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Provides basic scientific knowledge on a range of HIV cure research related topics 2. Strengthens community capacity to participate in and make decisions about HIV cure research 3. Promotes the ethical development and implementation of HIV cure clinical studies 1.

THERAPEUTIC VACCINES AND IMMUNE-BASED THERAPIES HIV Cure Research Training Curriculum Richard Jefferys, Treatment Action Group Jeffrey Jacobson, Drexel University May 2015 The HIV CURE training curriculum is a collaborative project aimed at making HIV cure research science accessible to the community and the HIV research field.

Table of Contents Therapeutic Vaccines Passive immunization Adoptive immunotherapy Immune-based therapies (IBTs) Future directions and challenges

Therapeutic vaccination Rationale: strengthen or create new and more effective immune responses to HIV in HIV-positive individuals • Challenging because CD 4 T cells normally play a central role in coordinating the immune response to infection • • CD 4 T cells are the primary target of HIV and are disrupted and killed by the virus • CD 4 T cells targeting HIV (HIV-specific CD 4 T cells) are preferentially infected

Types of immune response • Innate immunity • Consists of non-specific responses to pathogens based on shared features • Transient activity • Adaptive immunity • Specifically recognizes pathogen fragments (antigens) • CD 4 T cells, CD 8 T cells, B cells (produce antibodies), natural killer cells (possibly) • Responses persist as “memory” cells

Therapeutic vaccination Generate long-lived adaptive immune responses targeting HIV antigens • Induction of innate immunity can help generate adaptive immune responses (e. g. via vaccine adjuvants) • Focus has been on CD 4 T cell and CD 8 T cell responses (cellular immunity) • Increasing interest in B cells due to potential to produce antibodies that can flag virusinfected cells for destruction •

Therapeutic vaccines Use various methods to deliver noninfectious HIV antigens into the body (most often injection into muscle tissue) • Antigens are picked up and processed by immune system sentinels called antigenpresenting cells (dendritic cells and macrophages) • Antigens then presented to CD 4 T cells, CD 8 T cells and B cells, inducing immune responses •

Types of therapeutic vaccines • DNA and RNA vaccines • Consist simply of genetic code for HIV antigens • Viral vector vaccines • Genetic code for HIV antigens inserted into modified non -pathogenic virus e. g. canarypox (ALVAC), modified Vaccinia Ankara strain (MVA), adenoviruses, lentiviruses • Protein or peptide vaccines • Mimics of HIV proteins or protein fragments (peptides) • Dendritic cell vaccines • Extract antigen-presenting dendritic cells, mix with HIV antigens outside the body (sometimes HIV antigens derived from individual’s virus), then injected as vaccine

Therapeutic vaccine studies So far, mostly studied in people on antiretroviral therapy (ART) (some exceptions) with impact on viral load measured after ART interruption • A few studies have reported significant reductions in viral load associated with therapeutic vaccination, albeit typically transient •

Fig. 2 Change in p. VL from baseline (before any antiretroviral therapy) after immunizations and second interruption of antiretroviral therapy. Felipe García et al. , Sci Transl Med 2013; 5: 166 ra 2 Published by AAAS

Therapeutic vaccines in cure research Goal for therapeutic vaccination has largely shifted to elimination of latent HIV reservoir • Therapeutic vaccines are being combined with latency-reversing agents (LRAs) • The rationale: • • LRA triggers latent HIV to produce viral proteins • HIV antigens are expressed by infected cell • Immune responses induced by therapeutic vaccine recognize HIV antigens and kill infected cell (T cells) or flag for destruction (antibodies)

Therapeutic vaccines in cure research Stephen A. Migueles and Mark Connors. Small Molecules and Big Killers: The Challenge of Eliminating the Latent HIV Reservoir, Cell, Volume 36, Issue 3, p 320– 321, 23 March 2012

Therapeutic vaccine trials 2015 2016 Q 1 Ch. Ad. V 63. HIVco ns + MVA. HIVconsv Q 2 AGS-004 Vac-3 s 2017 2018 GTU-Multi. HIV + LIPO-5 GTU®-Multi. HIV B Clade Vaccine Vac-3 s Tat-Oyi RIVER: Ch. Ad. V 63. HIVcons v + MVA. HIVconsv vaccines, vorinostat Q 3 Q 4 Vacc-4 x + romidepsin THV 01 HIVAX IHIVARNA-01 MAG-p. DNA + r. VSVIN HIV-1 Gag http: //www. treatmentactiongroup. org/cure/trial

