Direct effects of canagliflozin on human myocardial redox signalling: a novel role for SGLT1 inhibition

Background

Recent clinical trials have demonstrated a role for sodium glucose cotransporter 2 (SGLT2) inhibitors in improving cardiovascular outcomes in heart failure patients, but the underlying mechanisms remain unknown. We investigated the direct effects of canagliflozin, a non-selective SGLT1/SGLT2 inhibitor on myocardial redox signalling in humans.

Methods

Study 1 included 364 patients undergoing cardiac surgery. Human right atrial appendage biopsies, obtained during surgery, were used to quantify the sources of superoxide (O2.-) and the gene expression of inflammation, fibrosis and myocardial stretch markers. In Study 2, myocardial biopsies from 51 patients were used ex vivo to study the direct effects of canagliflozin on O2.- generation and understand its role in controlling the activity of NADPH-oxidases and uncoupled nitric oxide synthase (NOS). Finally, we used differentiated H9C2 and human primary cardiomyocytes (hCM) to further characterise the key regulatory mechanisms (Study 3).

Results

SGLT1 was abundantly expressed in the human myocardial biopsies and hCM whilst SGLT2 was barely detectable. SGLT1 expression levels were positively correlated with basal O2.- production and the expression of natriuretic peptides, proinflammatory cytokines and pro-fibrotic markers in human myocardial biopsies from study 1. Incubation of human myocardium with canagliflozin significantly reduced basal and NADPH-oxidase-derived O2.- via AMP kinase (AMPK)-mediated suppression of GTP-activation and consequent reduction of membrane translocation of Rac1, an NADPH-oxidase subunit. This resulted in reduced oxidation and increased bioavailability of tetrahydrobiopterin, the nitric oxide synthase (NOS) co-factor essential for enzymatic coupling, leading to improved NOS coupling. These findings were replicated in hCM, where canagliflozin was shown to regulate AMP/ATP ratio, which could be upstream of AMPK activation. The effects of canagliflozin were significantly attenuated by knocking-down SGLT1 in hCM. Transcriptional profiling of hCM treated with canagliflozin revealed that canagliflozin had striking effects on myocardial redox signalling, causing suppression of apoptotic and inflammatory pathways in the human heart.

Conclusions

We demonstrate for the first time in humans that canagliflozin suppresses myocardial NADPH-oxidase activity and improves NOS coupling through an SGLT1/AMPK/Rac1-mediated pathway, leading to global anti-inflammatory and anti-apoptotic effects in the human myocardium. These findings provide a mechanistic basis for the beneficial effects of SGLT1/2 inhibitors in patients with heart failure.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): 1. British Heart Foundation (FS/16/15/32047 and PG/13/56/30383 to CA, CH/16/1/32013 to KC, and Centre of Research Excellence award RG/13/1/30181), 2. The Japanese Heart Rhythm Society-European Heart Rhythm Association fellowship grant sponsored by Biotronik.

Differential impact of adiposity on risk of atrial fibrillation in men and women in UK Biobank

Background

Atrial fibrillation (AF) and obesity are common conditions with important health implications. Greater adiposity has been associated with higher risk of AF. However, body fat distribution differs between sexes, and the independent effects of different adiposity measures on AF risk remain unclear.

Purpose

To establish the independent effects of general and central adiposity on risk of incident AF in men and women.

Methods

UK Biobank is a prospective study involving 502,536 adults (aged 40–69). Participants underwent an extensive baseline interview and physical assessment (including bio-impedance measurements). Incident AF cases were identified by linkage to national hospital statistics and death registry data. Cox regression models adjusted for age, sex, ethnicity, deprivation, smoking and alcohol, were used to estimate effects of general adiposity (body mass index [BMI] and body fat mass), central adiposity (waist circumference [WC]), and lean mass, on risk of incident AF (per sex-specific standard deviation [SD]).

Results

Among 477,918 participants (mean age 56.4 years, SD 8.1; 45% men) with no history of AF, mean BMI was similar in women (27.0kg/m2, SD 5.0) and men (27.8kg/m2, SD 4.1). Conversely, mean WC was lower in women (84.5cm, SD 12.3) than men (96.8cm, SD 11.0), while mean body fat mass was higher in women (26.9kg, SD 9.8) than men (22.2kg, SD 8.0). A total of 14,362 incident AF events were identified (5,254 in women, 9,108 in men) over 8.1 years median follow-up.

AF was positively associated with adiposity. A 1-SD higher BMI, equivalent to 4.6kg/m2, and a 1-SD higher WC, equivalent to 11.7cm, were each associated with >30% higher risks of AF (hazard ratio [HR] BMI 1.32 [95% CI 1.30–1.34]; WC 1.37 [1.35–1.39]), and showed no sex differences. Lean mass was also strongly associated with AF (1.41 [1.39–1.43]), and similar between sexes. In contrast, a 1-SD higher body fat mass, equivalent to 9.0kg, was associated with a 34% higher risk of AF overall (1.34 [1.32–1.36]), but had a stronger effect in women (1.41 [1.38–1.45]) than men (1.30 [1.28–1.33]), p-interaction 1x10–6; albeit effects were comparable per kg).

After adjustment for body fat mass and lean mass, WC remained positively associated with AF overall (1.19 [1.15–1.23]) and in both sexes (1.14 [1.09–1.20] in women, 1.21 [1.17–1.26] in men). However, following adjustment for lean mass and WC, body fat mass remained positively associated with AF (1.09 [1.06–1.12]) overall, and in women (1.19 [1.14–1.26]) but was almost completely attenuated in men (1.04 [1.01–1.08]), p-interaction 0.004 (Figure). Associations were not materially changed by further adjustment for height, or by excluding those with prior vascular disease.

