Valvulopathy Research Articles

Nonclinical Profile of PF-06952229 (MDV6058), a Novel TGFβRI/Activin Like Kinase 5 Inhibitor Supports Clinical Evaluation in Cancer.

The development of transforming growth factor βreceptor inhibitors (TGFβRi) as new medicines has been affected by cardiac valvulopathy and arteriopathy toxicity findings in nonclinical toxicology studies. PF-06952229 (MDV6058) selected using rational drug design is a potent and selective TGFβRI inhibitor with a relatively clean off-target selectivity profile and good pharmacokinetic properties across species. PF-06952229 inhibited clinically translatable phospho-SMAD2 biomarker (≥60%) in human and cynomolgus monkey peripheral blood mononuclear cells, as well as in mouse and rat splenocytes. Using an optimized, intermittent dosing schedule (7-day on/7-day off/cycle; 5 cycles), PF-06952229 demonstrated efficacy in a 63-day syngeneic MC38 colon carcinoma mouse model. In the pivotal repeat-dose toxicity studies (rat and cynomolgus monkey), PF-06952229 on an intermittent dosing schedule (5-day on/5-day off cycle; 5 cycles, 28 doses) showed no cardiac-related adverse findings. However, new toxicity findings related to PF-06952229 included reversible hepatocellular (hepatocyte necrosis with corresponding clinically monitorable transaminase increases) and lung (hemorrhage with mixed cell inflammation) findings at ≥ targeted projected clinical efficacious exposures. Furthermore, partially reversible cartilage hypertrophy (trachea and femur in rat; femur in monkey) and partially to fully reversible, clinically monitorable decreases in serum phosphorus and urinary phosphate at ≥ projected clinically efficacious exposures were observed. Given the integral role of TGFβ in endochondral bone formation, cartilage findings in toxicity studies have been observed with other TGFβRi classes of compounds. The favorable cumulative profile of PF-06952229 in biochemical, pharmacodynamic, pharmacokinetic, and nonclinical studies allowed for its evaluation in cancer patients using the intermittent dosing schedule (7-day on/7-day off) and careful protocol-defined monitoring. SIGNIFICANCE STATEMENT: Only a few TGFβRi have progressed for clinical evaluation due to adverse cardiac findings in pivotal nonclinical toxicity studies. The potential translations of such findings in patients are of major concern. Using a carefully optimized intermittent dosing schedule, PF-06952229 has demonstrated impressive pharmacological efficacy in the syngeneic MC38 colon carcinoma mouse model. Additionally, a nonclinical toxicology package without cardiovascular liabilities and generally monitorable toxicity profile has been completed. The compound presents an acceptable International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use S9-compliant profile for the intended-to-treat cancer patients.

Preclinical mitigation of 5-HT2B agonism-related cardiac valvulopathy revisited

Cardiac valvulopathy (Cardiac Valve Disease; CVD) associated with off-target activation of the 5-hydroxytryptamine (5-HT) 2B receptor has been well recognized, but is still poorly predicted during drug development. The regulatory guidance proposes the use of 5-HT2B binding data (i.e., Ki values) and free maximum therapeutic exposure (Cmax) to calculate safety margins as a threshold of detection (>10) for eliminating the risk of drug-induced cardiac valvulopathy. In this paper, we provide additional recommendations for preclinical prediction of CVD risk based on clinical pharmacodynamic and pharmacokinetic data obtained from drugs with or without 5-HT2B receptor activation. Our investigations showed that 5-HT2B agonist affinity of molecules tested in an in vitro 5-HT2B cell-based functional assay, placed in perspective to their sustained plasma exposure (AUCs) and not to their peak plasma exposure, Cmax (i.e., maximum therapeutic exposure) provide a solid basis for interpreting 5-HT2B data, for calculating safety margins and then, accurately differentiate drugs associated with a clinical risk of CVD from those which are not (despite having some agonist 5-HT2B activity). In addition, we discuss the risk of multi-organ fibrosis linked to 5-HT2B receptor activation, often underestimated, however well reported in FAERS for 5-HT2B agonists. We believe that our recommendations have the potential to mitigate the risk for the clinical development of CVD and fibrosis.

Frequency of Cardiac Valvulopathies in Patients With Marfan Syndrome: A Systematic Review and Meta-Analysis.