Therapeutic vaccines in cure research Ongoing trial in Denmark is combining the LRA romidepsin (an HDAC inhibitor) with therapeutic vaccine Vacc-4 x (consisting of HIV peptides) • Planned UK trial named RIVER aims to combine an LRA with two viral vector-based therapeutic HIV vaccines (chimpanzee adenovirus & MVA) • Planned US CARE collaboratory trial will combine an LRA with a dendritic cell-based therapeutic HIV vaccine (AGS-004) •

Unconventional therapeutic vaccines • VAC-3 S aims to prevent CD 4 T cell depletion by inducing antibodies to block a mechanism believed to be involved in triggering immune activation and CD 4 T cell death (as opposed to targeting HIV directly) • Ongoing trials • Vacc-C 5 also aims to induce antibodies that may block immune activation • Trial completed, results pending • A vaccine that suppresses immune responses to SIV has been reported to protect macaques from infection and suggested to have therapeutic potential • Clinical trial planned, possible launch toward end of 2015

Passive immunization • • • The most effective type of antibody response is called a broadly neutralizing antibody (b. NAb) response b. NAbs can potently inhibit a broad array of different HIV isolates from multiple clades Unfortunately, no vaccine can induce the production of b. NAbs (as yet) b. NAbs have been isolated from the B cells of some HIV-positive individuals (not present at sufficient levels to benefit the individual) These isolated b. NAbs are being manufactured and can be administered via infusion or subcutaneous injection (passive immunization)

Single 3 BNC 117 infusion – Antiviral ac 30 mg/kg Dr. Sarah Schlesinger, Rockefeller University, AVAC webinar: New Frontiers in HIV Prevention, Treatment and Cure, Tuesday April 21, 2015: http: //www. avac. org/blog/new-frontiers-hiv-prevention-treatment-and-cure

Passive immunization in cure research Some antibodies have the capacity to flag infected cells expressing HIV antigens for destruction by antibody-mediated cellular cytotoxicity (ADCC) and antibody-mediated cellular phagocytosis (ADCP) • Destruction performed by natural killer (NK) cells and monocytes • As with therapeutic vaccines, interest in combining passive immunization with LRAs (promising results in humanized mice) •

Ariel Halper-Stromberg et al. Broadly Neutralizing Antibodies and Viral Inducers Decrease Rebound from HIV-1 Latent Reservoirs in Humanized Mice, Cell , Volume 158, Issue 5, p 989– 999, 28 August 2014

Passive immunization in cure research • Ongoing studies of b. NAbs in HIV-positive individuals • VRC 01 • 3 BNC 117 • Additional studies planned • VRC 01 + ART in acute HIV infection • 3 BNC 117 effect on HIV reservoir, effect on viral load rebound after ART interruption • PGT 121 • VRC 07 • 3 BNC 117 + 10 -1074 • b. NAbs + LRAs

Antibody gene transfer • • • An alternative approach to b. NAb delivery also being studied Employs adeno-associated virus (AAV) vector to deliver gene for making b. NAb(s) into muscle tissue AAV persists and produces supply of b. NAb Method used with some success to deliver factor IX to hemophiliacs Ongoing Phase I trial of AAV encoding b. NAb PG 9 in HIV- individuals in UK AAV also being considered to deliver potent antibody-like protein inhibitor of HIV (e. CD 4 -Ig) based on promising macaque results

Adoptive immunotherapy Instead of infusing b. NAbs, adoptive immunotherapy infuses HIV-specific T cells • T cells are extracted from an individual, cultured with HIV antigens and expanded in the laboratory, then reinfused into the individual • Goal of promoting elimination of HIV-infected cells (similar to therapeutic vaccination) • Clinical trials ongoing • • HXTC (US CARE collaboratory) • Autologous HIV-specific CD 8 T cells (China)

Immune-based therapies (IBTs) • Broad category of therapies including: • Substances produced by the immune system (e. g. cytokines) • Approaches that aim to work via modulation of the immune system

Cytokines Interleukin-7 (IL-7) studied as a latencyreversing agent but did not work (promoted proliferation of latently infected cells) • IL-15 being studied as a potential latencyreversing agent & promoter of natural killer cell activity • • Clinical trial of ALT-803 (recombinant human super agonist interleukin-15 complex) due to start soon

