Adoptive cell therapy using tumor-infiltrating lymphocytes (TIL) has demonstrated great potential for patients with treatment-refractory metastatic melanoma. However, the need for interleukin-2 (IL-2) co-administration during TIL cell therapy limits patient eligibility and restricts treatment to intensive care units due to the risk of severe side effects. Instead, engineering TIL with membrane-bound interleukin-15 (mbIL15) has the potential to promote TIL expansion, antitumor activity, and persistence of CD8+ T cells, without the use of IL-2. cytoTIL15 cells express mbIL15 fused to a drug-responsive domain (DRD) that is regulated by the Food and Drug Administration-approved small-molecule drug acetazolamide (ACZ). As such, cytoTIL15 cells are manufactured with ACZ instead of IL-2, in the presence of engineered feeder cells. The cytoTIL15 cell product exhibits ACZ dose-dependent expansion and persistence in vitro and in vivo and potent tumor-killing activity in human melanoma models in the absence of IL-2. In patient-derived xenograft (PDX) tumors, spatial profiling revealed infiltrating cytoTIL15 cells to be highly cytotoxic and less exhausted than non-engineered TIL. This novel platform creates a powerful, IL-2-free TIL cell therapy with a potentially improved tolerability and safety profile, while allowing individualized pharmacologic regulation of the TIL product.

PDF file - 112K, Supplementary Figure legends, primer sequences and Western blot antibody details.

PDF file - 2418K, MYOD is expressed across different molecular subgroups of medulloblastoma.

Background We have previously demonstrated the successful generation of membrane-bound IL15 (mbIL15) engineered TIL (cytoTIL15™ therapy) from solid tumors, and acetazolamide (ACZ)-driven regulated expression of mbIL15 resulted in TIL persistence in an antigen-independent preclinical model (SITC 2021, 2022). Here, we evaluated the function of pharmacologically tunable mbIL15 in the setting of chronic antigen stimulation by melanoma tumor-associated antigens (TAAs), such as MART1. Methods CytoTIL15 cells were manufactured from metastatic melanoma TIL donors by introducing mbIL15 under the pharmacological control of a carbonic-anhydrase-2 (CA2) drug responsive domain (DRD) via ACZ, the stabilizing ligand, and expanded through a proprietary rapid expansion process (REP). ACZ-dependent IL15 expression and downstream signaling were assessed. In vitro, we employed peptide-loaded HLA-A*0201 T2 cells to present MART-1 to TIL for evaluation of TCR-based functionality. CytoTIL15 cells treated with 0–25 µM ACZ were stimulated with antigen twice weekly over 28 days, with routine assessments of cell health, phenotype, cytokine production, and gene expression. In vivo, antigen-independent cytoTIL15 cell persistence in response to ACZ doses was evaluated after adoptive transfer of the TIL into immunodeficient NSG mice. Results Compared to unengineered TIL, generation of cytoTIL15 therapy from melanoma-derived TIL led to an overall 2.3-fold enrichment of MART1-reactive TIL. CytoTIL15 cells exhibited ACZ-dependent expansion in response to repeat MART1 stimulation, with TIL reaching maximums of 2, 9, and 18-fold expansion for 0, 1, and 25µM of ACZ, respectively. Chronic antigen exposure revealed an ACZ-driven IL15-dependent enrichment of >80% MART1-reactive TIL, and an increase in effector cytokine production and polyfunctionality (IFNγ, IL2Rα, TNFα, IL2, Perforin, CD107a, Granzyme B). CytoTIL15 cells driven by ACZ demonstrated maintenance of a functional cytotoxic signature, which was enriched in the antigen-reactive cell population. Despite repeated antigen-stimulation, withdrawal of ACZ reduced cytokine production and persistence of the MART1-enriched cytoTIL15 cell population in vitro. In vivo studies further underscored ACZ-dependent tunability of cytoTIL15 cells, as increased ACZ doses enhanced TIL persistence (AUC: 41, 111, and 306%TIL*day for 0, 30, and 200mg/kg ACZ QD), and ACZ withdrawal after 8 days reduced TIL persistence by 1.7-fold. Conclusions The expansion and persistence of tumor specific cytoTIL15 cells in the setting of chronic antigen exposure was regulatable by ACZ-dependent mbIL15 expression. This concept supports clinical evaluation of OBX-115 in the relapsed metastatic melanoma setting without concurrent IL-2 administration (NCT05470283).

