Mark Matijevic

Immunization with a poly (lactide co-glycolide) encapsulated plasmid DNA expressing antigenic regions of HPV 16 and 18 results in an increase in the precursor frequency of T cells that respond to epitopes from HPV 16, 18, 6 and 11

Abstract A phase II trial was conducted in subjects with human papillomavirus (HPV) associated high-grade cervical dysplasia testing the safety and efficacy of a microparticle encapsulated pDNA vaccine. Amolimogene expresses T cell epitopes from E6 and E7 proteins of HPV types 16 and 18. An analysis was performed on a subset of HLA-A2+ subjects to test whether CD8+ T cells specific to HPV 16, 18, 6 and 11 were increased in response to amolimogene immunization. Of the 21 subjects receiving amolimogene, 11 had elevated CD8+ T cell responses to HPV 16 and/or 18 peptides and seven of these also had increases to corresponding HPV 6 and/or 11 peptides. In addition, T cells primed and expanded in vitro with an HPV 18 peptide demonstrated cross-reactivity to the corresponding HPV 11 peptide. These data demonstrate that treatment with amolimogene elicits T cell responses to HPV 16, 18, 6 and 11.

Evasion of immunosurveillance by genomic alterations of PPARγ/RXRα in bladder cancer

Muscle-invasive bladder cancer (MIBC) is an aggressive disease with limited therapeutic options. Although immunotherapies are approved for MIBC, the majority of patients fail to respond, suggesting existence of complementary immune evasion mechanisms. Here, we report that the PPARγ/RXRα pathway constitutes a tumor-intrinsic mechanism underlying immune evasion in MIBC. Recurrent mutations in RXRα at serine 427 (S427F/Y), through conformational activation of the PPARγ/RXRα heterodimer, and focal amplification/overexpression of PPARγ converge to modulate PPARγ/RXRα-dependent transcription programs. Immune cell-infiltration is controlled by activated PPARγ/RXRα that inhibits expression/secretion of inflammatory cytokines. Clinical data sets and an in vivo tumor model indicate that PPARγHigh/RXRαS427F/Y impairs CD8+ T-cell infiltration and confers partial resistance to immunotherapies. Knockdown of PPARγ or RXRα and pharmacological inhibition of PPARγ significantly increase cytokine expression suggesting therapeutic approaches to reviving immunosurveillance and sensitivity to immunotherapies. Our study reveals a class of tumor cell-intrinsic “immuno-oncogenes” that modulate the immune microenvironment of cancer.Muscle-invasive bladder cancer (MIBC) is a potentially lethal disease. Here the authors characterize diverse genetic alterations in MIBC that convergently lead to constitutive activation of PPARgamma/RXRalpha and result in immunosurveillance escape by inhibiting CD8+ T-cell recruitment.

Use of Interferon-γ ELISPOT in Monitoring Immune Responses in Humans

: The interferon (IFN)-gamma enzyme-linked immunospot (ELISPOT) assay has become a useful tool for immunologists seeking to quantify immune responses on a per-cell basis. The assay is sensitive and allows for the enumeration of low-frequency T-cells. Many have applied this assay to clinical trials as a way to measure biological activity in a patient cohort. It is critical that each laboratory attempting to use the assay in their facility perform rigorous development and qualification work to establish an assay that suits their particular needs. This chapter serves as a demonstration of two practical and slightly different approaches to using the ELISPOT assay to monitor immune activity in the human periphery: (1) assays using whole samples of peripheral blood mononuclear cells with and without the use of additional antigen presenting cells and (2) assays using enriched T-cell populations. Detailed protocols and procedures will be covered, as well as a demonstration of results obtained from three separate applications.

A single dose of the beta-secretase inhibitor, e2609, decreases CSF bace1 enzymatic activity in cynomolgus monkeys

Figure 2. Correlation Between CSF BACE1 Activity Levels and CSF Ab 1-x levels in All Monkey Samples Mark Matijevic, Hideki Watanabe, Yoshiaki Sato, Francois Bernier, Shannon McGrath, Lynne Burns, Noboru Yamamoto, Makoto Ogo, Zoltan Dezso, Jesse Chow, Yoshiya Oda, June Kaplow, Bruce Albala, Eisai, Andover, MA, USA; Eisai, Tsukuba, Japan; Formerly Eisai (when work was completed), Worcester, MA, USA; Eisai, Woodcliff Lake, NJ, USA; Eisai,Woodcliffe Lake, NJ, USA. Contact e-mail: mark_matijevic@eisai.com

453PPHASE 1 STUDY OF THE PARP INHIBITOR E7449 AS A SINGLE AGENT IN PATIENTS WITH ADVANCED SOLID TUMORS OR B-CELL LYMPHOMA