Conclusions

Central adiposity is strongly and independently associated with AF in both sexes. Conversely, general adiposity is independently associated with risk of AF in women but not men. Suggesting the impact fat distribution on AF risk differs by sex.

Fat mass, waist circumference & AF risk

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Improving prediction of atrial fibrillation: the impact of polygenic risk scores over conventional risk factors amongst 270,000 individuals in UK Biobank

Background

Previous studies have suggested only modest benefits of adding genetic information to conventional risk factors for prediction of atrial fibrillation (AF). However, these studies have been based on limited numbers of AF cases and pre-date recent AF genetic discoveries.

Purpose

To examine the independent relevance of common genetic risk factors over and above established non-genetic risk factors for predicting AF amongst 270,000 participants from UK Biobank, and to determine potential clinical utility.

Methods

UK Biobank (UKB) is a large prospective study of over 500,000 British individuals aged 40 to 69 years at recruitment. Incident AF was ascertained using hospital episode statistics and death registry data. The CHARGE-AF score, which combines the relevance of age, height, weight, blood pressure, use of antihypertensives, diabetes, heart failure, and myocardial infarction (MI) was used to estimate 5-year risk of AF at baseline. A polygenic risk score (PRS) was constructed based on 142 independent variants previously associated with AF in a genome-wide meta-analysis of 60,620 AF cases from the AFGen Consortium, weighted by their published effect sizes. A total of 270,254 individuals were analysed after exclusions for genetic QC, non-White British ancestry, and prevalent AF. Cox proportional hazard models were used to estimate associations between risk scores (based on standard deviation [SD] units) and incident AF. Standard methods were used to assess predictive value.

Results

During a median follow-up of 8.1 years, 12,407 incident AF cases were identified. The CHARGE-AF risk score strongly predicted incident AF in UK Biobank, and was associated with a ∼3-fold higher risk of AF per SD (Hazard ratio [HR]=2.88; 95% CI: 2.82–2.94). The PRS was associated with a 54% higher risk of AF per SD (HR=1.54; 95% CI: 1.51–1.57). The independent impact of the PRS, after adjusting for the CHARGE-AF score, was unchanged and remained strongly predictive (HR=1.57, 95% CI: 1.54–1.60), with participants in the upper tertile of the PRS having more than a 2.5-fold higher risk (HR=2.59, 95% CI: 2.47–2.71) when compared with those in the lower tertile. The addition of the PRS improved the C-statistic from 0.758 (CHARGE-AF alone) to 0.783 (Δ=0.025) and correctly reclassified 8.7% of cases and 2.6% of controls at 5 years. Both non-genetic and genetic risk scores were well-calibrated in the UK Biobank participants, and sensitivity of the results to alternative PRS selection approaches and age at risk were also examined.

Conclusion

In a large prospective cohort, genetic determinants of AF were independent of conventional risk factors and significantly improved prediction over a well-validated clinical risk algorithm. This illustrates the potential added benefit of genetic information to identify higher-risk individuals who may benefit from earlier monitoring and personalised risk management strategies.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Potential survival benefit for patients receiving autologous hematopoietic stem cell transplantation after checkpoint inhibitors for relapsed/refractory Hodgkin lymphoma: A real-life experience

In recent years, novel drugs are available for the patients with relapsed/refractory Hodgkin lymphoma (HL), like immune checkpoint inhibitors (CPi). These drugs have been able to rescue a cohort of patients who subsequently could receive an allogeneic stem-cell transplant (SCT). No data were reported for subsequent autologous SCT (ASCT) after CPi. Here, we report our real-life experience in heavily pretreated HL patients undergoing ASCT as consolidation approach after CPi treatment. A retrospective observational study was conducted. Patients had CPi therapy in the context of clinical trials (n = 6) or in the named patient program (n = 7) between July 2014 and November 2019: 9 out of 13 received pembrolizumab and the remaining four underwent nivolumab. A median of 12 cycles (range, 3-16) of CPi therapy were infused. Thirteen patients underwent ASCT after CPi: 11 (84.6%) patients obtained a complete response (CR) and 2 had progression of disease, with an overall response rate of 84.6%. With a median follow-up of 3.3 years (range, 1.1-5.5), only one CR patient had disease relapse after 3.9 months from ASCT, leading to an estimated disease-free survival of 87.5% at 56.9 months. The estimated 5-year progression-free survival was 73.4% and overall survival was 92.3% at 4.8 years, respectively. No unexpected or cumulative toxicity was observed. Our results indicated that ASCT may represent a further effective therapeutic option as consolidation in HL after CPi treatment that today represents the last conventionally recognized therapeutic line.