PDF file - 4148K, Loss of MyoD does not influence its canonical targets in the myogenic differentiation program.

PDF file - 14123K, Mouse medulloblastomas with one allele of MyoD trend towards higher Ki67 index with reduction in total number of MyoD+ cells as well as cellular expression.

PDF file - 12536K, MyoD expression is higher in the tumor periphery compared to the inner core.

PDF file - 25456K, Comparative analysis of MyoD +/+; SmoA2, MyoD +/-; SmoA2 and MyoD-/-; SmoA2 mice.

Abstract Tumor infiltrating lymphocyte (TIL) therapy has shown promising results in the treatment of metastatic melanoma. However, TIL therapy has conventionally required co-administration of IL2, which is associated with toxicity in patients. We previously showed that melanoma TILs engineered to express membrane-bound IL15 (mbIL15) under the control of the ligand acetazolamide (ACZ) can achieve IL2-independent expansion during manufacturing, antigen-independent persistence in vitro and anti-tumor efficacy in vivo. In the current study, we extend the cytoTIL15 cell therapy product concept to indications beyond melanoma including non-small cell lung cancers (NSCLC), triple-negative breast cancers (TNBC) and head and neck squamous cell carcinomas (HNSCC), tumor types which represent significant unmet medical needs, particularly in the post-checkpoint inhibitor refractory setting. TILs from primary NSCLC, HNSCC and TNBC were engineered to express mbIL15 in the presence of ACZ and expanded in the absence of IL2 using our proprietary rapid expansion protocol (REP). CytoTIL15 cells were predominantly CD8 positive, enriched for mbIL15 expression and maintained T cell receptor variable beta chain (TCRVβ) diversity throughout expansion. In vitro antigen- and cytokine-independent survival and polyfunctionality of cytoTIL15 cells was measured from cultures that included ACZ. To assess anti-tumor activity, cytoTIL15 cells were co-cultured with autologous patient-derived cell lines (PDc) or tumor digests from patient-derived xenografts (PDx), and cytotoxicity and IFNγ release into supernatant was measured. In vitro, cytoTIL15 cells + ACZ exhibited similar or increased polyfunctionality compared to unengineered TIL + IL2. Unlike unengineered TILs, cytoTIL15 cells + ACZ persisted in an antigen-free setting without IL2, were cytotoxic to autologous PDc and released IFNγ in response to autologous PDx tumor digest. Taken together, these data show that IL2-independent, fully functional cytoTIL15 cells can successfully be generated from tumors such as NSCLC, HNSCC & TNBC, which afflict large numbers of patients. Citation Format: Kyle D. Pedro, Rachel Burga, Alonso Villasmil Ocando, Meghan Langley, Gauri Kulkarni, Zheng Ao, Benjamin Primack, Theresa Ross, Violet Young, Jeremy Tchaicha, Michelle Ols, Jan Ter Meulen. IL15-engineered tumor infiltrating lymphocytes (cytoTIL15TM) exhibit activity against autologous tumor cells from multiple solid tumor indications without IL2 [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 LB096.

PDF file - 1235K, MyoD is expressed in proliferating tumor cells in SmoA1, SmoA2 and Ptch conditional knock out medulloblastoma mouse models.

