Durable Suppression Research Articles

Evaluation and real-world experience of a neutralization susceptibility screening assay for broadly neutralizing anti-HIV-1 antibodies.

Development of a screening assay for the clinical use of broadly neutralizing antibodies (bnAbs) is a priority for HIV therapy and cure initiatives. We assessed the PhenoSense Monoclonal Antibody (mAb) Assay (Labcorp-Monogram Biosciences) which is CLIA-validated and has been used prospectively and retrospectively in multiple recent bnAb clinical trials. When performed on pre-ART plasma and on-ART longitudinal PBMC samples sourced from a recent clinical trial, the PhenoSense mAb Assay produced robust reproducibility, concordance across sample types, and expected ranges in the susceptibility measures of bnAbs in clinical development. PhenoSense mAb applied retrospectively to baseline samples from three recent studies correlated with published laboratory-based study evaluations, but baseline bnAb susceptibility was not consistently predictive of durable virus suppression. Assessment of the feasibility of the assay in four recent clinical studies provides estimates of assay success rate and processing time. The PhenoSense mAb Assay provides reproducible bnAb susceptibility measurements across relevant sample types yet was not consistently predictive of virus suppression. Logistical and operational assay requirements can impact timely clinical trial conduct. These results inform bnAb studies in development.

Evaluating Real-World Experience With Maribavir for Treatment of Refractory/Resistant Cytomegalovirus in Renal Transplant Recipients.

Maribavir was recently approved by the FDA, expanding treatment options for post-solid-organ transplant refractory/resistant CMV. We sought to describe the post-marketing experience with maribavir at a large academic transplant center. This was a retrospective observational study of all renal transplant recipients treated with maribavir for refractory/resistant CMV DNAemia/disease. CMV viral loads, immunosuppression regimens and management, resistance testing, and antiviral therapy durations were reviewed. Outcomes of interest included treatment success, defined as undetectable CMV DNAemia for two consecutive weeks or detected but unquantifiable DNAemia for five consecutive weeks, as well as the emergence of antiviral resistance, and recurrent DNAemia. From 2021 to 2023, 5/10 (50%) patients achieved durable virologic suppression with maribavir (classified as responders). Among responders, 2/5 (40%) experienced low-level CMV DNAemia recurrence (defined as a viral load less than 1000 IU/mL) within 8 weeks of antiviral discontinuation. Among nonresponders, 2/3 (66.7%) were found to have UL97 protein mutations associated with maribavir resistance identified 85 and 75 days after initiation of maribavir. Two patients are currently on maribavir with clinical outcomes that are yet to be determined. Responders had a mean reduction of 200mg (SD-274mg) in mycophenolate dosing with nonresponders having a mean increase of 167mg (SD-764mg). Maribavir, often in conjunction with mycophenolate dose reduction, was effective for many patients with refractory/resistant CMV DNAemia at our transplant center, though several experienced recurrent DNAemia. In patients who did not respond to therapy, resistance to maribavir was frequently detected. Clinicians treating these patients should remain vigilant for rebound CMV DNAemia and consider repeat antiviral resistance testing.

Alterations in circulating immunoregulatory proteins discriminate poor CD4 T lymphocyte trajectories in people with HIV on suppressive antiretroviral therapy.

It is essential to track immune perturbations related to insufficient CD4 T-cell recovery in PWH on suppressive ART as those with incomplete reconstitution are at a greater risk of non-AIDS-related morbidity and mortality. Several inflammatory soluble mediators have associated with poor immune reconstitution and adverse morbid outcomes in PWH, yet their implementation into routine clinical care to guide management remains inconsistent. Circulating immune checkpoint proteins have been linked to dysregulated immune pathways during suppressive ART and may serve as improved surrogate markers of clinical relevance. Here we investigate soluble lymphocyte-associated immunoregulatory proteins in virally suppressed PWH with no reported co-morbid outcomes and varying CD4 T-cell counts, to reveal underlying pathways that remain perturbed despite ART. This novel signature of immunoregulatory markers pertaining to poor CD4 T-cell trajectories uncover previously overlooked immune checkpoints as important targets for clinical monitoring of PWH in the setting of durable viral suppression by ART.

