Search

A number of studies of posttraumatic stress disorder (PTSD) report thinner cerebral cortical gyri using gyrus-based analysis or thinner foci within the gyri using vertex-based analysis. However, the locations of these findings are inconsistent across studies, and the spatial transformations required during vertex-based analysis may affect the focal findings. A mega-analysis using a large number of subjects from multiple PTSD studies could potentially identify more reproducible cortical thickness abnormalities. Investigating both the vertex and gyral thicknesses simultaneously may verify the vertex-based focal findings using gyral data without imposing any spatial transformation. Here we aggregated data from 24 international laboratories using ENIGMA standardized procedures for 949 adult PTSD patients and 1493 controls without PTSD (age 18 to 65 years). We examined whether gyral and vertex cortical thickness are (a) different between subjects with PTSD and controls and (b) associated with PTSD symptom severity in trauma-exposed subjects. Regions with overlapping thinner cortical gyri and thinner vertex clusters were located in frontal, temporal, parietal, and occipital cortices. Thinner right lateral orbitofrontal and right lingual gyri and concomitantly thinner vertex clusters in the anterior portions of both gyri were associated with PTSD symptom severity. Convergent findings in these locations suggest focally thinner cortex in these gyri, which may be involved in altered processing and regulation of emotion and sensory inputs underlying posttraumatic stress symptoms.

Background: Posttraumatic stress disorder (PTSD) is accompanied by disrupted cortical neuroanatomy. We investigated alteration in covariance of structural networks associated with PTSD in regions that demonstrate the case-control differences in cortical thickness (CT) and surface area (SA). Methods: Neuroimaging and clinical data were aggregated from 29 research sites in >1300 PTSD cases and >2000 trauma-exposed control subjects (ages 6.2–85.2 years) by the ENIGMA-PGC (Enhancing Neuro Imaging Genetics through Meta Analysis–Psychiatric Genomics Consortium) PTSD working group. Cortical regions in the network were rank ordered by the effect size of PTSD-related cortical differences in CT and SA. The top-n (n = 2–148) regions with the largest effect size for PTSD > non-PTSD formed hypertrophic networks, the largest effect size for PTSD < non-PTSD formed atrophic networks, and the smallest effect size of between-group differences formed stable networks. The mean structural covariance (SC) of a given n-region network was the average of all positive pairwise correlations and was compared with the mean SC of 5000 randomly generated n-region networks. Results: Patients with PTSD, relative to non-PTSD control subjects, exhibited lower mean SC in CT-based and SA-based atrophic networks. Comorbid depression, sex, and age modulated covariance differences of PTSD-related structural networks. Conclusions: Covariance of structural networks based on CT and cortical SA are affected by PTSD and further modulated by comorbid depression, sex, and age. The SC networks that are perturbed in PTSD comport with converging evidence from resting-state functional connectivity networks and networks affected by inflammatory processes and stress hormones in PTSD.

The human brain is organized into large-scale networks that can be noninvasively identified using functional connectivity (FC) functional magnetic resonance imaging. FC varies across individuals, and there is significant interest in associating individual variation in FC with external behavioral measures. However, only recently has FC variation been characterized by studying brain networks within individual humans. We review these recent efforts, and we argue that individual variation in FC networks comes in three distinct forms: 1) variability in connectional strength, in which brain regions in the same location have variable FC strength across subjects; 2) variability in spatial localization, in which regions exhibit the same connections across subjects, but are expanded/contracted or spatially displaced in specific subjects; and 3) topological variability, in which networks have variable sets of constituent nodes. Unfortunately, each of these three types of variation confounds attempts to measure the others, which significantly impacts research studying brain networks.

