Sanctuary Site Research Articles

Improved Automated Radiosynthesis of [18F]Dolutegravir: Toward Clinical Applications.

Positron emission tomography imaging using radiolabeled dolutegravir (DTG) is an interesting approach to understand the biodistribution of this antiretroviral drug at HIV-1 sanctuary sites. In the course of clinical translation, we depict herein an improved and pharmaceutically compliant radiosynthesis of [18F]DTG from an original tin precursor. The radiosynthesis was achieved in two steps by copper-mediated radiofluorination, followed by enol ether deprotection using a kit-based AllInOne module. Ready-to-inject [18F]DTG was obtained in 20 ± 5% (n = 12) decay-corrected radiochemical yield within 90 min, representing a 4-fold increase compared to the previously published three-step radiosynthesis. Quality control was carried out with three consecutive [18F]DTG productions according to the current European Pharmacopoeia guidelines, which include pH determination, identity and purity (chemical, radiochemical, and radionuclide) assessments, residual solvent quantification, dosage of lithium, copper, and tin traces, sterility and bacterial endotoxin tests. [18F]DTG (∼2 GBq) was obtained with a molar activity of 59 ± 2 GBq/μmol at the time of injection and was suitable for human applications.

Staging of immuno-virological dynamics during acute HIV infection in a Belgian prospective cohort study

BackgroundThe events during acute HIV infection (AHI) set the stage for the subsequent course of the disease. Early initiation of antiretroviral therapy (ART) has been associated with favorable immunovirological outcomes, yet the precise impact of ART timing during AHI remains unclear, particularly on lymphoid tissues. Materials and methodsThe ACS cohort is a prospective cohort study in Belgium, collecting longitudinal clinical data and human bodily material (HBM) from people diagnosed and treated during AHI. The aim of the cohort is to study the impact of ART initiation during AHI on HIV reservoir and immune dysfunction in peripheral blood and anatomical sanctuary sites, as well as its effect on the gut microbiome. The cohort consists of two HBM sampling trajectories: one limited (blood, stool and leukapheresis) and a more extensive one (blood, stool, leukapheresis, colonoscopy, inguinal lymph node excision and lumbar puncture). Here we describe the baseline characteristics, immunovirological outcomes, safety and tolerability of HBM sampling. ResultsBetween March 2016 and April 2024, 47 participants were enrolled, predominantly men who have sex with men (MSM), with a median age of 36 years [IQR 30–43.5]. Almost 90 % of participants initiated ART within 72 h after study inclusion, irrespective of HBM sampling trajectory. The timing of ART initiation according to the Fiebig stage did not significantly impact immune recovery (CD4/CD8 ratio ≥1) or the time to viral suppression. Approximately 40 % of participants opted for the extensive HBM sampling trajectory during AHI. However, the participation rate for the extensive trajectory decreased by nearly half at the longitudinal follow-up timepoint. In general, study-related procedures were safe and well-tolerated, with limited procedure-related adverse events (AEs). Inguinal lymph node excision was associated with the highest AE rate, in line with previous reports. ConclusionsOur findings reaffirm the beneficial effect of ART initiation during AHI on long term immunovirological outcomes, regardless of Fiebig stage at treatment initiation. Additionally, we demonstrate that the collection of HBM during and longitudinally after AHI is safe and feasible, without compromising time to ART initiation. Cohorts that integrate comprehensive clinical data with high-quality HBM samples are essential to longitudinally study the impact of early ART on reservoir dynamics and immune responses across various anatomical sites after AHI.