Abstract C026: Concurrent inhibition of the RAS ERK-MAPK pathway and PIKfyve as a therapeutic strategy for pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) is characterized clinically by poor survival and mechanistically by KRAS- and autophagy-dependent growth. We and others previously demonstrated that inhibition of KRAS signaling via downstream inhibition of the RAF-MEK-ERK pathway enhanced autophagic flux and dependency of PDAC on autophagy. Furthermore, we demonstrated that concurrent treatment with the nonspecific autophagy inhibitor chloroquine (CQ) and ERK MAPK inhibitors synergistically blocked PDAC growth. These findings provided rationale for our initiation of Phase I/II clinical trials evaluating the combination of MEKi (binimetinib; NCT4132505) or ERKi (LY3214996; NCT04386057) with HCQ in PDAC. However, a limitation of this approach is that CQ/HCQ is limited in terms of specificity and potency. Thus, we aimed to identify alternative anti-autophagy strategies. We performed a CRISPR-Cas9 loss- of-function screen in PDAC cell lines that identified the lipid kinase PIKfyve as a growth- promoting gene. PIKfyve is a lipid kinase that is essential for the generation of PI(3,5)P2 and critical for the dynamic regulation of lysosomal recycling. Because PIKfyve has been implicated in regulation of autophagy in other cellular contexts, we evaluated the effects of PIKfyve inhibition on growth and autophagic flux in PDAC cell lines and tumors. We demonstrated that PIKfyve inhibition by the small molecule apilimod resulted in durable growth suppression, with much greater potency than CQ treatment. PIKfyve inhibition potently reduced autophagy as indicated by decreased autophagic flux and the robust accumulation of autophagy-related proteins. Additionally, PIKfyve inhibition resulted in the accumulation of LAMP1 positive vacuoles that exhibited impaired cargo degradation, likely due to a lack of required acidity. Next, we hypothesized that PIKfye inhibition would sensitize PDAC cells to RAS pathway inhibition. We demonstrated that PIKfyve inhibition blocked the compensatory increases in autophagic flux associated both with MEK inhibition and with direct RAS inhibition. Accordingly, combined inhibition of PIKfyve and either the RAS ERK-MAPK pathway or RAS itself showed robust growth suppression across a panel of KRAS-mutant PDAC models. Growth suppression was due, in part, to potentiated cell cycle arrest and induction of apoptosis following loss of IAP proteins. These findings implicate PIKfyve as an effective anti-autophagy target when paired with RAS or ERK-MAPK pathway inhibition in pre-clinical models of PDAC. Citation Format: Jonathan M DeLiberty, Mallory K Roach, Clint A Stalnecker, Ryan Robb, Elyse G Schechter, Noah L Pieper, Runying Yang, Scott Bang, Khalilah E Taylor, Kristina Drizyte-Miller, John P Morris IV, Channing J Der, Adrienne D Cox, Kirsten L Bryant. Concurrent inhibition of the RAS ERK-MAPK pathway and PIKfyve as a therapeutic strategy for pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C026.

Combining Masculinizing Resistance, Rotation, and Biocontrol to Achieve Durable Suppression of the Potato Pale Cyst Nematode: A Model.

The pale cyst nematode, Globodera pallida, is a pest that poses a significant threat to potato crops worldwide. The most effective chemical nematicides are toxic to nontarget organisms and are now banned. Alternative control methods are therefore required. Crop rotation and biological control methods have limitations for effectively managing nematodes. The use of genetically resistant cultivars is a promising alternative, but nematode populations evolve, and virulent mutants can break resistance after just a few years. Masculinizing resistances, preventing avirulent nematodes from producing females, might be more durable than blocking resistances, preventing infection. Our demo-genetic model, tracking both nematode population densities and virulence allele frequencies, shows that virulence against masculinizing resistance may not be fixed in the pest population under realistic agricultural conditions. Avirulence may persist despite the uniform use of resistance. This is because avirulent male nematodes may transmit avirulent alleles to their progeny by mating with virulent females. Additionally, because avirulent nematodes do not produce females themselves, they weaken the reproductive rate of the nematode population, leading to a reduction in its density by at least 20%. This avirulence load can even lead to the collapse of the nematode population in theory. Overall, our model showed that combining masculinizing resistance, rotation, and biocontrol may achieve durable suppression of G. pallida in a reasonable time frame. Our work is supported by an online interactive interface allowing users (i.e., growers, plant health authorities, researchers) to test their own control combinations.

Supporting treatment adherence for resilience and thriving (START): protocol for a mHealth randomized controlled trial

BackgroundAlthough behavioral interventions show some promise for reducing stimulant use and achieving durable viral suppression in sexual minority men (SMM) with HIV, scalable mHealth applications are needed to optimize their reach and cost-effectiveness.MethodsSupporting Treatment Adherence for Resilience and Thriving (START) is a randomized controlled trial (RCT) testing the efficacy and cost-effectiveness of a mHealth application that integrates evidence-based positive affect regulation skills with self-monitoring of adherence and mood. The primary outcome is detectable HIV viral load (i.e., > 300 copies/mL) from self-collected dried blood spot (DBS) specimens at 6 months. Secondary outcomes include detectable DBS viral load at 12 months, self-reported stimulant use severity, anti-retroviral therapy (ART) adherence, and positive affect over 12 months. A national sample of up to 250 SMM with HIV who screen positive for stimulant use disorder and reporting suboptimal ART adherence is being recruited via social networking applications through April of 2024. After providing informed consent, participants complete a run-in period (i.e., waiting period) including two baseline assessments with self-report measures and a self-collected DBS sample. Those who complete the run-in period are randomized to either the START mHealth application or access to a website with referrals to HIV care and substance use disorder treatment resources. Participants provide DBS samples at baseline, 6, and 12 months to measure HIV viral load as well as complete self-report measures for secondary outcomes at quarterly follow-up assessments over 12 months.DiscussionTo date, we have paid $117,500 to advertise START on social networking applications and reached 1,970 eligible participants ($59.77 per eligible participant). Although we identified this large national sample of potentially eligible SMM with HIV who screen positive for a stimulant use disorder and report suboptimal ART adherence, only one-in-four have enrolled in the RCT. The run-in period has proven to be crucial for maintaining scientific rigor and reproducibility of this RCT, such that only half of consented participants complete the required study enrollment activities and attended a randomization visit. Taken together, findings will guide adequate resource allocation to achieve randomization targets in future mHealth research SMM with HIV who use stimulants.Trial RegistrationThis protocol was registered on clinicaltrials.gov (NCT05140876) on December 2, 2021.