Background Pediatric anxiety disorders are linked to dysfunction in multiple functional brain networks, as well as to alterations in the allocation of spatial attention. We used network-level analyses to characterize resting-state functional connectivity (rs-fc) alterations associated with 1) symptoms of anxiety and 2) alterations in stimulus-driven attention associated with pediatric anxiety disorders. We hypothesized that anxiety was related to altered connectivity of the frontoparietal, default mode, cingulo-opercular, and ventral attention networks and that anxiety-related connectivity alterations that include the ventral attention network would simultaneously be related to deviations in stimulus-driven attention. Methods A sample of children (n = 61; mean = 10.6 years of age), approximately half of whom met criteria for a current anxiety disorder, completed a clinical assay, an attention task, and rs-fc magnetic resonance imaging scans. Network-level analyses examined whole-brain rs-fc patterns associated with clinician-rated anxiety and with involuntary capture of attention. Post hoc analyses controlled for comorbid symptoms. Results Elevated clinician-rated anxiety was associated with altered connectivity within the cingulo-opercular network, as well as between the cingulo-opercular network and the ventral attention, default mode, and visual networks. Connectivity between the ventral attention and cingulo-opercular networks was associated with variation in both anxiety and stimulus-driven attention. Conclusions Pediatric anxiety is related to aberrant connectivity patterns among several networks, most of which include the cingulo-opercular network. These results help clarify the within- and between-network interactions associated with pediatric anxiety and its association with altered attention, suggesting that specific network connections could be targeted to improve specific altered processes associated with anxiety.

Resting-state functional magnetic resonance imaging (rs-fMRI) allows estimation of individual-specific cortical parcellations. We have previously developed a multi-session hierarchical Bayesian model (MS-HBM) for estimating high-quality individual-specific network-level parcellations. Here, we extend the model to estimate individual-specific areal-level parcellations. While network-level parcellations comprise spatially distributed networks spanning the cortex, the consensus is that areal-level parcels should be spatially localized, that is, should not span multiple lobes. There is disagreement about whether areal-level parcels should be strictly contiguous or comprise multiple noncontiguous components; therefore, we considered three areal-level MS-HBM variants spanning these range of possibilities. Individual-specific MS-HBM parcellations estimated using 10 min of data generalized better than other approaches using 150 min of data to out-of-sample rs-fMRI and task-fMRI from the same individuals. Resting-state functional connectivity derived from MS-HBM parcellations also achieved the best behavioral prediction performance. Among the three MS-HBM variants, the strictly contiguous MS-HBM exhibited the best resting-state homogeneity and most uniform within-parcel task activation. In terms of behavioral prediction, the gradient-infused MS-HBM was numerically the best, but differences among MS-HBM variants were not statistically significant. Overall, these results suggest that areal-level MS-HBMs can capture behaviorally meaningful individual-specific parcellation features beyond group-level parcellations. Multi-resolution trained models and parcellations are publicly available (https://github.com/ThomasYeoLab/CBIG/tree/master/stable_projects/brain_parcellation/Kong2022_ArealMSHBM).

Results of neuroimaging datasets aggregated from multiple sites may be biased by site- specific profiles in participants’ demographic and clinical characteristics, as well as MRI acquisition protocols and scanning platforms. We compared the impact of four different harmonization methods on results obtained from analyses of cortical thickness data: (1) linear mixed-effects model (LME) that models site-specific random intercepts (LMEINT), (2) LME that models both site-specific random intercepts and age-related random slopes (LMEINT+SLP), (3) ComBat, and (4) ComBat with a generalized additive model (ComBat-GAM). Our test case for comparing harmonization methods was cortical thickness data aggregated from 29 sites, which included 1,343 cases with posttraumatic stress disorder (PTSD) (6.2-81.8 years old) and 2,067 trauma-exposed controls without PTSD (6.3-85.2 years old). We found that, compared to the other data harmonization methods, data processed with ComBat-GAM were more sensitive to the detection of significant case-control differences in regional cortical thickness (X2(3) = 34.339, p < 0.001), and case-control differences in age-related cortical thinning (X2(3) = 15.128, p = 0.002). Specifically, ComBat-GAM led to larger effect size estimates of cortical thickness reductions (corrected p-values < 0.001), smaller age-appropriate declines (corrected p-values < 0.001), and lower female to male contrast (corrected p-values < 0.001) in cases compared to controls relative to other harmonization methods. Harmonization with ComBat-GAM also led to greater estimates of age-related declines in cortical thickness (corrected p-values < 0.001) in both cases and controls compared to other harmonization methods. Our results support the use of ComBat-GAM for harmonizing cortical thickness data aggregated from multiple sites and scanners to minimize confounds and increase statistical power.

