTNNB1 gene associate with sensitivity to CC-91516-mediated anti-proliferative activity while mutations in RB and PI3K/PTEN pathway associate with resistance. CC-91516 inhibits ex vivo colony formation of PDX models with BRAF and CTNNB1 mutations. In addition, CC-91516 potently induces apoptosis, inhibits survival, and overcomes resistance to MEK inhibitor trametinib of BRAF or CTNNB1 mutant cancer cells in long-term culture assay in vitro. CC-91516 has good oral bioavailability and shows excellent anti-tumor activity in vivo against both BRAF and CTNNB1 mutant xenograft models. DMPK and toxicology studies showed robust oral exposure across preclinical species. In summary, CC-91516 has demonstrated preclinical anti-tumor activities and DMPK and safety profiles in support of its clinical development. Citation Format: Shuichan Xu, Tam Tran, Dan Zhu, Tao Shi, David Mikolon, Jim Leisten, Philip Chamberlain, Laurie LeBrun, Sogole Bahmanyar, Ning Jiang, Jingjing Zhao, Mehnaz Malek, Ellen Filvaroff, Heather Raymon, Robert Hubbard, John Boylan. Discovery of CC-91516, a potent and selective ERK/NLK inhibitor, with anti-tumor activity in preclinical cancer models harboring BRAF or CTNNB1 mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1180.

Background: Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL) in the US accounting for about 22% of newly diagnosed cases of B-cell NHL. It is considered to be more aggressive and to have worse prognosis due to low response to existing treatments. KDM4 is a family of histone demethylases that can drive tumor growth by regulating transcription, cell cycle, and DNA replication/repair. Overexpression of KDM4 alters post-translational histone modification and is associated with many types of cancer, including DLBCL. TACH101 is a novel, potent small molecule inhibitor of KDM4 that is being developed for treatment of advanced cancers, including DLBCL. Methods: TACH101 was evaluated in vitro and in vivo using cancer cell lines and patient-derived organoid (PDO) and xenograft (PDX) models of DLBCL. Results: TACH101 is a reversible, α-ketoglutarate competitive, selective and potent inhibitor of KDM4 isoforms A-D with IC50 values < 0.100 μM for all four isoforms. An initial screen using a 301-cell line panel showed that DLBCL cell lines are sensitive to TACH101 (IC50 < 10 nM). In an additional panel of DLBCL cell lines, TACH101 inhibited proliferation in a dose-dependent manner in all DLBCL cell lines, independent of molecular subtype, with mean IC50’s of 0.03 ± 0.01 μM in ABC DLBCL cell lines (n=6); 0.02 ± 0.01 μM in GCB DLBCL cell lines (n=7) and 0.02 ± 0.01 μM in PMBL DLBCL cell lines (n=2). In OCI-LY19 DLBCL xenografts in vivo, TACH101 was well tolerated and inhibited tumor growth by 55% to 100%, depending on dosing regimen (either QD or BID following a 3 days on/4 days off schedule). In PK studies, TACH101 exhibited low clearance, moderate volume of distribution, and good oral bioavailability in mouse, rat, and dog. Moreover, treatment with TACH101 resulted in little or no inhibitory effects on CYP enzymes. Toxicity studies in rats and dogs identified potential target tissues and provided safety guidance for the use of TACH101 in human studies. Conclusions: The KDM4 inhibitor, TACH101, had compelling activity in preclinical DLBCL models, suggesting that TACH101 could be an effective therapy for DLBCL. Preparations to advance the drug into clinical trials are underway. Citation Format: Frank Perabo, Chandtip Chandhasin, Sanghee Yoo, Joselyn Del Rosario, Young K. Chen, Ellen Filvaroff, Jeffrey A. Stafford, Stephen Quake, Michael F. Clarke. TACH101, a first-in-class inhibitor of KDM4 histone lysine demethylase for the treatment of diffuse large B-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3720.