Predictors of HIV Care Outcomes among Recently Out-of-Care Individuals in The Massachusetts Cooperative Re-engagement Controlled Trial Cohort.

A cohort of individuals in care for HIV infection who were identified as being recently out-of-care (OOC) was recruited for a trial using a data-to-care approach and an intervention to facilitate re-engagement and retention in care. This allowed for analysis of demographic and clinical characteristics correlated with recently being OOC, re-engagement, and successful retention in care and viral suppression. Recently OOC persons with HIV infection (PWH) were identified for enrollment in the Cooperative Re-engagement Controlled Trial (CoRECT). CoRECT employed a data-to-care strategy, using both clinical and surveillance data, and an active public health re-engagement intervention. We estimated relative risks (RRs), unadjusted and with multivariate log binomial regression models, to analyze associations between sociodemographic and clinical predictors of being OOC, re-engagement, retention in care, and viral suppression. Of the 630 OOC PWH enrolled in CoRECT, most were male (72.7%) and over 30 years old (91.3%). Almost 40.0% were Black non-Hispanic, 29.7% were non-US born, and 41.6% were men who have sex with men (MSM). Possible predictors of re-engagement, retention in care, and viral suppression included younger age, Hispanic race/ethnicity, birth in a US dependency, AIDS status, and HIV exposure mode. Viral suppression status within 1-year pre-enrollment was significantly associated with all outcomes: re-engagement (aRR 1.28), retention (aRR 1.72), viral suppression (aRR 1.81), and durable viral suppression (aRR 3.30). Findings elucidate factors associated with care engagement and continuity for recently OOC PWH which can be used to inform targeted re-engagement activities for priority populations and guide future data-to-care interventions.

New Therapies for Highly Sensitized Patients on the Waiting List.

Exposure to HLA alloantigens through pregnancy, blood products, and previous transplantations induce powerful immunologic responses that create an immunologic barrier to successful transplantation. This is commonly detected through screening for HLA antibodies using Luminex beads coated with HLA antigens at transplant evaluation. Currently accepted approaches to desensitization include plasmapheresis/low-dose or high-dose intravenous Ig plus anti-CD20. However, these approaches are often unsuccessful because of the inability to remove high titer circulating HLA antibodies and limit rebound responses by long-lived anti-HLA antibody secreting plasma cells (PCs) and memory B cells (B MEM ). This is especially significant for patients with a calculated panel reactive antibody of 99%-100%. Newer desensitization approaches, such as imlifidase (IgG endopeptidase), rapidly inactivate IgG molecules and create an antibody-free zone by cleaving IgG into F(ab'2) and Fc fragments, thus eliminating complement and cell-mediated injury to the graft. This represents an important advancement in desensitization. However, the efficacy of imlifidase is limited by pathogenic antibody rebound, increasing the potential for antibody-mediated rejection. Controlling antibody rebound requires new strategies that address the issues of antibody depletion and inhibition of B MEM and PC responses. This will likely require a combination of agents that effectively and rapidly deplete pathogenic antibodies and prevent immune cell activation pathways responsible for antibody rebound. Here, using anti-IL-6 receptor (tocilizumab) or anti-IL-6 (clazakizumab) could offer long-term control of B MEM and PC donor-specific HLA antibody responses. Agents aimed at eliminating long-lived PCs (anti-CD38 and anti-B-cell maturation antigen×CD3) are likely to benefit highly HLA sensitized patients. Complement inhibitors and novel agents aimed at inhibiting Fc neonatal receptor IgG recycling will be important in desensitization. Administering these agents alone or in combination will advance our ability to effectively desensitize patients and maintain durable suppression post-transplant. After many years of limited options, advanced therapeutics will likely improve efficacy of desensitization and improve access to kidney transplantation for highly HLA sensitized patients.

Expression of Concern: Durable Suppression of Acquired MEK Inhibitor Resistance in Cancer by Sequestering MEK from ERK and Promoting Antitumor T-cell Immunity.