Posttraumatic stress disorder (PTSD) is a complex psychiatric condition that has generated much attention in the neuroimaging literature. A neurocircuitry model supporting fronto-limbic dysfunction as a major player in facilitating clinical symptoms of PTSD is well-characterized; however, recent literature suggests that network-based approaches may provide additional insight into neural dysfunction in PTSD. Our analysis uses resting-state neuroimaging scans of 1063 adults from the PGC-ENIGMA PTSD Consortium to investigate a network-based model of functional connectivity in PTSD. With a novel, resolution limit-free community detection approach, 16 communities corresponding to functionally meaningful networks were detected with high quality. After group-level community detection, participants were classified into three groups (PTSD, n=418, trauma-exposed controls without PTSD, n=434, and non-trauma exposed healthy controls, n=211). Individual network connectivity metrics were calculated, including whole-brain, default mode network, and central executive network participation coefficient and connectivity strength. Linear mixed effects models revealed group differences in the whole-brain, default mode, and central executive network participation coefficient and connectivity strength such that individuals with PTSD demonstrated overall greater values. We also described sex differences such that males demonstrate greater whole-brain participation coefficient vs. females and females demonstrate greater default mode network connectivity strength vs. males. Our results suggest that PTSD in adults is associated with reduced specialization and enhanced inter-module communication throughout the brain network, which may contribute to inefficient information processing and poor emotional regulation. This study presents a novel use of resolution limit-free community detection in a large PTSD sample, revealing robust differences in resting-state network topology.

Resting-state functional MRI (rs-fMRI) allows estimation of individual-specific cortical parcellations. We have previously developed a multi-session hierarchical Bayesian model (MS-HBM) for estimating high-quality individual-specific network-level parcellations. Here, we extend the model to estimate individual-specific areal-level parcellations. While network-level parcellations comprise spatially distributed networks spanning the cortex, the consensus is that areal-level parcels should be spatially localized, i.e., should not span multiple lobes. There is disagreement about whether areal-level parcels should be strictly contiguous or comprise multiple non-contiguous components, therefore we considered three areal-level MS-HBM variants spanning these range of possibilities. Individual-specific MS-HBM parcellations estimated using 10min of data generalized better than other approaches using 150min of data to out-of-sample rs-fMRI and task-fMRI from the same individuals. Resting-state functional connectivity (RSFC) derived from MS-HBM parcellations also achieved the best behavioral prediction performance. Among the three MS-HBM variants, the strictly contiguous MS-HBM (cMS-HBM) exhibited the best resting-state homogeneity and most uniform within-parcel task activation. In terms of behavioral prediction, the gradient-infused MS-HBM (gMS-HBM) was numerically the best, but differences among MS-HBM variants were not statistically significant. Overall, these results suggest that areal-level MS-HBMs can capture behaviorally meaningful individual-specific parcellation features beyond group-level parcellations. Multi-resolution trained models and parcellations are publicly available (https://github.com/ThomasYeoLab/CBIG/tree/master/stable_projects/brain_parcellation/Kong2022_ArealMSHBM).

Hemodynamically unstable trauma patients who would benefit from angioembolization (AE) typically also require emergent surgery for their injuries. The critical decision of transferring a patient to the operating room versus the interventional radiology (IR) suite can be bypassed with the advent of intra-operative AE (IOAE). Previously limited by the availability of costly rooms termed RAPTOR (resuscitation with angiography, percutaneous techniques and open repair) suites, it has been suggested that using C-arm digital subtraction angiography (DSA) is a comparable alternative. This case series aims to establish the feasibility and safety of IOAE.We conducted a retrospective analysis of all trauma patients at our level 1 trauma center who underwent IOAE with a concomitant surgical intervention from January 2011 to May 2019. Descriptive analyses were conducted.A total of 49 patients (80% male, 44 ± 17 years, 92% blunt) underwent IOAE using the C-arm DSA during the study period. All but one patient underwent exploratory laparotomy, 56% of which underwent an additional surgical procedure (ex. exploratory thoracotomy, orthopedic). Either GelfoamIOAE appears to be a feasible and safe management option in severe trauma patients with the advantage of concurrent operative intervention and ongoing active resuscitation with good success in hemorrhage control.