Viral-Host Interactions and Immune Responses in HIV-Infected Infants: A Review

Human Immunodeficiency Virus (HIV) infection in infants presents distinctive challenges due to their developing immune systems and unique viral-host interactions compared to adults. This review examines current knowledge on viral-host interactions and immune responses in HIV-infected infants, focusing on immune development, viral dynamics, and therapeutic implications. The immune system of infants undergoes rapid maturation during early life, influencing their susceptibility to HIV infection and responses to antiretroviral therapy (ART). Key aspects include thymic function, cytokine profiles, and the establishment of immune memory, which collectively shape immune responses against HIV. Viral dynamics in HIV-infected infants differ markedly from those in adults, characterized by high viral loads, diverse viral subtypes, and the early establishment of viral reservoirs within immune cells. These reservoirs, particularly in sanctuary sites like the central nervous system, pose challenges for achieving viral eradication and long-term remission. Effective management requires strategies to characterize and target these reservoirs, alongside early intervention to mitigate viral replication and preserve immune function. Advances in viral monitoring technologies and treatment regimens are essential for improving clinical outcomes and reducing the global burden of pediatric HIV infection. Keywords: HIV, infants, viral-host interactions, immune responses, immune development, viral dynamics, therapeutic interventions

Discovery of a Double-Stapled Short Peptide as a Long-Acting HIV-1 Inactivator with Potential for Oral Bioavailability.

Different from most antiretroviral drugs that act as passive defenders to inhibit HIV-1 replication inside the host cell, virus inactivators can attack and inactivate HIV-1 virions without relying on their replication cycle. Herein, we describe the discovery of a hydrocarbon double-stapled helix peptide, termed D26. D26 is based on the HIV-1 gp41 protein lentiviral lytic peptide-3 motif (LLP3) sequence, which can efficiently inhibit HIV-1 infection and inactivate cell-free HIV-1 virions. It was noted that D26 was highly resistant to proteolytic degradation and exhibited a remarkably extended in vivo elimination half-life. Additionally, relative to its linear, nonstapled version, D26 exhibited much higher exposure in sanctuary sites for HIV-1. Amazingly, this lead compound also demonstrated detectable oral absorption. Thus, it can be concluded that D26 is a promising candidate for further development as a long-acting, orally applicable HIV-1 inactivator for the treatment of HIV-1 infection.

Can artificially induced habitat complexity alter macroinvertebrates diversity? A case study from a freshwater wetland ecosystem

Habitat complexity can enhance the resilience of wetlands against environmental stressors such as extreme weather events, pollution, and habitat loss. The introduction of artificial induced complexity (AIC) can play a significant role in reshaping the macroinvertebrate communities within wetland ecosystems by enhancing habitat quality in protected areas. Therefore, this study was designed to examine the variation of macroinvertebrates community structure in artificially induced complex sanctuary site (SS), partially protected (PP) and open sites (OS) from July 2019-April 2020. AIC in the sanctuary sites was established through the installation of cemented hexapods and ring pipes. Over the study period, a total of 665 macroinvertebrates were gathered, with 55.55% originating from SS, 31.14% from PP, and 18.21% from OS sites. The community consists mainly of Lymnaea acuminatatea and Tubifex tubifex, with the most abundant species being Limnodrillus hoffmeisteri and Branchiura sowerbyi. A notable positive impact of AIC was evident in the increased total abundance and diversity indices of macroinvertebrate communities. The Analysis of Similarity (ANOSIM) revealed significant distinctions in community structures among various intervention types, which was further corroborated by a non-metric multidimensional scaling (nMDS) plot. Similarity of Percentage Analysis (SIMPER) highlighted that Limnodrillus hoffmeisteri made the most significant contribution to the dissimilarity observed among the different intervention types. Canonical Correspondence Analysis (CCA) revealed a close association between the structure of the macroinvertebrate community and three key ecological factors: periphyton biomass, macrophyte cover, and sediment properties. These findings could offer a more effective approach for managers and policymakers engaged in the conservation of macroinvertebrates and the sustainable management of fisheries resources within wetland ecosystems.

Introducing the Concept of Sanctuary Sites in Ischemic Stroke.