Cytokines IL-21 has been reported to limit the viral reservoir in SIV-infected macaques, researchers plan to study in HIV-positive individuals (already in trials for cancer) • Alpha interferon is approved for the treatment of hepatitis C, several trials are studying impact on the HIV reservoir • • Small study reported reductions in levels of integrated HIV DNA

Toll-like receptor (TLR) agonists Class of compounds that interact with immune cell receptors involved in nonspecific recognition of pathogens (toll-like receptors or TLRs) • Several TLR agonists being studied as potential latency-reversing agents & promoters of innate immunity • • MGN 1703 (TLR-9 agonist) • Poly-ICLC (TLR-3 agonist) • GS-9620 (TLR-7 agonist)

James Whitney et al. Treatment With a TLR 7 Agonist Induces Transient Viremia in SIV-Infected ART-Suppressed Monkeys, Abstract 108, CROI 2015, Seattle, Washington, February 23 -26, 2015

Immune checkpoint blockers Certain immune cell receptors known as immune checkpoints (or negative regulators) are involved in dampening immune responses • Expression of these receptors can impair HIV -specific T cell responses • Also appear involved in maintaining latently infected CD 4 T cells in quiescent state • Examples include PD-1, CTLA-4, LAG 3, TIGIT •

Immune checkpoint blockers • • • Antibodies that block these receptors (or the ligands they interact with) may both enhance HIV-specific T cell responses and reverse HIV latency Ongoing study of an antibody to PD-L 1 in HIV-positive individuals on ART Plans to study an antibodies to PD-1, CTLA-4 Several of these antibodies are now licensed treatments for cancers Can have significant side effects, including autoimmunity

Immune checkpoint blockers Stephen Mason, Bristol-Myers Squibb, The potential role of PD-1/PD-L 1 blockade in HIV Remission & Cure, Community Cure Workshop, February 22, 2015 Seattle, WA

Ethical considerations for therapeutic vaccines • Therapeutic vaccine trials often (although not always) include ART interruptions to assess if vaccine-induced immune responses can exert an anti-HIV effect in the absence of ART • There is a possible risk that a therapeutic vaccine could increase rather than decrease HIV replication by creating additional CD 4 T cell targets for the virus

Ethical considerations for therapeutic vaccines • Participation in a clinical trial of a therapeutic vaccine candidate may preclude participation in future trials of otherapeutic vaccine candidates • The multiplicity of factors that can influence adaptive immunity (genetics, sex, age) makes diversity of trial participants particularly key • The words “therapeutic vaccines” may be misleading and lead to therapeutic (or curative) misconception

Future directions & challenges • Likely need for more combination studies • May need cooperation of different corporate & academic partners • Raises complex regulatory (FDA) issues e. g. assessing safety and activity of each component Better understanding of effective immune responses needed (correlates of immunity, biomarkers of efficacy) • Immunologic mechanisms can be complex and unpredictable, relevance of animal models not always clear •

Future directions & challenges Incentives for industry limited by lack of precedents (no approved IBTs for HIV although recent significant progress in cancer) • History of immune-based approaches being perceived as off-the-wall compared to antiretroviral therapy • Research funding environment •

Future directions & challenges • Defining success • If a cure is not achieved (as defined by an absence of any detectable HIV), what degree of immune control of HIV might be considered “remission”? • Challenge of proving even strict immune control of HIV is clinically equivalent to ART (e. g. elite controllers may face elevated risk of inflammation-related disease vs. individuals on ART)

http: //www. avac. org/cureiculum

Modules will contain: Town Hall Meetings Concept CROI 2014 Power. Point Teaching Sets US AIDS Care Conference, October 4, 2014 Participatory Activities & Events Visual/ Graphic updates (Phase 2 Launch) NIH Martin Delaney Collaboratories meeting October 14, 2014 Pre- and Post-Test Assessments Webinar Recordings CROI February 2015 Launch

Upcoming Webinars Dates (2015) Topics July 15 Informed Consent August 6 Gene Therapy August 27 Ethics of HIV Cure Research September 10 Participation in HIV Cure Research October 8 Animal Models

