Current Clinical Therapies for HIV Remission. David Margolis MD UNC HIV Cure Center

Transcription

1 Current Clinical Therapies for HIV Remission David Margolis MD UNC HIV Cure Center

2 Aiming for sustained remission off ART Cohen J. Science 214

3 Luzuriaga et al. NEJM 3;8: 786

4 Effect of vorinostat, hydroxychloroquine and maraviroc combination therapy on viremia following treatment interruption in individuals treated during acute HIV infection (Fiebig III-IV) Eugène Kroon, Jintanat Ananworanich, Keith Eubanks, Jintana Intasan, Suteeraporn Pinyakorn, Nicolas Chomont, Sharon R Lewin, Sarah Palmer, Lydie Trautmann, Hua Yang, Nitiya Chomchey, Nittaya Phanuphak, Ken Cooper, Praphan Phanuphak, Mark de Souza on behalf of the SEARCH 19 study group

5 HIV Rebound after ART Interruption Median time to first VL detection: 22 days (range 14 to 77 days) ART resume at VL > 1 c/ml

6 Host cell modification Stochastic Reversal of Latency KO: CCR5 (Sangamo) KI: sh5/c46 (Calimmune) Chronically producing cell

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8 CCR5-modified CD4 T cells at 1 week post infusion constituted 13.9% of Challenges moving forward: circulating CD4 T cells Modified cells had an Is cytoreductive estimated mean therapy half-life needed? of weeks Acceptable? After ART interruption, decline in circulating CCR5-modified cells ( 1.81 cells Is there X4 escape? per day) was significantly less than the decline in unmodified cells ( 7.25 cells Scalability? Cost? per day) (P =.2) HIV RNA became undetectable in one of four patients who could be evaluated

9 A second first step step to to eliminate latent HIV infection Latency Reversal

10 Latency Reversal and Clearance Candidates Latency Reversing Agents (LRAs) 8 HDAC Baseline ART inhibitors Relative HIV-1 gag RNA copies VOR 4 mg lack potency and killing as single agents (Mellors)*! 14 daily doses of vorinostat! Elliot&PLoS&Path&214& Lewin CROI 213! *! HDAC inhibitors do not kill non-transformed cells at clinical exposures and Appropriate serial dosing regimens of HDAC inhibitors have not yet been performed (Margolis) *! *! *! 2 Pt. 1 Pt. 2 Pt. 3 Pt. 4 Pt. 5 Pt. 6 Pt. 7 Pt. 8 Thrice weekly cycles of Panobinostat 212! Weekly Romidepsin! Total CD4 cell-associated unspliced HIV-1 RNA! Days! Rasmussen Lancet ID 214 Sogaard IAS 214 Apologies, too many references to cite! Sogaard&PLoS&Path&215&

11 Latency Reversal and Clearance Candidates Latency Reversing Agents (LRAs) HDAC inhibitors lack potency and killing as single agents (Mellors) HDAC inhibitors do not kill non-transformed cells at clinical exposures and Appropriate serial dosing regimens of HDAC inhibitors have not yet been performed (Margolis) PKC agonists most potent activators but toxicity of concern Bryostatin clinical trial did not achieve effective drug exposures TLR agonists: activate HIV expression and immune control in SIV/macaques Apologies, too many references to cite!

12 TLR7 Agonists Induce Transient Plasma Viremia Plasma SIV (log 1 RNA copies/ml) Placebo GS-986 (.1 mg/kg) Plasma SIV RNA copies/ml 1 3 GS-962 (.5 mg/kg) GS-962 (.15 mg/kg) 1 2 V1 V2 Vehicle V1 V2 Vehicle Time after TLR7 agonist dose (Hours) Reduced frequency of blips 38-75% (doses 3-1) No more blips from animals dosed after 3 month pause (doses # 11-19) Whitney et al., CROI 216