The topography of arterial territories has been defined using digital maps of supratentorial infarcts. Regions with a high probability of infarction (Pi) exist in the deep compartment due to a paucity of collaterals. However, less attention has been given to regions with a low Pi. Using published digital maps, patients with cortical stroke and documented vessel occlusion were included. Infarcts from T2-weighted magnetic resonance images were segmented and registered onto a standard brain template (Montreal Neurological Institute 152). Segmented magnetic resonance images were averaged to yield the Pi at a voxel level. The overall Pi for the combined arterial territories was calculated to ensure that Pi was in the range of 0 to 1. Sanctuary sites were identified as regions with Pi <0.1. There were 154 patients (63% men; median age, 69 years; and interquartile range, 57-78 years). The magnetic resonance imaging scan used for segmentation was performed at a median interval of 35 (interquartile range, 3-66) days after stroke onset. Sanctuary sites were present in the frontal (gyrus rectus, the paracentral lobule, and orbitofrontal and precentral gyrus), parietal (postcentral, supramarginal, and angular gyrus, superior and inferior parietal lobule, and precuneus and posterior cingulate), and occipital cortex (cuneus, middle, and superior occipital gyrus). We propose that following vessel occlusion, there are cortical regions with a low Pi, which we termed sanctuary sites. The anatomic basis for this observation is the compensatory capacity of leptomeningeal collaterals.

Histomorphometric changes in testis following administration of tenofovir nanoparticles in an animal model

BackgroundNanoparticle-based drugs are new inventions in the management of the Human immunodeficiency virus (HIV) pandemic, especially resistant forms of the virus in anatomical sanctuary sites and organs such as the testis. However, safety issues must be resolved to attain the optimal potential of newer nano-drug formulations.AimThe study investigated the toxicological potential of synthesized Tenofovir Nanoparticles (TDF-N) on testicular indices when used for the prevention and treatment of HIV.MethodologyFifteen male Sprague–Dawley (SD) rats with weight ranging from 230 g to 250 g were randomly assigned into groups A (control, saline), B (TDF), and C (TDF-N). The testes were removed for sperm analysis and processed for H/E and PAS stains. Cell counts and cellular measurements; the diameter and the area of the testicular seminiferous tubules were measured using ImageJ and Leica software 2.0.ResultsA significant reduction (p < 0.05) in sperm count was noticed in the TDF-N group. Also observed in the TDF and TDF-N groups was a significant reduction (p < 0.05) in sperm motility and in the number of dead sperms compared with the control. Sperm abnormalities such as distorted basement membranes, loss of germ cells, hypocellular interstitium, and loss of spermatogenic series were increased in the TDF and TDF-N groups. There was also a significant reduction (p < 0.05) in the cell count, diameter, and area of seminiferous tubules observed in these groups.ConclusionTDF and TDF-N may be detrimental to the testis and testicular tissue, leading to significantly reduced sperm counts, motility, and ultimately–male fertility.

Whether the Corona Virus Has Completely Left the Human Body or Remains in the Body and Causes Other Viral Diseases

Whole viruses, also called virions, comprise either RNA or DNA surrounded by a protein coat. Those that persist in sanctuary sites can continue gradually infecting the cells around them. There they hijack the host cell(s) to make copies of themselves. RNA viruses such as hepatitis C virus5 and HIV6 can evade immune control and can continuously produce infectious virions throughout a patient’s life.

Motion Management: The Road Map to Accurate Radiation Treatment Delivery

Radiation therapy is a key contributor to positive outcomes in hematological malignancies. However, this is contingent on minimizing the exposure of critical normal organs. The introduction of computed tomography (CT) for radiation treatment planning and the development of sophisticated dose calculation algorithms has transformed the radiation therapy field and made it possible to transition from conventional involved-field radiation to modern involved-site radiation therapy. Thanks to rapid advances in drug discovery, treatment strategies for many hematological malignancies have evolved to incorporate targeted and cellular therapies, in some cases even allowing the replacement of chemotherapy. As a result, new opportunities have been created for radiation to address relapses after more lines of therapy, identify disease-involving sanctuary sites, and bridge to the subsequent therapy. When considering radiation in patients receiving novel therapies, who may also be more heavily pretreated, respecting the critical and normal structures at all costs is imperative. In this document, we will describe modern techniques used to deliver state-of-the-art radiation therapy and practical considerations to ensure the accurate treatment of the target while avoiding normal organs at risk.

