Les Huson

Use of the selective oral neuraminidase inhibitor oseltamivir to prevent influenza

BACKGROUND Safe and effective antiviral agents are needed to prevent infection with influenza A and B virus. Oseltamivir (GS4104), which can be administered orally, is the prodrug of GS4071, a potent and selective inhibitor of influenzavirus neuraminidases. We studied the use of oseltamivir for long-term prophylaxis against influenza in two placebo-controlled, double-blind trials at different U.S. sites during the winter of 1997-1998. METHODS We randomly assigned 1559 healthy, nonimmunized adults 18 to 65 years old to receive either oral oseltamivir (75 mg given once or twice daily, for a total daily dose of 75 or 150 mg) or placebo for six weeks during a peak period of local influenzavirus activity. The primary end point with respect to efficacy was laboratory-confirmed influenza-like illness (defined as a temperature of at least 37.2 degrees C accompanied by at least one respiratory and at least one systemic symptom). RESULTS In the two studies combined, the risk of influenza among subjects assigned to either once-daily or twice-daily oseltamivir (1.2 percent and 1.3 percent, respectively) was lower than that among subjects assigned to placebo (4.8 percent; P<0.001 and P=0.001 for the comparison with once-daily and twice-daily oseltamivir, respectively). The protective efficacy of oseltamivir in the two active-treatment groups combined was 74 percent (95 percent confidence interval, 53 to 88 percent) at all the sites combined and 82 percent (95 percent confidence interval, 60 to 93 percent) at sites in Virginia, where the rate of influenza infection was higher than the overall rate. For culture-proved influenza, the rate of protective efficacy in the two oseltamivir groups combined was 87 percent (95 percent confidence interval, 65 to 96 percent). The rate of laboratory-confirmed influenza infection was lower with oseltamivir than with placebo (5.3 percent vs. 10.6 percent, P<0.001). Oseltamivir was well tolerated but was associated with a greater frequency of nausea (12.1 percent and 14.6 percent in the once-daily and twice-daily groups, respectively) and vomiting (2.5 percent and 2.7 percent, respectively) than was placebo (nausea, 7.1 percent; vomiting, 0.8 percent). However, the frequency of premature discontinuation of drug or placebo was similar among the three groups (3.1 to 4.0 percent). CONCLUSIONS Oseltamivir administered daily for six weeks by the oral route is safe and effective for the prevention of influenza.

Reduced MicroRNA-150 Is Associated with Poor Survival in Pulmonary Arterial Hypertension

RATIONALE MicroRNAs (miRNAs or miRs) are implicated in the pathogenesis of various cardiovascular diseases, including pulmonary arterial hypertension (PAH). OBJECTIVES We sought to measure changes in plasma levels of miRNAs in patients with PAH and relate them to the severity of the disease. METHODS A microarray screen was performed on total plasma RNA from eight patients with PAH and eight healthy control subjects. Quantitative polymerase chain reaction confirmed reduced miR-150 concentrations and was then used to measure miR-150 levels in (1) two separate cohorts of patients with PAH, from London (n = 145) and Sheffield (n = 30), respectively; (2) circulating microvesicles and blood cells; and (3) lungs from a monocrotaline rat model. MEASUREMENTS AND MAIN RESULTS Fifty-eight miRNAs showed differences in plasma concentration and miR-150 the largest down-regulation in PAH. Receiver-operator-characteristic analysis showed both raw and normalized plasma miR-150 levels correlated with 2-year survival (P < 0.01) in patients with PAH. Cox regression analysis confirmed miR-150 levels as a significant predictor of survival. Age, baseline cardiac index, World Health Organization functional class, 6-minute walk distance, disease duration, and red cell distribution width also predicted survival. Entering these covariates in a multivariable model verified plasma miR-150 levels as an independent predictor of survival in PAH (hazard ratio, 0.533; P = 0.010). miR-150 levels also predicted survival in a second, independent PAH cohort. miR-150 levels were significantly reduced in circulating microvesicles from patients with PAH and the lungs of the monocrotaline rat. CONCLUSIONS Reduced circulating miR-150 levels are associated with poor survival in PAH.

Sustained Cardiovascular Actions of APJ Agonism During Renin–Angiotensin System Activation and in Patients With Heart Failure