Effectiveness of chemotherapy after anti-PD-1 blockade failure for relapsed and refractory Hodgkin lymphoma

Programmed death‐1 (PD1) blockade is an efficient and safe therapeutic option in patients with relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL). However, a substantial proportion of patients’ progresses or loses the response to anti‐PD1 treatment. We retrospectively investigated the effectiveness of salvage chemotherapies (CHT) for unsatisfactory response to anti‐PD1, in 25 R/R cHL patients. Twenty‐three patients (92%) were refractory to the last treatment before anti‐PD1. After a median of 14 cycles (range 3‐52), 68% (17/25) of patients had unsatisfactory responses to anti‐PD1 therapy, whereas 6 had a partial response (PR) and 2 patients achieved complete response (CR), with an overall response rate (ORR) of 32%. After a median time of 1.5 months, 15 patients received a single agent treatment and 10 had a multi‐agents regimen, due to the failure of PD1 blockade. The ORR was 60% (8 CR and 7 PR). Seven patients (3 in PR and 4 in CR) underwent a consolidation strategy with stem cell transplantation. Median progression‐free survival (PFS) with salvage treatment was reached at 19.1 months, while median PFS after anti‐PD1 has been reached at 8.2 months. After a median follow‐up of 32.4 months, 6 patients died while 13 are still in CR. The median overall estimated from the start of CHT was not reached. The efficacy of treatment following anti‐PD1 is not yet established, especially in lymphoma patients. To note, in our series, a subset of heavily pre‐treated and chemo‐refractory patients increased response rates to and survival with CHT given after exposure to immune‐checkpoint inhibitors.

Abstract 2682: Extrafollicular high CD163/CD8 ratio is associated with progression of disease within 24 months in follicular lymphoma patients

Follicular lymphoma (FL) still remains an incurable disease, with most of the patients undergoing subsequent phases of remission and relapse.

In the era of immunotherapy, understanding the immunobiology of FL patients who experience progression of disease within 24 months (POD24) and show chemotherapy resistance remains a priority and an unmet clinical need.

Tumor-associated macrophages (TAM) are multifaceted cellular components of the tumor microenvironment (TME). In concert with lymphoid-lineage B and T cells at various developmental stages, TAM can mediate enhanced tumor progression, often leading to poor clinical prognosis and impact the clinical response to chemotherapy. Recently, Joshua and colleagues demonstrated that a subset of FL patients with low immune infiltration was enriched in POD24 events.

In our work, we characterized the immune repertoire of lymph node biopsies collected retrospectively from 30 patients with histological diagnosis of FL according WHO criteria. Median follow up was 8 years. The expression levels of TAM (CD68, CD163, MS4a4a) and tumor-infiltrating T-lymphocytes (CD8, PD-1 positive subsets) were assessed by immunohistochemistry and summarized using descriptive statistics.

Our data highlighted that the subset of patients with a high extrafollicular CD163/CD8 ratio was enriched in POD24 events (p = 0.01). In addition, patients who showed an higher number of intrafollicular CD68+ macrophages, showed a longer disease free survival (p= 0.04).

Another difference was related to the number of CD68, CD163, MS4A4A-positive polarized macrophages that resulted higher in bcl-2 negative than bcl-2 positive cases (p< 0.05 for all markers).

In the evaluation of T lymphocytes, most relevant associations were found between the content and distribution of PD1+ cells and the treatment response: the higher the number of intrafollicular PD1+ lymphocytes the lower chemotherapy response rates (p= 0.04). No association was found between the number of positive elements in extrafollicular areas, where instead the PD1/CD8 ratio seems to be related with therapy response: the higher the ratio the lower response rate (p= 0.01). This finding could be explained assuming that there may be different types of cellular interactions inside and outside the neoplastic follicles.

No other statistically significant difference in terms of expression of these markers was observed in relation to clinical pathological features such as staging, grade and FLIPI score.

In conclusion, extrafollicular high CD163/CD8 ratio is associated with POD24 in FL patients, this finding underlines the pathological significance of CD163-expresing macrophages in TME, suggesting this biomarker as a potential therapeutic target in this disease.

Citation Format: Clara Bertuzzi, Maria Maddalena Tumedei, Sara Ravaioli, Claudio Agostinelli, Maurizio Puccetti, Sara Bravaccini, Simona Righi, Beatrice Casadei, Andrea Pession, Giovanni Martinelli, Giorgia Simonetti, Elena Sabattini, Serena De Matteis. Extrafollicular high CD163/CD8 ratio is associated with progression of disease within 24 months in follicular lymphoma patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2682.

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.

Bendamustine-rituximab regimen in untreated indolent marginal zone lymphoma: experience on 65 patients

First line therapy of patients with marginal zone lymphomas (MZL) is not well established and various regimens with chemo-immunotherapy can be used. Rituximab plus bendamustine (BR) is an effective and manageable treatment option for patients affected by indolent non-Hodgkin lymphoma. The aim of this monocentric retrospective study was to analyze the effectiveness and safety of the use of BR regimen in MZL patients in first line in daily clinical practice. The treatment schedule was rituximab at the dose of 375 mg/m² on day 1 of each cycle and bendamustine at the dose of 90 mg/m² on day 2 and 3, every 28 days for a maximum of 6 cycles. We analyzed 65 MZL patients (28 extranodal [EMZL], 23 splenic [SMZL], and 14 nodal [NMZL]) who underwent BR regimen as first line treatment. The median time from diagnosis to therapy was 2.5 months. Final responses were: 38 complete response (CR, 58.5%), 20 partial response and 7 progressive disease, leading to an overall response rate (ORR) of 89.2%. With respect to the histology, the ORR was 89.3% for EMZL, 82.6% for SMZL and 100% for NMZL, respectively (difference not statistically significant). With a median follow-up time of 44.6 months (range, 3.3-175.0 months), 2 (one EMZL after 42 months and one SMZL after 10 months) of 38 (5.2%) CR patients had disease relapse, yielding an estimated disease free survival of 89.2% at 61.1 months. The estimated 6-year progression free survival was 71.8% with 15 relapsed/progressed patients showing lymphoma recurrence within 48 months from end of treatment. The most frequently reported adverse events (any grade) were neutropenia (N = 35, 53.8%), fatigue (N = 15, 23.0%), and nausea (N = 12, 18.4%). All toxicities quickly resolved and no treatment-related death occurred. The BR regimen is effective and feasible in MZL patients inducing prolonged disease control with manageable toxicities.