Marfan syndrome (MFS) is a progressive connective tissue disease with a broad range of clinical manifestations. We sought to establish the spectrum of structural valvular abnormalities as cardiovascular involvement has been identified as the most life-threatening aspect of the syndrome. This was a systematic review with a meta-analysis of studies indexed in Medline from the inception of the database to November 7, 2022. Using the random-effects model, separate Forest and Galbraith plots were generated for each valvular abnormality assessed. Heterogeneity was assessed using the I2 statistics whilst funnel plots and Egger's test were used to assess for publication bias. From a total of 35studies, a random-effects meta-analysis approximated the pooled summary estimates for the prevalence of cardiac valve abnormalities as mitral valve prolapse 65% (95% CI: 57%-73%); mitral valve regurgitation 40% (95% CI: 29%-51%); aortic valve regurgitation 40% (95% CI: 28%-53%); tricuspid valve prolapse 35% (95% CI: 15%-55%); and tricuspid valve regurgitation 43% (95% CI: 8%-78%). Only one study reported on the involvement of the pulmonary valve (pulmonary valve prolapse was estimated at 5.3% (95% CI: 1.9%-11.1%) in a cohort of 114 patients with MFS). We believe this study provides a description of the structural valvular disease spectrum and may help inform providers and patients in understanding the clinical history of MFS in the current treatment era with its increased life expectancy.

Microdosing psychedelics and the risk of cardiac fibrosis and valvulopathy: Comparison to known cardiotoxins.

Though microdosing psychedelics has become increasingly popular, its long-term effects on cardiac health remain unknown. Microdosing most commonly involves ingesting sub-threshold doses of lysergic acid diethylamide (LSD), psilocybin, or other psychedelic drugs 2-4 times a week for at least several weeks, but potentially months or years. Concerningly, both LSD and psilocybin share structural similarities with medications which raise the risk of cardiac fibrosis and valvulopathy when taken regularly, including methysergide, pergolide, and fenfluramine. 3,4-Methylenedioxymethamphetamine, which is also reportedly used for microdosing, is likewise associated with heart valve damage when taken chronically. In this review, we evaluate the evidence that microdosing LSD, psilocybin, and other psychedelics for several months or more could raise the risk of cardiac fibrosis. We discuss the relationship between drug-induced cardiac fibrosis and the 5-HT2B receptor, and we make recommendations for evaluating the safety of microdosing psychedelics in future studies.

A non-hallucinogenic LSD analog with therapeutic potential for mood disorders

Hallucinations limit widespread therapeutic use of psychedelics as rapidly acting antidepressants. Here we profiled the non-hallucinogenic lysergic acid diethylamide (LSD) analog 2-bromo-LSD (2-Br-LSD) at more than 33 aminergic G protein-coupled receptors (GPCRs). 2-Br-LSD shows partial agonism at several aminergic GPCRs, including 5-HT2A, and does not induce the head-twitch response (HTR) in mice, supporting its classification as a non-hallucinogenic 5-HT2A partial agonist. Unlike LSD, 2-Br-LSD lacks 5-HT2B agonism, an effect linked to cardiac valvulopathy. Additionally, 2-Br-LSD produces weak 5-HT2A β-arrestin recruitment and internalization invitro and does not induce tolerance invivo after repeated administration. 2-Br-LSD induces dendritogenesis and spinogenesis in cultured rat cortical neurons and increases active coping behavior in mice, an effect blocked by the 5-HT2A-selective antagonist volinanserin (M100907). 2-Br-LSD also reverses the behavioral effects of chronic stress. Overall, 2-Br-LSD has an improved pharmacological profile compared with LSD and may have profound therapeutic value for mood disorders and other indications.

Binding and functional structure-activity similarities of 4-substituted 2,5-dimethoxyphenyl isopropylamine analogues at 5-HT2A and 5-HT2B serotonin receptors.

