536 In vitro and in vivo efficacy of nitric oxide-releasing antiviral therapeutic agents

Abstract

536 In vitro and in vivo efficacy of nitric oxide-releasing antiviral therapeutic agents KA McHale, K Balogh, H Wang, S Hollenbach, N Christensen, L Chow, T Broker and N Stasko 1 Novan, Inc, Durham, NC, 2 Department of Experimental Pathology, Pennsylvania State University at Hershey Park, Hershey, PA and 3 Department of Biochemistry & Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL The efficacy of topical nitric oxide-releasing therapeutics to inhibit viral replication was demonstrated in vitro and in vivo. NVN1000 or NVN4000 drug substance, dissolved in phosphate buffered saline, was applied 1 hour/day for 6 days to organotypic cultures of primary human keratinocytes containing HPV-18 genomic replicons. Preliminary results indicate a dose responsive reduction of viral DNA copy number to less than 20% of the untreated cultures. At the highest concentrations applied (1.5 mg or 2 mg/ml), no cytotoxicity was detected, as judged from hematoxylin and eosin staining of normal or HPV-18 containing raft cultures. The NVN1000 drug substance was formulated into SB206 gel and the ability of a daily topical drug product (5 doses/week for 8 weeks) to inhibit papilloma growth in vivo was assessed in the Cottontail Rabbit Papillomavirus (CRPV) model. Dosing of SB206 gel was initiated two weeks after inoculation of CRPV viral DNA into the scarified skin sites. Topical SB206 treatment inhibited papilloma formation in a dose dependent fashion with the highest dose, 10% SB206 gel, achieving 82% inhibition compared to the Vehicle control group. Blinded histological analysis of biopsies from 10% SB206-treated animals exhibited mild hyperplasias, with an absence of viral infection as evidenced by a lack of intra-nuclear basophilic inclusions. Qualitative assessment of inflammation and quantitative cytokine gene expression was similar across all dose groups, suggesting immune activation did not account for the efficacy observed in the CRPV model and supports a direct anti-viral effect of Novan’s nitric oxide releasing therapeutic agents. SB206 Gel is currently being evaluated as a topical therapy for external genital warts in a Phase 2 clinical trial. 537 Topical application of chitosan-based nanoformulated green tea polyphenol EGCG ameliorates imiquimod-induced psoriasis-like skin lesion in mice J Chamcheu, I Siddiqui, V Adhami, S Dodwad, D Bharali, G Wood, S Mousa and H Mukhtar Dermatology, University of Wisconsin Madison, Madison, WI Psoriasis is a chronic and currently incurable inflammatory skin disease characterized by hyperproliferation, aberrant differentiation and inflammation, leading to disrupted skin barrier function. The use of natural agents that possess the ability to abrogate these effects could be useful for the treatment of psoriasis. Earlier studies have shown that treatment of keratinocytes and mouse skin with the green tea polyphenol, epigallocatechin-3-gallate (EGCG), increased the expression of caspase-14 that is involved in epidermal differentiation and cornification. However, dose and bioavailability restrict the therapeutic development and application of EGCG in the treatment of psoriasis. To overcome these limitations, we developed fully characterized, chitosan-based nanocarrier to encapsulate EGCG (hereafter termed as nanoEGCG) suitable for topical delivery. Here, we assessed the efficacy of nanoEGCG (48mg/ animal) using an IMQ-induced mouse psoriasis-like skin model and compared the effects to free EGCG (1mg/amimal). Treatment with nanoEGCG resulted in significant (p<0.01) amelioration of pathological markers of psoriasiform lesions including reduction in i) ear and skin thickness, erytherma and scales, ii) proliferation (Ki-67), iii) infiltratory immune cells (mast cells, neutrophils, macrophages and CD4+ T cells), iv) angiogenesis (CD31), and v) increase in the protein expression of caspase-14, early (K1 and k10) and late (filaggrin and loricrin) differentiation markers and AP-1 factors (JunB and cJun), and (v) modulates several psoriasis-related inflammatory cytokines and chemokines analyzed compared to high dose of free EGCG (p<0.05). Taken together, topical application of nanoEGCG was found to ameliorate IMQ-induced Balb/c mouse psoriasis-like lesions with greater than 25-fold dose advantage over free EGCG. Our observations warrant further in vivo efficacy studies of this unique nanoEGCG formulation in robust inducible and genetic models of psoriasis.