Management of central nervous system relapse in a young patient affected by primary mediastinal large B-cell lymphoma: A case report

In primary mediastinal large B-cell lymphoma, central nervous system (CNS) relapse is an uncommon event with a dismal prognosis. We report about the successful management of CNS relapse with chemoimmunotherapy according to MATRix (methotrexate, cytarabine, thiotepa, and rituximab) protocol followed by autologous stem cell transplant.

Elderly Non-GCB Diffuse Large B-Cell Lymphoma Patient Responding to Lenalidomide after Epicardial Relapse: A Case Report

There is an unmet clinical need for elderly or unfit diffuse large B-cell lymphoma (DLBCL) patients ineligible for autologous stem cell transplantation. Lenalidomide is an immunomodulatory agent with antitumor activity in non-Hodgkin lymphoma, with an acceptable toxicity profile and manageable side effects. A 79-year-old Caucasian male with non-germinal center B-cell-like DLBCL achieved complete remission (CR) after first-line treatment with seven out of eight scheduled cycles of a polychemotherapy containing anthracycline, which had to be discontinued early due to the onset of atrial fibrillation. After 5 months, the patient had an early epicardial relapse. He underwent lenalidomide considering age, cardiological comorbidities, and chronic renal failure. After the third cycle, he achieved CR, confirmed at restaging after the sixth cycle of treatment. Lenalidomide was safe and well tolerated in a patient with atrial fibrillation developed after an anthracycline-based regimen and a relapse of the DLBCL. Moreover, this regimen was effective in a case with a rare extranodal involvement of the epicardium.

Dissection of DLBCL microenvironment provides a gene expression-based predictor of survival applicable to formalin-fixed paraffin-embedded tissue

Background

Gene expression profiling (GEP) studies recognized a prognostic role for tumor microenvironment (TME) in diffuse large B-cell lymphoma (DLBCL), but the routinely adoption of prognostic stromal signatures remains limited.

Patients and methods

Here, we applied the computational method CIBERSORT to generate a 1028-gene matrix incorporating signatures of 17 immune and stromal cytotypes. Then, we carried out a deconvolution on publicly available GEP data of 482 untreated DLBCLs to reveal associations between clinical outcomes and proportions of putative tumor-infiltrating cell types. Forty-five genes related to peculiar prognostic cytotypes were selected and their expression digitally quantified by NanoString technology on a validation set of 175 formalin-fixed, paraffin-embedded DLBCLs from two randomized trials. Data from an unsupervised clustering analysis were used to build a model of clustering assignment, whose prognostic value was also assessed on an independent cohort of 40 cases. All tissue samples consisted of pretreatment biopsies of advanced-stage DLBCLs treated by comparable R-CHOP/R-CHOP-like regimens.

Results

In silico analysis demonstrated that higher proportion of myofibroblasts (MFs), dendritic cells, and CD4⁺ T cells correlated with better outcomes and the expression of genes in our panel is associated with a risk of overall and progression-free survival. In a multivariate Cox model, the microenvironment genes retained high prognostic performance independently of the cell-of-origin (COO), and integration of the two prognosticators (COO + TME) improved survival prediction in both validation set and independent cohort. Moreover, the major contribution of MF-related genes to the panel and Gene Set Enrichment Analysis suggested a strong influence of extracellular matrix determinants in DLBCL biology.

Conclusions

Our study identified new prognostic categories of DLBCL, providing an easy-to-apply gene panel that powerfully predicts patients’ survival. Moreover, owing to its relationship with specific stromal and immune components, the panel may acquire a predictive relevance in clinical trials exploring new drugs with known impact on TME.

1348Impact of genetically determined differences in ECG parameters on risk of AF in c. 300,000 UK Biobank participants

Background

An abnormal electrical substrate has been associated with atrial cardiomyopathy, atrial fibrillation (AF), and other supraventricular tachycardias (SVT). However, many risk factors for AF influence ECG parameters, potentially confounding the association. As ECG intervals are highly heritable, using genetic scores as proxies limits confounding and the effects of reverse causation.

Purpose

To establish the nature of any causal relationship between ECG parameters and risk of AF using Mendelian randomisation (MR) techniques.

Methods

Genetic scores for P-wave duration, PR interval and QT interval were constructed from published genome-wide association studies and logistic regression models used to estimate their associations with AF using individual participant data in UK Biobank (UKB) (15,311 AF cases and 262,320 controls). Validation was performed using summary data from the AFGEN consortium (15,979 AF cases and 102,776 controls). Sensitivity analyses exploring the impact of potential pleiotropy were performed using conventional MR techniques (e.g. weighted median, MR-Egger etc).

Results

As expected, the genetic scores were strongly associated with their specified ECG parameters. Longer genetically determined P-wave and PR interval durations were associated with lower risks of AF. By contrast, a longer genetically determined QT interval was not associated with AF risk (Figure). To investigate the role of changes in electrical pathways affecting the ECG and AF risk, scores for each parameter were generated limited to genetic proxies associated with genes for known ion channels. Ion channel limited scores lowered risks of AF per 5ms increases in P-wave duration (odds ratio [OR]: 0.83; 95% confidence interval [CI]: 078–0.89, P=2×10–8) and PR interval (OR: 0.92; 95% CI: 0.90–0.95, P=4×10–10) with no change in AF risk with longer score for QT interval (OR: 0.99; 95% CI: 0.96–1.03, P=0.68). These effects were consistently replicated in the AFGEN dataset and multiple sensitivity analyses supported the conclusions.