Certain 4-substituted analogs of 1-(2,5-dimethoxyphenyl)isopropylamine (2,5-DMA) are psychoactive classical hallucinogens or serotonergic psychedelic agents that function as human 5-HT2A (h5-HT2A) serotonin receptor agonists. Activation of a related receptor population, h5-HT2B receptors, has been demonstrated to result in adverse effects including cardiac valvulopathy. We previously published on the binding of several such agents at the two receptor subtypes. We hypothesized that, due to their structural similarity, the 5-HT2A and 5-HT2B receptor affinities of these agents might be related, and that QSAR studies might aid future studies. For a series of 13 compounds, it is demonstrated here that i) their published rat brain 5-HT2 receptor affinities are significantly correlated with their h5-HT2A (r = 0.942) and h5-HT2B (r = 0.916) affinities, ii) as with r5-HT2 receptor affinity, h5-HT2A affinity is correlated with the lipophilicity of the 4-position substituent (r = 0.798), iii) that eight of the ten compounds examined in functional (Ca+2 mobilization in stable cell lines generated expressing the human 5-HT2B receptor using the Flp-In T-REx system) assays acted as h5-HT2B agonists (4-substituent = H, F, Br, I, OCH2CH3, NO2, nC3H7, tC4H9) and two (n-hexyl and benzyl) as antagonists, iv) h5-HT2B affinity but not action was correlated with the lipophilicity of the 4-position substituent (r = 0.750; n = 10). The findings suggest that h5-HT2B receptor affinity, and its relationship to substituent lipophilicity, might be approximated by rat and h5-HT2A affinity but cannot be used as a predictor of h5-HT2B agonist action of 2,5-DMA analogs. Furthermore, given that certain 2,5-DMA analogs are on the clandestine market, their potential to produce cardiac side effects following persistent or chronic use via activation of h5-HT2B receptors should be considered.

Dopamine agonist therapy for prolactinomas: do we need to rethink the place of surgery in prolactinoma management?

The current treatment paradigm for prolactinomas involves dopamine agonist (DA) therapy as the first-line treatment, with surgical resection reserved for cases where there is DA failure due to resistance or intolerance. This review highlights how DA therapy can be optimised to overcome its increasingly recognised pitfalls, whilst also addressing the potential for expanding the use of surgery in the management of prolactinomas. The first part of the review discusses the limitations of DA therapy, namely: DA resistance; common DA side effects; and the rare but serious DA-induced risks of cardiac valvulopathy, impulse control disorders, psychosis, CSF rhinorrhoea and tumour fibrosis. The second part of the review explores the role of surgery in prolactinoma management with reference to its current second-line position and recent calls for surgery to be considered as an alternative first-line treatment alongside DA therapy. Randomised trials comparing medical vs surgical therapy for prolactinomas are currently underway. Pending these results, a low surgical threshold approach is herein proposed, whereby DA therapy remains the default treatment for prolactinomas unless there are specific triggers to consider surgery, including concern regarding DA side effects or risks in vulnerable patients, persistent and bothersome DA side effects, emergence of any serious risks of DA therapy, expected need for long-term DA therapy, as well as the traditional indications for surgery. This approach should optimise the use of DA therapy for those who will most benefit from it, whilst instituting surgery early in others in order to minimise the cumulative burden of prolonged DA therapy.

Probing the Activity of Mitragyna Speciosa (Kratom) Alkaloids at Serotonin G Protein‐Coupled Receptors

The nation’s persistent opioid epidemic requires innovative treatment interventions. Mitragyna speciosa, or kratom, is an alkaloid‐containing tropical plant that has emerged as a potential opioid substitute therapy in recent decades. There are, however, no FDA‐approved uses for kratom, and scientists are actively engaged to elucidate the potential therapeutic benefits and harmful effects of kratom. Studies of kratom alkaloids have mainly focused on their opioid receptor activity, but emerging data show kratom has physiologically‐relevant activity at other biological targets. We recently reported that two kratom alkaloids prevalent in leaves of the kratom plant, speciogynine and paynantheine, bind to serotonin (5‐HT) 5‐HT1ARs and 5‐HT2BRs with affinities (Ki) less ≤100 nM and that their 9‐O‐desmethyl metabolites are efficacious agonists at 5‐HT1ARs (León et al., 2021 PMID: 34467758). We are undertaking studies to evaluate the pharmacology of the most prevalent alkaloids found in kratom leaves at each of the genetically‐encoded 5‐HT G protein‐coupled receptors (GPCRs). To further elucidate 5‐HTR G‐protein transduction pathways modulated by kratom alkaloids, we are utilizing the TRUPATH biosensor platform. By evaluating the potency and efficacy of kratom alkaloids to modulate the activity of unique G alpha subtypes linked to 5‐HTRs, we will provide fundamental 5‐HTR pharmacological characteristics of kratom alkaloids. The 5‐HT2BR is a crucial target for drug safety profiling since activation of this receptor can lead to cardiac valvulopathy. In addition, we are testing kratom alkaloids with an appreciable 5‐HT2BR affinity for their potential mitogenic activity in HEK cells utilizing [3H]thymidine incorporation. This research will provide crucial information about kratom’s pharmacological profile, independent of opioid receptors, that may contribute to its physiological effects.