Primary testicular lymphoma: A case report

ABSTRACT Primary testicular lymphoma is a rare and aggressive form of extranodal non-Hodgkin lymphoma. It has a predilection for relapse at sanctuary sites such as the contralateral testis and central nervous system. Herein, we present a case of primary testicular lymphoma in a 62-year-old man.

Ongoing HIV replication in lymph node sanctuary sites in treated individuals contributes to the total latent HIV at a very slow rate

Lymph nodes (LNs) serve as a sanctuary site for HIV viruses due to the heterogeneous distribution of the antiretrovirals (ARVs) inside the LNs. There is an ongoing debate whether this represents ongoing cycles of viral replication in the LNs or merely residual virus production by latently infected cells. Previous work has claimed that the measured levels of genetic variation in proviruses sampled from the blood were inconsistent with ongoing replication. However, it is not clear what rate of variation is consistent with ongoing replication in small sanctuary sites.In this study, we used a spherically symmetric compartmental ODE model to track the HIV viral dynamics in the LN and predict the contribution of ongoing replication within the LN to the whole-body proviral pool in an ARV-suppressed person living with HIV. This model tracks the reaction–diffusion dynamics of uninfected, actively infected, and latently infected T-cells as well as free virus within the LN parenchyma and the blood, and distinguishes between latently infected cells created before ARV therapy and during ARV therapy.We simulated suppressive therapy beginning in year 5 post-infection. Each LN sanctuary site had a volume of 1 ml, and we considered cases of 1 ml, 30 ml, and 250 ml total volume, which represent a single active sanctuary site, moderate systemic involvement, and involvement of the total lymphoid tissue. Viral load in the blood rapidly dropped and remained below the limit of detection in all cases but remained high in the LN sanctuary sites. Novel latent cells increased systemically over time but very slowly, taking between 25 and 50 years to reach 5 % of the total latent pool, depending on the volume of lymphoid tissue involvement.Putative sanctuary sites in LNs are limited in volume and produce novel latent cells slowly. Assays to detect genetic drift due to such sites would require very deep sequencing if sampling only from the blood. Previous studies showing a lack of genetic drift are consistent with the expected contribution of ongoing replication in lymph node sanctuary sites.

Total marrow lymphoid irradiation IMRT treatment using a novel CT-linac

BackgroundA novel CT-linac (kilovolt fan-beam CT-linac) has been introduced into total marrow and lymphoid irradiation (TMLI) treatment. Its integrated kilovolt fan-beam CT (kV FBCT) can be used not only for image guidance (IGRT) but also to re-calculate the dose.PurposeThis study reported our clinical routine on performing TMIL treatment on the CT-linac, as well as dose distribution comparison between planned and re-calculated based on IGRT FBCT image sets.Methods11 sets of data from 5 male and 6 female patients who had underwent the TMLI treatment with uRT-linac 506c were selected for this study. The planning target volumes consist of all skeletal bones exclusion of the mandible and lymphatic sanctuary sites. A planned dose of 10 Gy was prescribed to all skeletal bones exclusion of the mandible in two fractions and 12 Gy in two fractions was prescribed to lymphatic sanctuary sites. Each TMLI plan contained two sub-plans, one dynamic IMRT for the upper body and the other VMAT for the lower extremity. Two attempts were made to obtain homogeneous dose in the overlapping region, i.e., applying two plans with different isocenters for the treatment of two fractions, and using a dose gradient matching scheme. The CT scans, including planning CT and IGRT FBCT, were stitched to a whole body CT scan for dose distribution evaluation.ResultsThe average beam-on time of Planupper is 30.6 min, ranging from 24.9 to 37.5 min, and the average beam-on time of Planlower is 6.3 min, ranging from 5.7 to 8.2 min. For the planned dose distribution, the 94.79% of the PTVbone is covered by the prescription dose of 10 Gy (V10), and the 94.68% of the PTVlymph is covered by the prescription dose of 12 Gy (V12). For the re-calculated dose distribution, the 92.17% of the PTVbone is covered by the prescription dose of 10 Gy (V10), and the 90.07% of the PTVlymph is covered by the prescription dose of 12 Gy (V12). The results showed that there is a significant difference (p < 0.05) between planning V10, V12 and delivery V10, V12. There is no significant difference (p > 0.05) between planned dose and re-calculated dose on selected organs, except for right lens (p < 0.05, Dmax). The actual delivered maximum dose of right lens is apparently larger than the planned dose of it.ConclusionTMLI treatment can be performed on the CT-linac with clinical acceptable quality and high efficiency. Evaluation of the recalculated dose on IGRT FBCT suggests the treatment was delivered with adequate target coverage.