To test associations between the ECG genetic scores and a specific AF subtype, 3,843 participants with AF but without known coronary heart disease, heart failure, hypertension or diabetes and 273,788 controls were identified. Overall odds ratio estimates were similar to the primary outcomes for each of the ECG parameters investigated (Figure).

To investigate the effects of altered electrical substrate on other related arrhythmias, 2,621 cases of SVT and 275,010 controls were identified. Longer genetic P-wave and PR intervals were associated with lower risks of SVT. The genetic QT interval was not associated with SVT risk (Figure).

Figure 1

Conclusions

Genetically determined ECG parameters associated with shorter atrial electrical conduction times increased risk of AF and SVT. These findings provide a novel mechanistic insight into understanding the underlying pathophysiology of AF and potential development of therapeutic strategies.

Acknowledgement/Funding

British Heart Foundation

2161Redox-mediated PKA-RIalpha localisation to the lysosome inhibits myocardial calcium release and robustly reduces myocardial injury

Background

Kinase oxidation is a critical signalling mechanism through which changes in the intracellular redox state alter cardiac function. In the myocardium, type-1 protein kinase A (PKARIα) can be reversibly oxidised, forming interprotein disulphide bonds within the holoenzyme complex. However, the effect of PKARIα oxidation on downstream signalling in the heart, particularly under states of oxidative stress, remains unexplored.

Purpose

To determine the direct functional consequences of PKARIα oxidation in the heart and investigate their impact on ischaemia/reperfusion (I/R) injury.

Methods and results

Experiments using the AKAR3ev FRET biosensor in murine left ventricular (LV) myocytes and Fluorescence Recovery After Photobleaching (FRAP) of GFP-tagged wild-type (WT) and mutant RIα proteins expressed in RIα-null fibroblasts showed that PKARIα oxidation does not increase the kinases' catalytic activity, but enhances its binding to A-kinase anchoring proteins (AKAP; n=30–39/N=3, p<0.01). Super-resolution microscopy revealed localisation of oxidised PKARIα to lysosomes in WT myocytes, which was completely absent in “redox dead” Cys17Ser PKARIα knock-in mice (KI; panel A; n=38–41/N=3, p<0.01) and reduced when AKAP binding was prevented using the RIAD disruptor peptide (30.6±5.1% reduction; n=35–37/N=3, p<0.01).

Displacement of PKARIα from lysosomes resulted in spontaneous sarcoplasmic reticulum calcium release and dramatic calcium oscillations in KI LV myocytes (panel B), which were preventable by ryanodine receptor blockade (1 mM tetracaine; n=14, p<0.01), acute depletion of endolysosomal calcium stores (100 nM bafilomycin; n=7; p<0.01), or lysosomal two-pore channel inhibition (5 μM Ned-19; n=9; p<0.05).

I/R (secondary to cardiopulmonary bypass) was found to induce PKARIα oxidation in the myocardium of patients undergoing cardiac surgery (panel C; n=18, p<0.05). Absence of this response in KI mouse hearts resulted in 2-fold larger infarcts (p<0.01) and a concomitant reduction in LV contractile recovery (final LVDP of 55.9±8.6 vs 82.5±7.1 mmHg in WT; n=7–8, p<0.05), both which were prevented by addition of Ned-19 at the time of reperfusion (panel D; n=4, p<0.01).

Conclusions

Oxidised PKARIα acts as a potent inhibitor of intracellular calcium release in the heart through its redox-dependent interaction with the lysosome. In the setting of I/R, where PKARIα oxidation is induced, this regulatory mechanism is critical for protecting the heart from injury and offers a novel target for the design of cardioprotective therapeutics.

Acknowledgement/Funding

British Heart Foundation CH/12/3/29609, RG/16/12/32451; Garfield-Weston Foundation MPS/IVIMS-11/12-4032; Wellcome Trust Fellowship 0998981Z/12/Z

P5662Development of a prognostic model for prevalent atrial fibrillation using individual patient data: Results of CATCH ME

Background/Introduction

Atrial fibrillation (AF) can be challenging to diagnose due to asymptomatic and paroxysmal presentation. Identifying prognostic factors of AF would elucidate potential mechanisms causing AF and refine screening for at risk patients.

Purpose

To identify the main predictors of AF and to develop a prognostic model for prevalent AF.

Methods

Data of 120 potential predictors were harmonised in individual patient data from 4 independent European studies. A three stage Delphi expert consensus process identified predictors based on clinical knowledge. The predictors were further reduced using statistical selection (backward elimination), and a logistic regression model was fitted. We calculated odds ratios (OR) for each of the selected predictors and evaluated model performance using the C-statistic.

Results

Overall, 2420 patients (mean [standard deviation] age = 62.7 [14.5] years, 35.6% female, 43.1% with AF) were included in the analysis. Thirty-one potential predictors identified from the Delphi process which had sufficient data across all datasets were modelled. Of these 14 were deemed prognostic in predicting AF (age, sex, BMI, height, hypertension, diabetes, history of coronary artery disease, left atrial volume, left ventricular end systolic diameter, abnormality on echo, tricuspid valve disease of at least moderate intensity, aldosterone-antagonists, beta-blockers and P2Y12 blockers; see Figure 1). There was a clear interaction between age and sex indicating that males are at higher risk than females early in life, while females are at increased risk of AF at older age (Figure 1). The risk prediction model combining these prognostic factors performed well (C-statistic 0.79; 95% CI 0.77–0.81).

