Lymphomatoid Papulosis With T-cell Receptor-Gamma Delta Expression: A Clinicopathologic Case-series of 26 Patients of an Underrecognized Immunophenotypic Variant of Lymphomatoid Papulosis

Lymphomatoid papulosis (LyP) has several histopathologic presentations. LyP featuring gamma-delta (γδ) T-cell receptor expression may masquerade as and may be misdiagnosed as aggressive cutaneous T-cell lymphoma, particularly primary cutaneous γδ T-cell lymphoma (PCGDTL) or γδ mycosis fungoides. We performed a clinicopathologic analysis of the largest series of LyP featuring γδ T-cell expression. We identified 26 patients with a diagnosis of LyP with γδ T cells from our institutions, as well as through a comprehensive review of the literature, and characterized these cases. Most cases were treated with topical steroids or not treated at all. The majority of cases showed a CD4 - CD8 + phenotype and featured at least one cytotoxic marker. Histopathologic features included an intraepidermal or dermal infiltrate with large cells and frequent angiotropism. One case was initially misdiagnosed as PCGDTL, requiring further therapy. Our case series, the largest international cohort of γδ T cell predominant LyP cases, confirms marked clinicopathologic heterogeneity that may contribute to misdiagnosis, reasserting the need to identify classic clinical features, CD30 + T-cell components, and markers of cytotoxicity when dealing with this differential diagnosis. A limitation of this study includes somewhat limited follow-up, histologic, and immunophenotypic information for some cases.

Current and upcoming treatment approaches to uncommon subtypes of PTCL (EATL/MEITL, SPTCL, HSTCL)

Rare subtypes of peripheral T-cell lymphoma (PTCL) including enteropathy-associated T-cell lymphoma (EATL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), subcutaneous panniculitis-like T-cell lymphoma (SPTCL) and hepatosplenic T-cell lymphoma (HSTCL) are underrepresented in most registry and clinical studies. Most of the literature is obtained from small case series, single-institution retrospective studies and subgroup analyses of the largest studies with few recent and ongoing exceptions. While the pathogenesis and biology of these entities have yet to be fully elucidated, global efforts by the scientific community have started to shed some light on the most frequently deregulated pathways. In this review, we highlight the most pertinent clinical and pathologic features of rare subtypes of PTCL including EATL/MEITL, SPTCL and HSTCL. We also summarize the results of recent developments identifying potential targets for novel therapeutic strategies based on molecular studies. Finally, we highlight the underrepresentation of these rare subtypes in most clinical trials, making evidence-based therapeutic decisions extremely challenging.

β-Actin G342D as a Cause of NK Cell Deficiency Impairing Lytic Synapse Termination

NK cell deficiency (NKD) occurs when an individual's major clinical immunodeficiency derives from abnormal NK cells and is associated with several genetic etiologies. Three categories of β-actin-related diseases with over 60 ACTB (β-actin) variants have previously been identified, none with a distinct NK cell phenotype. An individual with mild developmental delay, macrothrombocytopenia, and susceptibility to infections, molluscum contagiosum virus, and EBV-associated lymphoma had functional NKD for over a decade. A de novo ACTB variant encoding G342D β-actin was identified and was consistent with the individual's developmental and platelet phenotype. This novel variant also was found to have direct impact in NK cells because its expression in the human NK cell line YTS (YTS-NKD) caused increased cell spreading in lytic immune synapses created on activating surfaces. YTS-NKD cells were able to degranulate and perform cytotoxicity, but they demonstrated defective serial killing because of prolonged conjugation to the killed target cell and thus were effectively unable to terminate lytic synapses. G342D β-actin results in a novel, to our knowledge, mechanism of functional NKD via increased synaptic spreading and defective lytic synapse termination with resulting impaired serial killing, leading to overall reductions in NK cell cytotoxicity.

Mature T-cell and NK-cell lymphoma involvement of the central nervous system: a single center experience

Mature T-cell and NK-cell lymphomas (MTNKL) are rare and heterogeneous lymphoproliferative disorders with poor clinical outcomes despite novel therapeutic advances. Although infrequent, central nervous system (CNS) involvement by MTNKL is associated with poor outcomes with a median overall survival (OS) of <12 months based on retrospective studies. We performed a retrospective analysis of patients who developed CNS involvement of MTNKL diagnosed at a single center from 1999 through 2020. Twenty-five patients were identified. Characteristics such as a diagnosis of adult T-cell leukemia/lymphoma, extranodal involvement, and poor performance status were associated with a higher risk of CNS involvement (p < 0.01). The median OS after diagnosis with CNS involvement was approximately 1 month (0.03-103.97 months). Patients exposed to novel therapeutics and/or clinical trial enrollment tolerated treatment without safety concerns and appeared to derive reasonable therapeutic benefit. Despite advances in the field, new therapeutic approaches are needed for patients with MTNKL with CNS involvement.

A real-world experience of combined treatment with romidepsin and azacitidine in patients with peripheral T-cell lymphoma

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Background: Patients with peripheral T-cell lymphoma (PTCL) lack good treatment options, particularly in the relapsed and refractory setting. Our work suggested that epigenetic therapies can be safe and effective for patients with PTCL, particularly those with T-cell lymphomas with a follicular helper (TFH) phenotype. It is thought that recurrent mutations in epigenetic factors, including Ten-Eleven Translocation-2 (TET2), DNA methyl transferase-3A (DNMT3A) and isocitrate dehydrogenase-2 (IDH2) may contribute to PTLC vulnerability to epigenetic drugs. Methods: Objective of this study was to evaluate the merits of romidepsin plus subcutaneous azacitidine in patients with PTCL when administered in a ‘real-world’ scenario. We retrospectively identified 17 PTCL patients world-wide that were treated with azacitidine and romidepsin outside of a clinical trial based upon queries regarding off study use. The study was reviewed and approved by each Medical Center Institutional Review Board. Their pretreatment characteristics are shown in Table. Results: Eleven patients had angioimmunoblastic lymphoma (AITL), 2 had adult T-cell leukemia/lymphoma (ATLL), 2 had TFH PTCL, 1 had PTCL-NOS and 1 had composite lymphoma (TFH PTCL with diffuse large B cell lymphoma). Ten patients had next generation sequencing performed. Most common mutations found were those of TET2 (7 pts), RHOA (4pts), IDH2 (3pts) and DNMT3A (1 pt). One ATLL patient had mutations in TRAF3, FAT1 and MED12. Among these 17 patients, overall response rate (ORR) was 76% and the complete response rate (CR) was 52%. Median number of cycles was 4 (range 1-12). Treatment was well tolerated but notable adverse effects included nausea, fatigue, rash, neutropenia and thrombocytopenia. One patient experienced febrile neutropenia while another had pulmonary infiltrates (differential diagnosis included drug toxicity versus infection). In 4 patients, azacitidine and romidepsin were used to achieve remission prior to allogeneic transplant (range of cycles 1-3), with all 4 patients were in CR at their last disease assessment. Conclusions: Subcutaneous azacitidine and romidepsin administered in a ‘real-world’ situation is highly effective in patients with relapsed PTCL with tolerable toxicity, and can be used to successfully bridge patients to stem cell transplant.[Table: see text]