Expression of Concern: Durable Suppression of Acquired MEK Inhibitor Resistance in Cancer by Sequestering MEK from ERK and Promoting Antitumor T-cell Immunity.

Combining the constitutive TRAIL-secreting induced neural stem cell therapy with the novel anti-cancer drug TR-107 in glioblastoma

Tumor-homing neural stem cell therapy (tNSC) is emerging as a promising treatment for aggressive cancers of the brain. Despite their success, developing tNSC therapies that maintain durable tumor suppression remains a challenge. Herein, we report a synergistic combination regimen where the novel small molecule TR-107 augments NSC-TRAIL therapy (hiNeuroS-TRAIL) in models of incurable brain cancer glioblastoma (GBM) in vitro. We report that the combination of hiNeuroS-TRAIL and TR-107 synergistically upregulated caspase markers and restored sensitivity to the intrinsic apoptotic pathway by significantly downregulating inhibitory pathways associated with chemoresistance and radioresistance in the TRAIL-resistant LN229 cell line. This combination also showed robust tumor suppression and enhanced survival of mice bearing human xenografts of both solid and invasive GBM. These findings elucidate a novel combination regimen and suggest combination of these clinically relevant agents may represent a new therapeutic option with increased efficacy for GBM patients.

Longitudinal Trajectories of Antiretroviral Treatment Adherence and Associations With Durable Viral Suppression Among Adolescents Living With HIV in South Africa.

Compared with other age groups, adolescents living with HIV (ALHIV) are estimated to have lower levels of adherence to antiretroviral treatment. Despite this, we lack evidence on adolescents' adherence patterns over time to inform the customization of intervention strategies. Eastern Cape province, South Africa. We analyzed data from a cohort of ALHIV (N = 1046, aged 10-19 years at baseline) recruited from 53 public health facilities. The cohort comprised 3 waves of data collected between 2014 and 2018 and routine viral load data from the National Institute for Communicable Disease data warehouse (2014-2019). Durable viral suppression was defined as having suppressed viral load (<1000 copies/mL) at ≥2 consecutive study waves. Group-based multitrajectory model was used to identify adherence trajectories using 5 indicators of self-reported adherence. Logistic regression modeling evaluated the associations between adherence trajectories and durable viral suppression. Overall, 933 ALHIV (89.2%) completed all 3 study waves (55.1% female, mean age: 13.6 years at baseline). Four adherence trajectories were identified, namely, "consistent adherence" (49.8%), "low start and increasing" (20.8%), "gradually decreasing" (23.5%), and "low and decreasing" (5.9%). Adolescents experiencing inconsistent adherence trajectories were more likely to be older, live in rural areas, and have sexually acquired HIV. Compared with the consistent adherence trajectory, the odds of durable viral suppression were lower among adolescents in the low start and increasing (adjusted odds ratio [aOR]: 0.62, 95% CI: 0.41 to 0.95), gradually decreasing (aOR: 0.40, 95% CI: 0.27 to 0.59), and the low and decreasing adherence (aOR: 0.25, 95% CI: 0.10 to 0.62) trajectories. Adherence to antiretroviral treatment remains a challenge among ALHIV in South Africa. Identifying adolescents at risk of nonadherence, based on their adherence trajectories may inform the tailoring of adolescent-friendly support strategies.

Personalized Nanovaccines Enhance Lymph Node Accumulation and Reprogram the Tumor Microenvironment for Improved Photodynamic Immunotherapy.

Tumor immunotherapy has emerged as an efficacious therapeutic approach that mobilizes the patient's immune system to achieve durable tumor suppression. Here, we design a photodynamic therapy-motivated nanovaccine (Dex-HDL/ALA-Fe3O4) co-delivering 5-aminolevulinic acid and Fe3O4 nanozyme that demonstrate a long-term durable immunotherapy strategy. After vaccination, the nanovaccine exhibits obvious tumor site accumulation, lymph node homing, and specific and memory antitumor immunity evocation. Upon laser irradiation, Dex-HDL/ALA-Fe3O4 effectively generates reactive oxygen species at the tumor site not only to induce the immunogenic cell death-cascade but also to trigger the on-demand release of full types of tumor antigens. Intriguingly, Fe3O4 nanozyme-catalyzed hydrogen peroxide generated oxygen for alleviating tumor hypoxia and modifying the inhibitory tumor microenvironment, thereby exhibiting remarkable potential as a sensitizer. The intravenous administration of nanovaccines in diverse preclinical cancer models has demonstrated remarkable tumor regression and inhibition of postoperative tumor recurrence and metastasis, thereby enabling personalized treatment strategies against highly heterogeneous tumors.