e15105 Background: Cancer stem cells (CSCs) are believed to be responsible for both therapy resistance and metastasis. Until now, these resistant CSCs have not been well-characterized, and potential treatments targeting these cells have yet to be identified. Epigenetic modifiers, such as KDM4 histone demethylase, have been shown to play an important role in CSC renewal and maintenance. TACH101 is a novel, first-in-class pan inhibitor of KDM4 that has promising pre-clinical and pharmacologic properties as a possible cancer therapeutic. Methods: Effects of TACH101 on CSC population were evaluated in the colorectal cancer SU60 xenograft model. Mice engrafted with SU60 cells were treated with TACH101 or vehicle. The day after the last dose, tumors from each group were dissociated into single cells and used to perform (1) flow cytometry analysis of the tumorigenic cell population using markers CD44 and EpCAM, (2) single cell gene expression analysis using quantitative reverse transcription polymerase chain reaction (RT-qPCR), and (3) functional tumorigenicity assays (limiting dilution assays). Results: TACH101 administration reduced SU60 tumor growth by 62% compared to vehicle-treated mice (p < 0.0005). Flow cytometry analysis of SU60 tumor cells showed the proportion of cells with cancer stem cell features (CD44HighEpCAM+) was 2.5-fold lower in TACH101-treated mice as compared to vehicle-treated animals. Single cell gene expression analysis followed by hierarchical clustering based on expression of immature and mature cell markers showed that TACH101-treated tumors had a significant reduction in the proportion of progenitor-like cells (p = 0.01) and an increase in number of both intermediate-like and differentiated-like cells although the increase was not significant (p = 0.07). In limiting dilution assay experiments, result showed that tumors were bigger/grew faster in animals receiving tumor cells derived from vehicle-treated animals compared to TACH101-treated animals. Furthermore, TACH101 was shown to reduce the number of tumor-initiating cancer stem cells by 4.4-fold. Further evaluation of TACH101 across additional xenograft models including esophageal, gastric, breast, and lymphoma showed tumor growth inhibition of up to 100%. TACH101 demonstrated favorable cell permeability, good oral bioavailability, and high metabolic stability. Toxicity studies in rats and dogs identified potential target tissues and provided safety guidance for the use of TACH101 in human trials. Conclusions: TACH101 inhibited proliferation of and tumor initiation by CSCs. As therapy resistance and metastatic dissemination are grave consequences of CSC activity, TACH101 provides a novel approach to eradicating this population and shows broad applicability as a potential therapeutic agent. Preparations to advance TACH101 into clinical trials are underway.

As a critical signaling node, ERK1/2 are attractive drug targets, particularly in tumors driven by activation of the MAPK pathway. Utility of targeting the MAPK pathway has been demonstrated by clinical responses to inhibitors of MEK1/2 or RAF kinases in some mutant BRAF-activated malignancies. Unlike tumors with mutations in BRAF, those with mutations in KRAS (>30% of all cancers and >90% of certain cancer types) are generally not responsive to inhibitors of MEK1/2 or RAF. Here, a covalent ERK1/2 inhibitor, CC-90003, was characterized and shown to be active in preclinical models of KRAS-mutant tumors. A unique occupancy assay was used to understand the mechanism of resistance in a KRAS-mutant patient-derived xenograft (PDX) model of colorectal cancer. Finally, combination of CC-90003 with docetaxel achieved full tumor regression and prevented tumor regrowth after cessation of treatment in a PDX model of lung cancer. This effect corresponded to changes in a stemness gene network, revealing a potential effect on tumor stem cell reprograming. Implications: Here, a covalent ERK1/2 inhibitor (CC-90003) is demonstrated to have preclinical efficacy in models of KRAS-mutant tumors, which present a therapeutic challenge for currently available therapies.

Background: TACH101 is a novel, selective and potent inhibitor of KDM4 in development for advanced cancers. KDM4 plays a key role in epigenetic regulation by removing methyl marks on histone H3K9 and H3K36. Overexpression of KDM4 leads to dysregulation of transcription, cell cycle, and DNA replication/repair processes and has been associated with many cancer types. Methods: Candidate pharmacodynamic (PD) and sensitivity biomarkers for TACH101 were evaluated in vitro and in vivo using cancer cell lines, mouse xenograft models, gene microarrays, ChIP-seq, and ChIP-qPCR. Results: Evaluation of differential gene expression from tumor tissue identified several candidates as potential PD markers for TACH101 activity. In particular, direct binding of KDM4 to Protein Phosphatase 1 Regulatory subunit 10 (PPP1R10 or PNUTS) was confirmed by ChIP-seq in cell lines from esophageal (KYSE-150), breast (MDA-MB-231) and lymphoma (OCI-Ly19) cancers. TACH101 treatment caused 86% repression of PNUTS mRNA, as well as a 51% increase in H3K9me3, a mark of repressed transcription. A 78% decrease in H3K36me3 at the PNUTS gene was also observed. PNUTS as a target of KDM4 was validated via ChIP-qPCR in xenograft tumors of KYSE-150, OCI-Ly19 and SU-60 (colorectal). In vivo, maximum inhibition of PNUTS was reached at 8 hours post TACH101 administration, when TACH101 concentration was 100-200 nM in tumors. In addition, extensive bioinformatics analysis using >300 cancer cell lines showed that cell lines with MSI-high (MSI-H) status tended to be more sensitive to TACH101 in vitro. This association was found with other markers of MSI-H status such as MMR gene mutations, MLH1 methylation status, and overall mutation frequency. To further test this association, TACH101 was evaluated in a panel of patient-derived xenograft (PDX) and organoid models. The results showed a strong correlation of TACH101 sensitivity with MSI-H status (IC50 ranges 1-150 nM). Conclusions: Candidate PD biomarkers of TACH101 activity for clinical evaluation have been identified and further studies are ongoing to explore current and additional markers. In addition, MSI-H status was associated with increased sensitivity to TACH101, which may be useful for enriching for select patient populations in clinical studies. Citation Format: Frank Perabo, Sanghee Yoo, Chandtip Chandhasin, Joselyn Del Rosario, Young K. Chen, Ellen Filvaroff, Jeffrey A. Stafford, Stephen Quake, Michael F. Clarke. Identification of pharmacodynamic and sensitivity biomarkers for TACH101, a pan-inhibitor of KDM4 histone lysine demethylase [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P086.