13 Phase I/II trial of GS-962 in HIVinfection Design: 3 escalating dose cohorts 1 mg, 2 mg, 4 mg every 2 weeks for 6 doses Placebo-controlled, randomized, double-blinded (6 active, 2 placebo per cohort) Study Population: HIV-infected adults (n=) Virologically suppressed 12 months on ART Study Monitoring: Close follow-up VL 2-3x/w Repeat dosing only if VL <5 copies/ml Safety review prior to initiation of each cohort Current status: Enrolling Cohort 3

14 Latency Reversal and Clearance Candidates Latency Reversing Agents (LRAs) HDAC inhibitors lack potency and killing as single agents (Mellors) HDAC inhibitors do not kill non-transformed cells at clinical exposures (Margolis) PKC agonists most potent activators but toxicity of concern Bryostatin clinical trial did not achieve effective drug exposures TLR agonists: activate HIV expression and immune control in SIV/macaques Other Epigenetic targets Bromodomain inhibitors Histone methyltransferase inhibitors (eg. EZH2 inhibitors) Others in development High-throughput library screening efforts Apologies, too many references to cite!

15 Merck HIV Latency HDAC Inhibitor Synergy Screen Objective: To identify compounds that potentially act synergistically with HDACis to induce HIV transcription 2,9, Compounds HIV LTR Induction With 25nM SAHA Initial Screen, n=3 Dose Response Assays, n=2 HIV LTR Induction With 25nM SAHA HIV LTR Induction Without SAHA HIV LTR Induction With 25nM SAHA Hours CTG NFkB BLA Reporter Counter Screen Confirmatory Assays, n=3 Data Analysis/ Hit Selection ~4,5 Compounds Follow-up Analysis 17.4% 16.1% 66.5% Known HDAC Inhibitors Known Farnesyl-Transferase Inhibitors Compounds with unknown mechanism

16 Testing interventions in vivo LRAs Immunodulators HIV vaccines Novel approaches After * Baseline ART Leukapheresis for QVOA and ca-hiv RNA SCA Immune assays Host cell assays & biomarkers Novel assays, eg. Quanterix Simoa intervention Leukapheresis for QVOA and ca-hiv RNA SCA Immune assays Host cell assays & biomarkers Novel assays, eg. Quanterix Simoa Reduction in: Resting CD4 cell infection Low-level viremia

17 HIV DNA, RNA, antigen & viruses HIV DNA QVOA Replicationcompetent virus Ho, Cell 213 Ericksson, PLoS Path 213 HIV RNA in cells or culture HIV Antigen (protein) detector The Real Reservoir

18 Frequency (per 1 6 cells) Persistent HIV infection despite ART Time to eradication > 73.4 years Residual Replication or Cell Proliferation - Viral Activation & Clearance or Cell Death Given assay variance, a more than 6-fold RCI decrease would have likelihood.23 (2.3%) Therefore a measurable goal is therapy that can reduce the latent reservoir by half a log Time on ART (years) Margolis, Garcia, Hazuda, Crooks Haynes et Science al. JID

19 Challenges to clearing persistent infection after latency reversal Recent absence of antigen low frequency of HIV-specific antiviral responses Immune dysfunction, deletion, or exhaustion Archived viral diversity, including immune escape Viral antigen is rare, dispersed, compartmentalized, and may be transient Latency Reversing Agents (LRAs) are hosttargeted, and alone or in combination may alter antiviral immune response

20 Latency Reversal Agent Discovery New metric of viral antigen production or presentation - Antigen required to allow clearance Assessment of LRA effect on immune function as part of development path - Immune function required for clearance

21 Quanterix Simoa Technology 1. Single-protein molecules are captured and labeled on individual beads using standard ELISA reagents 2. Beads + substrate are loaded in individual femtoliter wells. Oil added to seal well 3. Digital or analog fluorescence readout of individual beads Quanterix Simoa Platform Ultrasensitive platform (sub-pg/ml sensitivity) Full automation (samples in data out) Rapid readout (~1 hr), >5 data points per day Broad dynamic range (>4 logs) Commercial p assay applied to plasma and serum (Chang L, et al. J Virol Methods. 213;188(1-2): ) In-house Merck assay optimized to reduce nonspecific binding and enhance sensitivity, thus enabling p quantitation in cell lysates Howell et al. submitted