Abstract ND03: Discovery of RMC-9805, an oral, covalent tri-complex KRASG12D(ON) inhibitor

Abstract RASG12D mutant cancers represent a significant unmet medical need with 55,000 new diagnoses annually in the US. The RASG12D mutation increases the abundance of the active, GTP-bound state of RAS (RASG12D(ON)) and occurs commonly in multiple tumor histotypes, including about 20%, 29% and 17% of RAS mutant colorectal, pancreatic, and non-small cell lung cancers, respectively. RMC-6236, an investigational RASMULTI(ON) inhibitor currently in clinical testing, selectively targets the active, GTP-bound state of both mutant and wild-type RAS variants, including RASG12D(ON) and has shown clinical anti-tumor activity against tumors harboring KRASG12D. Efforts to find a mutant-selective RASG12D(ON) inhibitor led to the discovery of RMC-9805.The investigational agent RMC-9805 is a first-in-class, orally bioavailable, mutant selective covalent inhibitor of RASG12D(ON) that forms a tri-complex between the abundant intracellular chaperone cyclophilin A (CypA) and the “ON” state of RASG12D, enabling selective covalent engagement of Asp-12 and disrupting downstream RAS signaling by steric occlusion of effector binding. In contrast to other examples in the literature of covalent inhibitors of KRASG12D that rely on highly reactive, low stability warheads to overcome the low intrinsic reactivity of aspartic acid, RMC-9805 employs a warhead with low intrinsic reactivity and high stability under biological conditions. Rapid, selective, covalent modification of RASG12D by RMC-9805 is enabled by our tri-complex technology. We used structure-guided design to position the warhead in the CypA-RAS interface in an optimal orientation that enhanced crosslinking of Asp-12 allowing us to use a warhead that showed no intrinsic reactivity to a model aspartic acid system and was stable to enable oral dosing. RMC-9805 drove selective and persistent covalent modification of KRASG12D in human cancer cell lines in vitro, leading to deep and durable suppression of RAS pathway activity, inhibition of cell proliferation, and apoptosis. RMC-9805 monotherapy induced tumor regressions at well-tolerated doses in a majority of preclinical PDAC and NSCLC models harboring KRASG12D. Though a more heterogeneous response was observed in KRASG12D CRC models, combinations of RMC-9805 with either RMC-6236 (RASMULTI(ON) inhibitor) or an anti-EGFR antibody improved the depth of response and delayed the onset of resistance in vivo. In addition, RMC-9805 promoted cancer-associated neoantigen recognition and synergized with immunotherapy in preclinical models. RMC-9805 is also CNS penetrant and drove regressions in intracranial xenograft models of human KRASG12D PDAC. RMC-9805 is a first-in-class orally bioavailable, mutant selective and covalent RASG12D inhibitor currently in Phase 1 clinical trial (NCT06040541). Citation Format: John E. Knox, G. Leslie Burnett, Caroline Weller, Lingyan Jiang, Dongyu Zhang, Nicole Vita, Abby Marquez, Kyle J. Seamon, Andrea Gould, Marie Menard, Elsa Quintana, Zhe Chen, Zhican Wang, Zhengping Wang, Elena S. Koltun, Malika Singh, Jingjing Jiang, David Wildes, Jacqueline A.M. Smith, Adrian L. Gill. Discovery of RMC-9805, an oral, covalent tri-complex KRASG12D(ON) inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr ND03.

Using Causal Bayesian Networks to Assess the Role of Patient-Centered Care and Psychosocial Factors on Durable HIV Viral Suppression.

We assessed the role of patient-centered care on durable viral suppression (i.e., all viral load test results < 200 copies per ml during 2019) by conducting a retrospective cohort study of clients medically case managed by the Miami-Dade County Ryan White Program (RWP). Summary measures of patient-centered care practices of RWP-affiliated providers were obtained from a survey of 1352 clients. Bayesian network models analyzed the complex relationship between psychosocial and patient-centered care factors. Of 5037 clients, 4135 (82.1%) had durable viral suppression. Household income was the factor most strongly associated with durable viral suppression. Further, mean healthcare relationship score and mean "provider knows patient as a person" score were both associated with durable viral suppression. Healthcare relationship score moderated the association between low household income and lack of durable viral suppression. Although patient-centered care supports patient HIV care success, wrap around support is also needed for people with unmet psychosocial needs.

Patient Education and Decision Support for Long-Acting Injectable HIV Antiretroviral Therapy: Protocol for Tool Development and Pilot Testing with Ryan White HIV/AIDS Program Medical Case Management Programs in New York.

