Short-Course Toll-Like Receptor 9 Agonist Treatment Impacts Innate

Clinical Infectious Diseases Head1=Head2=Head1=Head2/Head1 MAJOR ARTICLE Head2=Head3=Head2=Head3/Head2 Head1_First=Head2=Head1_First=Head2/Head1 NList_dot_numeric2=NList_lc_dot_alpha_Sub1=NList_dot_ numeric=NList_lc_dot_alpha_Sub Short-Course Toll-Like Receptor 9 Agonist Treatment App_Head1=App_Head2=App_Head1=App_Head2/Head1 Impacts Innate Immunity and Plasma Viremia in Individuals With Human Immunodeficiency Virus Infection Line Vibholm,1,2,a Mariane H. Schleimann,1,2,a Jesper F. Højen,1,2 Thomas Benfield,3 Rasmus Offersen,1,2 Katrine Rasmussen,1 Rikke Olesen,1 Anders Dige,2,4 Jørgen Agnholt,2,4 Judith Grau,5 Maria Buzon,5 Burghardt Wittig,6 Mathias Lichterfeld,7 Andreas Munk Petersen,8,9 Xutao Deng,10,11 Mohamed Abdel-Mohsen,10,11,12 Satish K. Pillai,10,11 Sofie Rutsaert,13 Wim Trypsteen,13 Ward De Spiegelaere,13,14 Linos Vandekerchove,13 Lars Østergaard,1,2 Thomas A. Rasmussen,1 Paul W. Denton,1,2 Martin Tolstrup,1,2 and Ole S. Søgaard1,2 1Department of Infectious Diseases, Aarhus University Hospital, 2Institute of Clinical Medicine, Aarhus University, 3Department of Infectious Diseases, Hvidovre Hospital, University of Copenhagen, and 4Department of Hepatology and Gastroenterology, Aarhus University Hospital, Denmark; 5Hebron Institute of Research, Department of Infectious Diseases, Barcelona, Spain; 6Foundation Institute Molecular Biology and Bioinformatics, Freie Universitaet, Berlin, Germany; 7Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Boston; Departments of 8Gastroenterology and 9Microbiology, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark; 10Blood Systems Research Institute, San Francisco, California, and 11University of California, San Francisco; 12The Wistar Institute, Philadelphia, Pennsylvania; and Departments of 13Internal Medicine; and 14Morphology, Faculty of Veterinary Medicine, Ghent University, Belgium (See the Editorial Commentary by Cyktor and Mellors on pages 1696–8.) Background. Treatment with latency reversing agents (LRAs) enhances human immunodeficiency virus type 1 (HIV-1) transcription in vivo but leads to only modest reductions in the size of the reservoir, possibly due to insufficient immune-mediated elimination of infected cells. We hypothesized that a single drug molecule—a novel Toll-like receptor 9 (TLR9) agonist, MGN1703— could function as an enhancer of innate immunity and an LRA in vivo. Methods. We conducted a single-arm, open-label study in which 15 virologically suppressed HIV-1–infected individuals on antiretroviral therapy received 60 mg MGN1703 subcutaneously twice weekly for 4 weeks. We characterized plasmacytoid dendritic cell, natural killer (NK), and T-cell activation using flow cytometry on baseline and after 4 weeks of treatment. HIV-1 transcription was quantified by measuring plasma HIV-1 RNA during MGN1703 administration. Results. In accordance with the cell type–specific expression of TLR9, MGN1703 treatment led to pronounced activation of plasmacytoid dendritic cells and substantial increases in plasma interferon-α2 levels (P < .0001). Consistently, transcription of interferon-stimulated genes (eg, OAS1, ISG15, Mx1; each P < .0001) were upregulated in CD4+ T cells as demonstrated by RNA sequencing. Further, proportions of activated cytotoxic NK cells and CD8+ T cells increased significantly during MGN1703 dosing, suggesting an enhancement of cellular immune responses. In 6 of 15 participants, plasma HIV-1 RNA increased from <20 copies/ mL to >1500 copies/mL (range, 21–1571 copies/mL) during treatment. Conclusions. TLR9 agonist treatment in HIV infection has a dual potential by increasing HIV-1 transcription and enhancing cytotoxic NK cell activation, both of which are key outcomes in HIV-1 eradication therapy. Clinical Trials Registration. NCT02443935. Keywords. latent HIV-1 infection; latency reversal; TLR9 agonist; immune therapeutic treatment; NK cell activation. Antiretroviral therapy (ART) effectively suppresses human capable of eliminating this latent viral reservoir [6]. Proof-of- immunodeficiency virus type 1 (HIV-1) [1]. However, replica- concept trials testing the “shock and kill” approach [7] to eradi- tion-competent proviruses persist in long-lived resting memory cate the reservoir have demonstrated that treatment with latency CD4+ T cells [2–5] and neither ART nor the immune system is reversing agents (LRAs) can enhance transcription of HIV-1 RNA from latently infected cells in vivo [8–12]. Yet clinical trials have Received 17 December 2016; editorial decision 21 January 2017; accepted 3 March 2017; found no, or only modest, reductions in the size of the HIV-1 published online March 9, 2017. reservoir, possibly due to insufficient