Tumor infiltrating lymphocytes (TIL) have shown promising efficacy in immunologically “hot” solid tumors that have a high level of T cell infiltration, such as melanoma. However, current treatment regimens require high dose IL-2 administration to support TIL survival, which limits their clinical applications due to IL-2 related toxicity. Obsidian Therapeutics is engineering TIL with membrane bound IL-15 (mbIL15) to eliminate the dependence of TIL on exogenous IL-2, potentially enhancing the tolerability of TIL therapies. Because there is a high unmet medical need in patients with tumors colder than melanoma, we evaluated mbIL15-engineered TIL expansion and functionality from colorectal cancer (CRC) and sarcoma biopsies. Using an IL2-independent, proprietary rapid expansion process (REP) we successfully expanded mbIL15-engineered TIL from both CRC and sarcoma, despite significantly lower T-cell numbers in the tumor tissues (average of 12-15% CD45+ TIL versus 64% in melanoma). mbIL15-engineered TIL showed an enrichment for CD8+ T cells throughout the REP and high T cell receptor variable beta chain (TCR Vbeta) diversity. mbIL15-engineered TIL also exhibited lower immune checkpoint expression (LAG3/PD-1) and higher activation marker expression (CD25/CD27/CD28) when compared with unengineered TIL expanded from the same tumors using a conventional REP with IL-2. mbIL15-engineered TIL were polyfunctional, as defined by expression of more than one effector molecules (CD107a, perforin, interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), and granzyme b) in response to CD3/CD28 stimulation. To examine the cytotoxic function of mbIL15-engineered TIL, we developed autologous cell lines from the same tumors that were used to generate the TIL. Using whole exome and RNA sequencing we found that the autologous tumor cell lines maintained expression of conserved tumor antigens and HLA-expression when compared with the primary tumor. When co-cultured with the autologous tumor cell lines, mbIL15-engineered TIL secreted higher levels of IFN-γ and induced higher cytotoxicity as compared to unengineered TIL cultured with IL-2. Taken together, these data demonstrate that mbIL15-engineered TIL can successfully be expanded from comparatively “cold” tumors with low T-cell infiltration, such as CRC and sarcoma, while maintaining high TCR diversity and polyfunctionality and demonstrating higher cytokine production and cytotoxic activity against autologous tumor lines, compared to conventional TIL with IL2. Citation Format: Zheng Ao, Carmela Passaro, Bulent A. Aksoy, Balazs Koscso, Rachel Burga, Kyle Pedro, Natasha Ly, Nirzari Shah, Alonso V. Ocando, Gauri Kulkarni, Trisha Timpug, Seth M. Pollack, Jan ter Meulen, Michelle L. Ols. Engineering tumor infiltrating lymphocytes from sarcoma and colorectal tumors with membrane bound IL-15 for IL-2 independent expansion and enhanced cytotoxicity against autologous tumor cell lines [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 LB093.

Background CytoTIL15® therapy is an IL2-independent, engineered TIL product which allows pharmacological control of membrane-bound IL15 (mbIL15). We have previously shown that cytoTIL15® TILs demonstrate enhanced persistence and anti-tumor efficacy in a human allogeneic melanoma PDX model. Here we use digital spatial profiling and single cell sequencing to characterize the RNA expression profile and phenotypic markers of tumor infiltrating immune cells as well as tumor cells in this model and compare the results to unengineered, IL2-dependent TIL. Methods cytoTIL15® therapy contains TILs engineered with mbIL15 under the control of a carbonic-anhydrase-2 drug responsive domain, regulated by the ligand acetazolamide (ACZ). cytoTIL15® cells were generated from human melanomas through a proprietary rapid expansion process. Expanded TILs were phenotyped and assayed for in vitro polyfunctionality, cytotoxicity, and frequency of tumor-associated antigen-specific TCR. In vivo phenotype and anti-tumor functionality was examined through adoptive transfer of TILs into NSG mice bearing subcutaneous, HLA-matched, patient-derived-xenograft (PDX) tumors expressing melanoma-associated antigen MART-1, in IACUC approved animal studies. Tumors, spleen, bone marrow, and blood were harvested 14-21 days following adoptive cell transfer and assessed by flow cytometry, GeoMx digital spatial profiling, and single cell sequencing for characterization of TIL and the tumor microenvironment (TME). Results cytoTIL15® cells demonstrated enrichment and reactivity for melanoma antigen-specific TCRs, while maintaining TCRβ diversity. Fifteen days post-ACT, tumors from animals treated with cytoTIL15® cells exhibited significantly (p=0.0175) higher frequency (3.4-fold) of TILs, in which MART-1 tetramer positive cells demonstrated increased T-cell factor 1 (TCF-1) and CD69 expression, and secreted significantly greater amounts of IFNγ and TNFα cytokines into the TME, compared to unengineered TILs with IL2. In addition, cytoTIL15® TILs had a distinct differential gene expression profile, demonstrating an increase in effector genes such as IL2RB, GZMB, GNLY and CCL5 and reduction in exhaustion-related genes such as EOMES. cytoTIL15® cells accumulating in the bone marrow exhibited a lower frequency of CD39+ terminally differentiated CD8+ T cells, while maintaining higher levels of memory phenotype makers. Conclusions In this allogeneic melanoma PDX model, cytoTIL15® cells showed a distinct profile of RNA expression and phenotypic markers, consistent with their increased persistence and anti-tumor efficacy. Interestingly, the subpopulation of cytoTIL15® cells reactive to tumor-associated antigen MART-1 displayed increased expression of TCF-1, which in melanoma patients has been associated with responses to immune checkpoint blockade, in addition to progression-free and overall survival. Ethics Approval All animal studies were IACUC approved.