The dramatic clinical benefit of immune checkpoint blockade for a fraction of cancer patients suggests the potential for further clinical benefit in a broader cancer patient population by combining immune checkpoint inhibitors with active immunotherapies. The anti-tumor efficacy of MVA-BN-HER2 poxvirus-based active immunotherapy alone or in combination with CTLA-4 checkpoint blockade was investigated in a therapeutic CT26-HER-2 lung metastasis mouse model. MVA-BN-HER2 immunotherapy significantly improved the median overall survival compared to untreated controls or CTLA-4 blockade alone (p

We demonstrate the ability to chemically transform bulk silicon into a nanotextured surface that exhibits excellent electrochemical stability in aqueous conditions for water photo-oxidation. Conformal defective graphene coatings on nanotextured silicon formed by thermal treatment enable over 50× corrosion resistance in aqueous electrolytes based upon Tafel analysis and impedance spectroscopy. This enables nanotextured silicon as an effective oxygen-evolution photoanode for water splitting with saturation current density measured near 35 mA cm(-2) under 100 mW cm(-2) (1 sun) illumination. Our approach builds upon simple and scalable processing techniques with silicon to develop corrosion resistant electrodes that can benefit a broad range of catalytic and photocatalytic applications.

Poxvirus-based active immunotherapies mediate anti-tumor efficacy by triggering broad and durable Th1 dominated T cell responses against the tumor. While monotherapy significantly delays tumor growth, it often does not lead to complete tumor regression. It was hypothesized that the induced robust infiltration of IFNγ-producing T cells into the tumor could provoke an adaptive immune evasive response by the tumor through the upregulation of PD-L1 expression. In therapeutic CT26-HER-2 tumor models, MVA-BN-HER2 poxvirus immunotherapy resulted in significant tumor growth delay accompanied by a robust, tumor-infiltrating T cell response that was characterized by low to mid-levels of PD-1 expression on T cells. As hypothesized, this response was countered by significantly increased PD-L1 expression on the tumor and, unexpectedly, also on infiltrating T cells. Synergistic benefit of anti-tumor therapy was observed when MVA-BN-HER2 immunotherapy was combined with PD-1 immune checkpoint blockade. Interestingly, PD-1 blockade stimulated a second immune checkpoint molecule, LAG-3, to be expressed on T cells. Combining MVA-BN-HER2 immunotherapy with dual PD-1 plus LAG-3 blockade resulted in comprehensive tumor regression in all mice treated with the triple combination therapy. Subsequent rejection of tumors lacking the HER-2 antigen by treatment-responsive mice without further therapy six months after the original challenge demonstrated long lasting memory and suggested that effective T cell immunity to novel, non-targeted tumor antigens (antigen spread) had occurred. These data support the clinical investigation of this triple therapy regimen, especially in cancer patients harboring PD-L1neg/low tumors unlikely to benefit from immune checkpoint blockade alone.

Previous studies have shown that brief access to cocaine yields an increase in D2 receptor binding in the medial prefrontal cortex (mPFC), but that extended access to cocaine results in normalized binding of D2 receptors (i.e. the D2 binding returned to control levels). Extended-access conditions have also been shown to produce increased expression of the NR2 subunit of the N-Methyl-D-aspartate receptor in the mPFC. These results implicate disrupted glutamate and dopamine function within this area. Therefore, in the present study, we monitored glutamate and dopamine content within the mPFC during, or 24 hours after, cocaine self-administration in animals that experienced various amounts of exposure to the drug. Naive subjects showed decreased glutamate and increased dopamine levels within the mPFC during cocaine self-administration. Exposure to seven 1-hour daily cocaine self-administration sessions did not alter the response to self-administered cocaine, but resulted in decreased basal dopamine levels. While exposure to 17 1-hour sessions also resulted in reduced basal dopamine levels, these animals showed increased dopaminergic, but completely diminished glutamatergic, response to self-administered cocaine. Finally, exposure to 17 cocaine self-administration sessions, the last 10 of which being 6-hour sessions, resulted in diminished glutamatergic response to self-administered cocaine and reduced basal glutamate levels within the mPFC while normalizing (i.e. causing a return to control levels) both the dopaminergic response to self-administered cocaine as well as basal dopamine levels within this area. These data demonstrate directly that the transition to escalated cocaine use involves progressive changes in dopamine and glutamate function within the mPFC.