Vanishing splendor: a comprehensive review of the decline in the original fish fauna of Lake Victoria

The presence of the non-native Nile perch (Lates niloticus) in Lake Victoria and the resulting ecological transformations have garnered significant attention from the scientific community. However, details regarding the timing, origin, and purpose of the fish introduction have remained elusive. This paper reviews fish fauna changes in Lake Victoria, investigates causes, and advocates for biodiversity conservation through diversity and sanctuary sites. It examines different historical periods to understand changes and guide effective conservation strategies. The introduction of Nile perch has led to a substantial decline and even extinction of many native fish species, particularly cichlids, resulting in ecological imbalances and economic challenges for local fishing communities. To address these pressing issues, ongoing conservation efforts are being implemented. These initiatives focus on promoting sustainable fishing practices, safeguarding critical habitats, and reintroducing native fish species. Furthermore, cage fish farming is being explored as a potential solution to alleviate pressure on wild populations, as suggested by various authors. Recommendations stemming from this study include conducting virtual population analysis for stock assessments of indigenous species, intensify conservation efforts, diversify fishing practices, expand cage fish farming, increase public awareness and education, and enhance policy and governance frameworks. By implementing these recommendations, there is optimism for the recovery and resilience of indigenous fish species in Lake Victoria, leading to the conservation of biodiversity and the promotion of sustainable livelihoods for local communities.

Children's Oncology Group blueprint for research: Acute lymphoblastic leukemia.

Cure rates for acute lymphoblastic leukemia (ALL), the most common childhood cancer have steadily improved over the past five decades. This is due to intensifying systemic therapy, recognizing and treating the central nervous system as a sanctuary site, and implementing modern risk stratification to deliver varying intensities of therapy based on age, presenting white blood count, sentinel somatic genetics, and therapy response. Recently, numerous Children's Oncology Group trials have demonstrated the lack of benefit of intensifying traditional chemotherapy, providing evidence that new approaches are needed to cure the patients for whom cure has been elusive. Distinguishing those who require intensive or novel therapeutic approaches from others who will be cured with minimal therapy is key for future trials. Incorporating new genomic biomarkers and more sensitive measures of minimal/measurable residual disease provide opportunities to achieve these goals.

Population dynamics of immunological synapse formation induced by bispecific T cell engagers predict clinical pharmacodynamics and treatment resistance.

Effector T cells need to form immunological synapses (IS) with recognized target cells to elicit cytolytic effects. Facilitating IS formation is the principal pharmacological action of most T cell-based cancer immunotherapies. However, the dynamics of IS formation at the cell population level, the primary driver of the pharmacodynamics of many cancer immunotherapies, remains poorly defined. Using classic immunotherapy CD3/CD19 bispecific T cell engager (BiTE) as our model system, we integrate experimental and theoretical approaches to investigate the population dynamics of IS formation and their relevance to clinical pharmacodynamics and treatment resistance. Our models produce experimentally consistent predictions when defining IS formation as a series of spatiotemporally coordinated events driven by molecular and cellular interactions. The models predict tumor-killing pharmacodynamics in patients and reveal trajectories of tumor evolution across anatomical sites under BiTE immunotherapy. Our models highlight the bone marrow as a potential sanctuary site permitting tumor evolution and antigen escape. The models also suggest that optimal dosing regimens are a function of tumor growth, CD19 expression, and patient T cell abundance, which confer adequate tumor control with reduced disease evolution. This work has implications for developing more effective T cell-based cancer immunotherapies.