The combination of the IAP antagonist, tolinapant and hypomethylating agents (HMA) is highly synergistic in in vitro models of T-cell lymphoma (TCL)

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Background: Peripheral T-cell lymphoma (PTCL) are a highly aggressive and heterogeneous group of non-Hodgkin lymphomas that often carry a poor prognosis with standard chemotherapy. Tolinapant is a potent antagonist of inhibitors of apoptosis proteins (cIAP1/2 and XIAP). In a phase 2 trial (NCT02503423), tolinapant showed activity against heavily pre-treated patients with TCL. We explored the sensitivity of a range of TCL lines to tolinapant, established the synergy coefficient and interrogated the mechanism of synergy between tolinapant and drugs active against PTCL including romidepsin, pralatrexate, and the HMAs; azacytidine and decitabine. Methods: A panel of 10 human TCL lines were tested in proliferation assays (CellTiterGlo) for sensitivity to tolinapant in the presence or absence of 10 ng/ml of TNFα. For combination studies, each drug was tested, in the presence or absence of TNFα. Synergy coefficient was calculated using Excess over Bliss. Additionally, the on-target effects of the drugs were measured by analyzing levels of the IAPs, acetylated histones, DNMTs and key apoptosis and necroptosis markers by Western blotting. Results: TCL Lines demonstrated varying sensitivities to tolinapant with the most sensitive cell line, ALK+ ALCL SUP-M2, having an IC50 as low as 20 nM ± 1 nM while a resistant CTCL cell line HH had an IC50 of over 20 µM. In combination experiments using both cell lines, tolinapant plus azacytidine or decitabine displayed the highest degree of synergism, compared to romidepsin or pralatrexate. Of note, a high degree of synergism was also seen with concentrations 10 folds lower of azacytidine or 100 folds lower of decitabine, added daily (Table). The combination of tolinapant and the HMAs led to a decrease in the levels of cIAP1 and DNMT3a in TCL lines, demonstrating on-target activity of tolinapant and the HMAs, respectively. In addition, both azacytidine and decitabine increased the levels of RIPK3 and MLKL by western blot analysis, indicating activation of the necroptosis pathway. Conclusions: Tolinapant has demonstrated varying cytotoxic effects against a range of TCL lines as a monotherapy and displays a very high degree of synergism in combination with the HMAs, azacytidine and decitabine, also at low concentration, in vitro. The HMAs were also able to activate the necroptosis pathway, providing a possible mechanism for the high degree of synergism displayed when combined with tolinapant in the TCL lines in vitro. These data provide the rationale to initiate phase I trials with the combination of tolinapant and HMAs. Average synergy scores at 48 hrs for drugs used in combination with tolinapant in a CTCL line HH and ALK+ ALCL line SUP-M2. Above 10 indicates synergy.[Table: see text]

Expression of type I interferon-associated genes at antiretroviral therapy interruption predicts HIV virological rebound

Although certain individuals with HIV infection can stop antiretroviral therapy (ART) without viral load rebound, the mechanisms under-pinning 'post-treatment control' remain unclear. Using RNA-Seq we explored CD4 T cell gene expression to identify evidence of a mechanism that might underpin virological rebound and lead to discovery of associated biomarkers. Fourteen female participants who received 12 months of ART starting from primary HIV infection were sampled at the time of stopping therapy. Two analysis methods (Differential Gene Expression with Gene Set Enrichment Analysis, and Weighted Gene Co-expression Network Analysis) were employed to interrogate CD4+ T cell gene expression data and study pathways enriched in post-treatment controllers versus early rebounders. Using independent analysis tools, expression of genes associated with type I interferon responses were associated with a delayed time to viral rebound following treatment interruption (TI). Expression of four genes identified by Cox-Lasso (ISG15, XAF1, TRIM25 and USP18) was converted to a Risk Score, which associated with rebound (p < 0.01). These data link transcriptomic signatures associated with innate immunity with control following stopping ART. The results from this small sample need to be confirmed in larger trials, but could help define strategies for new therapies and identify new biomarkers for remission.

Clonal cutaneous and neurosyphilis: A pitfall in pseudolymphoma diagnosis

Syphilis is a sexually transmitted infectious disease caused by the bacterium Treponema pallidum and can cause a wide variety of cutaneous manifestations, most commonly, a papulosquamous eruption of the trunk and extremities. Treatment with penicillin is curative. We report a case of a 69-year-old man who presented with recent onset of blurry vision and a nonpainful, nonpruritic eruption of pink-to-violaceous dermal nodules on his upper trunk and upper extremities. Biopsies of two separate locations revealed a dense superficial and deep perivascular atypical lymphocytic infiltrate with admixed plasma cells, histiocytes, and eosinophils. Some scattered cells expressed CD30, PD1, BCL-6, and ICOS. T-cell receptor (TCR)-rearrangement showed an identical TCR-gamma clone between both biopsy specimens. The patient was subsequently seen by ophthalmology and diagnosed with acute anterior uveitis. Rapid plasma reagin was reactive and cerebrospinal fluid studies showed findings consistent with a diagnosis of neurosyphilis. A T. pallidum immunostain of the skin biopsies was performed upon re-review, and was diffusely positive for spirochetes at the dermal-epidermal junction and within injured vessels. The patient was treated with penicillin G with near-resolution of his skin lesions. This case highlights the unusual ability of syphilis to mimic a T-cell lymphoma with matching clones across two different biopsy sites.

Targeting the T-Cell Lymphoma Epigenome Induces Cell Death, Cancer Testes Antigens, Immune-Modulatory Signaling Pathways

The peripheral T-cell lymphomas (PTCL) could be considered the prototypical epigenetic disease. As a disease, they are uniquely sensitive to histone deacetylase (HDAC) and DNA methyltransferase (DNMT) inhibitors, both alone and in combination, are characterized by a host of mutations in epigenetic genes, and can develop spontaneously in genetically engineered murine models predicated on established recurring mutations in (RHOAG17V) and TET2, an epigenetic gene governing DNA methylation. Given the clinical benefit of HDAC inhibitors (HDACi) and hypomethlyation agents alone and in combination in PTCL, we sought to explore a mechanistic basis for these agents in PTCL. Herein, we reveal profound class synergy between HDAC and DNMT inhibitors in PTCL, and that the combination induces degrees of gene expression that are substantially different and more extensive than that observed for the single agents. A prominent signature of the combination relates to the transcriptional induction of cancer testis antigens and genes involved in the immune response. Interestingly, TBX21 and STAT4, master regulators of TH1 differentiation, were among the genes upregulated by the combination, suggesting the induction of a TH1-like phenotype. Moreover, suppression of genes involved in cholesterol metabolism and the matrisome were also identified. We believe that these data provide a strong rationale for clinical studies, and future combinations leveraging an immunoepigenetic platform.

Management of Angioimmunoblastic T-Cell Lymphoma (AITL) and other T Follicular Helper Cell lymphomas (TFH PTCL)

Despite the remarkable improvements in the treatment and outcome of patients with aggressive B-cell lymphoma, the peripheral T-cell lymphomas (PTCL) continue to carry a poor prognosis with the presently available treatment options. The PTCL are very rare diseases that account for only 10,000 to 15,000 new cases per year in the United States. The World Health Organization's 2016 classification describes 29 distinct subtypes of PTCL, thus making these both rate and incredibly heterogenous. The 2 most common forms of PTCL, for example, peripheral T-cell lymphoma-not otherwise specified and angioimmunoblastic T-cell lymphoma , have an incidence of only 2500 and 1800 cases per year respectively, in the United States.