Figure 1. (a) Forest plot; (b) Interaction

Conclusion(s)

Our preliminary analysis identified important prognostic factors and a complex relationship between age and sex, which predicts prevalent AF, highlighting the different potential causes of AF in different patients. There is a clear need to validate these factors in external datasets and for further investigation into the molecular mechanism underlying these factors.

Acknowledgement/Funding

European Commission H2020 framework

Lenalidomide in Pretreated Patients with Diffuse Large B-Cell Lymphoma: An Italian Observational Multicenter Retrospective Study in Daily Clinical Practice

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma subtype, and approximately 50% of the patients are >60 years of age. Patients with relapsed/refractory (rr) disease have a poor prognosis with currently available treatments. Lenalidomide is available in Italy for patients with rrDLBCL based on a local disposition of the Italian Drug Agency.

SUBJECTS, MATERIALS, AND METHODS

An observational retrospective study was conducted in 24 Italian hematology centers with the aim to improve information on effectiveness and safety of lenalidomide use for rrDLBCL in real practice.

RESULTS

One hundred fifty-three patients received lenalidomide for 21/28 days with a median of four cycles. At the end of therapy, there were 36 complete responses (23.5%) and 9 partial responses with an overall response rate (ORR) of 29.4%. In the elderly (>65 years) subset, the ORR was 33.6%. With a median follow-up of 36 months, median overall survival was reached at 12 months and median disease-free survival was not reached at 62 months. At the latest available follow-up, 29 patients are still in response out of therapy. Median progression-free survivals differ significantly according to age (2.5 months vs. 9.5 in the younger vs. elderly group, respectively) and to disease status at the latest previous therapy (15 months for relapsed patients vs. 3.5 for refractory subjects). Toxicities were manageable, even if 30 of them led to an early drug discontinuation.

CONCLUSION

Lenalidomide therapy for patients with rrDLBCL is effective and tolerable even in a real-life context, especially for elderly patients.

IMPLICATIONS FOR PRACTICE

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma, and approximately 50% of the patients are >60 years of age. Patients with relapsed/refractory (rr) disease have a poor prognosis, reflected by the remarkably short life expectancy of 12 months with currently available treatments. The rrDLBCL therapeutic algorithm is not so well established because data in the everyday clinical practice are still poor. Lenalidomide for patients with rrDLBCL is effective and tolerable even in a real-life context, especially for elderly patients.

A case report of the long treatment experience of a Sézary syndrome responder patient: 16 years through all the systemic and innovative therapies

Existing therapies for Sézary syndrome (SS) are limited in efficacy and in disease control, and patients have very poor prognosis. Here, we report a case report of a patient who has a 16-year history of SS and related treatments (both standard and experimental). In particular, two drugs, one conventional (gemcitabine) and one experimental (mogamulizumab), were able to induce long lasting response. Patient refused to undergo allogeneic stem cell transplantation. After eleven lines of therapeutic approaches, the patient is in very good partial response and free of therapy at the latest available follow-up.

Italian real life experience with ibrutinib: results of a large observational study on 77 relapsed/refractory mantle cell lymphoma

Although sometimes presenting as an indolent lymphoma, mantle cell lymphoma (MCL) is an aggressive disease, hardly curable with standard chemo-immunotherapy. Current approaches have greatly improved patients' outcomes, nevertheless the disease is still characterized by high relapse rates. Before approval by EMA, Italian patients with relapsed/refractory MCL were granted ibrutinib early access through a Named Patient Program (NPP). An observational, retrospective, multicenter study was conducted. Seventy-seven heavily pretreated patients were enrolled. At the end of therapy there were 14 complete responses and 14 partial responses, leading to an overall response rate of 36.4%. At 40 months overall survival was 37.8% and progression free survival was 30%; disease free survival was 78.6% at 4 years: 11/14 patients are in continuous complete response with a median of 36 months of follow up. Hematological toxicities were manageable, and main extra-hematological toxicities were diarrhea (9.4%) and lung infections (9.0%). Overall, 4 (5.2%) atrial fibrillations and 3 (3.9%) hemorrhagic syndromes occurred. In conclusions, thrombocytopenia, diarrhea and lung infections are the relevant adverse events to be clinically focused on; regarding effectiveness, ibrutinib is confirmed to be a valid option for refractory/relapsed MCL also in a clinical setting mimicking the real world.

Impressive Response to Pixantrone after Allogeneic Transplant in a Multiple Relapsed Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma is the most frequent histology at diagnosis among non-Hodgkin B lymphomas and can be cured in 50-70% of cases after the first-line chemotherapy regimen. Patients who do not respond to first-line treatment can undergo numerous subsequent steps, culminating in allogeneic stem cell transplant (alloSCT). A relapse after alloSCT, however, carries an awful prognosis, seeing the demise of the patient usually in the following months. Here we present the case of a multiple relapsed patient who successfully underwent therapy with pixantrone after alloSCT, obtaining a complete remission without any considerable side effects.