22 Latency Clearance Assay CD8+ by negative selection PBMCs Resting CD4+ cells by negative selection CD8+ or CD8+, HXTCs, or DARTs or No Effectors Culture Resting CD4+ cells Latency Reversing Agent Add Effectors Limiting Dilution Co-culture Measure HIV Production at 2 weeks Remove Effectors

23 % Viral recovery Number of positive wells (out of 12 total) HXTCs Reduce Recovery of Virus from autologous resting CD4+ T cells stimulated with: PHA Patient 423 No Effectors CD8 HXTC Patient 25 Patient 231 Patient 492 Patient 532 Patient 425 Patient 425 VOR 12 1 p<.5 compared to No Effector p<.5 compared to BOTH Patient 425 Patient 532 Patient 25 Sung et al. JID 215

24 Latency Reversal and Clearance Candidates Natural and Engineered Antibodies Broadly-neutralizing monoclonal antibodies (bnmabs) Can delay rebound and promote cell clearance in humans (3BNC117) Resistance can rapidly develop (VRC1, 3BNC117) Effect in individuals on ART? (VRC1) Engineered bnmab Can prolong half-life and enhance Fc effector functions (e.g. PGT-151) Bispecific Ab (anti-hiv/anti-host, e.g. CD3 or CD16) Enhance effector function ex vivo and in animal models Apologies, too many references to cite!

25 A5342/VRC1 Study Double-blind, randomized, placebo-controlled, Phase I study 4 participants (2 per arm) VRC1 4 mg/kg IV at Day & 21 (Arm A) or Day 42 & 63 (Arm B) Trial Completed and Analyses Underway!

26 SIV-infected monkeys were treated with a 9-day course of ART initiated 5 weeks post infection 9 weeks post infection infused with primatized monoclonal antibody against the α4β7 integrin every 3 weeks until week 32 All animals subsequently maintained low to undetectable viral loads and normal CD4+ T cell counts for more than 9 months, after all treatment was withdrawn. Human trial underway at NIH

27 Dual Affinity ReTargeting (DARTs) Molecules for HIV Do not require pre-existing HIV specificity Not impacted by archived CTL escape variants Anti-Env arm based on well characterized mabs that have: Are broad neutralizing antibodies -- bind virions and infected cells: DH542 (V3 glycan bnab), CH557 (CD4bs bnab), DH511-K3 (gp41 MPER bnab) Are ADCC mediating antibodies -- bind only infected cells: (7B2, gp41 immunodominant), A32 (C1)

28 Dual Affinity Re-Targeting proteins direct T cell mediated cytolysis of latently HIV-infected cells. Sung, JA, Pickeral, J, Liu, L, Stanfield-Oakley, SA, Lam, CY, Garrido, C, Pollara, J, LaBranche C. Bonsignori, M. Moody, MA,..Haynes, BF, Nordstrom JL, Margolis, DM, Ferrari, G. JCI 215 Targeting HIV Reservoir in Infected CD4 T cells by DARTs that bind Envelope and Recruit CTLs. Sloan DD et al. PLoS Pathogens, 215 Sung et al.: Screened ADCC, non-neutralizing Abs that bound HIV-infected CD4 T cells for optimal ADCC Constructed DARTs with non- Neutralizing mabs A32XCD3 and 7B2XCD3 Showed DARTs + CD8 CTL eliminated HIV-infected CD4 T cells in vitro by CD8 T cell-mediated cytolysis. Sloan et al.: Constructed bnab PGT145 (V1V2), PGT121 (V3 glycan), VRC1 (CD4 bs), and 1E8 (distal MPER)--- compared to A32 and 7B2 nonneutralizing DARTs Best were PGT121, A32 and 7B2 DARTs