Low dose continuous lenalidomide in heavily pretreated patients with relapsed or refractory classical Hodgkin lymphoma: a retrospective case series

Patients with relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL) following autologous stem cell transplant (ASCT) remain a management challenge with few reliably effective treatments. Lenalidomide, an immunomodulatory drug approved for patients with myelodysplastic syndrome with del(5q), multiple myeloma, and mantle cell lymphoma, has demonstrated some activity in patients with R/R cHL, though the toxicity of traditional doses and schedules has been a barrier to consistent use. Low dose continuous (LDC) schedules have emerged as promising, with a more favorable safety profile. We report herein that LDC schedules are associated with a far more tolerable toxicity profile, and exhibit at least equivalent efficacy in this patient population. We report that patients diagnosed with R/R cHL who previously underwent, or were not candidates for, ASCT and/or clinical trials, were administered daily LDC lenalidomide (20 mg orally with dose reduction for toxicity). Among the 19 patients included in this analysis, 11% of patients achieved a partial response (PR), with no documented complete responses (CR). A total of 12 (63%) patients maintained stable disease (SD), with 7 patients (37%) remaining in SD for more than 6 months. The clinical benefit rate (comprised of CR, PR, and SD for greater than 6 months) was 47% (7 out of 19 patients). The median progression-free survival and overall survival of all patients were 9.4 months (range, 4.6–14.4 months) and 90 months (range, 63.6–166.8 months), respectively. In general, the treatment was well tolerated, with grade 3 or 4 adverse events consisting of neutropenia (n = 4), and one case each of thrombocytopenia, fatigue, rash, creatinine elevation, aspartate transaminase/alanine transaminase elevation, and treatment related secondary malignancy. In a heavily treated R/R cHL patient population, daily LDC lenalidomide was associated with a high disease control rate with a favorable toxicity profile.

Generation of pralatrexate resistant T-cell lymphoma lines reveals two patterns of acquired drug resistance that is overcome with epigenetic modifiers

While pralatrexate (PDX) has been successfully developed for the treatment of T-cell lymphoma, the mechanistic basis for its T-cell selectivity and acquired resistance remains elusive. In an effort to potentially identify synergistic combinations that might circumnavigate or delay acquired PDX resistance, we generated resistant cells lines over a broad concentration range. PDX-resistant cell lines H9-12 and H9-200 were developed, each exhibiting an IC50 of 35 and over 1000 nM, respectively. These lines were established in vitro from parental H9 cells. Expression analysis of the proteins known to be important determinants of antifolate pharmacology revealed increase expression of dihydrofolate reductase (DHFR) due to gene amplification, and reduced folate carrier1 downregulation, as the putative mechanisms of resistance in H9-12 and H9-200 cells. Cross resistance was only seen with methotrexate but not with romidepsin, azacitidine (AZA), decitabine, gemcitabine, doxorubicin, or bortezomib. Resistance to PDX was reversed by pretreatment with hypomethylating agents in a concentration-dependent fashion. Comparison of gene expression profiles of parental and resistant cell lines confirmed markedly different patterns of gene expression, and identified the dual specificity phosphatase four (DUSP4) as one of the molecular target of PDX activity. Reduced STAT5 phosphorylation following exposure to PDX was observed in the H9 but not in the H9-12 and H9-200 cells. These data suggest that combination with hypomethylating agents could be potent, and that DUSP4 and STAT5 could represent putative biomarkers of PDX activity.

A survey of cancer testis antigen (CTA) expression across T-cell lymphoma subtypes

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Background: T-cell lymphomas (TCL) are a rare and heterogeneous group of non-Hodgkin lymphomas (NHL) that originate from T- and NK-cells and portends a poor prognosis. One promising therapeutic strategy involves generation of tumor associated antigen directed T-cells (TAA-T) against specific CTA. RNAseq have established that combinations of histone deacetylase inhibitors and hypomethylating agents uniquely induce genes characterized as cancer testes antigens (CTA), which may increase immunogenicity. There is a lack of data on the baseline expression of CTA across the TCL, limiting application of TAA-T. We sought to establish the baseline expression of CTA in PTCL using immunohistochemistry to better understand treatment effects. Methods: A tissue microarray was created using formalin-fixed paraffin embedded tissue from 40 patients with diverse T-cell neoplasms. Expression of WT1, SCP1, survivin, PLAC1, SSX2, and PRAME was evaluated by immunohistochemistry. The percentage of positive tumor cells (divided into quartiles), staining intensity (weak, moderate, strong), and subcellular localization (nuclear, cytoplasmic) was assessed. Results: Forty patients with T-cell lymphomas were included in the analysis. The median age of diagnosis and median number of treatments was 60.2 years and 2 (0-9), respectively. Thirty-nine (98%) patients expressed at least one CTA. A high frequency of survivin, which is associated with cell proliferation and is expressed on normal lymphoid tissue, was expressed in 98% of TCL, 5% expressed WT1, and 12.5% expressed SCP1, and expression of other CTA was not observed. Of five patients with anaplastic large cell lymphoma, 3 samples were positive for SCP1 and one was also positive for WT1. One of 9 angioimmunoblastic T-cell lymphoma samples was positive for SCP1. Of 4 T-lymphoblastic lymphoma patients, 1 was positive for WT1, and of 3 transformed mycosis fungoides specimens, 1 demonstrated SCP1 expression. In this sample set, we did not find a correlation with expression and response to chemotherapy. There were no patients with CTA expression who were treated with epigenetic treatments. Conclusions: We described low expression of CTA on T-cell lymphomas, which is consistent with the literature on expression by RT-PCR. By establishing this baseline expression of CTA, we have the foundation on which to measure changes in CTA expression pre- and post-treatment by immunohistochemistry.

The Integration of PD1 blockade with epigenetic therapy is highly active and safe in heavily treated patients with T-cell lymphoma (PTCL) and cutaneous T-cell lymphoma (CTCL)

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Background: Our group has demonstrated that combinations of epigenetic modifiers produce potent synergy in pre-clinical models of PTCL and induce the expression of cancer testis antigen, suggesting a role in the addition of the immune-checkpoint inhibitor, pembrolizumab. Methods: This is a phase 1b study of pembrolizumab combined with pralatrexate alone (Arm A), with pralatrexate + decitabine (Arm B), or decitabine alone (Arm C) in patients with relapsed and refractory PTCL and CTCL. A standard 3+3 dose-escalation is applied in the triplet Arm (Arm B) while in the doublet Arms (A and C) de-escalation is applied in case of toxicity. Pharmacokinetic and pharmacodynamic studies are ongoing. Results: We treated a total of 12 patients with 4 patients in each Arm. All patients that received at least one dose of drug were evaluable for toxicity. There was a dose limiting toxicity (DLT) in each arm including prolonged grade 3 thrombocytopenia (Arm A), febrile neutropenia (Arm B), grade 3 hyponatremia, and rash (Arm C). There were no treatment-related deaths. Six patients out of 12 were evaluable for response at the time of this analysis. One patient achieved a complete remission, 2 had partial remission, 1 had stable disease, and 2 experienced progression of disease. Interestingly, all of the responses were seen in the triple combination of pralatrexate, decitabine, and pembrolizumab. Table summarizes the patient characteristics, toxicities, and response rates. Conclusions: These preliminary clinical data suggest that the integration of pembrolizumab on an epigenetic backbone is safe and demonstrates encouraging responses in patient with PTCL and CTCL. Clinical trial information: 03240211 . [Table: see text]