Second-generation mammalian target of rapamycin (mTOR) inhibitors such as CC-223 may have theoretical advantages over first-generation drugs by inhibiting TOR kinase in mTOR complex 1 (mTORC1) and 2 (mTORC2), potentially improving clinical efficacy for well-differentiated neuroendocrine tumors (NET).Enrolled patients had metastatic, well-differentiated NET of non-pancreatic gastrointestinal or unknown origin, with/without carcinoid symptoms, had failed ≥1 systemic chemotherapy, and were taking a somatostatin analog (SSA). Oral once-daily CC-223 was administered in 28-day cycles starting at 45 mg (n = 24), with a subsequent cohort starting at 30 mg (n = 23). Objectives were to evaluate tolerability, preliminary efficacy, and pharmacokinetic and biomarker profiles of CC-223. Forty-seven patients completed the study, with mean treatment duration of 378 days and mean dose of 26 mg; 26% of patients remained on the starting dose. Most frequent grade ≥3 toxicities were diarrhea (38%), fatigue (21%), and stomatitis (11%). By investigator, 3 of 41 evaluable patients (7%) showed partial response (PR) and 34 (83%) had stable disease (SD) for a disease control rate (DCR) of 90% (95% confidence interval [CI] 76.9-97.3%). Duration of PR was 125-401 days; median SD duration was 297 days (min-max, 50-1519 days). Median progression-free survival was 19.5 months (95% CI 10.4-28.5 months). Carcinoid symptoms of flushing, diarrhea, or both improved in 50%, 41%, and 39% of affected patients, respectively. For the first time, this study describes that a second-generation mTOR pathway inhibitor can result in highly durable tumor regression and control of NET carcinoid symptoms. The manageable safety profile, high DCR, and durable response, coupled with reduction in carcinoid symptoms refractory to SSA, make CC-223 a promising agent for further development. We thank the patients and their families, and the principal investigator study teams, for enabling this study to complete successfully. We also thank the many support staff at Celgene who were involved in the operational aspects of the study, including Angela Joubert James and Torsten Trowe, who were employees of Celgene at the time of the study. The authors received medical writing assistance from Amy Agbonbhase, PhD, of The Lockwood Group, funded by Celgene Corporation. Sí

Purpose: DNA-dependent protein kinase catalytic subunit (DNA-PK) is a pleiotropic kinase involved in DNA repair and transcriptional regulation. DNA-PK is deregulated in selected cancer types and is strongly associated with poor outcome. The underlying mechanisms by which DNA-PK promotes aggressive tumor phenotypes are not well understood. Here, unbiased molecular investigation in clinically relevant tumor models reveals novel functions of DNA-PK in cancer. Experimental Design: DNA-PK function was modulated using both genetic and pharmacologic methods in a series of in vitro models, in vivo xenografts, and patient-derived explants (PDE), and the impact on the downstream signaling and cellular cancer phenotypes was discerned. Data obtained were used to develop novel strategies for combinatorial targeting of DNA-PK and hormone signaling pathways. Results: Key findings reveal that (i) DNA-PK regulates tumor cell proliferation; (ii) pharmacologic targeting of DNA-PK suppresses tumor growth both in vitro, in vivo, and ex vivo; (iii) DNA-PK transcriptionally regulates the known DNA-PK–mediated functions as well as novel cancer-related pathways that promote tumor growth; (iv) dual targeting of DNA-PK/TOR kinase (TORK) transcriptionally upregulates androgen signaling, which can be mitigated using the androgen receptor (AR) antagonist enzalutamide; (v) cotargeting AR and DNA-PK/TORK leads to the expansion of antitumor effects, uncovering the modulation of novel, highly relevant protumorigenic cancer pathways; and (viii) cotargeting DNA-PK/TORK and AR has cooperative growth inhibitory effects in vitro and in vivo. Conclusions: These findings uncovered novel DNA-PK transcriptional regulatory functions and led to the development of a combinatorial therapeutic strategy for patients with advanced prostate cancer, currently being tested in the clinical setting.

