HIV Lifecycle and Mechanisms of Antiretroviral Therapy July 24th, 2008 HIV Lifecycle and Mechanisms of Antiretroviral Therapy David Spach, MD I’d like to welcome everyone to the University of Washington I-TECH HIV/AIDS Clinical Seminar Series. We have with us today Dr. David Spach. Dr. Spach is a Professor of Medicine in the Division of Infectious Diseases at the University of Washington and the Clinical Director of the Northwest HIV/AIDS Education and Training Center. He has published in numerous medical journals, including The New England Journal of Medicine, JAMA, The Annals of Internal Medicine, Emerging Infectious Diseases, and The Journal of Infectious Diseases. Dr. Spach is the editor-in-chief of HIV Web Study (www.hivwebstudy.org) and has received multiple teaching honors. Today he will be presenting on HIV Lifecycle and Mechanisms of Antiretroviral Therapy. Before we begin, I’d like to ask all the sites to type in how many participants are at their sites.

HIV/AIDS 2008 Treatment Update An In-Depth Look at the Viral Life Cycle to Understand Old and New Antiretroviral Medications David H. Spach, MD Professor of Medicine Division of Infectious Diseases University of Washington, Seattle DHS/PP 1

HIV/AIDS 2008 Treatment Update Overview of HIV Structure and Life Cycle 2008 DHHS Antiretroviral Therapy Guidelines Mechanisms of Action of Antiretroviral Medications DHS/PP 1

HIV Structure and Life Cycle DHS/PP 1

HIV: Basic Structure HIV RNA DHS/PP 1

HIV: Basic Structure Envelope Nucleocapsid (p7) HIV RNA Capsid (p24) gp120 gp41 Nucleocapsid (p7) HIV RNA Capsid (p24) Matrix (p17) DHS/PP 1

HIV: Functional Enzymes What are the three key HIV enzymes involved in HIV replication? DHS/PP 1

Reverse Transcriptase HIV Enzymes Reverse Transcriptase Integrase Protease DHS/PP 1

Host (Human) Cell: Key HIV Receptors CD4 Receptor CCR5 Co-Receptor CXCR4 Co-Receptor Host Cell DHS/PP 1

Question What genetic alteration in human co-receptors is associated with relative resistance to HIV infection? DHS/PP 1

CCR5-∆32 CCR-∆32 CCR5 Extracellular Space Host Cell Membrane Intracellular Space DHS/PP 1

HIV: Life Cycle Nucleus CCR5 CD4 Host DNA HIV Host Cell 1

HIV: Life Cycle Entry 3 Nucleus 2 CCR5 1 CD4 HIV Host Cell 1

HIV: Life Cycle Host Cell Entry Uncoating HIV Nucleus HIV RNA CCR5 CD4 1

HIV: Life Cycle Host Cell Entry Uncoating Reverse Transcription Nucleus CCR5 CD4 HIV RNA HIV DNA HIV Reverse Transcriptase Host Cell 1

Reverse Transcription HIV: Life Cycle Entry Uncoating Reverse Transcription Integration Integrase Nucleus CCR5 CD4 HIV RNA HIV DNA HIV Proviral DNA HIV Host Cell 1

Reverse Transcription HIV: Life Cycle Entry Uncoating Reverse Transcription Integration Transcription Nucleus CCR5 gRNA CD4 HIV RNA HIV DNA HIV mRNA Host Cell 1

Reverse Transcription HIV: Life Cycle Entry Uncoating Reverse Transcription Integration Transcription Translation Nucleus CCR5 CD4 gp160 HIV RNA HIV DNA Protease mRNA HIV Myr Gag Host Cell Gag-Pol 1

Reverse Transcription HIV: Life Cycle Entry Uncoating Reverse Transcription Integration Transcription Translation Assembly & Budding HIV Nucleus CCR5 CD4 HIV RNA HIV DNA mRNA HIV Myr Gag Host Cell Gag-Pol 1

HIV: Life Cycle Host Cell Entry Inhibitors Nucleoside RTI Integrase Inhibitors HIV Nucleus CCR5 CD4 HIV RNA HIV DNA mRNA HIV Non-Nucleoside RTI Gag Protease Inhibitors Host Cell Gag-Pol 1

2008 DHHS Antiretroviral Therapy Guidelines DHS/PP 1

Case History A 32-year-old HIV-infected woman returns to clinic to discuss starting antiretroviral therapy. Her CD4 count is 330 cells/m3 and her HIV RNA is 79,000 copies/ml. According to the 2008 DHHS Antiretroviral Therapy Guidelines: - When should you start antiretroviral therapy on this patient? DHS/PP 1