The anti-tumor activity of pralatrexate (PDX) correlates with the expression of RFC and DHFR mRNA in preclinical models of multiple myeloma

Multiple myeloma (MM) is the second most common hematologic malignancy. While major advances have been made in the disease, it is still incurable. Although antifolate-based drugs are not commonly used to treat myeloma, new generation analogs with distinct patterns of preclinical and clinical activity may offer an opportunity to identify new classes of potentially active drugs. Pralatrexate (PDX), which was approved for the treatment of relapsed or refractory peripheral T-cell lymphoma in 2009, may be one such drug. Pralatrexate exhibits a potency and pattern of activity distinct from its predecessors like methotrexate (MTX). We sought to understand the activity and mechanisms of resistance of multiple myeloma to these drugs, which could also offer potential strategies for selective use of the drug. We demonstrate that PDX and MTX both induce a significant decrease in cell viability in the low nanomolar range, with PDX exhibiting a more potent effect. We identified a series of myeloma cell lines exhibiting markedly different patterns of sensitivity to the drugs, with some lines frankly resistant, and others exquisitely sensitive. These differences were largely attributed to the basal RFC (Reduced Folate Carrier) mRNA expression levels. RFC mRNA expression correlated directly with rates of drug uptake, with the most sensitive lines exhibiting the most significant intracellular accumulation of pralatrexate. This mechanism explains the widely varying patterns of sensitivity and resistance to pralatrexate in multiple myeloma cell lines. These findings could have implications for this class of drugs and their role in the treatment of multiple myeloma.

The rapidly changing landscape in mature T-cell lymphoma (MTCL) biology and management

Historical advances in the care of patients with non-Hodgkin lymphoma (NHL) have been restricted largely to patients with B-cell lymphoma. The peripheral T-cell lymphomas (PTCLs), which are rare and heterogeneous in nature, have yet to experience the same degree of improvement in outcome over the past 20 to 30 years. It is estimated that there are approximately 80,000 and 14,000 cases, respectively, of NHL and Hodgkin lymphoma per year in the United States. As a subgroup of NHL, the PTCLs account for 6% to 10% of all cases of NHL, making them exceedingly rare. In addition, the World Health Organization 2017 classification describes 29 distinct subtypes of PTCL. This intrinsic diversity, coupled with its rarity, has stymied progress in the disease. In addition, most subtypes carry an inferior prognosis compared with their B-cell counterparts, an outcome largely attributed to the fact that most treatment paradigms for patients with PTCL have been derived from B-cell neoplasms, a radically different disease. In fact, the first drug ever approved for patients with PTCL was approved only a decade ago. The plethora of recent drug approvals in PTCL, coupled with a deeper understanding of the molecular pathogenesis of the disease, has stimulated the field to pursue new avenues of research that are now largely predicated on the development of novel, targeted small molecules, which include a host of epigenetic modifiers and biologics. There is an expectation these advances may begin to favorably challenge the chemotherapy paradigms that have been used in the T-cell malignancies.

Survival benefit in patients with peripheral T-cell lymphomas after treatments with novel therapies and clinical trials

The peripheral T-cell lymphomas (PTCL) are rare and heterogeneous diseases characterized by an unfavorable prognosis. Chemotherapy is standard upfront treatment in most patients, but responses are short-lived with few FDA-approved "novel" agents available. We sought to define the impact of these novel agents as single agents or in clinical trials on the outcomes of patients with PTCL. From January 1994 to May 2019, adult patients with PTCL who were managed at our institution were included in this analysis. In addition to patients with incomplete data, those diagnosed with large granular lymphocytic leukemia and cutaneous T-cell lymphoma (CTCL) except for transformed mycosis fungoides were excluded. Statistical analyses were performed using SAS version 9.4. There were 219 patients included in the analysis. The median age at diagnosis was 56 years (range, 18-90 years). First line therapies mostly consisted of combination chemotherapy (75%). There was a statistical difference among patients who received chemotherapy, novel agents alone and in chemotherapy-free combinations, other, and no treatment (P < .0001). In patients who were treated with second line chemotherapy, novel agents alone and in combination without chemotherapy, or other, there was a still a survival benefit favoring novel agents (P = .0417). In the third line, there was no statistical difference among the three groups (P = .569). All patients who received novel therapies and underwent autologous stem cell transplant (autoSCT) achieved a complete response (CR) and had a better survival compared with patients who underwent chemotherapy who had a 70% CR rate prior to autoSCT (P = .046). Exposure to FDA-approved novel agents, immunoepigenetic trials, and clinical trials in general was associated with an overall survival (OS) benefit (P = .003, P = .04, and P = .006, respectively). These data suggest that patients who receive novel agents have superior outcomes compared with patients without exposure to novel therapies who receive chemotherapy-predicated treatments.

An objective based model of published treatment options for relapsed or refractory (R/R) peripheral t-cell lymphoma (PTCL): An evidence-based decision-making approach

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Background: PTCL are rare diseases with a poor prognosis. Front line therapy achieves CR in 30% to 60% and OS of 25%. Patients with R/R disease have an even worse prognosis. There is no consensus on the management of R/R disease because evidence supporting most treatment approaches is modest. Many approaches are often not supported by literature, and categorizations regarding efficacy and toxicity without attention to details are ignored. Treatments that have achieved regulatory approval with stringent independent assessment of pathology and response are viewed as less established, or equivalent to smaller published experiences. In the effort to take a critical and comprehensive evidence-based approach to available standards in R/R PTCL we developed an objective scoring system for all types of studies published in the literature (eg randomized phase 3, case match control, phase 2, phase 1, case reports and small series) to aid decision-making based on an assessment of all the available data. Methods: An extensive review on PubMed of clinical trials published in literature for R/R PTCL was performed. A rigorous scoring system based on a survey from 100 authorities in the field to quantitate scientific impact of each study based was developed. These include: type of study (randomized phase 3, case match control analysis, phase 2 weighted based on number of PTCL patients [ > 100 vs < 100 patients], phase 1 with > 5 or < 5 PTCL patients enrolled, and retrospective); weighting for use of central pathology or response review; weighting for detailed study metrics (ORR, CR, DoR, PFS). The scoring system included a penalty for omission detail. The proposed scoring system was evaluated by a panel of experts. The scoring system was modified based on recommendations made by 2 or more panel members. Results: We identified 58 publications between 2004 and 2018. The scoring system spanned from 0 to 9. Only 12 of the 58 studies had a score above 5; 15 of 58 had a score between 1 - 5; remaining publications scored 0 - 1. Conclusions: Our analysis suggests practice patterns are based on studies with low priority scores, and underweight robust clinical experiences. This analysis aims to produce an evidenced based approach for R/R PTCL.