Purpose: In a recent phase II study of onartuzumab (MetMAb), patients whose non–small cell lung cancer (NSCLC) tissue scored as positive for MET protein by immunohistochemistry (IHC) experienced a significant benefit with onartuzumab plus erlotinib (O+E) versus erlotinib. We describe development and validation of a standardized MET IHC assay and, retrospectively, evaluate multiple biomarkers as predictors of patient benefit. Experimental Design: Biomarkers related to MET and/or EGF receptor (EGFR) signaling were measured by IHC, FISH, quantitative reverse transcription PCR, mutation detection techniques, and ELISA. Results: A positive correlation between IHC, Western blotting, and MET mRNA expression was observed in NSCLC cell lines/tissues. An IHC scoring system of MET expression taking proportional and intensity-based thresholds into consideration was applied in an analysis of the phase II study and resulted in the best differentiation of outcomes. Further analyses revealed a nonsignificant overall survival (OS) improvement with O+E in patients with high MET copy number (mean ≥5 copies/cell by FISH); however, benefit was maintained in “MET IHC-positive”/MET FISH-negative patients (HR, 0.37; P = 0.01). MET, EGFR, amphiregulin, epiregulin, or HGF mRNA expression did not predict a significant benefit with onartuzumab; a nonsignificant OS improvement was observed in patients with high tumor MET mRNA levels (HR, 0.59; P = 0.23). Patients with low baseline plasma hepatocyte growth factor (HGF) exhibited an HR for OS of 0.519 (P = 0.09) in favor of onartuzumab treatment. Conclusions: MET IHC remains the most robust predictor of OS and progression-free survival benefit from O+E relative to all examined exploratory markers. Clin Cancer Res; 20(17); 4488–98. ©2014 AACR.