ABSTRACT Aim: E7449 is an orally bioavailable, brain penetrable, potent small-molecule inhibitor of poly (ADP-ribose) polymerase (PARP) 1 and PARP 2 with an IC50 of 1.0 and 1.2 nmol/L respectively. E7449 is a poor P-gp substrate. Preclinically, E7449 potentiates the antitumour activity of chemotherapy and radiotherapy and has activity as a single-agent in BRCA-deficient and other tumours. A Phase 1 study of E7449 as a single agent is underway to determine the MTD, safety, PK, PD, preliminary activity and perform exploratory biomarker analysis. Methods: Patients (pts) with advanced solid tumours or B-cell lymphoma, ECOG PS 0-1, > 18 years (yrs) and adequate organ function are eligible. E7449 is administered orally, once daily (QD), continuously. Blood samples for PK, PD and biomarkers are collected at multiple time points. Results: 28 pts have been treated at 6 dose levels: 50, 100, 200, 400, 800 and 600 mg QD. Tumour types most frequently included were pancreatic (n = 5), ovarian (n = 5) and lung (n = 4). Five DLTs have been observed, four at 800 mg: Gr3 fatigue (n = 1) and Gr2 fatigue requiring more than 7days (d) dose interruption (n = 3) and one at 600 mg, drug interruption for more than 7d and Gr3 allergic reaction. The MTD was achieved at 600 mg QD. Frequently occurring related adverse events (AEs) (any grade) are fatigue: 48% (Gr3: 12%), photosensitive rash (48%), diarrhoea and nausea: 32% each, chromaturia: 28%, depression: 20%, and decreased appetite: 20% (Gr3: 4%). No significant haematological toxicity and no Gr4 related or fatal AEs have been reported. One PR in a high grade serous ovarian (HGSO) cancer pt (BRCA unknown) and 6 SD for >23 weeks have been observed (one in a pancreatic cancer pt with BRCA2 variant of uncertain significance, one in a HGSO cancer pt BRCA mutant). E7449 PK exhibits rapid absorption, tmax ∼1.5 hrs and elimination t1/2 ∼9 hrs, with dose proportional exposures. Sustained PARP inhibition (PARPi) of ∼90% is observed in PMBCs at 600 mg QD. Predictive biomarker analysis is ongoing. Conclusions: In this study, E7449 was generally well tolerated at the MTD of 600 mg QD, with preliminary evidence of antitumour activity and sustained PARPi in PMBCs. Further evaluation will continue in Phase 1b/2 combination studies. Disclosure: B.D.L. Heras: I am Director of Clinical Development, Eisai Inc; B. Ink: I am Director of Project Management, Eisai Ltd; M. Matijevic: Associate Director, Eisai Inc.; D. Sarker: I have a consultant/advisory relationship to disclose at Eisai Inc.All other authors have declared no conflicts of interest.

Abstract B185: Phase I study of the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of the poly(ADP-ribose) polymerase (PARP) inhibitor E7016 in combination with temozolomide (TMZ) in patients with advanced solid tumors.

Background: E7016 is an orally bioavailable, nicotinamide mimetic PARP1 and PARP2 inhibitor. E7016 was shown to enhance the cytotoxic effect of the alkylating agent temozolomide (TMZ) in vivo through inhibition of PARP-mediated DNA repair. This phase I study was conducted to determine the maximum tolerated dose (MTD), dose-limiting toxities (DLTs), pharmacokinetics (PK) and pharmacodynamics (PD) of E7016 in combination with TMZ in patients (pts) with advanced solid tumors. Methods: Eligible pts had performance status 0–2; ≥ 18 yrs of age; adequate bone marrow, hepatic and renal function. Treatment cycles were 28 days. E7016 was administered orally once on Day −7 and then orally once daily on Days 1 through 7 of each 28-day cycle. TMZ was administered orally once daily at 150 mg/m 2 /d on Days 1 through 5 of the same 28-day cycle. Blood samples for PK assessment of E7016 and its two metabolites M1 and M2 were collected post-dose on Day −7 and then on Days 1, 5 and 7 of Cycle 1 and for PK assessment of TMZ on Days 1 and 5 of Cycle 1. Peripheral blood mononuclear cells (PBMCs) were collected for PD assessments including, PARP inhibition and DNA damage using COMET assay. Results: 12 pts were enrolled with carcinomas arising in kidney (1), breast (5), lung (1), ovary (2), colon (1), uterus (1), nasopharynx (1); median age was 55 years (38–64); M:33%, F:67%; median ECOG PS was 1 (0–2). Three patients were treated at the starting dose of 8 mg/kg which was found to be intolerable due to DLTs comprising tachychardia (n=2), hypotension (n=1) and presyncope (n=2). The dose was subsequently reduced to 4 mg/kg and 9 pts were treated at this dose level with no DLTs were observed. The most frequent adverse events (AEs) (all grades) at this dose level were fatigue 55.6% (Gr3: 33%), nausea 44.4% (Gr3: 0%), vomiting 44.4% (Gr3: 0%), headache 33.3% (Gr3: 11.1%), decreased appetite 22.2% (Gr3: 0%), anaemia 22.2% (Gr3: 11.1%). There was one grade 4 event at 4 mg/kg with hyponatraemia. PARP inhibition and increased DNA damage were observed in PBMC up-to 10 h after treatment with E7016 alone or in combination with TMZ. E7016 mean C max and AUC demonstrated a non-linear increase with dose. E7016 exhibited terminal half-life (12–16 h) with a T max between 3–8 h. Metabolic ratio of M1 and M2 was Conclusions: The combination of E7016 with TMZ was feasible with MTD established as 4 mg/kg of E7016 oral once daily given Days 1–7 and 150 mg/m 2 /d TMZ given Days 1–5 (28-day cycles). PD analysis demonstrated that E7016, administered alone or in combination with TMZ, inhibited PARP activity in PBMCs with a concomitant increase in DNA damage. Further evaluation of E7016 in combination with TMZ will continue in a planned Phase 2 Study of E7016 and TMZ in advanced melanoma patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B185.