Long-acting injectable (LAI) HIV antiretroviral therapy (ART) presents a major opportunity to facilitate and sustain HIV viral suppression, thus improving health and survival among people living with HIV and reducing the risk of onward transmission. However, realizing the public health potential of LAI ART requires reaching patients who face barriers to daily oral ART adherence and thus can clinically benefit from alternative treatment modalities. Ryan White HIV/AIDS Program Part A medical case management (MCM) programs provide an array of services to address barriers to HIV care and treatment among economically and socially marginalized people living with HIV. These programs have demonstrated effectiveness in improving engagement along the continuum of care, but findings of limited program impact on durable viral suppression highlight the need to further innovate and hone strategies to support long-term ART adherence. This study aims to adapt and expand Ryan White MCM service strategies to integrate LAI ART regimen options, with the larger goal of improving health outcomes in the populations that could most benefit from alternatives to daily oral ART regimens. In 3 phases of work involving patient and provider participants, this study uses role-specific focus groups to elicit perceptions of LAI versus daily oral ART; discrete choice experiment (DCE) surveys to quantify preferences for different ART delivery options and related supports; and a nonrandomized trial to assess the implementation and utility of newly developed tools at 6 partnering Ryan White HIV/AIDS Program Part A MCM programs based in urban, suburban, and semirural areas of New York. Findings from the focus groups and DCEs, as well as feedback from advisory board meetings, informed the design and selection of the tools: a patient-facing, 2-page fact sheet, including frequently asked questions and a side-by-side comparison of LAI with daily oral ART; a patient-facing informational video available on YouTube (Google Inc); and a patient-provider decision aid. Implementation outcomes, measured through provider interviews, surveys, and service reporting, will guide further specification of strategies to integrate LAI ART options into MCM program workflows. The study was funded in late April 2021 and received approval from the institutional review board in May 2021 under protocol 20-096. Focus groups were conducted in late 2021 (n=21), DCEs ran from June 2022 to January 2023 (n=378), and tools for piloting were developed by May 2023. The trial (May 2023 through January 2024) has enrolled >200 patients. This study is designed to provide evidence regarding the acceptability, feasibility, appropriateness, and utility of a package of patient-oriented tools for comparing and deciding between LAI ART and daily oral ART options. Study strengths include formative work to guide tool development, a mixed methods approach, and the testing of tools in real-world safety-net service settings. Clinicaltrials.gov NCT05833542; https://clinicaltrials.gov/study/NCT05833542. DERR1-10.2196/56892.

Abstract 417: Chromosomal instability leads to durable tumor suppression upon macrophage-checkpoint disruption, with induction of anti-tumor IgG

Abstract Solid tumors generally exhibit chromosome copy number variation caused by chromosomal instability (CIN) in mitosis, and the resulting aneuploidy associates with poor prognosis in various cancer types and poor Tcell checkpoint blockade response in melanoma. In such contexts, however, macrophages and the SIRPa-CD47 checkpoint are understudied. Here, CIN is induced pharmacologically in poorly immunogenic B16F10 mouse melanoma cells, generating micronuclei plus diverse aneuploidy and skewing macrophages towards an anti-cancer phenotype based on markers and short-term tumor studies. Mice bearing CIN-afflicted tumors with wild-type CD47 levels survive only slightly longer compared to chromosomally stable controls, but long-term survival can be maximized when anti-tumor IgG opsonization is combined with adoptive transfer of macrophages with SIRPa blockade or with CD47 knockout of the B16F10. Multi-epitope, de novo anti-cancer IgG in survivors promote phagocytosis of CD47 knockout B16F10 cells by macrophages and suppress tumoroids in vitro and growth of tumors in vivo. An unexpected benefit of pairing CIN with maximal macrophage anti-cancer activity is thus an anti-cancer vaccination-like response that can lead to durable cures and potentiate cell-mediated acquired immunity. Citation Format: Dennis E. Discher. Chromosomal instability leads to durable tumor suppression upon macrophage-checkpoint disruption, with induction of anti-tumor IgG [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 417.

Abstract 4735: Targeting CDK1/2-driven mechanisms of resistance to BRAF and EGFR inhibition in BRAF(V600E) colorectal cancer restores therapeutic response