Anomalies in prefrontal cortex (PFC) function are posited to underpin difficulties in learning to suppress drug-seeking behavior during abstinence. Because group 1 metabotropic glutamate receptors (mGluRs) regulate drug-related learning, we assayed the consequences of extended access to intravenous cocaine (6 h/d; 0.25 mg/infusion for 10 d) on the PFC expression of group 1 mGluRs and the relevance of observed changes for cocaine seeking. After protracted withdrawal, cocaine-experienced animals exhibited a time-dependent intensification of cue-induced cocaine-seeking behavior and an impaired extinction of this behavior. These behavioral phenomena were associated with a time-dependent reduction in mGluR1/5 expression within ventromedial PFC (vmPFC) of cocaine-experienced animals exposed to extinction testing but not in untested ones. Interestingly, pharmacological manipulations of vmPFC mGluR1/5 produced no immediate effects on cue-induced cocaine-seeking behavior but produced residual effects on a subsequent test for cocaine seeking. At 3 d withdrawal, cocaine-experienced rats infused intra-vmPFC with mGluR1/5 antagonists, either before or after an initial test for cocaine seeking, persisted in their cocaine seeking akin to cocaine-experienced rats in protracted withdrawal. Conversely, cocaine-experienced rats infused with an mGluR1/5 agonist before the initial test for cocaine-seeking at 30 d withdrawal exhibited a facilitation of extinction learning. These data indicate that cue-elicited deficits in vmPFC group 1 mGluR function mediate resistance to extinction during protracted withdrawal from a history of extensive cocaine self-administration and pose pharmacological stimulation of these receptors as a potential approach to facilitate learned suppression of drug-seeking behavior that may aid drug abstinence.

Previous studies have shown that brief access to cocaine yields an increase in D2 receptor binding in the medial prefrontal cortex (mPFC), but that extended access to cocaine results in normalized binding of D2 receptors (i.e. the D2 binding returned to control levels). Extended-access conditions have also been shown to produce increased expression of the NR2 subunit of the N-Methyl-D-aspartate receptor in the mPFC. These results implicate disrupted glutamate and dopamine function within this area. Therefore, in the present study, we monitored glutamate and dopamine content within the mPFC during, or 24 hours after, cocaine self-administration in animals that experienced various amounts of exposure to the drug. Naïve subjects showed decreased glutamate and increased dopamine levels within the mPFC during cocaine self-administration. Exposure to seven 1-hour daily cocaine self-administration sessions did not alter the response to self-administered cocaine, but resulted in decreased basal dopamine levels. While exposure to 17 1-hour sessions also resulted in reduced basal dopamine levels, these animals showed increased dopaminergic, but completely diminished glutamatergic, response to self-administered cocaine. Finally, exposure to 17 cocaine self-administration sessions, the last 10 of which being 6-hour sessions, resulted in diminished glutamatergic response to self-administered cocaine and reduced basal glutamate levels within the mPFC while normalizing (i.e. causing a return to control levels) both the dopaminergic response to self-administered cocaine as well as basal dopamine levels within this area. These data demonstrate directly that the transition to escalated cocaine use involves progressive changes in dopamine and glutamate function within the mPFC.