Primary testicular lymphoma demonstrates overexpression of the Wilms tumor 1 gene and different mRNA and miRNA expression profiles compared to nodal diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) shows a high degree of clinical and biological heterogeneity. Primary testicular lymphoma (PTL) is an extranodal variant of DLBCL associated with a higher risk of recurrence, including contralateral testicles and central nervous system sanctuary sites. Several molecular aberrations, including somatic mutation of MYD88, CD79B, and upregulation of NF-kB, PDL-1, and PDL-2, are thought to contribute to the pathogenesis and poor prognosis of PTL. However, additional biomarkers are needed that may improve the prognosis and help understand the PTL biology and lead to new therapeutic targets. RNA from diagnostic tissue biopsies of the PTL-ABC subtype and matched nodal DLBCL-ABC subtype patients was evaluated by mRNA and miRNA expression. Screening of 730 essential oncogenic genes was performed, and their epigenetic connections were examined using the nCounter PAN-cancer pathway, and Human miRNA assays with the nCounter System (NanoString Technologies). PTL and nodal DLBCL patients were comparable in age, gender, and putative cell of origin (p>0.05). Wilms tumor 1 (WT1) expression in PTL exceeded that in nodal DLBCL (>6-fold; p=0.01, FDR <0.01) and WT1 associated pathway genes THBS4, PTPN5, PLA2G2A, and IFNA17 were upregulated in PTL (>2.0-fold, p<0.01, FDR <0.01). Additionally, miRNAs targeting WT1 (hsa15a-5p, hsa-miR-16-5p, has-miR-361-5p, has-miR-27b-3p, has-miR-199a-5p, has-miR-199b-5p, has-miR-132-3p, and hsa-miR-128-3p) showed higher expression in PTL compared to nodal DLBCL (≥2.0-fold; FDR 0.01). Lower expression of BMP7, LAMB3, GAS1, MMP7, and LAMC2 (>2.0-fold, p<0.01) was observed in PTL compared to nodal DLBCL. This research revealed higher WT1 expression in PTL relative to nodal DLBCL, suggesting that a specific miRNA subset may target WT1 expression and impact the PI3k/Akt pathway in PTL. Further investigation is needed to explore WT1's biological role in PTL and its potential as a therapeutic target.

In Vitro and In Vivo Models for Drug Transport Across the Blood-Testis Barrier.

The blood-testis barrier (BTB) is a selectively permeable membrane barrier formed by adjacent Sertoli cells (SCs) in the seminiferous tubules of the testes that develops intercellular junctional complexes to protect developing germ cells from external pressures. However, due to this inherent defense mechanism, the seminiferous tubule lumen can act as a pharmacological sanctuary site for latent viruses (e.g., Ebola, Zika) and cancers (e.g., leukemia). Therefore, it is critical to identify and evaluate BTB carrier-mediated drug delivery pathways to successfully treat these viruses and cancers. Many drugs are unable to effectively cross cell membranes without assistance from carrier proteins like transporters because they are large, polar, and often carry a charge at physiologic pH. SCs express transporters that selectively permit endogenous compounds, such as carnitine or nucleosides, across the BTB to support normal physiologic activity, although reproductive toxicants can also use these pathways, thereby circumventing the BTB. Certain xenobiotics, including select cancer therapeutics, antivirals, contraceptives, and environmental toxicants, are known to accumulate within the male genital tract and cause testicular toxicity; however, the transport pathways by which these compounds circumvent the BTB are largely unknown. Consequently, there is a need to identify the clinically relevant BTB transport pathways in in vitro and in vivo BTB models that recapitulate human pharmacokinetics and pharmacodynamics for these xenobiotics. This review summarizes the various in vitro and in vivo models of the BTB reported in the literature and highlights the strengths and weaknesses of certain models for drug disposition studies. SIGNIFICANCE STATEMENT: Drug disposition to the testes is influenced by the physical, physiological, and immunological components of the blood-testis barrier (BTB). But many compounds are known to cross the BTB by transporters, resulting in pharmacological and/or toxicological effects in the testes. Therefore, models that assess drug transport across the human BTB must adequately account for these confounding factors. This review identifies and discusses the benefits and limitations of various in vitro and in vivo BTB models for preclinical drug disposition studies.

