CROI 2024 Abstract eBook

Abstract eBook

Oral Abstracts

the level of 3BNC secretion by CD4 T cells was 4.6 times as high as that by CD8 T cells. For in vivo evaluation, 30 million T cells (59.4% were 3BNC+) were intrasplenically injected into NSG mice and when the mice were sacrificed at 8 weeks, 46.6% of spleen human T cells were 3BNC+. Weekly measurement of plasma 3BNC concentration remained above 1,500 ng/ml for the full 8 weeks before sacrifice. In HIV-infected NSG mice, spleen CD4 T cells were preserved in the combinational 3BNC-T and CAR-T cell treated (25.2%), and CAR-T cell only treated (23.1%) animals, but not in 3BNC-T cell only treated (9.9%) or control (11.8%) animals. Plasma 3BNC was detected in 3BNC-T cell only (471.5 ng/ml) and combinational therapy (1504.8 ng/ml) treated animals. Plasma HIV RNA was most suppressed in combinational therapy treated mice (91.7%), and CAR-T cell only treated mice (65.9%), comparing to control mice. Consistently, spleen HIV DNA was most suppressed in combinational therapy treated mice (78.8%), and CAR-T cell only treated mice (55.4%), compared to control mice. Conclusion: We successfully engineered T cells that secrete bNAb in vitro and exhibited sustained in vivo bNAb production. BNAb-secreting T cells synergized with CAR-T cells to potently suppress in vivo HIV infection. This combinational therapy incorporating cellular and humoral anti-HIV approach provides a new strategy to generate more potent immunotherapeutics to contribute to a functional cure of HIV infection. Autologous Neutralizing Antibodies Contribute to Virus Control in a Subset of PWH Treated With bNAbs Francesco E Marino 1 , Maxime Bellefroid 2 , Ryan Krause 1 , Marie Armani Tourret 2 , Suvadip Mallick 1 , Emmanouil Papasavvas 3 , Matthew Fair 3 , Karam Mounzer 4 , Pablo Tebas 1 , Luis J. Montaner 3 , Mathias Lichterfeld 2 , Katharine J. Bar 1 1 University of Pennsylvania, Philadelphia, PA, USA, 2 Harvard Medical School, Boston, MA, USA, 3 Wistar Institute, Philadelphia, PA, USA, 4 Philadelphia FIGHT, Philadelphia, PA, USA Background: BnAbs are being tested in clinical trials of treatment and cure in people with HIV (PWH) who have existing autologous neutralizing antibody (anAb) responses. To determine the relative selective pressure of bnAbs and anAbs in the BEAT2 study of 3BNC117, 10-1074, and IFNa2b, we performed a sieve analysis comparing the potency of administered bnAbs and host anAbs against reservoir and rebound Envs. Methods: In 8 participants of BEAT2 (NCT03588715), we sequenced provirus from PBMCs collected at study enrollment via FLIPseq or MIPseq (n= 314) to identify intact HIV-1 genomes in single and clonally-expanded populations. In 12 participants, plasma rebound envs (n=233) were sequenced by SGS at first detectable rebound viremia. Reservoir and rebound Envs were cloned and tested for neutralization sensitivity via TZM.bl assay to bnAbs and longitudinal plasma IgG (collected at a median of 8 time points over 12-24 study months). Statistical comparisons were by Wilcoxon matched-pairs test. Results: In all 8 participants, rebound envs aligned within reservoir phylogenies, but were not identical to any sampled reservoir viruses. Comparing rebound Envs (1 per participant) and reservoir Envs (2-6 per participant), rebound Envs were significantly more resistant to 10-1074 (IC 50 6.44 μg/ml vs. 0.71 μg/ml; p=0.02), and trended towards greater resistance to 3BNC117 (ns). When tested against baseline plasma IgG (prior to bnAb dosing), rebound Envs were generally more resistant than reservoir Envs, with markedly greater resistance (30- fold difference in IC 50 ) in the 2 participants with most delayed rebound (>12 weeks post-bnAb dosing). Potency of plasma IgG against both rebound and reservoir Envs rose significantly during bnAb dosing (mean >3-fold change in IC 50 for both; p=0.001). Post-ART restart, after bnAbs had waned and anAbs had responded to recent rebound viremia, plasma IgG potency increased vs. rebound Envs (mean 2.5-fold change in IC 50 ; p=0.001), but not reservoir Envs (ns). Conclusion: In the BEAT2 study of 2 bnAbs and IFNa2b, the greater potency of the administered bnAbs against reservoir vs. rebound Envs indicates bnAb selective pressure. In 2 participants with delayed rebound, baseline anAbs also exerted selective pressure. After rebound and ART restart, anAbs evolved to selectively target rebound Envs. Together, results suggest that anAbs contributed to virus suppression in a subset (25%) of studied bnAb trial participants. Approaches to boost anAbs may increase this proportion.

