Search

Resumen Introduccion La pandemia de COVID-19 ha ocasionado cerca de 25 millones de casos en el mundo Se ha descrito que los pacientes asintomaticos pueden ser fuentes de transmision Sin embargo, es dificil detectarlos y no es claro su papel en la dinamica de transmision del virus, lo que obstaculiza la implementacion de estrategias para la prevencion Objetivo Describir el comportamiento de la infeccion asintomatica por SARS-CoV-2 en una cohorte de trabajadores del Aeropuerto Internacional El Dorado "Luis Carlos Galan Sarmiento" de Bogota, Colombia Materiales y metodos Se diseno una cohorte prospectiva de trabajadores del Aeropuerto El Dorado El seguimiento se inicio en junio de 2020 con una encuesta a cada trabajador para caracterizar sus condiciones de salud y trabajo Cada 21 dias se tomo una muestra de hisopado nasofaringeo para detectar la presencia del SARS-CoV-2 mediante reaccion en cadena de la polimerasa con transcriptasa inversa (RT-PCR) Se analizo el comportamiento del umbral del ciclo (cycle threshold) de los genes ORFlab y N segun el dia de seguimiento Resultados En los primeros tres seguimientos de la cohorte se encontro una incidencia de la infeccion por SARS-CoV-2 del 16,51 % La proporcion de contactos positivos fue del 14,08 % La mediana del umbral del ciclo fue de 33,53 Conclusion Se determinaron las caracteristicas de la infeccion asintomatica por el SARS-CoV-2 en una cohorte de trabajadores La deteccion de infectados asintomaticos sigue siendo un reto para los sistemas de vigilancia epidemiologica Introduction: The 2019 coronavirus pandemic (COVID-19) has caused around 25 million cases worldwide Asymptomatic patients have been described as potential sources of transmission However, there are difficulties to detect them and to establish their role in the dynamics of virus transmission, which hinders the implementation of prevention strategies Objective: To describe the behavior of asymptomatic SARS-CoV-2 virus infection in a cohort of workers at the El Dorado "Luis Carlos Galan Sarmiento" International Airport in Bogota, Colombia Materials and methods: A prospective cohort of 212 workers from the El Dorado airport was designed The follow-up began in June, 2020 A survey was used to characterize health and work conditions Every 21 day, a nasopharyngeal swab was taken to identify the presence of SARS-CoV-2 using RT-PCR We analyzed the behavior of the cycle threshold (ORFlab and N genes) according to the day of follow-up Results: In the first three follow-ups of the cohort, we found an incidence of SARS-CoV-2 infection of 16 51% The proportion of positive contacts was 14 08% The median threshold for cycle threshold was 33 53 Conclusion: We characterized the asymptomatic SARS-CoV-2 infection in a cohort of workers The identification of asymptomatic infected persons continues to be a challenge for epidemiological surveillance systems

BackgroundAdoptive cell therapy with chimeric antigen receptor T cells (CAR-T) has become a standard treatment for patients with certain aggressive B cell malignancies and holds promise to improve the care of patients suffering from numerous other cancers in the future. However, the high manufacturing cost of CAR-T cell therapies poses a major barrier to their broader clinical application. Among the key cost drivers of CAR-T production are single-use reagents for T cell activation and clinical-grade viral vector. The presence of variable amounts of contaminating monocytes in the starting material poses an additional challenge to CAR-T manufacturing, since they can impede T cell stimulation and transduction, resulting in manufacturing failure.MethodsWe created K562-based artificial antigen-presenting cells (aAPC) with genetically encoded T cell stimulation and costimulation that represent an inexhaustible source for T cell activation. We additionally disrupted endogenous expression of the low-density lipoprotein receptor (LDLR) on these aAPC (aAPC-ΔLDLR) using CRISPR-Cas9 gene editing nucleases to prevent inadvertent lentiviral transduction and avoid the sink effect on viral vector during transduction. Using various T cell sources, we produced CD19-directed CAR-T cells via aAPC-ΔLDLR-based activation and tested their in vitro and in vivo antitumor potency against B cell malignancies.ResultsWe found that lack of LDLR expression on our aAPC-ΔLDLR conferred resistance to lentiviral transduction during CAR-T production. Using aAPC-ΔLDLR, we achieved efficient expansion of CAR-T cells even from unpurified starting material like peripheral blood mononuclear cells or unmanipulated leukapheresis product, containing substantial proportions of monocytes. CD19-directed CAR-T cells that we produced via aAPC-ΔLDLR-based expansion demonstrated potent antitumor responses in preclinical models of acute lymphoblastic leukemia and B-cell lymphoma.ConclusionsOur aAPC-ΔLDLR represent an attractive approach for manufacturing of lentivirally transduced T cells that may be simpler and more cost efficient than currently available methods.