Background Bromodomain and extra-terminal (BET) proteins are epigenetic readers that regulate the expression of genes involved in cell growth and oncogenesis. CC-90010 is a potent, reversible oral BET inhibitor that reduces tumor growth in xenograft models. Methods CC-90010-ST-001 (NCT03220347; 2015-004371-79) is a phase I, first-in-human study of CC-90010 in patients (pts) with advanced solid tumors and R/R NHL. Four dosing schedules and 11 dose levels were evaluated (Table). Primary objectives were to determine maximum-tolerated dose, safety, and/or recommended phase II dose (RP2D). A Bayesian logistic regression model guided the dose escalation. Secondary objectives were to identify early activity signals, pharmacokinetics, and pharmacodynamics (PD). Results As of 4 Mar 2019, 69 pts were enrolled, 67 with solid tumors, including 10 with glioblastoma and 2 with R/R NHL. Median age was 57 y (range, 21–80), 38 (55%) were men, and median number of prior systemic anticancer regimens was 3 (range, 1–9). Two RP2Ds were identified (dose cohorts 3A and 4B); 4B was selected for expansion. Dose-limiting toxicities (n = 6) occurred in dose cohorts 3A, 3C, and 4B. Grade 3/4 treatment-related adverse events (TRAEs) occurred in 21 pts (30%), most commonly (>2 pts) thrombocytopenia (16%), asthenia/fatigue (4%), and anemia (4%). Seven pts died, all from progressive disease.Eleven pts remained on treatment >6 mo with clinical benefit. Two pts (endometrial carcinoma and astrocytoma) had a partial response, and 6 had prolonged stable disease ≥9 mo. Plasma exposures and PD marker regulation increased with each dose level; terminal half-life was ∼73 h. Conclusions Most TRAEs were mild or moderate in severity and manageable with dose modifications. CC-90010 had a long terminal half-life that enabled less frequent dosing and promising anticancer activity. Dose escalation is complete, and expansion in select advanced malignancies is ongoing. Table: 1075P . Dose Level: 1 (n = 7) 2 (n = 7) 3A (n = 4) 3B (n = 6) 3C (n = 6) 4A (n = 7) 4B (n = 7) 4C (n = 7) 5A (n = 6) 5B (n = 6) 5C (n = 6) Dose, mg 15 15 25 30 15 40 45 25 30 55 35 Schedule, days on/off 3/4 3/11 3/11 4/24 2/5 3/11 4/24 2/5 3/11 4/24 2/5 Clinical trial identification NCT03220347; 2015-004371-79. Editorial acknowledgement Tisheeka Graham-Steed, PhD BioConnections, LLC. Legal entity responsible for the study Celgene Corporation. Funding Celgene Corporation. Disclosure V. Moreno: Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: BMS; Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Regeneron; Speaker Bureau / Expert testimony: Bayer/Loxo. I. Brana: Research grant / Funding (self): Celgene. J.M. Sepulveda Sanchez: Advisory / Consultancy, Research grant / Funding (self): Pfizer; Advisory / Consultancy, Travel / Accommodation / Expenses: AbbVie; Advisory / Consultancy: Celgene; Advisory / Consultancy: GW Pharma; Speaker Bureau / Expert testimony: Astellas; Travel / Accommodation / Expenses: Ipsen. M. Vieito Villar: Travel / Accommodation / Expenses: Roche. O. Saavedra: Travel / Accommodation / Expenses: Mundipharma; Travel / Accommodation / Expenses: Teva; Travel / Accommodation / Expenses: MSD; Travel / Accommodation / Expenses: Grunenthal; Travel / Accommodation / Expenses: Kyowakirin; Travel / Accommodation / Expenses: Boehringer-Ingelheim; Travel / Accommodation / Expenses: Debiopharm. G. Musuraca: Advisory / Consultancy: Servier. P.A. Asierto: Advisory / Consultancy: Pierre Fabre; Advisory / Consultancy: Incyte; Advisory / Consultancy: Newlinks Genetics; Advisory / Consultancy: Genmab; Advisory / Consultancy: Medimmune; Advisory / Consultancy: Sindax; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Sun Pharma; Advisory / Consultancy: Sanofi; Research grant / Funding (institution): BMS; Research grant / Funding (institution): ROCHE Genentech; Research grant / Funding (institution): Array; Travel / Accommodation / Expenses: MSD. C. Carlo-Stella: Honoraria (self): BMS; Honoraria (self): MSD; Honoraria (self), Advisory / Consultancy: Servier; Honoraria (self), Advisory / Consultancy: Amgen; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Janssen; Advisory / Consultancy, Research grant / Funding (institution): Sanofi; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: ADC Therapeutics; Advisory / Consultancy, Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Rhizen Pharma; Research grant / Funding (institution), Travel / Accommodation / Expenses: Roche; Travel / Accommodation / Expenses: Takeda. R. Sarmiento: Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Full / Part-time employment: Celgene. J. Di Martino: Leadership role, Shareholder / Stockholder / Stock options, Licensing / Royalties, Full / Part-time employment: Celgene Corp. M. Zuraek: Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Full / Part-time employment: Celgene Corp. T. Sanchez Perez: Full / Part-time employment: Celgene Corp. E. Filvaroff: Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Licensing / Royalties, Full / Part-time employment: Celgene Corp.; Shareholder / Stockholder / Stock options: Amgen; Shareholder / Stockholder / Stock options: Gilead; Shareholder / Stockholder / Stock options: Genentech/Roche. B. Hanna: Research grant / Funding (self), Shareholder / Stockholder / Stock options, Full / Part-time employment: Celgene Corp. Z. Nikolova: Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Full / Part-time employment: Celgene Corp. All other authors have declared no conflicts of interest.