Abstract LB203: Targeted inhibition of IRAK-4 with CA-4948 (emavusertib) sensitizes metastatic brain melanoma to anti-PD-1 immune checkpoint blockade

Abstract Introduction: The unique microenvironment within the brain alongside restrictions imparted by the blood brain barrier (BBB) create a sanctuary site for tumors to thrive. Melanoma is often responsive to therapy when present in peripheral tissue, but becomes recalcitrant when sequestered beyond the BBB. An estimated 40-60% of metastatic melanoma patients will develop a brain lesion, even while receiving treatment. Stereotactic radiosurgery (SRS) is the gold standard in intervention for metastatic brain melanoma (MBM), often given with anti-PD1 immune checkpoint blockade (ICB). While this therapy is initially effective, resistance occurs rapidly and ~50% of patients will develop new brain lesions within a year. Treatments at this stage are limited, necessitating the discovery of new therapies. Recent studies have shown that myeloid differentiation primary response protein 88 (MyD88) is activated in melanoma in tumor-associated myeloid cells where chronic myddosome signaling results in defective immunological responses. We have found that myddosome signaling is also prevalent in MBM, likely protecting brain metastases against effector immune detection. We recently identified that CA-4948, a small molecule inhibitor of interleukin (IL)-1 receptor-associated kinase (IRAK-4) and rate-limiting step in the myddosome cascade, can reach therapeutic levels in the brain and demonstrates on-target inhibition in preclinical models of MBM. These data highlight a unique therapeutic opportunity where selective inhibition of pro-tumorigenic cells in the MBM tumor microenvironment (TME) via targeted IRAK-4 inhibition may recondition the immunological landscape of these tumors, sensitizing these difficult-to-treat tumors to immunotherapy. Hypothesis: Selective inhibition of pro-tumorigenic cells via targeted inhibition of IRAK-4 with CA-4948 will recondition the immunological landscape of MBM, improving anti-tumor response to anti-PD-1 ICB. Methods: Patient MBM samples were assessed by IHC to define the distribution of myddosome signaling. Preclinical syngeneic MBM tumor models were treated with CA-4948 alone and in combination with anti-PD-1 ICB. Tumors were examined by flow cytometry and IHC to characterize the composition of the immune TME and evaluate the distribution of T lymphocytes. Overall survival was compared between control, single agent, and combination treated animals. Results: Tumor-associated immune cells and astrocytes comprise the majority of active myddosome signaling in patient MBM. Preclinical models corroborate these findings, with targeted inhibition of IRAK-4 through CA-4948 treatment effective at reducing activation and validating anti-tumor activity in the CNS. Analysis of treated tumors reveal decreased expression of Programmed Death Ligand 1 (PD-L1), and increased numbers of tumor-infiltrating T lymphocytes. Combination CA-4948 with anti-PD-1 ICB resulted in reduced tumor growth, and improved survival over single agent therapy. Conclusions: Therapeutic inhibition of IRAK-4 in MBM mitigates immune suppression mediated by tumor-associated cells, allowing for improved immune surveillance and tumor infiltration by effector T lymphocytes, resulting in enhanced anti-tumor activity. Thus, CA-4948 may be an effective treatment alongside anti-PD-1 ICB for patients with MBM. Citation Format: Christina A. von Roemeling, Bently P. Doonan, Rylynn A. Russell, Tyler V. Elliott, Erica Matich, Vincent Archibald, Lan Hoang-Minh, Reinhard W. von Roemeling, Dora Ferrari, Jamison Hoffman, Duane A. Mitchell. Targeted inhibition of IRAK-4 with CA-4948 (emavusertib) sensitizes metastatic brain melanoma to anti-PD-1 immune checkpoint blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB203.