Standard tumor-infiltrating lymphocyte (TIL) therapy requires IL-2 administration to support TIL expansion and survival, but this cytokine is associated with T cell exhaustion and can result in severe toxicities that limit patient eligibility (1). To this end, we genetically engineered TIL to express membrane-bound IL-15 (mbIL15) under the control of Obsidian’s cytoDRIVE® technology (cytoTIL15࣪), which allows regulation of protein expression via a drug-responsive domain upon acetazolamide (ACZ) administration. IL-15 is a preferred cytokine over IL-2 to mediate TIL activation and expansion, because it does not result in CD8 T cell exhaustion or stimulate regulatory CD4 T cells, and enhances development of a memory T-cell phenotype. We have previously demonstrated IL-2-independent, 3-6-fold increased cytoTIL15 persistence in an antigen-independent setting relative to unengineered TIL therapy with IL-2 (uTIL) (2). Due to the challenge of generating autologous tumor/TIL-matched pairs and most importantly, to assess cytoTIL15 cell’s functional impact on anti-tumor growth across multiple donors, we developed an allogeneic patient-derived xenograft (PDX) model. To establish the model, different melanoma tumor digests were co-incubated in vitro with select HLA-A*02-matched, allogeneic melanoma TIL donors to assess their reactivity. Tumors were screened for expression of shared antigens, such as gp100 and MART1, and TIL donor TCRs were screened with tetramers. Once established, serially passaged tumor fragments were grown, measured, and randomized into groups to receive intravenous transfer of TIL (n=8/cohort). Mice receiving uTIL were treated with four saturating doses of recombinant IL-2, and mice receiving cytoTIL15 cells received either vehicle or oral 200 mg/kg ACZ daily for the entire study, without any IL-2. Three of four cytoTIL15 cell preparations from different donors dosed with ACZ achieved significant tumor growth inhibition compared to uTIL. Four mice developed complete responses as early as 17 days post cytoTIL15 cell transfer. The level of anti-tumor response was associated with increased frequency of MART1-reactive cytoTIL15 cells. On day 20 after TIL transfer, tumors and secondary lymphoid organs were collected (n=4/cohort). Tumors treated with cytoTIL15 cells + ACZ showed an 8-10-fold increased TIL infiltration compared to uTIL or cytoTIL15 cells + vehicle. Moreover, enhanced cytoTIL15 cell infiltration and anti-tumor activity was associated with increases in pro-inflammatory cytokines (e.g., IFNγ). Taken together, these data clearly demonstrate the superiority of cytoTIL15 cells over uTIL for controlling or eradicating melanoma tumor outgrowth and the utility of an allogeneic PDX model for comparative evaluation of tumor-antigen specific TIL reactivity. References: 1. Yang JC. Toxicities associated with adoptive T-cell transfer for Cancer. Cancer J. 2015. 2. Burga R. et al Genetically engineered tumor-infiltrating lymphocytes (cytoTIL15) exhibit IL-2-independent persistence and anti-tumor efficacy against melanoma in vivo. SITC 36th annual meeting 2021. Citation Format: Jeremy H. Tchaicha, Scott Lajoie, Rachel Burga, Theresa Ross, Benjamin Primack, Meghan Langley, Violet Young, Alonso Villasmil Ocando, Kyle Pedro, Jack Tremblay, Gauri Kulkarni, Mithun Khattar, Dhruv Sethi, Michelle Ols, Gabriel Helmlinger, Gary Vanasse, Shyam Subramanian, Jan ter Meulen. Allogeneic, IL-2-independent tumor-infiltrating lymphocytes expressing membrane-bound IL-15 (cytoTIL15࣪) eradicate tumors in a melanoma PDX model through recognition of shared tumor antigens [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB212.

The molecular networks involved in the regulation of HIV replication, transcription, and latency remain incompletely defined. To expand our understanding of these networks, we performed an unbiased high-throughput yeast one-hybrid screen, which identified 42 human transcription factors and 85 total protein-DNA interactions with HIV-1 and HIV-2 long terminal repeats. We investigated a subset of these transcription factors for transcriptional activity in cell-based models of infection. KLF2 and KLF3 repressed HIV-1 and HIV-2 transcription in CD4+ T cells, whereas PLAGL1 activated transcription of HIV-2 through direct protein-DNA interactions. Using computational modeling with interacting proteins, we leveraged the results from our screen to identify putative pathways that define intrinsic transcriptional networks. Overall, we used a high-throughput functional screen, computational modeling, and biochemical assays to identify and confirm several candidate transcription factors and biochemical processes that influence HIV-1 and HIV-2 transcription and latency.