The success of chimeric antigen receptor (CAR)–mediated immunotherapy in acute lymphoblastic leukemia (ALL) highlights the potential of T-cell therapies with directed cytotoxicity against specific tumor antigens. The efficacy of CAR T-cell therapy depends on the engraftment and persistence of T cells following adoptive transfer. Most protocols for T-cell engineering routinely expand T cells ex vivo for 9 to 14 days. Because the potential for engraftment and persistence is related to the state of T-cell differentiation, we hypothesized that reducing the duration of ex vivo culture would limit differentiation and enhance the efficacy of CAR T-cell therapy. We demonstrated that T cells with a CAR-targeting CD19 (CART19) exhibited less differentiation and enhanced effector function in vitro when harvested from cultures at earlier (day 3 or 5) compared with later (day 9) timepoints. We then compared the therapeutic potential of early versus late harvested CART19 in a murine xenograft model of ALL and showed that the antileukemic activity inversely correlated with ex vivo culture time: day 3 harvested cells showed robust tumor control despite using a 6-fold lower dose of CART19, whereas day 9 cells failed to control leukemia at limited cell doses. We also demonstrated the feasibility of an abbreviated culture in a large-scale current good manufacturing practice–compliant process. Limiting the interval between T-cell isolation and CAR treatment is critical for patients with rapidly progressing disease. Generating CAR T cells in less time also improves potency, which is central to the effectiveness of these therapies. Cancer Immunol Res; 6(9); 1100–9. ©2018 AACR.

Tolerance to self-antigens prevents the elimination of cancer by the immune system1,2. We used synthetic chimeric antigen receptors (CARs) to overcome immunological tolerance and mediate tumor rejection in patients with chronic lymphocytic leukemia (CLL). Remission was induced in a subset of subjects, but most did not respond. Comprehensive assessment of patient-derived CAR T cells to identify mechanisms of therapeutic success and failure has not been explored. We performed genomic, phenotypic and functional evaluations to identify determinants of response. Transcriptomic profiling revealed that CAR T cells from complete-responding patients with CLL were enriched in memory-related genes, including IL-6/STAT3 signatures, whereas T cells from nonresponders upregulated programs involved in effector differentiation, glycolysis, exhaustion and apoptosis. Sustained remission was associated with an elevated frequency of CD27+CD45RO–CD8+ T cells before CAR T cell generation, and these lymphocytes possessed memory-like characteristics. Highly functional CAR T cells from patients produced STAT3-related cytokines, and serum IL-6 correlated with CAR T cell expansion. IL-6/STAT3 blockade diminished CAR T cell proliferation. Furthermore, a mechanistically relevant population of CD27+PD-1–CD8+ CAR T cells expressing high levels of the IL-6 receptor predicts therapeutic response and is responsible for tumor control. These findings uncover new features of CAR T cell biology and underscore the potential of using pretreatment biomarkers of response to advance immunotherapies. An IL-6/STAT3 signature and memory CD8 T cell subset in preinfusion chimeric antigen receptor–expressing T cells associate with response in patients with high-risk chronic lymphocytic leukemia.

The recent clinical success of CD19-directed chimeric antigen receptor (CAR) T cell therapy in chronic and acute leukemia has led to increased interest in broadening this technology to other hematological malignancies and solid tumors. Now, advances are being made using CAR T cell technology to target myeloma antigens such as B cell maturation antigen (BCMA), CD138, and kappa-light chain as well as CD19 on putative myeloma stem cells. To date, only a limited number of multiple myeloma patients have received CAR T cell therapy but preliminary results have been encouraging. In this review, we summarize the recently reported results of clinical trials conducted utilizing CAR T cell therapy in multiple myeloma (MM).