Primary Testicular Lymphoma: Single Center Experience.

Primary testicular lymphoma (PTL) is an exceedingly rare and aggressive form of non-Hodgkin's lymphoma; the most common subtype is diffuse large B-cell (DLBCL). Standard treatment includes orchiectomy, chemotherapy, central nervous system (CNS) prophylaxis, and prophylactic radiation to the contralateral testis. PTL can reoccur years after complete remission. Treatment to immune sanctuary sites, CNS and contralateral testis, is crucial in preventing relapse. There are limited data characterizing this entity and this study aimed to add to existing literature. This descriptive retrospective study characterized twelve patients with PTL from years 2010-2021 at Allegheny Health Network. Their demographic data, prognostic factors, treatment regimens, and relapse sites (if any) were tabulated. The mean progression-free survival (PFS) was calculated to describe our experience in treating PTL. Twelve patients were diagnosed with PTL; 10/12 (83.33%) patients were diagnosed with ABC PTL-DLBCL. Median age of diagnosis was 67 years. Eight of the 12 (66.66%) were African American, 4/12 (33.33%) were Caucasian. At the time of diagnosis, 8/12 (66.66%) patients presented with an elevated lactate dehydrogenase (LDH) and 8/12 (66.66%) presented with a left testicular mass. Most were treated with R-CHOP (9/12), intrathecal methotrexate (IT-MTX) (10/12), and radiation to the contralateral testis (9/12). Three of the twelve (25%) patients relapsed. Median time to relapse was 8 months. Mean PFS was 50.417 months. We discuss our experience in treating PTL with RCHOP, IT-MTX, and irradiation to the contralateral testis and add to the limited pre-existing data that exist.

Bone marrow niche chemoprotection of metastatic solid tumors mediated by CYP3A4.

The bone/bone marrow is one of the most common sites for metastatic solid tumors. Moreover, the tumor microenvironment is an essential part of cancer homeostasis. Previously, it was shown that cytochrome P450 enzymes (CYPs) are present in the bone marrow (BM) microenvironment, particularly in the mesenchymal stroma cells, at levels comparable to those of hepatocytes. It was found that the CYPs play important roles in nurturing and maintaining normal hematopoietic stem cells as well as multiple myeloma and leukemia cells, including protecting them from toxic insults. It was hypothesized that the CYPs in the BM microenvironment might play a similar role in solid tumors metastatic to bone. The interaction between the BM microenvironment and malignant cells that routinely metastasize to the bone (lung, breast, and prostate cancer) was modeled. Via genetic engineering and pharmacological approaches, the role of stromal cytochrome P450 3A4 (CYP3A4) in drug resistance promoted by the BM microenvironment in niche-cancer models in vitro and in vivo was interrogated. BM stroma protected prostate, breast, and lung cancer cells from cytotoxic chemotherapy. Stromal CYP3A4 was at least partially responsible for this protection in vitro and in vivo. Moreover, inhibiting CYP3A4 with clarithromycin overcame the stroma-mediated chemoresistance toward prostate, breast, and lung cancer cells. These results suggest that, similar to observations from hematologic malignancies, the BM microenvironment, through expression of CYPs, creates a sanctuary site from chemotherapy for metastatic solid tumors. Targeting these sanctuaries holds promise for eradicating bone metastasis in solid tumors.