Treatment with poxvirus-based active immunotherapies shows evidence of robust immune responses against a variety of tumor-associated antigens in preclinical and clinical studies. Poxvirus-based immunotherapies in development include PSA-targeted PROSTVAC, now in Phase 3 clinical development; CV-301 (targeting CEA and MUC-1); as well as MVA-BN-HER2 and MVA-BN-Brachyury (targeting HER-2 and the transcription factor Brachyury, respectively). Evidence of robust and productive anti-tumor efficacy in preclinical models was accompanied by treatment-emergent infiltration of tumors by activated cytotoxic CD8 T cells producing high amounts of IFNγ. Treatment with immune checkpoint inhibitors such as anti-PD-1 antibodies is showing significant clinical benefit by re-activating dormant tumor-specific T cells. Furthermore, preclinical studies have shown further synergistic efficacy by combining PD-1 blockade with inhibition of LAG-3, which acts independently of PD-1 to modulate T cell function. We hypothesized that poxvirus-based active immunotherapy may provide even greater improvements to patient outcome when used in combination with immune checkpoint blockade, by inducing new productive tumor-specific responses. This may be especially important in patients lacking an endogenous T cell response against their tumors. In therapeutic CT26-HER2 solid and metastatic tumor models, mice were administered MVA-BN-HER2 immunotherapy alone or in combination with anti-PD-1 and/or anti-LAG-3 antibodies. Synergistic benefit for anti-tumor efficacy was observed when combining MVA-BN-HER2 immunotherapy with anti-PD-1 alone, while combination with anti-LAG-3 alone had little effect. Notably, a further enhancement occurred when MVA-BN-HER2 immunotherapy was combined with PD-1 and LAG-3 blockade as shown by complete tumor regression in 20/20 mice. Subsequent rejection of HER-2 negative tumors 6 months after the original challenge revealed that immune responses were durable and included antigen spread to additional tumor antigens. Flow cytometric analysis demonstrated that tumor infiltrating lymphocytes (TILs) in untreated tumors were PD-1hi and LAG-3+, a more exhausted phenotype. Poxvirus-based immunotherapy led to the induction of activated TILs characterized by low to mid-levels of PD-1 expression. While PD-1 blockade prevented binding to PD-L1 it also caused an increase in LAG-3 expression on T cells. Together these data provide further rationale for why combination therapy of poxvirus-based immunotherapy with inhibition of PD-1 plus LAG-3 resulted in synergistic efficacy in preclinical tumor models. Overall these data demonstrate that combining complementary immune-based therapies such as poxvirus-based active immunotherapy and PD-1 plus LAG-3 immune checkpoint blockade result in synergistic anti-tumor efficacy. Citation Format: Barbara Sennino, Susan P. Foy, Ryan B. Rountree, Tracy dela Cruz, Evan J. Gordon, Veronica Xavier, Felicia Kemp, Alex Franzusoff, James Breitmeyer, Stefanie J. Mandl. Poxvirus-based active immunotherapy synergizes with PD-1 plus LAG-3 immune checkpoint inhibition to enhance antitumor efficacy in preclinical models. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-234. doi:10.1158/1538-7445.AM2015-LB-234

3079 Background: Treatment with poxvirus-based active immunotherapies shows evidence of robust immune responses against a variety of tumor-associated antigens in preclinical and clinical studies. T...

3058 Background: PROSTVAC PSA-targeted immunotherapy for metastatic castration-resistant prostate cancer is being tested in the PROSPECT phase 3 trial. Another poxvirus-based immunotherapy product,...

3013 Background: PROSTVAC PSA-targeted immunotherapy for metastatic castration-resistant prostate cancer is being tested in the PROSPECT Phase 3 trial. Another poxvirus-based immunotherapy product,...