Lung-restricted ALK5 inhibition avoids systemic toxicities associated with TGFβ pathway inhibition

Systemic therapies targeting transforming growth factor beta (TGFβ) or TGFβR1 kinase (ALK5) have been plagued by toxicities including cardiac valvulopathy and bone physeal dysplasia in animals, posing a significant challenge for clinical development in pulmonary indications. The current work aims to demonstrate that systemic ALK5-associated toxicities can be mitigated through localized lung delivery. Lung-selective (THRX-144644) and systemically bioavailable (galunisertib) ALK5 inhibitors were compared to determine whether lung selectivity is sufficient to maintain local tissue concentrations while mitigating systemic exposure and consequent pathway-related findings. Both molecules demonstrated potent ALK5 activity in rat precision cut lung slices (PCLS; p-SMAD3 half-maximal inhibitory concentration [IC50], 141 nM and 1070 nM for THRX-144644 and galunisertib, respectively). In 14-day repeat-dose studies in rats, dose-related cardiac valvulopathy was recapitulated with oral galunisertib at doses ≥150 mg/kg/day. In contrast, inhaled nebulized THRX-144644 did not cause similar systemic findings up to the maximally tolerated doses in rats or dogs (10 and 1.5 mg/kg/day, respectively). THRX-144644 lung-to-plasma ratios ranged from 100- to 1200-fold in rats and dogs across dose levels. THRX-144644 lung trough (24 h) concentrations in rats and dogs ranged from 3- to 17-fold above the PCLS IC50 across tolerated doses. At a dose level exceeding tolerability (60 mg/kg/day; 76-fold above PCLS IC50) minimal heart and bone changes were observed when systemic drug concentrations reached pharmacologic levels. In conclusion, the current preclinical work demonstrates that localized pulmonary delivery of an ALK5 inhibitor leads to favorable TGFβ pathway pharmacodynamic inhibition in lung while minimizing key systemic toxicities.

A Scoping Review of Alternative Anticoagulation Strategies for Hemodialysis Patients with a Mechanical Heart Valve

Introduction: Patients with end-stage renal disease (ESRD) have high rates of cardiac valvulopathy but can develop contraindications for vitamin K antagonist (VKA) therapy. We explored the evidence for alternative anticoagulation strategies in patients with ESRD with a contraindication for VKA therapy. Methods: A scoping review was completed, searching MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Conference abstracts from inception to March 30, 2021. The study population was patients with ESRD who were on VKA therapy and developed a contraindication to VKA therapy use. All data regarding studies, patient characteristics, anticoagulation strategy, and clinical outcomes were summarized. Results: Twenty-three articles met inclusion criteria. These articles included 57 patients. Contraindications to VKA therapy included calcific uremic arteriolopathy (CUA) (n = 55) and warfarin-induced skin necrosis (n = 2). All studies were either case reports or case series. There were 10 anticoagulation strategies identified. Continuation of VKA therapy was associated with increased death and decreased rates of CUA resolution (80.0% and 10.0%, respectively), compared to apixaban (24.0% and 70.8%), subcutaneous (SC) low-molecular-weight heparin (LMWH) (14.3%, 85.7%), and SC unfractionated heparin (0.0%, 100.0%). While only 5 patient cases were reported with mechanical heart valves, SC LMWH use has been reported in this context with good outcomes. Conclusions: In patients with ESRD who develop a contraindication to VKA therapy, several alternative anticoagulation strategies have been reported with superior outcomes to VKA continuation. While outcomes appear superior to continuation of VKA therapy, more data are required before definitive recommendations can be made for the patient with ESRD and a mechanical heart valve.