2577 Background: CC-90003 is an irreversible inhibitor of ERK 1/2 with potent anti-proliferative activity in KRAS and BRAF mutant tumor models. We conducted a first-in-human study of CC-90003 in patients with RAS or BRAF mutant tumors. Methods: Patients received escalating doses of oral CC-90003 on a 21/28 day cycle. Standard safety (adverse events, chemistry/hematology, physical findings, ECGs and cardiac ECHO/MUGA scans) and PK parameters were assessed. Response was assessed per RECIST 1.1. A proprietary ELISA-based assay measured ERK levels unbound to CC-90003 in peripheral blood mononuclear cells. Results: Nineteen patients (median age: 60 yrs) harboring KRAS (n = 15), NRAS (n = 1), or BRAF (n = 3) mutant tumors received CC-90003 doses from 20 to 160 mg /day. The MTD was 120 mg based on the occurrence of Grade 3 transaminase elevations (n = 2) and hypertension (n = 1) observed at 160 mg (the NTD). Patients completed a median of 2 cycles (range: 1 to 5). AEs (mostly Grade 1 or 2) reported in ≥ 3 patients included constitutional (asthenia, fatigue), gastrointestinal (anorexia, nausea/vomiting, diarrhea), hepatic (transaminase elevations) and neurologic (dizziness, gait disturbance, paresthesias) toxicities. Grade 1-3 neurotoxicity was observed primarily at doses from 80 to 160 mg/day and resolved with dose reduction/interruption. PK parameters were highly variable, with AUC and Cmax increasing overall, with increasing dose. CC-90003 accumulation was observed after multiple doses. There were no objective responses. Levels of free ERK were reduced by ≥80% compared to baseline by C1D8 at doses ≥ 80 mg/day. Conclusions: ERK inhibition may be an attractive target for the management of mutant RAS or BRAF-driven tumors, however proof-of-concept demonstration for CC-90003 was limited by a lack of objective responses, an unfavorable PK profile and unanticipated neurotoxicity. Clinical trial information: NCT02313012.

Onartuzumab, a humanized, monovalent monoclonal anti-MET antibody, antagonizes MET signaling by inhibiting binding of its ligand, hepatocyte growth factor (HGF). We investigated the effects of onartuzumab on cell-associated and circulating (shed) MET (sMET) and circulating HGF in vitro and nonclinically to determine their utility as pharmacodynamic biomarkers for onartuzumab. Effects of onartuzumab on cell-associated MET were assessed by flow cytometry and immunofluorescence. sMET and HGF were measured in cell supernatants and in serum or plasma from multiple species (mouse, cynomolgus monkey, and human) using plate-based immunoassays. Unlike bivalent anti-MET antibodies, onartuzumab stably associates with MET on the surface of cells without inducing MET internalization or shedding. Onartuzumab delayed the clearance of human xenograft tumor-produced sMET from the circulation of mice, and endogenous sMET in cynomolgus monkeys. In mice harboring MET-expressing xenograft tumors, in the absence of onartuzumab, levels of human sMET correlated with tumor size, and may be predictive of MET-expressing tumor burden. Because binding of sMET to onartuzumab in circulation resulted in increasing sMET serum concentrations due to reduced clearance, this likely renders sMET unsuitable as a pharmacodynamic biomarker for onartuzumab. There was no observed effect of onartuzumab on circulating HGF levels in xenograft tumor-bearing mice or endogenous HGF in cynomolgus monkeys. Although sMET and HGF may serve as predictive biomarkers for MET therapeutics, these data do not support their use as pharmacodynamic biomarkers for onartuzumab. Mol Cancer Ther; 13(2); 540–52. ©2013 AACR.

SummaryMetastasis, which commonly uses lymphatics, accounts for much of the mortality associated with cancer. The vascular endothelial growth factor (VEGF)-C coreceptor, neuropilin-2 (Nrp2), modulates but is not necessary for developmental lymphangiogenesis, and its significance for metastasis is unknown. An antibody to Nrp2 that blocks VEGFC binding disrupts VEGFC-induced lymphatic endothelial cell migration, but not proliferation, in part independently of VEGF receptor activation. It does not affect established lymphatics in normal adult mice but reduces tumoral lymphangiogenesis and, importantly, functional lymphatics associated with tumors. It also reduces metastasis to sentinel lymph nodes and distant organs, apparently by delaying the departure of tumor cells from the primary tumor. Our results demonstrate that Nrp2, which was originally identified as an axon-guidance receptor, is an attractive target for modulating metastasis.