The treatment of primary mediastinal large B-cell lymphoma: a two decades monocentric experience with 98 patients

Background

The purpose of this study is to investigate the most suitable first-line approach and the best combination treatment for primary mediastinal large B-cell lymphoma (PMLBCL) as they have been matter of debate for at least two decades.

Methods

Our single centre experience in the treatment of 98 de novo PMLBCL patients over the last 20 years is reviewed. All patients received MACOP-B chemotherapy. Thirty-seven received both rituximab and mediastinal radiotherapy; 30 were irradiated after chemotherapy, although not receiving rituximab and 20 received rituximab without radiotherapy consolidation. Eleven patients received chemotherapy only.

Results

Sixty-one (62.2%) patients achieved a complete response after MACOP-B (with or without rituximab); among the 27 (27.6%) partial responders, 21 obtained a complete response after radiotherapy. At the end of their scheduled treatment, 82 patients (83.7%) had a complete and 6 a partial response (6.1%). Eleven patients relapsed within the first 2 years of follow-up. The 17-year overall survival is 72.0% (15 patients died); progression-free and disease-free survival are 67.6% and 88.4%, respectively. A statistically significant difference in overall and progression-free survival was noted among treatment groups, although no disease-free survival difference was documented.

Conclusions

Our data indicate that a third-generation regimen like MACOP-B could be considered a suitable first-line treatment. Mediastinal consolidation radiotherapy impacts on survival and complete response rates and remains a good strategy to convert partial into complete responses. Data suggest that radiotherapy may be avoided in patients obtaining a complete response after (immuno)chemotherapy, but this requires confirmation with further ad hoc studies.

Long-Term Responders After Brentuximab Vedotin: Single-Center Experience on Relapsed and Refractory Hodgkin Lymphoma and Anaplastic Large Cell Lymphoma Patients

BACKGROUND

Brentuximab vedotin (BV) has shown high overall response rate in refractory/relapsed Hodgkin lymphoma (HL) and systemic anaplastic large cell lymphoma (sALCL) with reported long-term response duration in clinical trials, but few data are available regarding its role in long-term outcomes in real life.

PATIENTS AND METHODS

A single-center observational study was conducted on patients treated with BV in daily clinical practice to evaluate the long-term effectiveness of BV in HL and sALCL patients and to check whether clinical trial results are confirmed in a real-life context.

RESULTS

The best response rate in the treated 53 patients (43 HL and 10 sALCL) was 69.8% (with 46.5% complete response [CR]) in HL and 100% (80% CR) for sALCL, respectively. With a median patient follow-up of 36.8 months, the estimated median duration of response was 31.5 months for HL and 17.8 for sALCL, respectively. At the latest available follow-up, 75% of patients were still in response, with 43% without any consolidation. Toxicity was primarily neurological and it was rarely so serious to require dose reduction or interruption. In addition, it always reversed completely after the end of treatment.

CONCLUSION

Our data showed that 51% of patients treated with BV can be regarded as "long-term responders." Among these cases, for all patients who underwent stem cell transplantation immediately after BV, the procedure was consolidative. For patients who have remained in continuous CR without any consolidation after therapy, BV can induce prolonged disease control.

IMPLICATIONS FOR PRACTICE

Brentuximab vedotin (BV) has shown a high overall response rate in refractory/relapsed Hodgkin lymphoma and systemic anaplastic large cell lymphoma, with reported long-term response duration in clinical trials, whereas few data are available regarding its role in long-term outcomes in real life. The data reported in this study suggest that BV can induce the same results in daily clinical practice. The data showed that 51% of patients treated with BV can be regarded as "long-term responders." Among these cases, BV can induce prolonged disease control in patients who have remained in continuous complete response without any consolidation after the drug.

90-yttrium-ibritumomab tiuxetan consolidation of fludarabine, mitoxantrone, rituximab in intermediate/high-risk follicular lymphoma: updated long-term results after a median follow-up of 7 years

Radioimmunotherapy (RIT) after an induction phase with conventional chemoimmunotherapy became an attractive strategy of consolidation for patients with advanced follicular lymphoma: in particular, in many studies RIT was represented by yttrium-90-ibritumomab tiuxetan ((90) Y-IT). Independently by the different front-line treatment, updates on the long-term follow-up of these studies are needed because the disease course of follicular lymphoma is characterised by multiple relapses and progressively shorter durations of response. We report updated long-term efficacy and toxicity results of a multicenter phase II study on sequential treatment with four cycles of fludarabine, mitoxantrone, and rituximab followed by (90) Y-IT as front-line therapy for untreated patients with intermediate/high-risk follicular lymphoma. With a median follow-up of 84 months, only 19/49 (38.8%) complete response patients relapsed, yielding an estimated long-term disease-free survival of 62.6%. The 7-year overall survival was 72.7%. Four (7.3%) second acute myeloid leukemia occurred, with a median time following RIT of 42 months. A relevant patients' responsiveness to subsequent therapies occurred: approximately 65% of relapsed patients obtained a good clinical response after the second-line treatment. These data represented the first evidence of a real role even in the long period of 90Y-IT after a fludarabine-containing regimen plus rituximab in the treatment of high-risk follicular lymphoma.