Prolactinomas

Hyperprolactinemia, defined by a level of serum prolactin above the standard upper limit of normal range, is a common finding in clinical practice and prolactinomas are the main pathological cause. Prolactinomas lead to signs and symptoms of hormone oversecretion, such as galactorrhea and hypogonadism, as well as symptoms of mass effect, including visual impairment, headaches and intracranial hypertension. Diagnosis involves prolactin measurement and sellar imaging, but several pitfalls are involved in this evaluation, which may difficult the proper management. Treatment is medical in the majority of cases, consisting of dopamine agonists, which present high response rates, with a very favorable safety profile. Major adverse effects that should be monitored consist of cardiac valvulopathy and impulse control disorders. Other treatment options include surgery and radiotherapy. Temozolomide may be used for aggressive or malignant carcinomas. Finally, pregnancy outcomes are similar to general population even when dopamine agonist treatment is maintained.

Fenfluramine for seizures associated with Sunflower syndrome.

To determine the efficacy of fenfluramine on seizure frequency in patients with Sunflower syndrome. Secondary endpoints were changes in electroencephalogram (EEG) characteristics, cognitive functioning, executive functioning, and quality of life. In this open-label study, patients underwent a 4-week baseline period, followed by 3months of treatment. An oral solution of fenfluramine was administered twice daily for 3 months. The dose was titrated up to a maximum dose of 0.7mg/kg/day or 26mg/day. Cardiac safety was monitored by transthoracic echocardiogram and electrocardiogram. EEGs, abbreviated neuropsychological testing, and questionnaires were administered before starting the study medication and again at the end of the treatment period. Ten patients (eight females, two males; mean age 13y 4mo [SD 4y 11mo], range 7-24y) were enrolled in the study. Nine of the 10 patients completed the core study, eight of whom met the primary endpoint. There were no observations of cardiac valvulopathy or pulmonary hypertension during the study. Treatment with low-dose fenfluramine resulted in a clinically significant reduction in seizure frequency, including hand-waving episodes. Fenfluramine may be an effective treatment option for patients with Sunflower syndrome. What this paper adds Nine patients with Sunflower syndrome were treated with fenfluramine. Eight patients were responders, displaying a ≥30% reduction in seizure activity. Six patients experienced a ≥70% reduction in hand-waving episodes. Improvements on electroencephalogram were observed after treatment with fenfluramine. None of the patients developed evidence of cardiac valvulopathy or pulmonary hypertension.

Evaluation of antibiotic prophylaxis use in a university dental clinic in the Lisbon area

Introduction Antibiotic prophylaxis (AP) in dentistry is recommended before dental procedures that involve manipulation of gingival tissue or periapical region, and perforation of oral mucosa in order to prevent a serious bacterial infection. The American Heart Association (AHA) Guideline recommends that the cardiac conditions with the highest risk of infective endocarditis (IE), for which AP is reasonable are: prosthetic cardiac valves, previous IE, congenital heart disease and cardiac transplantation with cardiac valvulopathy [1,2,3]. The aim of this study is to evaluate the use of AP in a University dental practice compared to AHA guidelines. Materials and methods An observational and descriptive study was conducted between June and August 2016 at Clínica Dentária Egas Moniz (CDEM), a University Dental Clinic in the greater Lisbon Area. A total of 4000 patient records were analysed. 60 records were selected according to predefined inclusion criteria: patients submitted to endodontics and/or periodontology and/or surgery appointments, patients with IE/prosthetic cardiac valves/cardiac bypass/cardiac valvular disease/rheumatic fever or hip/knee joint prosthesis and patients who required AP before an invasive dental procedure. Clinical processes analysis were authorised by the patients through a declaration of informed consent. This study was authorised by the Clinical Director of CDEM and approved by Egas Moniz Ethics Committee. Results Periodontology patients had AP indication in: congenital cardiac disease (4/16), cardiac valvular disease (5/13), rheumatic fever (3/7), and prosthetic cardiac valves (7/8). Surgery patients had AP indication in: IE (2/2), congenital cardiac disease (4/12), cardiac valvular disease (4/6), rheumatic fever (2/4) and prosthetic cardiac valves (6/8). Endodontic records were not enough to have significant results to compare. Discussion and conclusions There is some disparity between the AHA guideline and the attitudes of dentists towards AP indication [4]. The use of antibiotics in dental medicine is characterised by empirical prescription based on epidemiological and clinical factors, using broad spectrum antibiotics and for short periods of time. The abuse of unjustified antibiotics and the lack of knowledge about the application of AP ultimately encourages bacterial resistance and the increase in untreatable infections. Antimicrobial resistance is a current serious global threat accordingly to WHO. It is no longer a prediction for the future, as it is happening in all regions of the world and has the potential to reach anyone [5]. The knowledge and communication over this topic must be stressed, even more in newly graduated dentists, to encourage evidence based homogeneous prescription patterns that promote good and safe clinical practices.