Background and Aim: Advanced pancreatic cancer is both deadly and difficult to treat with success. Here, we disseminate the results of comprehensive preclinical studies which laid a strong foundation for the rapid bench to bedside development of nab-paclitaxel, an albumin-bound formulation of paclitaxel, in combination with gemcitabine, a regimen recently approved by U.S. Food and Drug Administration as a first-line treatment for patients with metastatic pancreatic cancer. Materials and Methods: We enrolled a total of 650 mice with established pancreatic tumors originated from a collection of patient-derived pancreatic cancer xenografts. The present study investigated the anti-tumor activity, survival advantage and mechanism of action of nab-paclitaxel or Cremophor EL™ (CreEL)-based paclitaxel monotherapy and in combination with gemcitabine. Results: When tested in mice with subcutaneous tumors originating from 11 separate individual patient xenografts, nab-paclitaxel plus gemcitabine treatment demonstrated superior tumor regression response, robustly depleted the tumor desmoplatic stroma, leading to enhanced gemcitabine uptake (2.8-fold) in the tumor compared to tumors in the gemcitabine alone treated mice. In orthotopic models, nab-paclitaxel treatment leads to an average of 3.64-fold decrease in primary tumor volumes compared to CreEL-based paclitaxel. Intra-tumor stromal collapse combined with decreased tumor cell proliferation was clearly evident in the primary tumors of nab-paclitaxel treated mice compared to CreEL-based paclitaxel, when the mice were sacrificed immediately after five consecutive day's treatment or three weeks after the final dose of the agents. In a highly aggressive orthotopic model, nab-paclitaxel plus gemcitabine treatment prevented primary tumor progression, and metastatic spread to liver, lymph nodes and diaphragm. While CreEL-based paclitaxel plus gemcitabine treatment failed to enhance mouse survival compared to gemcitabine monotherapy, the nab-paclitaxel plus gemcitabine combination proved statistically significant (p=0.0133) in enhancing survival. nab-paclitaxel monotherapy demonstrated statistically significant survival advantage compared to CreEL-based paclitaxel monotherapy (p=0.0072). Remarkably, nab-paclitaxel monotherapy was equivalent to nab-paclitaxel plus gemcitabine in providing survival advantage in a highly aggressive metastatic model of pancreatic cancer. Conclusion: Our results demonstrated that co-treatment with nab-paclitaxel and gemcitabine resulted in superior tumor regression response, stromal depletion and enhanced intra-tumoral gemcitabine uptake compared with either single agent alone. nab-paclitaxel demonstrated superior anti-tumor activity and provided a statistically significant survival advantage compared to CreEL-based paclitaxel. Our results provide further rationale for future preclinical and clinical trials in pancreatic cancer using nab-paclitaxel as a backbone therapy in combination with novel experimental and targeted agents. Acknowledgements: The study was supported by funding from Celgene Corporation and AACR-Stand Up To Cancer Dream Team Translational Cancer Research Grant (SU2C-AACR-DT0509). Citation Format: N.V Rajeshkumar, Shinichi Yabuuchi, Shweta G. Pai, Scott Bateman, Ellen Filvaroff, Daniel W. Pierce, Carla Heise, Daniel D. Von Hoff, Anirban Maitra, Manuel Hidalgo. Highlights of innovative preclinical studies which guided the rapid bench to bedside development of nab-paclitaxel plus gemcitabine combination for the treatment of pancreatic cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-94. doi:10.1158/1538-7445.AM2014-LB-94

Proper selection of anti-cancer agents at the earliest stage of patient treatment following diagnosis of disease relapse is expected to substantially impact clinical response to treatment. Currently, genomic approaches to personalized cancer treatments have been yielded mixed results, while empirical tests to assess tumor responsiveness have been limited to ex vivo systems that disrupt the native tumor microenvironment and show limited predictive value. To address the need for multiplexed in vivo chemosensitivity testing, we have developed a technology that allows simultaneous assessment of multiple cancer therapeutics directly in a patient's tumor. This technology could provide a valuable decision-making tool to prioritize effective treatments in the oncology clinic. Data herein highlight how this technology enables controlled and reliable microinjection of multiple drugs simultaneously in preclinical tumor models, canine lymphoma, and human lymphoma patients. Consistent with the controlled drug delivery of this system, spatially localized, readily detectable, and mechanism-specific cellular changes were observed around sites of microinjection in response to classic chemotherapy drugs (vincristine and doxorubicin) as well as to a small molecule inhibitor of TOR kinase. Importantly, localized response (or lack thereof) to individual components of CHOP combination therapy correlated with response to long-term systemic drug administration across multiple cell line and patient-derived xenograft models of lymphoma. Underscoring the importance of assessing drug efficacy in the context of an intact in vivo system, tumor responses to vincristine were impacted by the local tumor microenvironment. Our results also emphasize the importance of selecting effective therapies early in the course of treatment, as drug resistance mechanisms induced cross-resistance to otherwise efficacious drugs. These studies set the stage for use of this platform in oncology drug development, where the ability to more rapidly assess drug efficacy using clinically relevant in vivo tumors may decrease the current reliance on in vitro cell-based models of cancer and possibly increase the likelihood of clinical success. This platform may thus be useful a clinical decision-making tool for selection of patient-specific anti-cancer therapies. Citation Format: Richard Klinghoffer, Alicia Moreno-Gonzalez, Michael Carleton, Jason Frazier, Marc Grenley, Ilona Tretyak, Nathan Hedin, Joyoti Dey, Joseph Casalini, Beryl Hatton, Sally Ditzler, James Olson, Daniel Pierce, Ellen Filvaroff, Nathan Caffo. A platform to assess multiple therapy options simultaneously in a patient's own tumor. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3129. doi:10.1158/1538-7445.AM2014-3129