Background—To assess cardiovascular actions of APJ agonism during prolonged (Pyr1)apelin-13 infusion and renin–angiotensin system activation. Methods and Results—Forty-eight volunteers and 12 patients with chronic stable heart failure attended a series of randomized placebo–controlled studies. Forearm blood flow, cardiac index, left ventricular dimensions, and mean arterial pressure were measured using bilateral venous occlusion plethysmography, bioimpedance cardiography, transthoracic echocardiography, and sphygmomanometry, respectively, during brief local (0.3–3.0 nmol/min) and systemic (30–300 nmol/min) or prolonged systemic (30 nmol/min) (Pyr1)apelin-13 infusions in the presence or absence of renin–angiotensin system activation with sodium depletion or angiotensin II coinfusion. During sodium depletion and angiotensin II coinfusion, (Pyr1)apelin-13–induced vasodilatation was preserved (P<0.02 for both). Systemic intravenous (Pyr1)apelin-13 infusion increased cardiac index, whereas reducing mean arterial pressure and peripheral vascular resistance index (P<0.001 for all) irrespective of sodium depletion or angiotensin II (0.5 ng/kg per minute) coinfusion (P>0.05 for all). Prolonged 6-hour (Pyr1)apelin-13 infusion caused a sustained increase in cardiac index with increased left ventricular ejection fraction in patients with chronic heart failure (ANOVA; P<0.001 for all). Conclusions—APJ agonism has sustained cardiovascular effects that are preserved in the presence of renin–angiotensin system activation or heart failure. APJ agonism may hold major promise to complement current optimal medical therapy in patients with chronic heart failure. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00901719, NCT00901888, NCT01049646, NCT01179061.

Effects of light treatment upon mood and melatonin in patients with seasonal affective disorder

Ten patients with seasonal affective disorder received the following treatments for 5 days each: (a) artificial daylight (2500 lux) from 20.00 to 23.00 and from 07.00 to 10.00 hours; (b) red light (300 lux) from 20.00 to 23.00 and from 07.00 to 10.00 hours; (c) artificial daylight (2500 lux) from 22.00 to 23.00 and from 07.00 to 08.00 hours. The antidepressant effect of treatment (a) was superior to that of treatment (b), suggesting that the effect of light treatment in winter depression is more than that of a placebo. The antidepressant effect of treatment (a) was superior to that of treatment (c), although these two treatments equally suppressed plasma melatonin concentrations. Consequently, in these patients there is a dissociation between the effect of light treatment on melatonin and the reduction of depression ratings.

Neurokinin 3 receptor antagonism as a novel treatment for menopausal hot flushes: A phase 2, randomised, double-blind, placebo-controlled trial

Summary Background Hot flushes affect 70% of menopausal women and often severely impact physical, psychosocial, sexual, and overall wellbeing. Hormone replacement therapy is effective but is not without risk. Neurokinin B signalling is increased in menopausal women, and has been implicated as an important mediator of hot flushes. Methods This phase 2, randomised, double-blind, placebo-controlled, single-centre, crossover trial assessed the effectiveness of an oral neurokinin 3 receptor antagonist (MLE4901) on menopausal hot flushes. Eligible participants were healthy women aged 40–62 years, having seven or more hot flushes in every 24 h of which some were reported as being severe or bothersome, who had not had a menstrual period for at least 12 months, and who had not been taking any medication shown to improve menopausal flushes in the preceding 8 weeks. Participants received 4 weeks of MLE4901 (40 mg, orally, twice daily) and placebo (orally, twice daily) in random order separated by a 2 week washout period. Randomisation was completed by a central computer, and participants were allocated to treatment number in numerical order. The primary outcome was the total number of hot flushes during the final week of both treatment periods. Analyses were by intention to treat and per protocol using generalised linear mixed models and standard crossover analysis. All analyses were prespecified in the study protocol. The trial is registered at ClinicalTrials.gov, number NCT02668185. Findings 68 women were screened between Feb 3 and Oct 10, 2016, of which 37 were randomly assigned and included in an intention-to-treat analysis. 28 participants completed the trial and were included in a per-protocol analysis. MLE4901 significantly reduced the total weekly number of hot flushes by 45 percentage points (95% CI 22–67) compared with the placebo (intention-to-treat adjusted means: placebo 49·01 [95% CI 40·81–58·56] vs MLE4901 19·35 [15·99–23·42]; adjusted estimate of difference 29·66 [17·39–42·87], p<0·0001). Treatment was well tolerated. Three participants developed a transaminase rise (alanine aminotransferase 4·5–5·9 times the upper limit of normal) with a normal bilirubin 28 days after starting MLE4901, which normalised within 90 days. Interpretation Treatment with a neurokinin 3 receptor antagonist (MLE4901) could be practice changing as it safely and effectively relieves hot flush symptoms without the need for oestrogen exposure. Larger scale studies of longer duration are now indicated. Funding UK Medical Research Council and National Institute for Health Research.

Quality of Life and Physical Function in Older Patients on Dialysis: A Comparison of Assisted Peritoneal Dialysis with Hemodialysis

