ERA/EDTA Sunday, May 22, 2016. Conference runs May 21 to May 24.

Poster Session: Renal pathology. Experimental and clinical - 1

[SP071] APABETALONE (RVX-208), A SELECTIVE BROMODOMAIN AND EXTRA-TERMINAL (BET) PROTEIN INHIBITOR, DECREASES ABUNDANCE AND ACTIVITY OF COMPLEMENT PROTEINS IN VITRO, IN MICE AND IN CLINICAL STUDIES

Norman C. W. Wong1, Kamyar Kalantar-Zadeh2, Ewelina Kulikowski1, Sylwia Wasiak1, Dean Gilham1, Christopher Halliday1, Mike Sweeney3, Jan Johansson3, 1Resverlogix Corp, Scientific Development, Calgary, AB, CANADA, 2University of California Irvine, School of Medicine, Irvine, CA, 3Resverlogix Corp, Clinical Development, Calgary, AB, CANADA.

INTRODUCTION AND AIMS: RVX-208, an orally active small molecule, reduced incidence of major acute cardiac events in patients with cardiovascular disease (CVD) and potentially improved eGFR in a subpopulation with chronic kidney disease (CKD) in phase II clinical studies. RVX-208 inhibits the epigenetic readers bromodomain and extraterminal (BET) proteins by competing with acetylated lysines on histones tails that are associated with active transcription. Previously, microarray studies of primary human hepatocytes (PHH) have shown a downregulation of several complement genes (19 of 26). Since activation of complement in the kidney has been associated with renal disease and reduction in complement activation is beneficial for kidney function, we have examined the effect of RVX-208 on complement expression and activity in vitro, in mice and in clinical samples.

METHODS: Effects of RVX-208 on mRNA expression and secretion of complement proteins was examined in cultured PHH. Expression of complement genes was studied in mice treated with RVX-208 (150 mg/kg, 3 days, b.i.d.). Circulating complement proteins and complement activity were quantified in clinical samples using proteomics approaches and hemolytic assays, respectively.

RESULTS: RVX-208 downregulated basal and inflammatory mRNA expression and protein secretion of complement C3, C4, C5 and C9 in cultured PHH by 10%-100%. Chimeric mice with humanized livers treated with RVX-208 decreased expression of C4, C9 and MBL2 mRNA by 36%, 46% and 61%, respectively. Proteomic analysis of clinical samples showed a significant decrease in circulating complement proteins following treatment with RVX-208 (between -5% and -20%, vs. baseline). To establish if the observed decrease in protein abundance affected activity, CH50 and AH50 hemolytic assays were performed on 11 plasma samples from patients with CVD at baseline and after 26 weeks of RVX-208 treatment. A significant decrease in activity of approximately 26% (p<0.01) was observed in both assays. No increase in infections was reported in phase II trials.

CONCLUSIONS: RVX-208 decreases complement component expression and cascade activity, which may result decreased pathologic activation of complement in CKD. The potential of RVX-208 for the treatment of high-risk diabetes and CKD patients is currently being explored in the phase III BETonMACE clinical study.

EAS Monday May 30, 2016. Coonference runs from May 29 to June 1

YIS03 Young Investigator Session, Clinical Epidemiology and Pharmacology

Oral Presentation

Abstract: APABETALONE (RVX-208) DECREASES ATHEROGENIC, THROMBOTIC AND INFLAMMATORY MEDIATORS IN VITRO AND IN PLASMA OF PATIENTS WITH CARDIOVASCULAR DISEASE (CVD).

N. Wong 1, E. Kulikowski 1, S. Wasiak 1, D. Gilham 1, C. Calosing 1, T. Laura 1, C. Halliday 1, J. Johansson 2, M. Sweeney 2. 1Resverlogix Corporation, Pharmacology, Calgary, Canada; 2Resverlogix Corporation, Clinical Development, San Francisco, USA

Aim: RVX-208 inhibits bromodomain and extra-terminal (BET) proteins from binding to acetyl-lysine marks on histone tails, thereby modulating gene activity. In SUSTAIN and ASSURE phase IIb trials of patients (n=499) with CVD, RVX-208 lead to a 55% relative risk reduction in major adverse cardiovascular events (MACE) vs. placebo. This marked reduction is unlikely from RVX-208’s modest induction of ApoA-I/HDL, thus prompting studies of RVX-208 for benefits beyond lipids.

Methods: Microarrays of human whole blood (WB) or primary hepatocytes (PH) exposed to RVX-208. Cytokines assayed in LPS and RVX-208 treated U937 macrophage and peripheral blood mononuclear cells (PBMC). Patient’s plasma proteins assayed by SOMAScan.

Results: In WB, microarray data showed RVX-208 affected atherogenesis by suppressing 37/46 pro-atherogenic while inducing 8/18 anti-atherogenic genes. In addition, RVX-208 had potential anti-thrombotic properties by affecting 18 genes related to platelet function (e.g. downregulation of CD64 and thrombospondin 1). RVX-208 had anti-inflammatory effects on expression of >25 cytokines, including downregulation of MCP-1, osteopontin and PARC genes in WB, U937 and/or PBMCs. Furthermore, plasma protein levels of MCP-1, osteopontin and PARC were lower in treated patients. Why RVX-208 affected genes connected to CVD was explored by exposing PH to RVX-208. This lead to a 25% reduction in mRNA encoding flavin mono-oxygenase-3 (FMO3), an enzyme that produces trimethylamine oxide (TMAO) a metabolite which predicts CVD risk.

Conclusion: Epigenetic actions of RVX-208 leading to beneficial effects on many genes with known roles in atherogenesis, thrombosis and inflammation may underlie the ability of RVX-208 to reduce MACE in clinical trials.