Assessing the Impact on Health of Pharmacovigilance Activities: Example of Four Safety Signals

The impact of pharmacovigilance activities on public health remains under-investigated, and measuring the impact on health of pharmacovigilance activities for a specific safety signal is challenging. To gain more insight into the methodological challenges and the data required, we assessed the impact of pharmacovigilance on public health for four identified product-specific safety signals using publicly available data in the Netherlands. The assessment was on the impact of the intertwined and complementary steps of the pharmacovigilance pathways. The impact of pharmacovigilance on public health was assessed using the assessment support tool and 'open data' from the Netherlands for four different types of pharmacovigilance safety signals: (1) off-label use of cyproterone acetate/ethinyloestradiol (CPA/EE) and thrombotic risk after pharmacovigilance measures after 2014; (2) pergolide and the risk of cardiac valvulopathy after pharmacovigilance activities in 2003; (3) proton pump inhibitors and the risk of hypomagnesaemia after pharmacovigilance activities in 2011; (4) rosiglitazone withdrawal from the market because of cardiovascular effects in 2010. For the signals on CPA/EE and pergolide, a crude estimation of the impact could be made with varying degrees of assumptions based on the risk described in the literature and utilisation data. This article highlights the methodological challenges and the data required to assess the impact of product-specific safety signals. A structured assessment support tool can be used as a guide for the necessary data elements and steps needed for the measurement or estimation of impact of pharmacovigilance activities on public health, provided that the appropriate data are available.

Patients with atherosclerotic peripheral arterial disease have a high risk of lung cancer: Systematic review and meta-analysis of literature.

Lung cancer and atherosclerosis share common risk factors. Literature data suggest that the prevalence of lung malignancy in patients with peripheral arterial disease (PAD) is higher than in the general population. Our goal was to determine, through a systematic literature review, the prevalence of lung cancer in patients with PAD. We consulted available publications in the Cochrane library, MEDLINE, PUBMED, EMBASE, and ClinicalTrials.gov. We included all articles, written in English or French, published between 1990 and 2020 reporting the prevalence of lung cancer in patients with PAD (atherosclerotic aortic aneurysm or peripheral occlusive diseases). Patients with coronary artery disease, cardiac valvulopathy or carotid stenosis were not included. We did not include case reports. We performed a critical analysis of each article. Data were collected from two independent readers. A fixed effect model meta-analysis allowed to estimate a summary prevalence rate. We identified 303 articles, and selected 19 articles according to selection criteria. A total of 16849 patients were included (mean age 68.3 years, 75.1% of males). Aortic aneurysms were found in 29% of patients and atherosclerotic occlusive disease in 66% of patients. Lung cancer was identified in 538 patients, representing a prevalence of 3%. Lung cancer is found in 3% of patients with atherosclerotic PAD. This prevalence is higher than that found in lung cancer screening programs performed in the general population of smokers and former smokers. These patients should be screened for lung cancer. Their selection may dramatically increase the benefit of lung cancer screening.

Data-driven machine-learning analysis of potential embolic sources in embolic stroke of undetermined source.