BACKGROUND AND OBJECTIVES In-center hemodialysis (HD) is often the default dialysis modality for older patients. Few centers use assisted peritoneal dialysis (PD), which enables treatment at home. This observational study compared quality of life (QoL) and physical function between older patients on assisted PD and HD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Patients on assisted PD who were >60 years old and on dialysis for >3 months were recruited and matched to patients on HD (needing hospital transport) by age, sex, diabetes, dialysis vintage, ethnicity, and index of deprivation. Frailty was assessed using the Clinical Frailty Scale. QoL assessments included Hospital Anxiety and Depression Scale (HADS), Short Form-12, Palliative Outcomes Symptom Scale (renal), Illness Intrusiveness Rating Scale, and Renal Treatment Satisfaction Questionnaire (RTSQ). Physical function was evaluated by Barthel Score and timed up and go test. RESULTS In total, 251 patients (129 PD and 122 HD) were recruited. In unadjusted analysis, patients on assisted PD had a higher prevalence of possible depression (HADS>8; PD=38.8%; HD=23.8%; P=0.05) and higher HADS depression score (median: PD=6; HD=5; P=0.05) but higher RTSQ scores (median: PD=55; HD=51; P<0.01). In a generalized linear regression model adjusting for age, sex, comorbidity, dialysis vintage, and frailty, assisted PD continued to be associated with higher RTSQ scores (P=0.04) but not with other QoL measures. CONCLUSIONS There are no differences in measures of QoL and physical function between older patients on assisted PD and comparable patients on HD, except for treatment satisfaction, which is higher in patients on PD. Assisted PD should be considered as an alternative to HD for older patients, allowing them to make their preferred choices.

TSPO mutations in rats and a human polymorphism impair the rate of steroid synthesis

The 18 kDa translocator protein (TSPO) is a ubiquitous conserved outer mitochondrial membrane protein implicated in numerous cell and tissue functions, including steroid hormone biosynthesis, respiration, cell proliferation, and apoptosis. TSPO binds with high affinity to cholesterol and numerous compounds, is expressed at high levels in steroid-synthesizing tissues, and mediates cholesterol import into mitochondria, which is the rate-limiting step in steroid formation. In humans, the rs6971 polymorphism on the TSPO gene leads to an amino acid substitution in the fifth transmembrane loop of the protein, which is where the cholesterol-binding domain of TSPO is located, and this polymorphism has been associated with anxiety-related disorders. However, recent knockout mouse models have provided inconsistent conclusions of whether TSPO is directly involved in steroid synthesis. In this report, we show that TSPO deletion mutations in rat and its corresponding rs6971 polymorphism in humans alter adrenocorticotropic hormone-induced plasma corticosteroid concentrations. Rat tissues examined show increased cholesteryl ester accumulation, and neurosteroid formation was undetectable in homozygous rats. These results also support a role for TSPO ligands in diseases with steroid-dependent stress and anxiety elements.

Missing Data Imputation in Two Phase III Trials Treating HIV1 Infection

In most longitudinal clinical trials, some patients drop out before the end of the planned follow-up, and, in order to allow an all-patient intent-to-treat analysis to be performed, it is common practice to use some method of imputation to estimate values for missing data. However, different imputation methods may provide different results, and it is essential to investigate the sensitivity of the analysis using different imputation rules. In our analysis of two trials of the new HIV1 fusion inhibitor enfuvirtide, we compared some standard methods of imputing and analyzing HIV1-RNA data with two novel alternatives, to check the robustness of the primary endpoint results. The standard methods were: (1) last-observation-carried-forward, (2) baseline carried forward, and (3) multiple imputation. These were compared with a nearest-neighbour hot-deck method, specifically proposed for imputation of missing HIV1-RNA data, and with a heuristic approach: censored regression analysis of the last-observation-carried-forward. To supplement this analysis of real clinical trial data, we investigated the performance of the same imputation methods on simulated datasets designed to cover a broader range of missing data patterns.

Risk of Ovarian Cancer Relapse Score: A Prognostic Algorithm to Predict Relapse Following Treatment for Advanced Ovarian Cancer

Objective The aim of this study was to construct a prognostic index that predicts risk of relapse in women who have completed first-line treatment for ovarian cancer (OC). Methods A database of OC cases from 2000 to 2010 was interrogated for International Federation of Gynecology and Obstetrics stage, grade and histological subtype of cancer, preoperative and posttreatment CA-125 level, presence or absence of residual disease after cytoreductive surgery and on postchemotherapy computed tomography scan, and time to progression and death. The strongest predictors of relapse were included into an algorithm, the Risk of Ovarian Cancer Relapse (ROVAR) score. Results Three hundred fifty-four cases of OC were analyzed to generate the ROVAR score. Factors selected were preoperative serum CA-125, International Federation of Gynecology and Obstetrics stage and grade of cancer, and presence of residual disease at posttreatment computed tomography scan. In the validation data set, the ROVAR score had a sensitivity and specificity of 94% and 61%, respectively. The concordance index for the validation data set was 0.91 (95% confidence interval, 0.85-0.96). The score allows patient stratification into low (<0.33), intermediate (0.34–0.67), and high (>0.67) probability of relapse. Conclusions The ROVAR score stratifies patients according to their risk of relapse following first-line treatment for OC. This can broadly facilitate the appropriate tailoring of posttreatment care and support.

Definition and properties of a coefficient of sensitivity for mathematical models

Abstract This paper contains a definition of a measure of the uncertainty inherent in the output of a mathematical model. The definition is essentially a formalisation of the kind of uncertainty measures that have been previously used in various modelling applications in many disciplines. The characteristics of the measure are described, and an example is given of its use with a particular mathematical model.