at present but may include sex-specific immune responses. The HIV reservoir in women is associated with features of deeper latency; therefore, women may be primed to achieve a state of HIV control, and the inclusion of women in cure studies should be a priority. AAV-Expressed HIV IgG Biologics Enable Durable ART-Free Viral Control in Infant Macaques Daniel O'Hagan 1 , Tracy Ordonez 2 , Lucas Costa 1 , Shilpi Pandey 2 , Siddhartha Shandilya 1 , Jeremy Smedley 2 , Diogo M. Magnani 3 , Deborah Persaud 4 , Ann Chahroudi 5 , Matthew R. Gardner 5 , Michael D. Alpert 6 , Ann J. Hessell 2 , Michael Farzan 7 , Nancy L. Haigwood 2 , Mauricio A. Martins 1 1 University of Florida, Gainesville, FL, USA, 2 Oregon Health and Sciences University, Portland, OR, USA, 3 University of Massachusetts, Worcester, MA, USA, 4 The Johns Hopkins University, Baltimore, MD, USA, 5 Emory University, Atlanta, GA, USA, 6 Emmune, Inc, Jupiter, FL, USA, 7 Boston Children's Hospital, Boston, MA, USA Background: There were 1.5 million children living with HIV (CLWH) in 2022, only half of whom had access to antiretroviral therapy (ART). Even when ART is available, lifelong daily adherence can be challenging for CLWH, emphasizing the need for alternative strategies to durably suppress HIV replication. Here we evaluated whether a combination of early ART initiation and adeno-associated virus (AAV)-vectored delivery of HIV IgG biologics could maintain ART-free virus control in simian-HIV (SHIV)-infected infant rhesus macaques (RMs). Methods: Ten 4-week-old infant RMs (7 males; 3 females) were orally infected with SHIV-SF162P3 and placed on ART 7 days later, at which time the animals also received intramuscular injections of AAV9 vectors encoding IgG2 versions of the V3 glycan bNAb 10-1074 and the immunoadhesin eCD4-Ig. Three control RMs (2 males; 1 female) were similarly infected and placed on ART but did not receive AAV vectors. After 30 weeks, ART was interrupted and the kinetics of virus rebound compared between the two groups. Results: Peak SHIV plasma viral loads pre-ART ranged from 1.8E+6 to 1.9E+7 vRNA copies/ml. All 10 AAV- treated RMs developed persistent levels of eCD4-Ig in plasma; expression of 10-1074 was more variable due to fluctuating anti-10-1074 antibodies. Following ART interruption (ATI), control RMs became viremic within 2 weeks, whereas 7/10 AAV-treated RMs remained aviremic for over 6 months (P = 0.0005). Low plasma amounts of 10-1074 (<6.0 μg/ml) were associated with virus rebound or "blips" in viremia in 3/10 AAV-treated RMs, even when concentrations of eCD4-Ig exceeded 10 μg/ml. One year after ATI, two aviremic experimental RMs were treated with a neonatal Fc receptor (FcRn)-blocking antibody to probe the mechanism of virus suppression. FcRn blockade markedly reduced plasma levels of total IgG, including eCD4-Ig and 10-1074, resulting in breakthrough viremia 2 weeks later, thus demonstrating the direct role of AAV-expressed HIV IgG biologics in ART-free viral control. Conclusion: A one-time dose of AAV vectors given to 5-week-old infant RMs starting ART early after SHIV infection was safe and resulted in levels of eCD4-Ig and 10-1074 that prevented virus rebound and maintained virus control for up to 1 year post ATI. Maintenance of virus control required continuous expression of both eCD4-Ig and 10-1074 in plasma at >6.0 μg/ml. In sum, AAV-vectored delivery of HIV biologics holds promise for achieving sustained virologic remission in CLWH in a practical and scalable manner. Broadly Neutralizing Antibody-Secreting T Cells and CAR-Ts Potently Suppress In Vivo HIV Infection Hang Su 1 , Jenny Zheng 1 , Scott Garforth 1 , Kim Anthony-Gonda 2 , Rimas J. Orentas 2 , Boro Dropulic 2 , Steven Almo 1 , Harris Goldstein 1 1 Albert Einstein College of Medicine, Bronx, NY, USA, 2 Caring Cross, Gaithersburg, MD, USA Background: We hypothesized that combining anti-HIV CAR-T cells and with T cells engineered to secrete broadly neutralizing antibodies (bNAbs) could provide an approach to achieve ART-free HIV remission. As a proof-of-concept, we engineered a lentiviral vector (LV) encoding 3BNC117 bNAb (3BNC) to transduce T cells. We further evaluated the in vivo synergistic effects of 3BNC expressed T (3BNC-T) cells and anti-HIV CAR-T cells against HIV infection in a humanized mouse model. Methods: CD3 T cells were purified from HIV-seronegative donors and transduced with 3BNC LV and evaluated for in vitro and in vivo 3BNC production in NSG mice. In vivo synergistic antiviral function was tested by intrasplenically co-injecting autologous HIV-infected PBMCs with 3BNC-T cells or CAR-T cells or both into NSG mice for 3 weeks. Mouse serum and tissue HIV levels were measured to determine viral suppression. Results: Using the same MOI, the level of 3BNC LV transduction in CD4 T cells was 2.8 times as high as that in CD8 T cells. When normalizing to a single cell,

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CROI 2024