Abstract P5-06-03: Combination of the PARP inhibitor E7449 with eribulin +/- carboplatin in preclinical models of triple negative breast cancer

Introduction: In a small neoadjuvant study in patients with triple negative breast cancer (TNBC) the combination of eribulin plus carboplatin was effective, with a pathologic complete response rate of 43% following 4 cycles of treatment. Significant numbers of sporadic TNBC tumors are deficient in DNA repair capacity and share clinical and pathological features with hereditary BRCA1 mutant disease. PARP inhibitors have demonstrated synthetic lethality in cancer cells with defective DNA repair and have therapeutic potential for TNBC. In this study we describe the combination of PARP inhibitor E7449 with eribulin +/- carboplatin in preclinical models of TNBC. Methods: E7449, an orally available PARP inhibitor, was administered in combination with eribulin +/- carboplatin to 4 s.c. xenograft models of TNBC: MDA-MB-436 (BRCA1 mutant, PTEN deficient), MDA-MB-468 (BRCA wild type, PTEN deficient), HCC1806 and MDA-MB-231 (BRCA and PTEN wild type). Results and Discussion: Addition of E7449 to eribulin significantly delayed tumor progression in PTEN deficient MDA-MB-468 xenografts. In the BRCA1 mutant and PTEN deficient MDA-MB-436 xenograft model, combination of E7449 with eribulin enhanced antitumor activity versus eribulin alone. Similar potentiation was observed for carboplatin upon combination with E7449. Treatment of MDA-MB-436 xenografts with the triple combination of E7449 + eribulin + carboplatin was more efficacious than any double combination and was well tolerated at the doses examined. In contrast, no significant combination activity was observed for E7449 plus eribulin in the BRCA and PTEN wild type xenografts HCC1806 and MDA-MB-231, and similarly no potentiation of carboplatin was observed in an MDA-MB-231 xenograft. Notably, combination activity was observed in the BRCA1 mutant (MDA-MB-436) and PTEN deficient (MDA-MB-436 and MDA-MB-468) xenografts and not in the BRCA and PTEN wild-type models (HCC1806 and MDA-MB-231). Data from ongoing studies to evaluate the combination activity of E7449 + eribulin in patient-derived xenograft (PDx) models of TNBC will be presented at the meeting. Potential biomarkers of sensitivity to the combination are under investigation in both cell line xenograft and PDx models and will be described. Conclusion: The addition of E7449 to eribulin +/- carboplatin increased antitumor activity in a subset of TNBC models. Biomarker studies aimed at a better understanding of the underlying cause of sensitivity are underway. The preclinical data support assessment of E7449 + eribulin + carboplatin combination therapy in the current phase I/II clinical trial. Citation Format: Sharon McGonigle, Jiayi Wu, Donna Kolber-Simonds, Natalie C Twine, Jue-lon Shie, Noel Taylor, Sergei Agoulnik, Zoltan Dezso, Shannon McGrath, Mark Matijevic, Shanqin Xu, Galina Kuznetsov, Mary Woodall-Jappe, Kenichi Nomoto. Combination of the PARP inhibitor E7449 with eribulin +/- carboplatin in preclinical models of triple negative breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-06-03.