29 % v ir a l r e c o v e r y (n o r m a liz e d to n o E ffe c to rs c o n tro l) HIVxCD3 DART Mediated Clearance of Resting Patient CD4 Cells Exposed to Vorinostat V O R -E x p o s e d L a te n tly In fe c te d C e lls N o E ffe c to rs C D 8 o n ly C D 3 x C o m b o D A R T s P a tie n t 2 4 h r c u ltu re w ith D A R T s 9 6 h r HIVxCD3 DART-mediated virus clearance in 4 of 4 patients (longer time needed for Pt 795) Sung, et al. JCI 215

30 Latency Reversal and Clearance Candidates Immune Checkpoint Blocking Antibodies Major advance in cancer immunotherapy Reverse immune exhaustion Examples: Anti-PD-1/PD-L1, LAG-3, 2B4, CD16, TIM-3, others Cellular therapies CD8+T-cells with chimeric antigen receptors Ex-vivo Effector cell expansion/re-infusion Activated NK cells Therapeutic Vaccines Multiple approaches Chimp Adeno vector, CMV vector, VSV vector, Ad26/MVA vectors, Dendritic cells Can induce broad CTL responses Covering immune escape variants is critical! Apologies, too many references to cite!

31 Tools to Test Latency Reversal and Clearance Autologous DC vaccine Minimal effect of VOR on immune function Clutton Sci Rep 216 Persistent LRA activity of multiple VOR doses p<.1 H IV - 1 g a g R N A c o p ie s p e r w e ll Baseline Multidose Archin Keystone Symposium on HIV Persistence 216

32 Combination Latency Reversal and Clearance Trial I Step 1 Screen Approximately Weeks - 8 BASELINE Step 2 Enrollment ~Week 6 - Week 13 Visits 1&2 Visit 3 & 4 Step 3 Interval ~Week 1 - Week 18 Vists 5-7 Step 4 AGS ~Week 15 - Week EOS Term ~Week 73 - Week 89 Visit 8 Visit 9-13 Visits Visits Visits AGS Manufacturing Step 5 AGS Dosing ~ Week 27 - Week 46 Step 6 Multiple VOR Dosing ~Week 39 - Week 54 Step 7 AGS Dosing ~Week 52 - Week 73 Step 8 Multiple VOR Dosing ~Week 64 - Week 81 EOS Single Dose Paired Doses Interval dosing X 1 doses Interval dosing X 1 doses Injections X4 Injections X4 LRA x 1 LRA x 2 LRA x 1 LRA x 1 Vaccine Vaccine Vaccine = Argos dendritic cell therapy LRA = vorinostat

33 Combination Latency Reversal and Clearance Trial II STEP 1 Pretreatm ent Phase Exhibit Exvivo response to VOR STEP 2: Single VOR 4mg dose STEP 3: HXTCs produce d STEP 4: First STEP Combination 1 STEP REST 2: STEP STEP 3: 5: First STEP Combination 4: First Combination STEP 6: Immune REST Response STEP 5: monitoring First Combination treatment Pretreatm Single PERIO HXTCs treatment treatment PERIO treatment VOR every ent hours Phase x 1 VORD produce VOR every VOR every hours and hours x 1 D VOR every hours and doses and Exhibit Exvivo 4mg d 2 HXTC Infusions doses and 2 HXTC Infusions 2 HXTC Infusions dose 2 HXTC Infusions response to VOR ~4 weeks ~8 weeks ~6-8 weeks 4 weeks ~4 weeks ~8 2-4 weeks weeks HXTC HXTC ~6-8 4 weeks 4 weeks ~45 weeks2-4 weeks weeks Visits Visits HXTC HXTC HXTC 4 weeks ART VOR every hours x 1 doses cart VOR every VOR hours every hours x 1 doses x 1 doses cart VOR every hours x 1 doses Cath Bollard Immune Response Assays Immune HXTC Infusion Response Clio Assays Rooney Leukapheresis HXTC Infusion Leu

34 Steps to eliminate HIV infection Latency Reversal Finally: the addition of durable vaccine protection if rebound or reexposure occurs