Hierarchical clustering, a common 'unsupervised' machine-learning algorithm, is advantageous for exploring potential underlying aetiology in particularly heterogeneous diseases. We investigated potential embolic sources in embolic stroke of undetermined source (ESUS) using a data-driven machine-learning method, and explored variation in stroke recurrence between clusters. We used a hierarchical k-means clustering algorithm on patients' baseline data, which assigned each individual into a unique clustering group, using a minimum-variance method to calculate the similarity between ESUS patients based on all baseline features. Potential embolic sources were categorised into atrial cardiopathy, atrial fibrillation, arterial disease, left ventricular disease, cardiac valvulopathy, patent foramen ovale (PFO) and cancer. Among 800 consecutive ESUS patients (43.3% women, median age 67years), the optimal number of clusters was four. Left ventricular disease was most prevalent in cluster 1 (present in all patients) and perfectly associated with cluster 1. PFO was most prevalent in cluster 2 (38.9% of patients) and associated significantly with increased likelihood of cluster 2 [adjusted odds ratio: 2.69, 95% confidence interval (CI): 1.64-4.41]. Arterial disease was most prevalent in cluster 3 (57.7%) and associated with increased likelihood of cluster 3 (adjusted odds ratio: 2.21, 95% CI: 1.43-3.13). Atrial cardiopathy was most prevalent in cluster 4 (100%) and perfectly associated with cluster 4. Cluster 3 was the largest cluster involving 53.7% of patients. Atrial fibrillation was not significantly associated with any cluster. This data-driven machine-learning analysis identified four clusters of ESUS that were strongly associated with arterial disease, atrial cardiopathy, PFO and left ventricular disease, respectively. More than half of the patients were assigned to the cluster associated with arterial disease.

Efficacy and safety of Fenfluramine hydrochloride for the treatment of seizures in Dravet syndrome: A real-world study.

Dravet syndrome (DS) is a drug-resistant, infantile onset epilepsy syndrome with multiple seizure types and developmental delay. In recently published randomized controlled trials, fenfluramine (FFA) proved to be safe and effective in DS. DS patients were treated with FFA in the Zogenix Early Access Program at four Italian pediatric epilepsy centers. FFA was administered as add-on, twice daily at an initial dose of 0.2mg/kg/d up to 0.7mg/kg/d. Seizures were recorded in a diary. Adverse events and cardiac safety (with Doppler echocardiography) were investigated every 3 to 6months. Fifty-two patients were enrolled, with a median age of 8.6years (interquartile range [IQR] = 4.1-13.9). Forty-five (86.5%) patients completed the efficacy analysis. The median follow-up was 9.0months (IQR = 3.2-9.5). At last follow-up visit, there was a 77.4% median reduction in convulsive seizures. Thirty-two patients (71.1%) had a ≥50% reduction of convulsive seizures, 24 (53.3%) had a ≥75% reduction, and five (11.1%) were seizure-free. The most common adverse event was decreased appetite (n=7, 13.4%). No echocardiographic signs of cardiac valvulopathy or pulmonary hypertension were observed. There was no correlation between type of genetic variants and response to FFA. In this real-world study, FFA provided a clinically meaningful reduction in convulsive seizure frequency in the majority of patients with DS and was well tolerated.

Cardiovascular safety of fenfluramine in the treatment of Dravet syndrome: Analysis of an ongoing long-term open-label safety extension study.

ObjectiveFenfluramine, which was previously approved as a weight loss drug, was withdrawn in 1997 when reports of cardiac valvulopathy emerged. The present study was conducted in part to characterize the cardiovascular safety profile of low‐dose fenfluramine when used in a pediatric population to reduce seizure frequency in patients with Dravet syndrome.MethodsPatients 2‐ to 18‐years‐old with Dravet syndrome who had completed any of three randomized, placebo‐controlled clinical trials of fenfluramine were offered enrollment in this open‐label extension (OLE) study. All patients were treated with fenfluramine starting at a dose of 0.2 mg/kg/day (oral solution dosed twice per day), which was titrated to maximal effect with a dose limit of 0.7 mg/kg/day (maximum 26 mg/day) or 0.4 mg/kg/day (maximum 17 mg/day) in patients receiving concomitant stiripentol. Standardized echocardiographic examinations were conducted at Week 4 or 6 and then every 3 months during the OLE study to monitor cardiac valve function and structure and pulmonary artery pressure. The primary end point for the echocardiography analysis was the number of patients who developed valvular heart disease or pulmonary artery hypertension (PAH) during treatment.ResultsA total of 232 patients were enrolled in the study. The average age of patients was 9.1 ± 4.7 years, and 55.2% were male. The median duration of treatment with fenfluramine was 256 days (range = 58‐634 days), and the mean dose of fenfluramine was 0.41 mg/kg/day. No cases of valvular heart disease or PAH were observed.SignificanceLongitudinal echocardiography over a median 8.4 months of treatment with fenfluramine suggests a low risk of developing cardiac valvulopathy and PAH when used to treat pediatric patients with Dravet syndrome.