Strategy for Assessing New Drug Value in Orphan Diseases: An International Case Match Control Analysis of the PROPEL Study

Background

Although randomized studies are designed to assess overall survival (OS) benefit, the conduct of regulatory studies in patients with orphan diseases can be timely and costly without offering the same commercial return on the investment. The peripheral T-cell lymphomas (PTCL) represent a rare group of heterogeneous lymphoid malignancies with very poor prognosis. PROPEL was a pivotal phase II study that led to the accelerated approval of pralatrexate for patients with relapsed or refractory PTCL.

Methods

An international database of 859 patients was assembled from four institutions with an interest in PTCL, of which 386 were considered eligible for matching against the PROPEL criteria. Using a rigorous propensity score matching algorithm, a unique 1:1 case match of 80 patients was performed.

Results

The analysis demonstrated an OS benefit for the PROPEL population with a median OS of 4.07 and 15.24 months (hazard ratio = 0.432, 95% confidence interval = 0.298 to 0.626), respectively, for the control and PROPEL populations. Highly statistically significant improvements in OS were noted for the PROPEL population about the subtype of PTCL (save anaplastic large cell lymphoma) and all age groups, including the elderly (>65 years of age). For patients on PROPEL, there was a statistically significant prolongation in progression free survival compared with the line of prior therapy, including those with refractory disease.

Conclusion

In the context of this case-match-control study, patients treated on PROPEL experienced an OS advantage compared with an international database of historical controls. This information can help inform critical decision-making regarding clinical studies in PTCL.

Therapeutic Effect of a Low Molecular Weight Dermatan Sulphate (Desmin 370) in Rat Venous Thrombosis - Evidence for an Anticoagulant-Independent Mechanism

We evaluated the capacity of a low molecular weight dermatan sulphate (D370) to prevent thrombus formation and to induce a reduction of a stabilized thrombus in a rat venous thrombosis model. Injection of D370, 10 min before induction of venous stasis (prevention model), prevented thrombus formation in a dose-dependent way (ED50: 2.3 mg/kg). When given to rats 6 h after induction of venous stasis (therapeutic model), D370 caused a time- and dose-dependent reduction in thrombus size (60% to 70% reduction 2 h after injection of 10 mg/kg). At comparable antithrombotic dosages (i.e. minimum dose giving complete inhibition of thrombus formation), heparin (0.5 mg/kg) only caused 40% reduction of a preformed thrombus while hirudin (1 mg/kg) was virtually ineffective (less than 10% reduction in weight). All three compounds inhibited 125I-fibrin(ogen) deposition on 6-h aged thrombi by more than 85%, suggesting that D370 and, to a lesser extent, heparin reduce thrombus size via mechanisms other than inhibition of thrombus accretion. The involvement of a fibrinolysis-mediated mechanism in the D370-induced effect is suggested by the following. EACA (1 g/kg), when given to thrombus-bearing control animals, did not influence thrombus weight. However, when administered before D370 treatment, it prevented the expected reduction in thrombus weight by more than 80%, without influencing the effect of D370 on 125I-fibrin(ogen) accumulation onto preexisting thrombi. D370 injection caused neither an enhancement of fibrinolytic activity nor a reduction of PAI in plasma. In vitro, D370 (200 μg/ml) was unable to potentiate the spontaneous or PA-induced lysis of 125I-fibrinogen labelled blood, plasma, or purified fibrin clots. It is suggested that prevention of thrombus formation by D370 is related mainly to inhibition of blood coagulation, whereas reduction of the weight of aged thrombi is primarily due to an anticoagulant-independent mechanism, most probably involving local enhancement of the fibrinolytic process. D370 may represent an alternative pharmacologic agent both in the prevention and in the therapy of venous thrombosis.

Brentuximab vedotin plus bendamustine in relapsed or refractory Hodgkin's lymphoma: an international, multicentre, single-arm, phase 1-2 trial

Background:

The major objective of this study was to explore the safety and clinical activity of Brentuximab vedotin (Bv) and bendamustine in combination in patients with relapsed or refractory Hodgkin Lymphoma. Bv produces high response rates and durable progression-free survival (PFS) in CD30-expressing lymphomas and is approved for the treatment of relapsed Hodgkin lymphoma (HL) and relapsed ALCL. Bendamustine (B) is active agent across the lymphoproliferative malignancies, though the PFS among patients with HL and PTCL is modest.

Methods:

This was an international, multicenter, single-arm, Phase 1–2 study of BvB in patients with relapsed or refractory HL and ALCL. Eligible patients were required to have relapsed/refractory CD30+ biopsy proven HL or ALCL and an ECOG Performance Status ≤2. In the Phase 1, HL patients were deemed eligible if they developed progressive disease following or after declining ASCT, or had at least 2 prior multi-agent chemotherapy regimens. In the Phase 2, patients with HL were eligible if they had relapsed or refractory disease after one line of therapy. Eligible ALCL patients were required to have relapsed after at least one prior multi-agent chemotherapy regimen and if they were not eligible for or have declined ASCT. The primary objective of the Phase I portion of this study was to identify the maximum tolerated dose (MTD) and dose limiting toxicity (DLT). The primary endpoint of the Phase 2 portion was to determine the overall response rate (ORR; complete response [CR] plus partial response [PR])) based on an intention to treat analysis (ITT). Secondary objectives of Phase 1–2 included assessing for duration of response, progression free survival and overall survival. Response was evaluated using International Harmonization Project Group 2007 Revised Response Criteria. Bv was escalated from 1.2mg/kg Day 1, and B from 70mg/m2 Days 1 and 2 every 21 days until the MTD or recommended phase 2 dose (RP2D) was reached. The study is ongoing but no longer recruiting patients. This trial is registered with ClinicalTrials.gov number NCT01657331.

Findings:

65 patients (only 1 ALCL) were treated, 28 on the Phase 1 and 37 on the phase 2. While the MTD of the combination was not reached, the single agent MTD of Bv (1.8mg/kg Day 1) and RP2D of B (90mg/m2 Days 1 and 2) were identified as the RP2D of the combination. Patients were heavily treated, 65% (42 of 65) had an autologous or allogeneic stem cell transplant or both. The Phase 1 revealed modest toxicity. The major Grade 3/4 toxicities included Grade 3 lung infection in 5 (14%) patients in the Phase 2, and Grade 3/4 neutropenia in 13 (24%) patients across the Phase 1 and 2. The Phase 1 and 2 overall response rates (ORR) were 61% and 78% respectively, with 43% (16 of 27) patients treated in the Phase 2 attaining a complete remission (CR). In the Phase 2, the median PFS has not been reached and duration of response (DOR) was 3.4 months. There was a total of 23 deaths with 21 due to progression of disease, 2 occurring after being transplanted, and none of which were treatment related.

Interpretation:

This demonstrates that BvB might be an effective salvage regimen for patients with HL, with a favorable safety profile.