immune-mediated killing aL. V. and M. H. S. contributed equally to this work. Correspondence: O. Søgaard, Department of Infectious Diseases, Aarhus University Hospital, of infected cells [13]. In vivo and ex vivo studies demonstrate that Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark ([email protected]). priming of specific effector cells, such as cytotoxic T lymphocytes Clinical Infectious Diseases® 2017;64(12):1686–95 (CTLs) and natural killer (NK) cells, can enhance their capacity © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: [email protected]. to recognize and kill infected cells [13–17]. This indicates that DOI: 10.1093/cid/cix201 therapeutic interventions boosting NK and CTL activity could 1686 • CID 2017:64 (15 June) • Vibholm et al lead to elimination of cells expressing HIV-1 antigens. MGN1703 available at ClinicalTrials.gov, identifier NCT02443935). Prior (lefitolimod), a novel Toll-like receptor 9 (TLR9) agonist, belongs to enrollment, subjects underwent a general physical examina- to a class of drugs referred to as immune surveillance reactiva- tion, electrocardiogram recording, and safety laboratory tests. tors and is currently in phase 3 testing for treatment of metastatic The study was approved by the National Health Ethics colorectal cancer [18]. Preclinical testing and data from cancer Committee, Denmark (case number 1-10-72-10-15), the Danish trials demonstrates that MGN1703 activates immune functions Medicines Agency (case number 2015014125), and the Danish through TLR9 stimulation. MGN1703-induced TLR9 signaling Data Protection Agency. The trial was monitored in accordance leads to increased secretion of a range of cytokines (eg, interferon with the principles for good clinical practice. Each patient pro- [IFN] α) and activation of plasmacytoid dendritic cells (pDCs) vided written informed consent prior to any study procedures. and B cells [18]. Furthermore, MGN1703 increases activation and cytotoxicity of NK cells in vitro [19]. We recently demon- Procedures strated ex vivo that MGN1703 stimulation of peripheral blood As 120 mg MGN1703 per week is considered safe in can- mononuclear cells from HIV-1–infected donors enhanced the cer patients and healthy controls [18, 21, 22], study partici- cellular immune response and increased HIV-1 transcription in pants received 4 weeks of 60 mg (concentration 15 mg/mL) of CD4+ T cells [20]. Based on our ex vivo findings, we hypothesized MGN1703 (MOLOGEN AG, Berlin, Germany), administered that adjunctive MGN1703 treatment in individuals with HIV subcutaneously by the study investigator as two 2-mL bilateral infection would (1) augment NK and CD8+ T-cell activation and injections twice weekly. ART was maintained during the entire (2) induce plasma viremia. To test our hypotheses, we enrolled 15 study period. The study comprised 15 visits and the total dura- virologically suppressed HIV-1–infected individuals on ART to tion was 141 days for each participant. Blood samples for safety receive MGN1703 for 4 consecutive weeks. and laboratory analyses were collected 2–5 times per week during dosing, always prior to MGN1703 administration if sched- uled. Participants returned for postdosing visits 14 days and MATERIALS AND METHODS 6 weeks after completion of MGN1703 treatment. Safety was Study Design assessed at each visit. Laboratory abnormalities were registered This trial was an investigator-initiated, single-arm, open-la- as adverse events (AEs) when they were associated with clinical bel phase 1b/2a trial conducted from April to December 2015. symptoms or objective signs, with the exception of neutropenia. We enrolled adults from the HIV outpatient clinics of Aarhus AEs were graded in accordance with the Common Terminology University Hospital and Hvidovre Hospital, Denmark (Figure Criteria for Adverse Events (CTCAE) version 4.0, and the inves- + 1). Inclusion criteria were CD4 T-cell count >350 cells/μL, tigators assessed causality to the study drug. Nonstandard lab- plasma HIV-1 RNA < 50 copies/mL, and on ART >12 months. oratory analyses are described in the Supplementary Materials. Exclusion criteria were hepatitis B or C coinfection, fever of unknown origin, antibiotic treatment or significant acute med- Biostatistical Analyses ical illness 2 weeks prior to inclusion, autoimmune disease, As NK cell activation was the primary outcome, the study was and pregnancy (complete list of inclusion/exclusion criteria is powered to detect change in CD69+ expression on NK cells Figure 1. Recruitment of participants and outline of study design. A, Flow diagram depicting the recruiting of human immunodeficiency virus–infected participants for MGN1703 treatment. B, Outline of

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