BackgroundAdoptive cell therapy with tumor-infiltrating lymphocytes (TILs) has demonstrated tremendous promise in clinical trials for patients with solid or metastatic tumors.1 However, current TIL therapy requires systemic administration of IL-2 to promote TIL survival, and IL-2-associated toxicities greatly limit patient eligibility and reduce the long-term clinical benefit of TIL therapy.2 3 Unlike IL-2, which promotes T cell exhaustion, IL-15 maintains antigen-independent TIL persistence through homeostatic proliferation and supports CD8+ T cell anti-tumor activity without stimulating regulatory T cells. We designed genetically engineered TILs to express a regulated form of membrane-bound IL-15 (mbIL15) for tunable long-term persistence, leading to enhanced efficacy and safety for the treatment of patients with solid tumors.MethodsObsidian’s cytoDRiVE™ platform includes small human protein sequences called drug responsive domains (DRD)s that enable regulated expression of a fused target protein under control of FDA-approved, bioavailable small molecule ligands. cytoTIL15 contains TILs engineered with mbIL15 under the control of a carbonic-anhydrase-2 DRD, controlled by the ligand acetazolamide (ACZ). After isolation from tumors, TILs were transduced and expanded in vitro through a proprietary TIL expansion process. cytoTIL15 were immunophenotyped and assessed for in vitro antigen-independent survival and co-cultured with tumor cells to assess polyfunctionality and cytotoxicity. In vivo TIL persistence and anti-tumor efficacy was evaluated through adoptive transfer of TILs into immunodeficient NSG mice, either naïve or implanted with subcutaneous patient-derived-xenograft (PDX) tumors.Results cytoTIL15 and conventional IL2-dependent TILs isolated from melanoma tumor samples expanded to clinically relevant numbers over 14 days. Throughout expansion, cytoTIL15 were enriched for CD8+ T cells and acquired enhanced memory-like characteristics, while maintaining diverse TCRVβ sub-family representation. cytoTIL15 demonstrated enhanced potency over conventional TILs, as measured by increased polyfunctionality and cytotoxicity against tumor and PDX lines in vitro (figure 1A). In a 10-day antigen-independent in vitro assay, cytoTIL15 persisted at greater frequencies than conventional TILs in the absence of IL-2 (figure 1B; *p<0.05). cytoTIL15 adoptively transferred into naïve NSG mice demonstrated ACZ-dependent long-term persistence without antigen or exogenous IL-2, whereas conventional TILs were undetectable >30 days following adoptive cell transfer (figure 1C). Importantly, cytoTIL15 achieved significant tumor control in a human PDX model (figure 1D), which correlated with increased TIL accumulation in secondary lymphoid organs.Abstract 166 Figure 1cytoTIL15 demonstrate superior persistence. cytoTIL15 is an engineered TIL product expressing regulatable mbIL15. (A) cytoTIL15 demonstrate enhanced in vitro cytotoxicity after co-culture with melanoma tumor lines (representative data from 3 TIL donors). (B) cytoTIL15 have improved persistence in antigen- and IL2- independent culture conditions in vitro compared to conventional TILs cultured in the absence of IL-2 as well as (C) in vivo compared to conventional TILs supplemented with IL-2, when engrafted into NSG mice (in vitro: representative data from 1 TIL donor, performed in >3 replicate donors, in vivo: n=5/group, representative of 1 TIL donor, performed in >3 replicate donors). (D) cytoTIL15 (with 200mg/kg ACZ PO QD) demonstrate enhanced anti-tumor efficacy in a xenograft melanoma model as compared to conventional TILs (with 50000 IU IL-2 q8h BID, IP for 5 days) (n=8/group, representative of 1 TIL donor, performed in >2 replicate donors; ACT = adoptive cell transfer).ConclusionsTaken together, the superior persistence and potency of cytoTIL15 in the complete absence of IL-2 highlights the clinical potential of cytoTIL15 as a novel TIL product with enhanced safety and efficacy for patients with melanomas, and other solid tumors.AcknowledgementsThe authors wish to acknowledge the Cooperative Human Tissue Network for the their supply of human tumor tissue, and the MD Anderson Cancer Center for technical support; schematic created with BioRender.com.ReferencesChandran SS, Somerville RPT, Yang JC, Sherry RM, Klebanoff CA, Goff SL, Wunderlich JR, Danforth DN, Zlott D, Paria BC, Sabesan AC, Srivastava AK, Xi L, Pham TH, Raffeld M, White DE, Toomey MA, Rosenberg SA, Kammula US. Treatment of metastatic uveal melanoma with adoptive transfer of tumour-infiltrating lymphocytes: a single-centre, two-stage, single-arm, phase 2 study. Lancet Oncol 2017 Jun;18(6):792–802. doi: 10.1016/S1470-2045(17)30251-6. Epub 2017 Apr 7. PMID: 28395880; PMCID: PMC5490083.Yang JC. Toxicities associated with adoptive T-cell transfer for Cancer. Cancer J 2015;21:506–9.Schwartz RN, Stover L, Dutcher JP. Managing toxicities of high-dose interleukin-2. Oncology (Williston Park) 2002 Nov;16(11 Suppl 13):11–20. PMID: 12469935.