Module Contributors

Additional citations Douek DC, Brenchley JM, Betts MR, et al. HIV preferentially infects HIV-specific CD 4+ T cells. Nature. 2002 May 2; 417(6884): 95 -8. Katlama C, Launay O, Gharakhanian S, et al. Evidence and potential immunotherapeutic applications of vaccine-induced antibodies against 3 S, a highly conserved motif of gp 41, in HIV-1 -infected patients treated with antiretroviral therapy (Abstract 145). Paper presented at: 30 Years of HIV Science conference; 2013 May 21– 23; Paris, France. Andrieu JM, Chen S, Lai C, Guo W, Lu W. Mucosal SIV Vaccines Comprising Inactivated Virus Particles and Bacterial Adjuvants Induce CD 8(+) T-Regulatory Cells that Suppress SIV-Positive CD 4(+) T-Cell Activation and Prevent SIV Infection in the Macaque Model. Front Immunol. 2014 Jun 30; 5: 297. doi: 10. 3389/fimmu. 2014. 00297. Caskey M, Klein F, Lorenzi JC, et al. Viraemia suppressed in HIV-1 -infected humans by broadly neutralizing antibody 3 BNC 117. Nature. 2015 Apr 8. doi: 10. 1038/nature 14411. Gardner MR, Kattenhorn LM, Kondur HR, et al. AAV-expressed e. CD 4 -Ig provides durable protection from multiple SHIV challenges. Nature. 2015 Mar 5; 519(7541): 87 -91. doi: 10. 1038/nature 14264. Epub 2015 Feb 18. Lam S, Sung J, Cruz C, et al. Broadly-specific cytotoxic T cells targeting multiple HIV antigens are expanded from HIV+ patients: implications for immunotherapy. Mol Ther. 2015 Feb; 23(2): 387 -95. doi: 10. 1038/mt. 2014. 207. Epub 2014 Nov 4. Sung JA, Lam S, Garrido C, et al. Expanded Cytotoxic T-cell Lymphocytes Target the Latent HIV Reservoir. J Infect Dis. 2015 Jan 13. pii: jiv 022. [Epub ahead of print] Katlama C, Lambert S, Assoumou L, et al. Impact of interleukin-7 and raltegravir + maraviroc intensification on total HIV DNA reservoir: results from ERAMUNE 01 (Abstract 170 a. LB). Paper presented at: 20 th Conference on Retroviruses and Opportunistic Infections; 2013 March 3– 6; Atlanta, GA. Jones RB, Mueller S, O’Connor R et al. Cytotoxic T-lymphocytes in combination with the IL-15 superagonist ALT-803 eliminate latently HIV-infected autologous CD 4+ T-cells from natural reservoirs (Abstract 2008). Keystone Symposia: Mechanisms of HIV Persistence: Implications for a Cure, 2015 April 26– May 1, Boston, Massachusetts, USA Micci L, Ryan E, Mc. Gary C, et al. IL-21 Reduces Inflammation and Virus Persistence in ART-Treated SIV-Infected Macaques (Abstract 168). 22 nd Conference on Retroviruses and Opportunistic Infections, Seattle, Washington 2015 Feb 23 -26. Available from: http: //www. croiwebcasts. org/console/player/25831? media. Type=slide. Video& Azzoni L, Foulkes AS, Papasavvas E, et al. Pegylated Interferon alfa-2 a monotherapy results in suppression of HIV type 1 replication and decreased cellassociated HIV DNA integration. J Infect Dis. 2013 Jan 15; 207(2): 213 -22. doi: 10. 1093/infdis/jis 663. Epub 2012 Oct 26. Winckelmann AA, Munk-Petersen LV, Rasmussen TA, et al. Administration of a Toll-like receptor 9 agonist decreases the proviral reservoir in virologically suppressed HIV-infected patients. PLo. S One. 2013 Apr 26; 8(4): e 62074. doi: 10. 1371/journal. pone. 0062074. Da. Fonseca S, Chomont N, El Far M, Boulassel R, Routy J and Sékaly R. Purging the HIV-1 reservoir through the disruption of the PD-1 pathway. J Int AIDS Soc. 2010; 13(Suppl 3): O 15. Published online 2010 Nov 4. doi: 10. 1186/1758 -2652 -13 -S 3 -O 15 Autran B, Murphy RL, Costagliola D, et al. Greater viral rebound and reduced time to resume antiretroviral therapy after therapeutic immunization with the ALVAC-HIV vaccine (v. CP 1452). AIDS. 2008 Jul 11; 22(11): 1313 -22. doi: 10. 1097/QAD. 0 b 013 e 3282 fdce 94.