Combining poxvirus-based immunotherapies which "step on the gas" to activate tumor antigen-specific T cell immune responses with immune checkpoint inhibitors (ICIs) which "release the brakes" on the immune system is a promising direction for enhancing cancer immunotherapy. Evidence for the potential clinical benefit from combination immunotherapy was obtained in a Phase I dose escalation trial. Cohorts of prostate cancer (mCRPC) patients were treated with a fixed dose of PROSTVAC, a poxvirus-based active immunotherapy, plus escalating doses of Ipilimumab, an anti-CTLA-4 ICI. The median overall survival (mOS) of 31.6 months [1] from the combined cohorts was notably longer than the mOS of mCRPC patients from an independent randomized Phase II study (PROSTVAC alone 25.1 months versus placebo 16.6 months; the most pronounced survival benefit (8.5 months) in mCRPC to date) [2]. This potentially synergistic combination of PROSTVAC and Ipilimumab warrants further exploration. We modeled the benefit of combining poxvirus-based immunotherapy with CTLA-4 blockade using MVA-BN-HER2, which is being developed for breast cancer. In preclinical studies a dramatic increase in mOS was observed in a therapeutic CT26-HER2 lung metastasis model when mice were treated with MVA-BN-HER2 plus CTLA-4 blockade compared to either treatment alone. The improved survival with the combination therapy was accompanied by a striking increase in the magnitude and functional quality of tumor infiltrating HER-2 specific CD8 T cells [3]. Additional ICIs are identified in our preclinical studies as promising candidates for combining with poxvirus-based immunotherapies. Immune checkpoint protein expression is normally induced on activated T cells to regulate activity, and we found that MVA-BN-HER2 treatment resulted in activated CD8 T cells and elevated expression of PD-1, TIM-3, or ICOS. However, immune checkpoint proteins are chronically elevated on exhausted T cells in an immunosuppressive tumor microenvironment. In untreated tumor-bearing mice, a potentially exhausted T cell phenotype was found on CD4 and CD8 T cells characterized by increased expression or co-expression of PD-1, TIM-3, and LAG-3. We compared treatment of MVA-BN-HER2 alone or in combination with ICI antibodies against these immune checkpoint molecules in solid or metastatic CT26-HER2 tumor models. Improved survival was observed with several different combinations, and synergistic efficacy was indicated using the Chou-Talalay method [4]. These studies provide data and rationale for combining poxvirus-based immunotherapies with a variety of ICIs in the clinic.

Bavarian Nordic, Inc. is developing poxvirus-based cancer immunotherapies. These therapies employ vaccinia-, Modified Vaccinia Ankara (MVA)-, and fowlpox-based vectors that were engineered to express one or more tumor-associated antigens (TAA). These vectors are used alone or in prime-boost strategies to generate an active immune response against a variety of cancers. The lead candidate PROSTVAC® employs a prime-boost strategy using vaccinia and fowlpox expressing PSA and TRICOM(TM) and is currently in a global Phase III clinical trial (PROSPECT) for castration-resistant metastatic prostate cancer. Other products such as recombinant MVA-BN® expressing HER2 have been tested in early phase clinical trials for the treatment of breast cancer. To further enhance the anti-tumor efficacy of the poxvirus-based immunotherapy, the present preclinical study focuses on combining the breast cancer candidate therapy MVA-BN® HER2 with a monoclonal antibody that blocks the activity of CTLA-4, an immune checkpoint protein that down-regulates T cell activation. In the CT26-HER2 experimental lung metastasis model, the median survival time increased from 30 days in untreated mice to 49.5 days with MVA-BN® HER2 treatment while anti-CTLA-4 treatment by itself showed little survival benefit (median survival 35 days). In contrast, MVA-BN® HER2 in combination with anti-CTLA-4 significantly increased the survival to greater than 100 days (p