HIV: Natural History Acute HIV Year 1 DHS/PP 1

Initiating Antiretroviral Therapy 500 350 200 Year 1 DHS/PP 1

Initiating Antiretroviral Therapy January 2008 DHHS Guidelines 500 Consider Antiretroviral Therapy 350 Initiate Antiretroviral Therapy Year 1 Source: DHHS Guidelines. www.aidsinfo.nih.gov DHS/PP 1

Question Why do you think we are more enthusiastic about starting antiretroviral therapy earlier now than 2-3 years ago? DHS/PP 1

Rationale for Earlier Antiretroviral Therapy More effective regimens More convenient regimens Less toxic regimens Expanding data suggesting benefit of earlier therapy DHS/PP 1

Case History A 32-year-old HIV-infected woman returns to clinic to discuss starting antiretroviral therapy. Her CD4 count is 330 cells/m3 and her HIV RNA is 79,000 copies/ml. According to the 2008 DHHS Antiretroviral Therapy Guidelines: - What regimen would you use? DHS/PP 1

DHHS Panel: January 2008 ARV Therapy Guidelines Initial Therapy: Preferred Regimens Construct Regimen by choosing one component from Column A and one component from Column B Column A Column B NNRTI Efavirenz PI Atazanavir + Ritonavir Fosamprenavir + Ritonavir BID Lopinavir/ritonavir (Kaletra) BID 2-NRTI Tenofovir/Emtricitabine (Truvada) Abacavir/Lamivudine (Epzicom): for patients who test negative for HLA-B5701 Picture Source: DHHS Guidelines. www.aidsinfo.nih.gov DHS/PP 1

DHHS Panel: January 2008 ARV Therapy Guidelines Initial Therapy: Alternative Regimens Construct Regimen by choosing one component from Column A and one component from Column B Column A Column B NNRTI Nevirapine PI Atazanavir (unboosted) Fosamprenavir (unboosted) Fosamprenavir + ritonavir qd Lopinavir/ritonavir (Kaletra) qd Saquinavir + ritonavir 2-NRTI Zidovudine/Lamivudine (Combivir) Didanosine + (Emtricitabine or Lamivudine) Picture Source: www.aidsinfo.nih.gov DHS/PP 1

Case History A 32-year-old HIV-infected woman returns to clinic to discuss starting antiretroviral therapy. Her CD4 count is 330 cells/m3 and her HIV RNA is 79,000 copies/ml. According to the 2008 DHHS Antiretroviral Therapy Guidelines: - How should you ideally monitor after treatment is started? DHS/PP 1

Antiretroviral Therapy: HIV RNA Monitoring Optimal Response: HIV RNA < 50 copies/ml Antiretroviral Therapy Started √ CD4 50 √ CD4 √ CD4 Goal: HIV RNA < 50 copies/ml 1 2 3 4 5 6 7 8 9 Time (Months) DHS/PP 1

Entry Inhibitors DHS/PP 1

HIV: Life Cycle Host Cell HIV Entry Inhibitors HIV Nucleus HIV RNA CCR5 CD4 HIV RNA HIV DNA mRNA HIV Myr Gag Host Cell Gag-Pol 1

HIV: Basic Structure Envelope gp120 gp41 DHS/PP 1

HIV: Envelope HIV gp41 gp120 CD4 Binding Groove V3 Region DHS/PP 1

HIV: gp41 HIV gp41 DHS/PP 1

Host Cellular Receptors CD4, CCR5, & CXCR4 Extracellular Space CD4 Receptor CCR5 CXCR4 Host Cell Membrane Intracellular Space DHS/PP 1

HIV Cell Binding and Entry gp120 CD4 Receptor CD4 Receptor Extracellular Space Host Cell Membrane CCR5 Intracellular Space DHS/PP 1

HIV Cell Binding and Entry CD4 Receptor Extracellular Space Host Cell Membrane CCR5 Intracellular Space DHS/PP 1

HIV Cell Binding and Entry CD4 Receptor V3 Region Extracellular Space Host Cell Membrane CCR5 Intracellular Space DHS/PP 1

HIV Cell Binding and Entry CD4 Receptor Extracellular Space Host Cell Membrane CCR5 Intracellular Space DHS/PP 1

HIV Cell Binding and Entry gp41 CD4 Receptor Extracellular Space Host Cell Membrane CCR5 Intracellular Space DHS/PP 1

HIV Cell Binding and Entry gp41 Extracellular Space Host Cell Membrane Intracellular Space DHS/PP 1

HIV Cell Binding and Entry Heptad Repeat 2 [HR2] HR2 gp41 HR1 Heptad Repeat 1 [HR1] Extracellular Space Host Cell Membrane Intracellular Space DHS/PP 1

HIV Cell Binding and Entry Extracellular Space Host Cell Membrane Intracellular Space DHS/PP 1