Abstract Purpose: Metastatic colorectal cancer (mCRC) is the second leading cause of cancer death worldwide. Roughly 8% of mCRC tumors harbor a BRAF(V600E) mutation, associated with the worst prognosis and limited treatment options. Most CRC research and most clinical trials of targeted therapies have narrowly focused on targeting vertical mechanisms of MAPK re-activation (i.e., EGFR-MAPK), with incremental advances for patients. New approaches are needed to address how therapeutic resistance is mediated by coordinated upregulation of multiple signaling pathways. Methods and Recent Advances: Using an innovative high-throughput kinase-activity mapping (HT-KAM) platform and kinase network resource (PhosphoAtlas), we discovered that SRC kinases drive resistance to BRAF ± anti-EGFR therapy independently of ERK signaling by inducing adaptive transcriptional changes via beta-catenin. This compensatory activation of SRC was mediated by an autocrine PGE2-loop that could be blocked with COX2 inhibitors (COX2i). Using patient-derived xenograft (PDX) models established from pre-treatment biopsies in clinical trial participants, we showed that targeting COX2 in combination with standard of care (SOC) BRAFi + EGFRi is an effective drug repurposing strategy to stabilize tumor growth in vivo. New, Unpublished Findings: Building on our drug discovery pipeline to find and target orthogonal modalities of therapeutic resistance, we leveraged our bank of residual PDX tumors collected after 21-day exposure to SOC therapy, and now report that CDK1 and CDK2 are at the center of a stress response program that enables BRAF(V600E) CRC tumor cells to survive under therapeutic pressure. We used HT-KAM to interrogate the activity of 165 kinases and kinase families, and integrated these profiles using computational methods to model signaling pathways. Out of the reprogrammed kinomes of BRAFi + EGFRi resistant tumors, the CDK1/2 kinases and mechanisms of cell cycle checkpoint emerged as critical dependencies. We validated these findings using multiplex immuno-fluorescence in residual tumors, protein/gene expression profile of tissues and cell lines (e.g., upregulation of Cyclins and CDC25s), and cell viability assay using dinaciclib, a CDK1/2 inhibitor. Considering that COX2i has minimal toxicity, yet improved tumor growth inhibition when added to SOC, we evaluated whether jointly blocking inflammatory pathway (COX2) and cell cycle checkpoints (CDK1/2) could overcome resistance. We found that co-targeting CDK1/2 along with BRAFi + EGFRi ± COX2i is well-tolerated in mice and promotes significant, durable suppression of tumor growth in multiple PDX models, including tumor regression, over 9 weeks of treatment. Conclusion: When tumors progress on SOC BRAFi + EGFRi, a therapeutic window remains open to switch to a CDK1/2i-containing regimen and restore cancer control. Citation Format: Jean-Philippe Coppe, Denise P. Muñoz, Chloe E. Atreya, Yeonjoo Hwang, Mehdi Bouhaddou, Louise E. Heinrich, Mohammad Naser, Ons Zakraoui, Roxana Pirker, Rupa Guha, Christina Moelders, Alessandro Scapozza, Cecilia Schwarzer, Layla Phillips, Changjun Wang, Laura van 't Veer, Veronica Steri, Scott R. VandenBerg. Targeting CDK1/2-driven mechanisms of resistance to BRAF and EGFR inhibition in BRAF(V600E) colorectal cancer restores therapeutic response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4735.

Temporal dynamics and drivers of durable HIV viral load suppression and persistent high- and low-level viraemia during Universal Test and Treat scale-up in Uganda: a population-based study.

Population-level data on durable HIV viral load suppression (VLS) following the implementation of Universal Test and Treat (UTT) in Africa are limited. We assessed trends in durable VLS and viraemia among persons living with HIV in 40 Ugandan communities during the UTT scale-up. In 2015-2020, we measured VLS (<200 RNA copies/ml) among participants in the Rakai Community Cohort Study, a longitudinal population-based HIV surveillance cohort in southern Uganda. Persons with unsuppressed viral loads were characterized as having low-level (200-999 copies/ml) or high-level (≥1000 copies/ml) viraemia. Individual virologic outcomes were assessed over two consecutive RCCS survey visits (i.e. visit-pairs; ∼18-month visit intervals) and classified as durable VLS (<200 copies/ml at both visits), new/renewed VLS (<200 copies/ml at follow-up only), viral rebound (<200 copies/ml at initial visit only) or persistent viraemia (≥200 copies/ml at both visits). Population prevalence of each outcome was assessed over calendar time. Community-level prevalence and individual-level predictors of persistent high-level viraemia were also assessed using multivariable Poisson regression with generalized estimating equations. Overall, 3080 participants contributed 4604 visit-pairs over three survey rounds. Most visit-pairs (72.4%) exhibited durable VLS, with few (2.5%) experiencing viral rebound. Among those with any viraemia at the initial visit (23.5%, n= 1083), 46.9% remained viraemic through follow-up, 91.3% of which was high-level viraemia. One-fifth (20.8%) of visit-pairs exhibiting persistent high-level viraemia self-reported antiretroviral therapy (ART) use for ≥12 months. Prevalence of persistent high-level viraemia varied substantially across communities and was significantly elevated among young persons aged 15-29 years (vs. 40- to 49-year-olds; adjusted risk ratio [adjRR] = 2.96; 95% confidence interval [95% CI]: 2.21-3.96), males (vs. females; adjRR = 2.40, 95% CI: 1.87-3.07), persons reporting inconsistent condom use with non-marital/casual partners (vs. persons with marital/permanent partners only; adjRR = 1.38, 95% CI: 1.10-1.74) and persons reporting hazardous alcohol use (adjRR= 1.09, 95% CI: 1.03-1.16). The prevalence of persistent high-level viraemia was highest among males <30 years (32.0%). Following universal ART provision, most persons living with HIV in south-central Uganda are durably suppressed. Among persons exhibiting any viraemia, nearly half exhibited high-level viraemia for ≥12 months and reported higher-risk behaviours associated with onward HIV transmission. Intensified efforts linking individuals to HIV treatment services could accelerate momentum towards HIV epidemic control.