Autologous T cells modified to recognize novel antigen targets are a novel form of therapy for cancer. We review the various potential forms of observed and hypothetical toxicities associated with genetically modified T cells. Despite the focus on toxicities in this review, re-directed T cells represent a powerful and highly effective form of anti-cancer therapy; we remain optimistic that the common toxicities will become routinely manageable and that some theoretical toxicity will be exceedingly rare, if ever observed.

137 Background: The adoptive transfer of autologous T cells genetically modified to express a CD19-specific, 4-1BB/CD3ζ-signaling CAR (CTL019) has shown remarkable activity and induces long-term remissions in a subset of patients with relapsed/refractory chronic lymphocytic leukemia (CLL) and acute lymphoblastic leukemia (ALL). In ALL, CTL019 induces a complete response (CR) in over 90% of patients while in CLL 25% of patients obtain a CR. It is not fully understood why only certain patients respond to therapy. Methods: We employed next generation sequencing of RNA (RNAseq) to identify predictive indicators of response to CTL019. We performed RNAseq on leukapheresis and manufactured product T cells prior to re-infusion from 35 CLL and 7 pediatric ALL patients with heavily pre-treated and high-risk disease. To characterize potency, we performed RNAseq on the infusion product after stimulation with the CAR. Results: We find that durable remission in CLL is associated with gene expression signatures of early memory and T-effector cells, while T cells from non-responding patients are enriched in signatures of T-regulatory cells, terminal differentiation, and exhaustion. In following the results from CLL, we find that pediatric ALL manufactured T cells are significantly enriched for an early memory, naïve T cell state and all achieved a CR. In parallel in vitro experiments, stimulation of the infusion product further demonstrated that CTL019 cells from CRs have an increased capacity for activation upon stimulation. We tested if we could extend these observations to identify a phenotype of T cells that is predictive of response prior to CTL019 manufacturing and find that the signatures predictive of response at the pre-infusion stage are also observed at the earlier leukapheresis time point. Conclusions: These findings suggest that intrinsic T cell fitness dictates response to CAR T cells. These gene expression signatures, along with additional immunological biomarkers, may be used to identify which patients are most likely to respond to adoptive transfer strategies and suggest manufacturing modifications that might potentiate the generation of maximally efficacious infusion products. Clinical trial information: NCT01029366, NCT01747486, NCT01626495.