HIV Cell Binding and Entry HIV Membrane Host Cell Membrane DHS/PP 1

HIV Cell Binding and Entry HIV Membrane Host Cell Membrane DHS/PP 1

R5-Tropic Virus: Binds to CCR5 R5-Tropic HIV V3 Region CD4 Receptor CD4 Receptor Extracellular Space CXCR4 Host Cell Membrane CCR5 Intracellular Space DHS/PP 1

X4-Tropic Virus: Binds to CXCR4 X4-Tropic HIV V3 Region CD4 Receptor CD4 Receptor Extracellular Space CXCR4 Host Cell Membrane CCR5 Intracellular Space DHS/PP 1

Dual-Tropic Virus: Binds to CCR5 or CXCR4 Dual Tropic HIV V3 Region CD4 Receptor CD4 Receptor Extracellular Space CXCR4 Host Cell Membrane CCR5 Intracellular Space DHS/PP 1

Question What human co-receptor does the drug Maraviroc block? DHS/PP 1

NOTE: Blocks Human Protein Entry Inhibitors CCR5 Inhibitor: Maraviroc (Selzentry) R5 HIV CD4 Receptor Maraviroc Extracellular Space NOTE: Blocks Human Protein Host Cell Membrane CCR5 Intracellular Space DHS/PP 1

HIV Co-Receptor Tropism Assay Monogram Biosciences Trofile Assay HIV-1 Tropism Assay Assay Measures HIV Tropism - R5 Tropic - X4 Tropic - Dual Tropic/Mixed Tropic Utilizes Entire Envelope Gene - Generates pseudoviruses Viral Load Required - Above 1,000 copies/ml Detection of Minor Species - Reliably detected at 5-10% R5-Tropic X4-Tropic R5X4 (Dual)-Tropic Mixed Tropic DHS/PP 1

$1960 DHS/PP 1

Entry Inhibitors Fusion Inhibitor: Enfuvirtide (Fuzeon) HIV Heptad Repeat 2 Heptad Repeat 2 Heptad Repeat 1 Enfuvirtide Fusion Peptide 36 amino acid peptide DHS/PP 1

Entry Inhibitors Fusion Inhibitors (Fuzeon) HIV Heptad Repeat 2 Heptad Repeat 1 Enfuvirtide Extracellular Space Fusion Peptide Host Cell Membrane Intracellular Space DHS/PP 1

Entry Inhibitors Fusion Inhibitors (Fuzeon) HIV Extracellular Space Enfuvirtide Host Cell Membrane Intracellular Space DHS/PP 1

Reverse Transcriptase Inhibitors DHS/PP 1

HIV: Life Cycle Host Cell Nucleoside RTI HIV HIV Nucleus HIV RNA CCR5 CD4 HIV RNA HIV DNA mRNA HIV Myr Gag Host Cell Gag-Pol 1

HIV Reverse Transcription Human Cell Human Nucleotides HIV RNA HIV Reverse Transcriptase 1

HIV Reverse Transcription Human Cell Human Nucleotides HIV RNA HIV Reverse Transcriptase 1

Nucleoside Reverse Transcriptase Inhibitors (NRTIs) Human Cell NRTI Human Nucleotides HIV RNA HIV Reverse Transcriptase 1

Fixed-Drug NRTI Combinations Preferred - Tenofovir-Emtricitabine (Truvada) - Abacavir-Lamivudine (Epzicom) Alternative - Zidovudine-Lamivudine (Combivir) 1

Case History A 38-year-old HIV-infected woman has a CD4 count of 257 cells/mm3 and a serum creatinine of 1.6. The provider would like to use abacavir + lamivudine. What test can you use to screen for abacavir hypersensitivity? Are there differences in the incidence of abacavir hypersensitivity in different races? DHS/PP 1

TDF + FTC + Efavirenz vs. ZDV + 3TC + Efavirenz Truvada versus Combivir Study Design Results: 48 Weeks (ITT) Patients (N = 517 randomized) - ARV naïve, HIV RNA > 10,000 copies/ml - Randomized trial Regimens (N = 487) - Tenofovir + Emtricitabine + Efavirenz - Zidovudine + Lamivudine + Efavirenz TDF= Tenofovir FTC = Emtricitabine ZDV = Zidovudine 3TC = Lamivudine EFV = Efavirenz P = 0.002 P = 0.02 From: Gallant JE et al. N Engl J Med. 2006;354:251-60. DHS/PP 1

HIV: Life Cycle Host Cell HIV HIV Non-Nucleoside RTI Nucleus HIV RNA CCR5 CD4 HIV RNA HIV DNA mRNA HIV Myr Non-Nucleoside RTI Gag Host Cell Gag-Pol 1

Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) DHS/PP 1

Tenofovir + Emtricitabine + Efavirenz (Atripla) Classification: (2) nRTI + (1) nNRTI Dose: 1 pill qd - Tenofovir 300 mg - Emtricitabine 200 mg - Efavirenz: 600 mg Meal Restrictions: without food Strong data from Study 934 Adverse Effects: CNS (efavirenz) 1