Abstract 1645: A new TGF-b pathway reporter mouse for analysis of TGF-β signaling in normal homeostasis and cancer

Abstract TGF-βs play a central regulatory role in maintaining homeostasis and coordinating response to injury in the adult animal. Consequently, dysregulation of TGF-β signaling has been implicated in many pathological states, including cancer. Several TGF-β pathway antagonists are now in early phase clinical oncology trials. However, surprisingly little is known about when and where the TGF-β pathway is activated in the adult animal. To address this need, we have generated a TGF-β pathway reporter mouse in which the expression of eGFP is driven by an artificial enhancer element consisting of 6 repeats of a strong Smad3 binding element from the distal region of the JunB promoter (S3 × 6>GFP reporter). This reporter was >10x more sensitive in vitro than the commonly used CAGA12-based reporter. The reporter construct was knocked into the mouse ROSA26 locus using CRISPR technology and a founder line was derived. Whole body fluorescent imaging of an adult female mouse highlighted TGF-β pathway activation in the gastrointestinal tract, lymph nodes, costal cartilage, brown adipose tissue, brain ventricles and choroid plexi, among other tissues. Since high dose pharmacologic inhibition of the TGF-β pathway has previously been associated with cardiac valvulopathy in preclinical toxicology studies, we immunostained heart sections from the reporter mouse for GFP and observed high endogenous TGF-β pathway activation in the atrioventricular valve leaflets. Quantitative IVIS fluorescent imaging of isolated organs confirmed TGF-β pathway activation in many different tissues in the normal adult mouse, with the pancreas showing the highest level of endogenous activation. Interestingly, the level of TGF-β pathway activation in different tissues was highly correlated with the frequency of inactivating mutations in TGF-β pathway components in tumors from the corresponding tissue in humans. This observation suggests that a high level of TGF-β pathway activation in normal tissues may reflect a non-redundant tumor suppressor role for the TGF-β pathway in maintaining homeostasis in those tissues. To specifically address the activation state of the TGF-β pathway during tumorigenesis, we intercrossed the S3 × 6>GFP reporter mouse with the MMTV-PyVT mouse model of metastatic breast cancer. Reporter activity was strongly upregulated in mammary tumors when compared with the surrounding mammary gland. Using cells cultured from the primary tumors, we confirmed that the reporter signal in the tumor cells can be blocked by small molecule antagonists of the TGF-β pathway. This reporter mouse should be a useful tool to assess the cellular location and extent of TGF-β pathway activation during tumor development, and the impact of TGF-β antagonists on TGF-β signaling in tumors and normal tissues. Citation Format: Yu-an Yang, Christina Stuelten, Youngjae Bahn, Ji-Hyeon Lee, Madhu Gargesha, Hibret Adissu, Mark Simpson, Caroline S. Hill, Sushil G. Rane, Lalage M. Wakefield. A new TGF-b pathway reporter mouse for analysis of TGF-β signaling in normal homeostasis and cancer [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 1645.

Monitoring patients receiving dopamine agonist therapy for hyperprolactinaemia

The surveillance strategy for patients taking low dose cabergoline for hyperprolactinaemia is controversial. As more evidence has emerged that the risks of cardiac valvulopathy in this population of patients are low, fewer and fewer endocrinologists adhere strictly to the original medicines and healthcare products agency MHRA guidance of “at least” annual echocardiography. Strict adherence to this guidance would be costly in monetary terms (£5.76 million/year in the UK) and also in resource use (90,000 extra echocardiograms/year). This article reviews the proposed pathophysiological mechanism underlying the phenomenon of dopamine agonist valvulopathy, the characteristic echocardiographic changes seen, summarises the published literature on the incidence of valvulopathy with low dose cabergoline and examines the previous and current evidence-based screening guidelines.