Funding:

Seattle Genetics, The Lymphoma Research Fund of Columbia University and National Center for Advancing Translational Sciences, National Institutes of Health, through Grant Number UL1TR001873 provided support for this investigator initiated sponsored trial. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Bone marrow aspirate quality assessment

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Background: Bone marrow evaluation is the cornerstone of diagnosis, staging, and measurement of treatment response for many hematologic diseases. Aspirate adequacy is defined by whether the procedure results in a specimen of sufficient quality for pathologic review. Between July 1, 2014 and June 30, 2015, 49.3% of inpatient bone marrow aspirates performed by Hematology/Oncology fellows at Columbia University Medical Center were classified as suboptimal. Methods: We used the Plan-Do-Study-Act methodology to 1) understand the factors contributing to suboptimal aspirates, 2) evaluate the scope of the problem at both fellowship and institutional levels, 3) develop a training seminar to educate fellows on the procedure techniques, and 4) monitor for improvement post-intervention. We identified inpatient bone marrow biopsies performed by Hematology/Oncology fellows between July 1, 2015 and June 30, 2016 and tabulated aspirate adequacy as noted in the reports. A faculty-led educational seminar was held on February 1, 2016. Fellows completed a pre- and post-intervention survey to assess knowledge and experience with bone marrow aspirates. Bone marrow biopsy billing data was used as a surrogate marker for attending supervision. Results: All Hematology/Oncology fellows (n = 19) at Columbia University Medical Center participated. The pre-intervention survey (18 responses; 94.7%) revealed 76.5% of fellows had formal bone marrow aspirate training, 66.6% had supervision 25% to 75% of the time, and 52.9% were uncomfortable performing the procedure alone. Of the 43 aspirates from the pre-intervention period, 22 (51.2%) were adequate. 94.7% of fellows attended the training seminar. Post-intervention, 27 of 50 (54%) bone marrow aspirates were adequate. The post-intervention survey (16 responses; 84.2%) showed 93.3% of fellows were confident performing the procedure alone. There were fewer procedures billed in the post-intervention period (20.9% pre vs 8% post). Conclusions: A formal educational seminar on bone marrow aspirate technique increased fellow comfort with the procedure and trended toward improved aspirate adequacy. The next study phase will institute an annual training session for incoming fellows and create a bone marrow specimen preparation checklist.

An improved method for detecting telomere size differences in T-lymphocyte interphases from older people with Down syndrome with and without mild cognitive impairment

Telomere size (quantified by fluorescence intensity and physical lengths) in short-term T-lymphocyte cultures from adults with Down syndrome (DS) with and without mild cognitive impairment (MCI-DS) or dementia was compared. For these studies, dementia status was determined based on longitudinal assessments employing a battery of cognitive and functional assessments developed to distinguish adult-onset impairment from preexisting developmental disability. In the course of our studies using a MetaSystems Image Analyzer in combination with ISIS software and a Zeiss Axioskop 2, we found that Fluorescein isothiocyanate (FITC) telomere fluorescence referenced to chromosome 2-identified FITC probe fluorescence as a nontelomere standard (telomere/cen2 ratio) showed great promise as a biomarker of early decline associated with Alzheimer's disease (AD) in this high-risk population. We have now obtained a cen (2) CY3 probe that can clearly be distinguished from the blue-green FITC interphase telomere probe, providing a clear distinction between telomere and centromere fluorescence in both interphase and metaphase. We used FITC/CY3 light intensity ratios to compare telomere length in interphases in adults with DS with and without MCI-DS or dementia. Five age-matched female and five age-matched male pairs (n = 10) all showed clear evidence of telomere shortening associated with clinical progression of AD (P < 0.002 - P < 0.000001), with distributions of mean values for cases and controls showing no overlap. We also examined the time needed for microscopy using interphase versus metaphase fluorescence preparations. With interphase preparations, examination time was reduced by an order of magnitude compared with metaphase preparations, indicating that the methods employed herein have considerable practical promise for translation into broad diagnostic practice.

Determining exhaust fumes exposure in chainsaw operations

The objective of this study was to investigate the inhalation exposure of forest operators to polycyclic aromatic hydrocarbons (PAHs) and BTEX (benzene, toluene, ethylbenzene and total xylenes) contained in the exhaust fumes released from chainsaws and to suggest possible countermeasures. The study was carried out in four silvicultural treatments (coppice clearcut, conifer thinning, conifer pruning, and sanitary cut), using three types of chainsaw fuel (normal two-stroke petrol mix and two alkylate fuels). Eighty personal air samples were collected; IOM samplers combined with Amberlite XAD-2 sorbent tubes were used for collecting PAHs and Radiello^® samplers were used for BTEX. Results indicate that none of the four silvicultural treatments significantly affected the PAHs and BTEX inhalation exposure of forest workers. On the other hand, statistically significant differences were recorded in the inhalation exposure to PAHs and BTEX when using different fuel types. In particular, the inhalation exposure to PAHs and BTEX was generally one order of magnitude lower when using modern alkylate fuels as compared to the traditional oil and lead-free petrol mixture. The small, non-statistically significant differences in inhalation exposure recorded between the two alkylate fuels suggests that the two fuels might be equivalent in terms of quality. Our study indicates that while forest workers are exposed to PAHs and BTEX, the maximum values are generally well below accepted occupational exposure limits.

The combination of hypomethylating agents and histone deacetylase inhibitors produce marked synergy in preclinical models of T-cell lymphoma

T-cell lymphomas (TCL) are aggressive lymphomas usually treated with CHOP (cyclophsophamide, doxorubicin, vincristine, prednisolone)-like regimens upfront. Recent data suggest that TCL are driven by epigenetic defects, potentially rendering them sensitive to epigenetic therapies. We explored the therapeutic merits of a combined epigenetic platform using histone deacetylase inhibitors (HDACIs) and DNA methyltransferase inhibitors (DNMT) in in vitro and in vivo models of TCL. The 50% inhibitory concentration (IC50 ) values revealed romidepsin was the most potent HDACI, with an IC50 in the low nanomolar range. The combination with a hypomethylating agent produced synergy across all cell lines, which was confirmed in cytotoxicity and apoptosis assays. An in vivo xenograft study demonstrated inhibition of tumour growth in the combination cohort compared to the single agent. Gene expression array and global methylation profiling revealed differentially expressed genes and modulated pathways for each of the single treatment conditions and the combination. Most of the effects induced by the single agent treatment were maintained in the combination group. In total, 944 unique genes were modulated by the combination treatment, supporting the hypothesis of molecular synergism. These data suggest combinations of hypomethylating agents and HDACIs are synergistic in models of TCL, which is supported at the molecular level.

The novel kinesin spindle protein (KSP) inhibitor SB-743921 exhibits marked activity in in vivo and in vitro models of aggressive large B-cell lymphoma

The kinesin spindle protein (KSP) is a mitotic protein essential for cell cycle control and motility. SB-743921 (hereafter SB-921) is an inhibitor that selectively targets the ATP-binding domain of the KSP. The preclinical activity of SB-921 was evaluated in models of diffuse large B-cell lymphoma (DLBCL). The cytotoxicity of SB-921 was evaluated in a series of germinal center (GC-DLBCL) and post-germinal center (ABC-DLBCL) DLBCL cell lines and a murine lymphoma xenograft model. GC-DLBCL lines generally demonstrated greater sensitivity to SB-921. IC50 values ranged between 1 nM and 900 nM for GC-DLBCL compared to 1 nM to 10 μM for ABC lines. SB-921 demonstrated marked activity in a xenograft model of Ly-1 (GC-DLBCL). While SB-921 was relatively more active in GC derived cell lines, ABC-derived lines still underwent apoptosis at higher concentrations. These results demonstrate that SB-921 inhibits proliferation and induces apoptosis in both GC-DLBCL and ABC-DLBCL.