Etravirine (Intelence) Second Generation NNRTI Dose: 200 mg bid High genetic barrier of resistance Adverse Effects: Mainly Rash (mild) Risk of Rash: No Correlation with Prior NNRTI Rash DHS/PP 1

Case History A 26-year-old HIV-infected man returns to clinic after failing a regimen of tenofovir + lamivudine + efavirenz. His CD4 count is 148 cells/m3 and his HIV RNA is 41,000 copies/ml. His genotype shows a M184V mutation (lamivudine resistance) and a K103N mutations (efavirenz resistance). Is it likely that he will respond to etravirine? DHS/PP 1

Baseline NNRTI Resistance & Response to Etravirine DUET 1 & 2 Studies Study Design Virologic Response: Week 24 Background - Pooled data from DUET 1 & 2 Patients (N = 599) - ARV experienced & failed NNRTI regimen - 3 or more PI mutations - HIV RNA > 1,000 copies/ml Etravirine Associated Mutations (n = 13) - V90I - A98G - L100I - K101E/P - V106I, - V179D/F - Y181C/I/V - G190S/A From: Cahn P, et al. 2007 ICAAC. Abstract H-717. DHS/PP 1

Integrase Inhibitors DHS/PP 1

HIV: Life Cycle Host Cell HIV Integrase Inhibitors HIV Nucleus HIV RNA CCR5 CD4 HIV RNA HIV DNA mRNA HIV Myr Gag Host Cell Gag-Pol 1

Raltegravir (Isentress) Strand Transfer Inhibitor Integrase Inhibitor Catalytic Core Domain Enzyme Active Site DDE Catalytic Triad Raltegravir Strand Transfer Inhibitor Spach 1

OBT + Raltegravir 400 mg bid Raltegravir in ARV-Experienced Patients BENCHMRK-1 & 2 Studies BENCHMRK 1: N = 350 (Europe, Asia, Peru) BENCHMRK 2: N = 349 (North & South America) Eligibility - HIV-infected - Treatment Experienced (Median 10 years) - HIV RNA > 1,000 copies/ml - Randomized, double-blind - Resistance to 3 classes of ARV drugs OBT + Placebo 1x 2x OBT + Raltegravir 400 mg bid From: Cooper DA, et al. 15th CROI 2008. Abstract 788. Steigbigel R, et al. 14th CROI 2008. Abstract 789. DHS/PP 1

Raltegravir in ARV-Experienced Patients BENCHMRK-1 & 2 Study: 48 Week Data * CD4 counts higher in LPV-RTV arms P < 0.001 P < 0.001 From: Cooper DA, et al. 15th CROI 2008. Abstract 788. Steigbigel R, et al. 14th CROI 2008. Abstract 789. DHS/PP 1

Protease Inhibitors DHS/PP 1

HIV: Life Cycle Host Cell HIV HIV Protease Inhibitors Nucleus HIV RNA CCR5 CD4 HIV RNA HIV DNA mRNA HIV Myr Gag Protease Inhibitors Host Cell Gag-Pol 1

HIV Precursor Polyprotein HIV: Life Cycle HIV Protease Nucleus HIV Precursor Polyprotein Host DNA Host Cell 1

HIV Precursor Polyprotein HIV: Life Cycle HIV Protease Nucleus HIV Precursor Polyprotein Proteins Host DNA Host Cell 1

HIV Protease Inhibitor Active Site DHS/PP 1

Recent Studies with Ritonavir-Boosted PIs KLEAN Trial - Fosamprenavir + Ritonavir = Lopinavir + Ritonavir (Kaletra) CASTLE Trial - Atazanavir + Ritonavir = Lopinavir + Ritonavir (Kaletra) GEMINI Trial - Saquinavir + Ritonavir = Lopinavir + Ritonavir (Kaletra) TITAN and ARTEMIS Trials - Darunavir + Ritonavir > Lopinavir + Ritonavir (Kaletra) DHS/PP 1

Questions DHS/PP 1

Listserv: itechdistlearning@u.washington.edu Next session: July 31st, 2008 Listserv: itechdistlearning@u.washington.edu Email: DLinfo@u.washington.edu Thank you for attending the session. We will email answers to the questions that we were unable to get to today to the Distance Learning listserv. If you have additional questions, please email them to the listserv. That listserv is: itechdistlearning@u.washington.edu. Please contact DLinfo@u.washington.edu if you would like to get on this listserv. Please be sure to fill out site coordinator and participant evaluations and return to Anya, we greatly appreciate your feedback.

Marcia Weaver, Debbie Winters, MaryAnn Vitello Next session: July 31st, 2008 Marcia Weaver, Debbie Winters, MaryAnn Vitello Task Shifting This will appear on the virtual classroom in between sessions.