The adoptive transfer of autologous T cells genetically modified to express a CD19-specific, 4-1BB/CD3z-signaling CAR (CTL019) has shown remarkable activity and induce long-term remissions in a subset of patients with relapsed/refractory chronic lymphocytic leukemia (CLL). To date, little is known about predictive indicators of efficacy. This study was designed to evaluate biomarkers of clinical response to CTL019 in CLL. We studied forty-one patients with advanced, heavily pre-treated and high-risk CLL who received at least one dose of CTL019 cells. We show that in vivo expansion and persistence are key quality attributes of CTL019 cells in CLL patients who have complete responses to therapy; in 2 patients responses are sustained beyond five years and accompanied by the persistence of functional CTL019 cells. Furthermore, durable remissions were associated with transcriptomic signatures of early memory T cells, while T cells from non-responding patients were enriched in genes belonging to known pathways of terminal differentiation and exhaustion. Polychromatic flow cytometry also demonstrated a significantly higher level of T cell exhaustion markers on the infused CAR T cells and reduced CD27 expression in non-responding patients. Accordingly, the combined assessment of PD1 and CD27 expression on CD8+ CTL019 cells in the infusion product accurately predicted response to treatment. Restimulation of the infusion product through the CAR further demonstrated that CTL019 cells from complete responders secreted significantly higher levels of several cytokines, including CCL20, IL-21, IL-22, IL-17, and IL-6, suggesting that the STAT3 signaling pathway may play a role in potentiating the enhanced potency of CTL019 cells. To identify a phenotype of T cells that is predictive of response prior to CTL019 manufacturing, we initially retrospectively evaluated the proportions of naïve, stem cell memory, central memory, effector memory and effector cells at the time of leukapheresis and observed either marginally significant or no significant correlations with clinical outcome. A systematic, unbiased analysis of the same biomarker panel revealed that the frequency of CD27+CD45RO- cells in the CD8+ T cell population correlated significantly with complete and durable responses to this therapy. Analysis of the infusion products using the same flow cytometric panel showed that most (>95%) of T cells expressed CD45RO at the end of the manufacturing run; CD27 expression frequencies, however, were maintained at the same level as in the leukapheresis. Together, these findings suggest that intrinsic T cell fitness dictates both response and resistance to highly active engineered CAR T cells. Thus, enrichment of T cells with optimal differentiation potential and proliferative capacity by timing of collection or culture modification might potentiate the generation of maximally efficacious infusion products. These data and additional immunological biomarkers may be used to identify which patients are most likely to respond to adoptive transfer strategies, leading to an enhanced personalized approach to cellular therapy. Disclosures Fraietta: Novartis: Patents & Royalties: Novartis, Research Funding. Lacey:Novartis: Research Funding. Wilcox:Novartis: Research Funding. Bedoya:Novartis: Research Funding. Chen:Novartis: Research Funding. Orlando:Novartis: Employment. Brogdon:Novartis: Employment. Hwang:Novartis: Research Funding. Frey:Novartis: Research Funding; Amgen: Consultancy. Pequignot:Novartis: Research Funding. Ambrose:Novartis: Research Funding. Levine:Novartis: Patents & Royalties, Research Funding; GE Healthcare Bio-Sciences: Consultancy. Bitter:Novartis: Employment. Porter:Genentech: Employment; Novartis: Patents & Royalties, Research Funding. Xu:Novartis: Research Funding. June:Immune Design: Consultancy, Equity Ownership; University of Pennsylvania: Patents & Royalties; Celldex: Consultancy, Equity Ownership; Novartis: Honoraria, Patents & Royalties: Immunology, Research Funding; Tmunity: Equity Ownership, Other: Founder, stockholder ; Pfizer: Honoraria; Johnson & Johnson: Research Funding. Melenhorst:Novartis: Patents & Royalties: Novartis, Research Funding.