Synthesis and solid-state fluorescence properties of pentacyclic 7-substituted-indeno[1′,2′:4,5]pyrido[2,1-a]isoindol-5-ones

New pentacyclic indeno[1′,2′:4,5]pyrido[2,1-a]isoindol-5-ones were designed which possess quantum yields in the solid state up to 32%. The importance of the substituent in 7-position was highlighted through crystal packing analysis.

Propolis and its Active Component, Caffeic Acid Phenethyl Ester (CAPE), Modulate Breast Cancer Therapeutic Targets via an Epigenetically Mediated Mechanism of Action

Alternative remedies for cancer treatment is a multi-billion dollar industry. In particular, breast cancer (BC) patients use alternative and natural remedies more frequently than patients with other malignancies. Propolis is an example of a honeybee-produced naturopathic formulation, contents of which differ by geographic location. It is readily available, affordable, and in use safely since ancient times globally. Caffeic acid phenethyl ester (CAPE) is a major active component in propolis and is thought to be responsible for its varied properties, including antibacterial, antiviral, antifungal, antioxidant, anti-inflammatory and anticancer. CAPE is effective in many models of human cancer, including BC as we have previously shown. CAPE affects genes associated with tumor cell growth and survival, angiogenesis and chemoresistance. We demonstrate that these are related in part to CAPE's role as a histone deacetylase inhibitor, a class of drugs designated as epigenetic agents that modulate the activities of oncogenes and tumor suppressor genes. CAPE and propolis, cause an accumulation of acetylated histone proteins in MCF-7 (ER+) and MDA-MB-231 (ER-/PR-/Her2-) cells with associated decreases in ER and PR in MCF-7 cells, and upregulation of ER and decrease in EGFR in MDA-231 cells. In addition, these products reduced activated phosphorylated Her2 protein in SKBR3 (Her2 +) cells. Interestingly, propolis, when normalized for CAPE content, appears to be more potent than CAPE alone similarly to the greater effects of complete foods than isolated components. These data provide a potential mechanistic basis for one of the oldest naturopathic agents used in medicine and cancer treatment.

Safety and efficacy of pralatrexate in the treatment of patients with relapsed or refractory peripheral T-cell lymphoma

T-cell lymphomas (TCL) are a diverse and heterogeneous group of malignancies that represent less than 15% of all non-Hodgkin lymphomas. Initial refinements of the clinical classification of these complex diseases have been made, but a better understanding of their molecular pathogenesis is still needed. Even if the paucity of insights into the underlying pathogenesis of TCLs has hindered our ability to develop rational targeted therapies, significant advances have been made. Pralatrexate (10-propargyl 10-deazaaminopterin) is a unique antifolate that has been rationally designed to have high affinity for the reduced folate receptor (RFC) and the folylpolyglutamate synthetase (FPGS) and was the first drug ever approved for the treatment of relapsed and refractory peripheral T-cell lymphomas (PTCL). This review describes the preclinical development of pralatrexate that led to early-phase clinical trials in lung cancer and lymphoma and its subsequent approval in PTCL. The review also describes how pralatrexate has been combined with other agents in both the preclinical and clinical settings. FDA approval for the use of pralatrexate in PTCL has been granted based on the results of the pivotal Phase II trial of this agent in relapsed and refractory PTCL patients. clinical development, pralatrexate, preclinical data, T-cell lymphoma.

Effect of a combination of epigenetic agents on the malignant phenotype in models of T-cell lymphoma

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Background: CHOP and CHOP-like chemotherapy are the most used regimens for the treatment of peripheral T-cell lymphomas (PTCLs) despite sub-optimal results. Histone deacetylase inhibitors (HDACIs) have shown class activity in PTCLs. The interaction between the HDACIs (depsipeptide (R), belinostat (B), vorinostat (V) and panobinostat (P)) and a DNMT inhibitor (decitabine (D) was investigated in vitro, in vivo and at the molecular level in T-cell lymphoma and leukemia cell lines (H9, HH, P12, PF-382). Methods: For cytotoxicity assays, luminescence cell viability assay was used (CellTiter-Glo). Drug:drug interactions were analyzed with relative risk ratios (RRR) based on the GraphPad software (RRR<1 defining synergism). Apoptosis was assessed by Yo-Pro-1 and propidium iodine followed by FACSCalibur acquisition. Gene expression profiling was analyzed using Illumina Human HT-12 v4 Expression BeadChip microarrays and Gene Spring Software for the analysis. Results: The IC50s for B, R, V, P, D and 5-Azacytidine alone were assessed at 24, 48 and 72 hours. In cytotoxicity assays the combination of D plus B, R, V or P at 72 hours showed synergism in all the cell lines (RRRs 0.0007-0.9). All the cell lines were treated with D, B or R for 72 hours and all the combinations showed significantly more apoptosis than the single drug exposures and controls (RRR < 1). In vivo, HH SCID beige mice were treated i.p. for 3 cycles with the vehicle solution, D or B or their combination at increasing dose. The combination cohort showed statistically significant tumor growth inhibition compared to all the other cohorts. Gene expression analysis revealed differentially expressed genes and modulated pathways for each of the single agent treatment and the combination. The effects of the two drugs were largely different (only 39 genes modified in common). Most of the effects induced by the single agent were maintained in the combination group. Interestingly, 944 genes were modulated uniquely by the combination treatment. Conclusions: The combination of a DNMTI and HDACIs is strongly synergistic in vitro, in vivo and at the molecular level in model of T-cell lymphoma and these data will constitute the basis for a phase I-II clinical trials.

Abstract 4705: Dual targeting of epigenetic pathways and NF-kappaB in diffuse large B-cell lymphoma