Abstract B080: Mutant-selective KRASG12D(ON) inhibitor suppresses proliferation in vitro and tumor growth in vivo of KrasG12D GEMM-derived PDAC organoids

Abstract KRAS is the most frequently mutated oncogene in pancreatic ductal adenocarcinoma (PDAC), with KRASG12D driving initiation and progression of ~40% of tumors. Mutant KRAS proteins exist predominantly in the GTP-bound (RAS(ON)) state, leading to excessive downstream signaling via interaction with effectors such as RAF kinases. RMC-9805 is an orally bioavailable, mutant-selective covalent inhibitor of the active state of KRASG12D. RM-044, used here, is the corresponding representative preclinical tool compound. RM-044, KRASG12D and cyclophilin A form a stable, high affinity tri-complex resulting in the disruption of interactions with downstream KRAS effectors and suppression of KRASG12D(ON) signaling. RM-044 decreased RAS pathway activity and inhibited proliferation in multiple human KRASG12D PDAC cell lines in vitro. While these data are encouraging, we sought to study models that more faithfully represent the heterogeneity and complex tumor microenvironment found in the tumors of patients with KRASG12D PDAC. To address this, we generated and characterized pancreatic organoids from the lox-STOP-lox-KrasG12D genetically engineered mouse model (GEMM) and introduced expression of the KrasG12D mutation and p53 loss (KP) through a vector containing a p53 sgRNA and Cre recombinase. GEMM-derived KP pancreatic organoid lines treated with RM-044 showed concentration-dependent proliferation inhibition in vitro. KP organoids were implanted orthotopically into mouse pancreas leading to the development of PDAC tumors in immunocompetent mice. Histopathological examination of KP organoid derived tumors revealed molecular and phenotypic features translatable to the tumors of patients with PDAC. In this orthotopic model, oral administration of RM-044 inhibited MAPK pathway activation and led to deep and durable tumor growth suppression at a well-tolerated dose. In summary, mutant-selective, covalent inhibition of KRASG12D(ON) inhibits cell proliferation and drives tumor growth suppression in both human and murine preclinical models of KRASG12D PDAC. The generation of preclinical models that allow for in-depth translational analyses of KRASG12D(ON) inhibition in vitro and in vivo can support identification of optimal therapeutic regimens. Collectively, these preclinical results indicate that direct targeting of KRASG12D(ON) in PDAC has the potential to translate into clinical benefit for patients with pancreatic cancer. Citation Format: Mark P. Labrecque, Lingyan Jiang, Nicole Nasholm, Biswadeep Nayak, Xinxing Yu, Avian Song, Caroline Weller, James W. Evans, Maria Paz Zafra, Marie Parsons, Marie Menard, Lukas E. Dow, Jingjing Jiang, Ida Aronchik, Mallika Singh. Mutant-selective KRASG12D(ON) inhibitor suppresses proliferation in vitro and tumor growth in vivo of KrasG12D GEMM-derived PDAC organoids [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B080.

Very-Low-Level Viremia, Inflammatory Biomarkers, and Associated Baseline Variables: Three-Year Results of the Randomized TANGO Study.

We compared proportions of participants with target detected, target not detected (TND), and elevated viral load (VL) and assessed baseline variables associated with week 144 inflammatory biomarker levels between dolutegravir-lamivudine (DTG/3TC) and tenofovir alafenamide-based regimens (TBRs) in the TANGO study (post hoc). TANGO is an open-label, multicenter, phase 3 study that randomized adults with VL <50 copies/mL to switch to once-daily fixed-dose DTG/3TC or continue TBR. At baseline and each study visit, the VL was measured. Elevated VL event frequencies were assessed, including "blips." Interleukin 6, D-dimer, high-sensitivity C-reactive protein, soluble CD14, and soluble CD163 were measured at baseline and at week 144. Loge-transformed week 144 biomarker levels were compared between treatment groups using an analysis of covariance model adjusting for baseline variables. High, comparable proportions of participants had VL <40 copies/mL and TND at week 144 (DTG/3TC, 279 of 369 [76%]; TBR, 267 of 372 [72%], intention-to-treat exposed Snapshot analysis; adjusted difference, 3.9% [95% confidence interval, -2.5% to 10.2%]), with similar TND proportions at all postbaseline visits (123 of 369 [33%] vs 101 of 372 [27%], respectively). Similar proportions of DTG/3TC participants had ≥1 postbaseline VL ≥50 copies/mL (28 of 369 [8%] vs 42 of 372 [11%] for TBR), primarily blips (18 of 369 [5%] and 26 of 372 [7%], respectively). Week 144 inflammatory biomarker levels were low and comparable between groups and associated with multiple demographic and baseline characteristics, including baseline biomarker levels, indicating a multifactorial inflammatory response. Week 144 biomarker levels were low and generally comparable between treatment groups, reflecting similar, robust, and durable viral suppression observed using the stringent TND end point. Trial registration: ClinicalTrials.gov, NCT03446573.