Introduction For chimeric antigen receptor T cell-based (CAR-T) and engineered T cell receptor (TCR) immunotherapies, T cell expansion methods and phenotype/s of transplanted T cells may heavily influence clinical outcomes. Much current focus is on the potential of defined CD4+/CD8+ T cell populations vs bulk, and on the potential superiority of CAR-T cells from naïve (TN) or central memory (TCM) versus effector memory (TEM) cells. Many commercial T cell activation and expansion methods utilize rigid magnetic beads bound to antibodies against CD3 and CD28 as substrates. These methods are often associated with high costs and licensing restrictions for clinical and commercial applications. Additionally, de-beading processes can be highly complex and inefficient, adding additional time, costs and risks. It has been shown that substrate rigidity influences T cell expansion and phenotype. We hypothesized that a novel phase-change substrate could modulate expanded T cell phenotype/s and address de-beading challenges. Methods An alginate-based phase-change hydrogel was synthesized and coated onto magnetic beads to form hydrogel-coated particles of approximately 10 µm diameter. This hydrogel, in the presence of chelating agents, rapidly dissolves, enabling removal magnetic bead removal. The coated particles were conjugated with streptavidin (SA) and bound to biotinylated antibodies against CD3 (OKT3) and CD28 (28.2) to form CD3/CD28 hydrogel particles (CD3/CD28-HP). Human CD3+ T cells from peripheral blood were seeded (Day 0) at 1x10E6 cells/mL in 24 well plates (n=3) in complete RPMI medium supplemented with IL-2. To each well, 25 µL of CD3/CD28-HP were added per 0.5x10E6 cells in a single stimulation. Media addition or change of culture vessel occurred each 2-3 days. Following expansion, chelating agent was added and magnetic beads removed. Flow cytometry was used to assess cell viability and expression of phenotypic markers including CD3, CD4, CD8, CD45RA and CCR7. ELISA was used to measure secretion of IL-2, IL-4, and IFNγ. Residual magnetic beads were counted via hemocytometer. Results CD3/CD28-HP promoted significant T cell expansion of 0.3, 1.4, 2.4, 4.8 and 6.6 population doublings (PD) by Days 2, 5, 6, 9, and 13 respectively (p Phenotypic markers were assessed on Days 6 and 13. Expansion using CD3/CD28-HP led to significantly more CD8+ cells and significantly fewer CD4+ cells versus the starting population on both days (p Following de-beading of expanded cells, cell recovery was 96% for the CD3/CD28-HP-expanded cells and 93% for cells expanded using commercial magnetic bead-based expansion product. Additionally, in de-beaded cells, fewer residual magnetic particles were present in the CD3/CD28-HP-expanded population than in cells expanded via the commercial magnetic bead-based expansion product. Conclusions These data demonstrate the utility of a novel phase-change hydrogel system to efficiently induce T cell proliferation, promote expansion of functional T cells expressing markers associated with CD8+, TN and TCM phenotypes, and to separate expanded cells efficiently from magnetic beads. In future studies, we will determine if T cells expanded using this method show increased stemness and persistence in in vivo models, and further explore the possibilities of this novel system for rapid expansion and recovery of specific T cell subtypes. Disclosures Jesuraj: Quad Technologies: Employment, Other: stock options. Cole:Quad Technologies: Employment, Other: Stock Options. Wells:Quad Technologies: Employment, Other: Stock Options. Qin:Quad Technologies: Employment, Other: Stock options. Kevlahan:Quad Technologies: Employment, Equity Ownership. Maus:Novartis: Patents & Royalties: related to CTL019, Research Funding. Ball:Quad Technologies: Employment, Other: Stock Options.

Adoptive cell therapy employing T cells equipped with a chimeric antigen receptor (CAR) containing a single chain antibody fragment fused to T cell signaling domains 4-1BB and CD3zeta (CTL019) has shown great potency against various hematopoietic malignancies, e.g. B cell acute lymphoblastic leukemia (ALL). However, it has not shown the same response rate in other malignancies such as chronic lymphocytic leukemia (CLL). We recently demonstrated that the in vivo expansion and persistence of CAR T cells is an important predictor of response to CTL019 in CLL (PMID: 26333935) and ALL (Thudium et al., ASH 2016; Fraietta et al., ASH 2016). Furthermore, it is well known that prolonged culture of T cells negatively impacts the in vivo expansion of the adoptively transferred cells. We therefore hypothesized that minimizing the ex vivo manipulation of T cells would improve the efficacy of CAR T cells. We tested this hypothesis by generating CART19 cells using our standard 9-day manufacturing process plus two abbreviated versions. Cells from normal donors (n=9) and from patients with adult ALL (n=6) were stimulated on day 0 followed by transduction with the CAR19-encoding lentiviral vector on day 1. Cells were harvested on days 3, 5, and 9. Cryopreserved aliquots were evaluated for T cell differentiation using polychromatic flow cytometry, cytokine secretion profile using Luminex, cytolytic ability against a leukemia cell line (NALM6), proliferative ability upon restimulation with CD19-expressing target cells, and in vivo control of our well-established xenogeneic ALL model employing NALM6 as the target. Our data show that all cultures contain a substantial proportion (40%-80%) of na•ve-like CD45RO-CCR7+ T cells that progressively differentiate leading to the accumulation of predominantly (60%-90%) central memory T cells by the end of expansion. Comparative assessment of the CART19 cells at all three time points demonstrated that the cells from the shorter cultures displayed a superior in vitrocytolytic activity, and proliferative response compared to the standard process. In addition,the cells from our standard and shortened cultures all secreted comparable levels of type I cytokines (i.e. IFN-g, IL-2, and TNF-α). Importantly, we investigated the therapeutic potential of cells harvested at day 3 versus later time points. We treated NALM6 xenograftmice with a low dose (0.5 x106 CAR+ T cell I.V.) or standard dose (3 x106 CAR+ T cell I.V.).We demonstrate that day 3 CART19 cells show superior anti-leukemic activity compared to day 5 or day 9 cells. Additionally, we show that mice treated at a low dose with day 3 cells exhibit the greatest anti-leukemic efficacy compared with day 9 cells where the latter fail to control leukemia (Figure 1). Our preclinical findings provide evidence that extended ex vivo manipulation of T cells negatively affects their in vivo potency.In summary, we show that limiting T cell culture ex vivo to the minimum required for lentiviral transduction provides the most efficacious T cells for adoptive T cell immunotherapy. Figure 1 Figure 1. Disclosures Ghassemi: Novartis: Research Funding. Scholler:Novartis: Patents & Royalties; University of Pennsylvania: Patents & Royalties: FAP-CAR US Patent 9,365,641 for targeting tumor microenvironment. Nunez-Cruz:Novartis: Research Funding. Barrett:Novartis: Research Funding. Bedoya:Novartis: Patents & Royalties. Fraietta:Novartis: Patents & Royalties: Novartis, Research Funding. Lacey:Novartis: Research Funding. Levine:GE Healthcare Bio-Sciences: Consultancy; Novartis: Patents & Royalties, Research Funding. Grupp:Novartis: Research Funding. June:Johnson & Johnson: Research Funding; Tmunity: Equity Ownership, Other: Founder, stockholder ; University of Pennsylvania: Patents & Royalties; Pfizer: Honoraria; Novartis: Honoraria, Patents & Royalties: Immunology, Research Funding; Immune Design: Consultancy, Equity Ownership; Celldex: Consultancy, Equity Ownership. Milone:Novartis: Patents & Royalties, Research Funding. Melenhorst:Novartis: Patents & Royalties, Research Funding.