Tumor-infiltrating lymphocyte (TIL) therapy is at the cusp of approval for heavily pretreated patients with solid tumor malignancies. TIL therapy currently requires IL2 for in vivo maintenance of TILs, significantly limiting its application due to patient safety and eligibility hurdles. cytoTIL15 is a TIL product engineered with regulatable membrane bound IL15 (mbIL15) designed via our cytoDRiVE® platform. Armoring TILs with endogenous mbIL15 has several advantages over systemic IL2. Unlike IL2, IL15 does not increase immunosuppressive regulatory T-cells and drives T-cell differentiation towards a stem-cell memory phenotype associated with long-term persistence. cytoTIL15 uses Obsidian’s cytoDRiVE® platform, which consists of a carbonic anhydrase 2 (CA2) derived drug responsive domain that enables regulated expression of mbIL15 under control of acetazolamide (ACZ), an FDA-approved orally bioavailable small molecule ligand. We use a proprietary process for high efficiency transduction of TILs with regulatable mbIL15 and expansion without IL2, after which TILs can be cryopreserved or used fresh in downstream in vitro and in vivo assays. Our process achieved robust expression of ACZ-regulatable mbIL15 on TILs that expand in the absence of IL2 to levels required for clinical manufacturing. Upon administration in NSG mice, cytoTIL15 exhibited significantly higher expansion and persistence compared to conventional TILs treated with clinically analogous IL2 dosing. cytoTIL15 have a CD8+ effector T-cell biased immunophenotypic profile distinct from conventional TILs, while maintaining a diverse TCR repertoire and tumor reactivity with robust IFNg production. In addition, cytoTIL15 demonstrated significantly higher tumor cytotoxicity in vitro in the absence of exogenous IL2 in comparison to conventional TILs, indicative of superior potency. cytoTIL15 is a more potent and persistent TIL product that does not require infusion of IL2, thereby enhancing the safety and durable efficacy of TIL therapy for patients with metastatic melanoma and other solid tumor malignancies.

•HIV-1 utilizes several forms of cell-to-cell transmission that influence viral dissemination, survival and pathogenesis.•HIV-1 cell-to-cell transmission mediates the generation of latent infection in CD4 + T cells.•HIV-1 cell-to-cell transmission affects the regulation of HIV-1 latency, challenging the development of curative therapies.

Brain tumors are the leading cause of cancer-related death in children. Genomic studies have provided insights into molecular subgroups and oncogenic drivers of pediatric brain tumors that may lead to novel therapeutic strategies. To evaluate new treatments, better preclinical models adequately reflecting the biological heterogeneity are needed. Through the Children's Oncology Group ACNS02B3 study, we have generated and comprehensively characterized 30 patient-derived orthotopic xenograft models and seven cell lines representing 14 molecular subgroups of pediatric brain tumors. Patient-derived orthotopic xenograft models were found to be representative of the human tumors they were derived from in terms of histology, immunohistochemistry, gene expression, DNA methylation, copy number, and mutational profiles. In vivo drug sensitivity of targeted therapeutics was associated with distinct molecular tumor subgroups and specific genetic alterations. These models and their molecular characterization provide an unprecedented resource for the cancer community to study key oncogenic drivers and to evaluate novel treatment strategies.