Constitutive activation of the DNA damage response pathway as a novel therapeutic target in diffuse large B-cell lymphoma

The recent finding that MYC-driven cancers are sensitive to inhibition of the DNA damage response (DDR) pathway, prompted us to investigate the role of DDR pathway as therapeutic target in diffuse large B-cell lymphoma (DLBCL), which frequently overexpresses the MYC oncogene. In a preliminary immunohistochemical study conducted on 99 consecutive DLBCL patients, we found that about half of DLBCLs showed constitutive expression of the phosphorylated forms of checkpoint kinases (CHK) and CDC25c, markers of DDR activation, and of phosphorylated histone H2AX (γH2AX), marker of DNA damage and genomic instability. Constitutive γH2AX expression correlated with c-MYC levels and DDR activation, and defined a subset of tumors characterised by poor outcome. Next, we used the CHK inhibitor PF-0477736 as a tool to investigate whether the inhibition of the DDR pathway might represent a novel therapeutic approach in DLBCL. Submicromolar concentrations of PF-0477736 hindered proliferation in DLBCL cell lines with activated DDR pathway. These results were fully recapitulated with a different CHK inhibitor (AZD-7762). Inhibition of checkpoint kinases induced rapid DNA damage accumulation and apoptosis in DLBCL cell lines and primary cells. These data suggest that pharmacologic inhibition of DDR through targeting of CHK kinases may represent a novel therapeutic strategy in DLBCL.

High efficacy of the MACOP-B regimen in the treatment of adult Langerhans cell histiocytosis, a 20 year experience

BACKGROUND

Adult Langerhans cell histiocytosis (LCH) is an orphan disease. Chemotherapy is usually reserved to patients presenting with single system multifocal (SS-m) or multisystem (MS) disease but due to the lack of randomized studies no standard first line therapy has been defined yet. Pediatric regimens based on the vinblastine/prednisone backbone are not well tolerated in adults and probably less effective. We previously demonstrated high efficacy of the dose dense polichemotherapy regimen MACOP-B in 7 adult patients with SS-m or MS-LCH, in terms of high response rate and durable responses. Here we report an update of these data with the purpose of evaluating the long term efficacy of MACOP-B in adult LCH.

METHODS

Clinical data of all adult LCH patients (n = 17) diagnosed and treated at our Institution during the past 20-year period were retrospectively reviewed.

RESULTS

A total of 11 patients (6 with SS-m and 5 with MS-LCH) were treated with MACOP-B from 1995 to 2014. The overall response rate was confirmed to be 100 %, with a complete response of 73 % and a partial response rate of 27 %. Overall progression free survival was 64 %, and disease free survival after achievement of initial CR was 87 %. Overall survival rate was 82 % after 6.7 years of median follow-up.

CONCLUSIONS

These data confirm high activity of MACOP-B in adult LCH, indicating that a substantial fraction of patients achieve long lasting responses and can be cured with this therapeutic approach.

Therapeutic implications of intratumor heterogeneity for TP53 mutational status in Burkitt lymphoma

Therapeutic implications of intra-tumor heterogeneity are still undefined. In this study we report a genetic and functional analysis aimed at defining the mechanisms of chemoresistance in a 43-year old woman affected by stage IVB Burkitt lymphoma with bulky abdominal masses and peritoneal effusion. The patient, despite a transient initial response to chemotherapy with reduction of the bulky masses, rapidly progressed and died of her disease. Targeted TP53 sequencing found that the bulky mass was wild-type whereas peritoneal fluid cells harbored a R282W mutation. Functional studies on TP53 mutant cells demonstrated an impaired p53-mediated response, resistance to ex vivo doxorubicin administration, overexpression of DNA damage response (DDR) activation markers and high sensitivity to pharmacologic DDR inhibition. These findings suggest that intra-tumor heterogeneity for TP53 mutational status may occur in MYC-driven cancers, and that DDR inhibitors could be effective in targeting hidden TP53 mutant clones in tumors characterized by genomic instability and prone to intra-tumor heterogeneity.

Hypertension in the military patient

Hypertension and hypertension-related diseases are a leading cause of morbidity and mortality worldwide. A diagnosis of hypertension can have serious occupational implications for military personnel. This article examines the diagnosis and management of hypertension in military personnel, in the context of current international standards. We consider the consequences of hypertension in the military environment and potential military-specific issues relating to hypertension.

The role of rituximab and positron emission tomography in the treatment of primary mediastinal large B-cell lymphoma: experience on 74 patients

Regarding primary mediastinal large B-cell lymphoma (PMLBCL), there are several controversial topics that warrant further investigation: the superiority of third-generation regimens, the impact of rituximab, the use of involved field radiotherapy (RT) and the assessment of clinical response by positron emission tomography (PET). We report our experience on 74 PMLBCL patients treated with a combination of a third-generation chemotherapy regimen (MACOP-B) and rituximab: an observational retrospective single-centre study was conducted on patients diagnosed and treated between February 2002 and July 2011. All patients were evaluated by computed tomography scan and PET scan; after the final PET evaluation, PET-negative patients were observed, whereas PET-positive patients underwent mediastinal RT. Sixty-one (82.4%) patients achieved a complete response after the MACOP-B plus rituximab regimen; 68.9% presented a positive final PET and were treated with local RT, whereas 31.1% had a negative PET. Five patients relapsed within 12 months. At 10 years, overall survival was 82%, progression-free survival was 87.6% and disease-free survival (DFS) was 90.5% (median follow-up 4 years). No statistically significant differences were observed in DFS between the patients treated also with RT (PET positive) and patients only observed (PET negative): 90.7% vs 90% (p = 0.85), respectively. In our experience, adding rituximab does not change the final results in terms of complete response and DFS utilizing third-generation regimen. Furthermore, the introduction of the PET-guided RT approach leads to a patient-tailored treatment, which preserves the outcome and, at the same time, allows reducing the use of RT.