The hepatocyte growth factor (HGF)/Met pathway drives cell proliferation, survival, migration and invasion, which are hallmarks of cancer. Animal models and microarray data suggest that elevated expression of Met is a poor prognostic factor in breast tumors. Our evaluation of primary breast tumors and cell lines has confirmed that expression of Met is found predominantly in the basal sub-type, which includes estrogen receptor (ER), progesterone receptor (PR) and HER2 triple negative (3N) tumors as well as some HER2+ basal tumors. In a panel of 3N basal breast tumors, 96% (25/26) of samples express Met by enzyme-linked immunosorbant assay (ELISA), with 42% (11/26) positive by immuno-histochemistry (IHC). All of the samples were positive for HGF as determined by ECLA, with 32% (8/25) of these primary tumors showing robust staining by IHC. To further explore the biological response of basal breast cancers to HGF, a panel of basal breast cancer cell lines were evaluated in cell proliferation, migration and invasion assays. While most lines tested showed a modest response to HGF in proliferation assays, the migratory and invasive response to HGF was more robust. Assessment of signaling pathways and gene signatures was also performed to better understand the nature of Met signaling leading to biological outcomes. HGF responsive lines were evaluated for growth in transgenic SCID mice expressing human HGF. MetMAb, a potent HGF-blocking Met monovalent monoclonal antibody, acts to inhibit HGF-driven effects in basal breast cancer cell lines in vitro and xenograft growth in vivo. Taken together, these data suggest that Met can drive invasive growth of basal breast tumors, and that treatment with MetMAb, alone or in combination with standard of care, may be therapeutically beneficial in these tumors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1203. doi:10.1158/1538-7445.AM2011-1203

The HGF/Met pathway has attracted interest as a promising target for cancer therapy both due to direct pathway activation in solid tumors as well as to activation as a mechanism of resistance to EGFR pathway inhibition. MetMAb is a recombinant, humanized, monovalent monoclonal antibody that antagonizes HGF driven Met signaling and is currently being evaluated in a clinical trial for NSCLC in combination with Erlotinib, and in phase 1 (in all solid tumors) in combination with Avastin. In this study we explored the utility of candidate pharmacodynamic biomarkers (PDB) in monitoring responses to MetMAb in the Phase Ia clinical trial, including a downstream marker of Met signaling, IL-8, and two proximal markers, serum HGF and shed Met (sMet) extracellular domain (ECD). A panel of four distinct secreted proteins including VEGF, PAI1, IL-8, uPAR were evaluated as potential biomarkers of Met pathway inhibition in preclinical models of efficacy. Of these, IL-8 demonstrated a desirable dynamic range that prompted its evaluation as a potential biomarker of drug activity in a Phase Ia dose ranging study with MetMAb using an MSD based ELISA assay. Circulating IL-8 levels, decreased as early as 24 hours after drug administration in patients that had higher than normal physiologic levels at baseline, irrespective of the MetMAb dose administered. In addition, a dose dependent increase in sMet was observed in all patients. These results are consistent with those obtained in preclinical studies that show that MetMAb can prevent normal clearance of hu-Met-ECD in mice. A trend towards increased circulating HGF levels post MetMAb administration was observed in most patients. However, an exception was noted in one gastric cancer patient that showed an objective complete response to MetMAb treatment. This patient demonstrated significantly higher levels of serum HGF and upon treatment showed an immediate and sustained decrease in circulating serum HGF. These data along with the observation that this patient's tumor co-expressed Met and HGF suggests that MetMAb decreased serum HGF by disrupting an autocrine loop that was driving high serum HGF levels and sustaining tumor growth. The data show that IL-8, HGF and sMet levels can be modulated by treatment with MetMAb. As modulation of IL-8 was observed in most dose groups the utility of this marker to guide dose response is minimal. MetMAb can bind to and prevent the clearance of the Met ECD and the results presented here confirm this phenomenon in patients. Correspondingly, there appears to be no utility of sMet as a biomarker for response to MetMAb. The reduction in serum HGF observed in one patient with an objective CR suggests utility HGF as a MetMAb biomarker may depend on tumor biology. Together, these data have allowed the translation of preclinical biology in humans and demonstrate Met pathway inhibition using MetMAb. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1670.