Adoptive T cell immunotherapy involves the isolation, ex vivo expansion and reinfusion of patient T cells. The efficacy of adoptive immunotherapy is dependent on the ability of T cells to engraft, expand and persist upon adoptive transfer. In this therapy, T cells are cultured ex vivo using natural or artificial antigen presenting cells that deliver signal 1 (TCR/CD3) and signal 2 (e.g. CD28 co-stimulation) along with exogenously added cytokines. IL-2 is the most commonly used cytokine for ex vivo T cell culture; however, there is renewed interest in IL-7 and IL-15 due to their ability to enhance the survival and proliferation of stem cell memory (Tscm) and central memory (Tcm) T cells. We show that primary human T cells freshly isolated from peripheral blood are heterogeneous with substantial numbers of Tscm and Tcm cells in addition to effector differentiated T cells. During ex vivo culture, these cells progressively differentiate into a population of T cells with a predominantly CD45RO+, CD27-, CCR7- effector differentiated phenotype. Exogenous IL-7 and IL-15 delay this transition in T cell phenotype and preserve a greater proportion of Tscm and Tcm cells in the final ex vivo culture product. We hypothesize that limited ex vivo culture of T cells in the presence of IL-7 and IL-15 rather than IL-2 will enhance engraftment and persistence of T cells in vivo contributing to enhanced efficacy in adoptive transfer. We show that T cells can be harvested and viably frozen from ex vivo cultures as early as day 3 following activation. Early activated T cells expressing a chimeric antigen receptor targeting CD19 (CART-19) show potent yet specific cytotoxicity and cytokine production in vitro. We investigated the therapeutic potential of cells harvested at day 3 versus later time points using a Nalm-6 leukemic cell xenograft mouse model. We demonstrate that day 3 CART-19 cells show potent anti-leukemic activity compared to day 5 or day 9 cells. Comparing CART19 cells cultured in either IL-2 or IL-7/15, we show that mice treated at a 10-fold lower dose with day 3 cells cultured in IL-7/15 exhibit the greatest anti-leukemic efficacy compared with day 9 cells where the latter fail to control leukemia. In summary, we show that limiting T cell culture ex vivo to the minimum required for lentiviral transduction in the presence of IL-7 and IL-15 provides the most efficacious T cells for adoptive T cell immunotherapy.