INTRODUCTION: Current immunochemotherapy can cure approximately two-thirds of patients with diffuse large B cell lymphoma (DLBCL), the most common type of non-Hodgkin's lymphoma. Drugs that selectively target specific mechanisms of pathogenesis to which the disease is known to be addicted, offer a unique opportunity to intervene in the natural history of the disease, and may hold the key to future breakthroughs in treating DLBCL. While several unique pathogenetic events have been recently identified in driving lymphomagenesis, two potentially interrelated events contributing to the underlying molecular pathogenesis of DLBCL have come to light. The first involves constitutive activation of NF-kappaB, as noted by Rosenwald and colleagues in their identification of the activated B-cell (ABC) subtype of DLBCL, while the second involves dysregulation of the protein acetylation-deacetylation balance due to either inactivating mutations of histone acetyltransferases (HATs) like p300 and CBP, or overexpression of histone deacetylases (HDACs). HATs and HDACs operate epigenetic pathways to modulate gene expression and to control the activity of important oncoproteins such as Bcl6 through posttranslational modification. While Bcl6 and NF-kappaB are known to be closely associated with the pathogenesis of GCB (germinal center B-cell) and ABC subtypes of DLBCL respectively, it has become clear that many ABC lymphomas can have dysregulation of Bcl6, and many cases of GCB DLBCL can have dysregulation of NF-kappaB. Therefore, strategies oriented toward modulation of these biological traits could offer a unique opportunity to treat DLBCL at its molecular roots, potentially sensitizing them to traditional chemotherapy approaches. RESULTS: We have conducted pharmacological and molecular studies of a novel IKKbeta inhibitor, LY2409881, in DLBCL cell lines. We found that LY2409881 specifically inhibited the activation of NF-kappaB and increased apoptosis, and inhibited both ABC and GCB cells that are addicted to NF-kappaB, with moderate potentcy. Furthermore, LY2409881 demonstrated marked anti-lymphoma synergism with HDAC inhibitors; the synergism varied significantly in a cell line and HDAC inhibitor-dependent manner. The discrete patterns of synergism among different HDAC inhibitors with LY2409881 were not solely attributable to acetylation of p65/RelA mediated by HDAC inhibitors, as these inhibitors all stimulated binding of p65/RelA to its target DNA. We will determine the mechanism of the drug: drug synergism by investigating whether knocking down HDAC molecules in lymphoma cells make them hypersensitive to IKK inhibitors. We are using xenograft lymphoma models in mice to confirm the in vivo activity of LY2409881, as a single agent and in combination with HDAC inhibitors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4705. doi:1538-7445.AM2012-4705

A novel approach combining the Calgary Biofilm Device and Phenotype MicroArray for the characterization of the chemical sensitivity of bacterial biofilms

A rapid method for screening the metabolic susceptibility of biofilms to toxic compounds was developed by combining the Calgary Biofilm Device (MBEC device) and Phenotype MicroArray (PM) technology. The method was developed using Pseudomonas alcaliphila 34, a Cr(VI)-hyper-resistant bacterium, as the test organism. P. alcaliphila produced a robust biofilm after incubation for 16 h, reaching the maximum value after incubation for 24 h (9.4 × 10(6) ± 3.3 × 10(6) CFU peg(-1)). In order to detect the metabolic activity of cells in the biofilm, dye E (5×) and menadione sodium bisulphate (100 μM) were selected for redox detection chemistry, because they produced a high colorimetric yield in response to bacterial metabolism (340.4 ± 6.9 Omnilog Arbitrary Units). This combined approach, which avoids the limitations of traditional plate counts, was validated by testing the susceptibility of P. alcaliphila biofilm to 22 toxic compounds. For each compound the concentration level that significantly lowered the metabolic activity of the biofilm was identified. Chemical sensitivity analysis of the planktonic culture was also performed, allowing comparison of the metabolic susceptibility patterns of biofilm and planktonic cultures.

Low abdominal contribution to breathing as daytime predictor of nocturnal desaturation in adolescents and young adults with Duchenne Muscular Dystrophy

In the respiratory management of DMD patients it is still under debate what parameter should indicate the correct timing for institution of nocturnal non-invasive ventilation (NIV), in addition to forced vital capacity, which is generally considered as a prognostic marker of disease progression. The aim of this study was to determine if volume variations of rib cage and abdominal compartments measured by Opto-Electronic Plethysmography can be helpful to distinguish between those patients who are in the early stages of nocturnal oxygen desaturation development and those who do not yet. Pulmonary function, abdominal contribution to tidal volume and to inspiratory capacity (%Abd IC) and a set of breathing pattern indexes were assessed in 40 DMD patients older than 14 years and not yet under nocturnal NIV. ROC analysis revealed that among all the considered parameters, %Abd IC in supine position was the best discriminator between DeSat (at least 10% of the night time with SpO(2) < 95%) and NonDeSat patients, providing an area under the curve with 95%CI equal to 0.752. In conclusion, in adolescents and adults DMD patients who present either no sign or only mild nocturnal oxygen desaturation, a reduced abdominal contribution to inspiratory capacity is a marker of the onset of diaphragm weakness and should be considered to identify the correct timing for the institution of nocturnal NIV.

Abstract A12: Validation of a novel bioluminescent mouse model of Sezary syndrome for preclinical drug screening

Background: Sezary syndrome (SS) is an aggressive leukemic form of cutaneous T cell lymphoma (CTCL). Until now no true animal model for SS exists which could be used for the screening of novel compounds against the disease. We successfully developed a bioluminescent xenograft mouse model for SS to noninvasively monitor tumor cell engraftment and progression and to measure the effects of treatments on tumor burden.

Methods: A fusion protein was constructed consisting of the monomeric mutant red fluorescent mCherry, and the synthetic-firefly Luciferase by cloning the mCherry gene into the plasmid vector pGL4.13 [luc2/SV40] (Promega) carrying the luciferase gene, thus obtaining the pGLCherryLuciferase plasmid, where the Cherry and the luciferase genes formed one open reading frame. H9 cell line derived from a SS patient was transfected with this plasmid using the transfection reagent, Effectene. Transfected H9 cells were injected subcutaneously into the 5–7 week old female SCID-Beige and NOG (NOD/Shi-scid/IL-2R null) mice. After confirmation of a bioluminescent signal, NOG mice were assigned to the vehicle control group or treatment groups, which received romidepsin (1.2 or 2.3mg/kg on day1, 4, 8 and 11, ip) or pralatrexate (30mg/kg on day1, 4, 8 and 11, ip). In vivo bioluminescence imaging over 3 weeks was performed using an IVIS imaging system (Caliper Life Sciences).

Results: SCID-Beige mice did not permit any engraftment of the H9 injected cells whereas all the NOG mice exhibited tumor growth and progression. This suggests that the NOG mice are superior animal recipients for xenotransplantation of Sezary cells, potentially making them a preclinical tool to understand tumorigenesis and drugs effects in this malignancy. Sequential quantitative signals from bioluminescent imaging over the 3-week period were significantly lower in the mice treated with pralatexate compared with the control group. The mice treated with 1.2mg/kg of romidepsin had no effect on tumor suppression whereas the mice that received the higher dose of romidepsin demonstrated decrease of tumor growth suggesting dose-dependent tumor inhibition. Mice treated with pralatrexate demonstrated diminished bioluminescent signal as early as after the first dose compared to the mice treated with higher dose of romidepsin which produced a slower time to onset of activity. No mice treated with pralatrexate or with the higher dose of romidepsin exhibited toxicity.

Conclusion: This novel bioluminescent xenograft mouse model of SS enables non-invasive, sensitive, quantitative evaluation of disease progression in living animals and evaluation of pharmacologic factors in real time. We are able to detect and monitor lymphoma cell growth before the presentation of clinical manifestations. Further this model recapitulates our understanding of behavior of drugs used in the treatment of lymphomas such as pralatrexate which has a rapid onset of action compared to romidepsin that has a delayed time to onset of activity. This represents the first bioluminescent animal model of human CTCL that is intended to be used to investigate novel treatment platforms in preclinical studies. This preclinical model also compliments the ongoing phase 2 trial of pralatrexate in relapsed or refractory CTCL. Further in vivo studies to evaluate synergy of promising new agents in this novel mouse model of SS have begun and will be reported.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A12.