BN ImmunoTherapeutics (BNIT) specializes in developing novel active immunotherapies for cancer. These therapies use recombinant poxviruses engineered to express tumor-associated antigens (TAAs), with the intent of generating effective immune responses against the patients' cancer. PROSTVAC® is a candidate product for the treatment of prostate cancer for which a global Phase III clinical trial (PROSPECT) was recently initiated. This product is composed of two different viral vectors derived from a recombinant vaccinia virus (PROSTVAC™-V) and a recombinant fowlpox virus (PROSTVAC™-F). Both vectors contain transgenes encoding prostate-specific antigen (PSA) and a triad of costimulatory molecules (B7-1, ICAM-1, and LFA-3), designated as TRICOM™. Patients are immunized using a prime-boost strategy consisting of an initial treatment with PROSTVAC™-V followed by repeated boosting with PROSTVAC™-F to maximize the immune responses against the PSA tumor-antigen. Here we show preclinical data characterizing PROSTVAC® activity in mice. Treatment with either PROSTVAC™-V or PROSTVAC™-F induced PSA-specific antibody and T cell responses; however, PSA-specific responses were further increased by the prime/boost strategy, particularly with respect to the frequency of responding CD8 T cells. These CD8 T cells produced IFN-gamma and degranulated in an antigen-specific manner. Furthermore, PROSTVAC® treatment resulted in strong efficacy in a mouse model of prostate cancer. In this model, treatment with PROSTVAC resulted in anti-tumor efficacy accompanied by a Th1-biased response against PSA. In contrast, growth of tumors in control mice induced only non-protective PSA-specific responses with strong Th2 bias. Overall, these animal studies help define the activity and mechanism of action of PROSTVAC® which is currently being evaluated in the clinic. R.B. Rountree and S.J. Mandl contributed equally to this work. Citation Format: Ryan B. Rountree, Stefanie J. Mandl, Joseph Cote, Tracy dela Cruz, Thierry Giffon, Evan Gordon, Susan P. Foy, John R. Lombardo, Erica Trent, Reiner Laus, Alain Delcayre. Active immunotherapy with PROSTVAC® demonstrates potent antitumor efficacy in a mouse model of prostate cancer. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology: Multidisciplinary Science Driving Basic and Clinical Advances; Dec 2-5, 2012; Miami, FL. Philadelphia (PA): AACR; Cancer Res 2013;73(1 Suppl):Abstract nr A21.

Background PROSTVAC®, an active immunotherapy currently studied for the treatment of metastatic castration-resistant prostate cancer (mCRPC), consists of a heterologous prime-boost regimen with two different poxvirus-based vectors to provoke productive immune responses against prostate specific antigen (PSA) as the target tumor antigen. A Phase 2 study of PROSTVAC immunotherapy showed significantly improved median overall survival by 8.5 months and is currently being validated in a global Phase 3 study (PROSPECT; NCT01322490). Here, preclinical models were explored to investigate the mechanism of action and immune signatures of anti-tumor efficacy with PROSTVAC immunotherapy with the goal to identify potential immune correlates of clinical benefit. Methods PROSTVAC-induced immune responses and anti-tumor efficacy were studied in male BALB/c mice. Functionality of the induced T cell response was characterized by interferon-gamma (IFNγ) ELISPOT, cytotoxic degranulation, multi-cytokine intracellular staining, and in vivo T cell depletion. Tumor infiltrating lymphocytes (TILs) were evaluated phenotypically by flow cytometry. Results The heterologous prime-boost regimen of the two PROSTVAC vectors significantly enhanced the magnitude and quality of activated PSA-specific CD4 and CD8 T cell responses compared to homologous, single vector regimens. PROSTVAC-activated CD4 and CD8 T cells were highly functional as evidenced by expression of activation markers, production of multiple cytokines, and amplified cytotoxic T cell activity. Importantly, PROSTVAC immunotherapy resulted in significant anti-tumor efficacy in a transplantable prostate cancer mouse model. Antigen-spreading occurred in PROSTVAC-treated animals that rejected PSA-expressing tumors, as shown by subsequent rejection of PSA-negative tumors. In vivo CD4 and CD8 depletion revealed that both T cell subsets contributed to anti-tumor efficacy. Characterization of TILs demonstrated that PROSTVAC immunotherapy greatly increased the intra-tumoral ratio of activated effector to regulatory T cells. Conclusions PROSTVAC immunotherapy activates broad, highly functional T cell immunity to PSA and to endogenous tumor antigens via immune-mediated antigen spreading. These preclinical results further elucidate the mode of action of PROSTVAC immunotherapy and its potential causal relationship to extended overall survival as observed in the PROSTVAC Phase 2 study. The clinical validation is ongoing in the PROSPECT Phase 3 clinical study. Electronic supplementary material The online version of this article (doi:10.1186/s40425-014-0034-0) contains supplementary material, which is available to authorized users.