Sample size re-estimation for superiority clinical trials with a dichotomous outcome using an unblinded estimate of the control group outcome rate

Superiority clinical trials are often designed with a planned interim analysis for the purpose of sample size re-estimation (SSR) when limited information is available at the start of the trial to estimate the required sample size. Typically these trials are designed with a two-arm internal pilot where subjects are enrolled to both treatment arms prior to the interim analysis. Circumstances may sometimes call for a trial with a single-arm internal pilot (enroll only in the control group). For a dichotomous outcome, Herson and Wittes proposed a SSR method (HW-SSR) that can be applied to single-arm internal pilot trials using an unblinded estimate of the control group outcome rate. Previous evaluations of the HW-SSR method reported conflicting results regarding the impact of the method on the two-sided Type I error rate and power of the final hypothesis test. In this research we evaluate the HW-SSR method under the null and alternative hypothesis in various scenarios to investigate the one-sided Type I error rate and power of trials with a two-arm internal pilot. We find that the one-sided Type I error rate is sometimes inflated and that the power is sometimes reduced. We propose a new method, the Critical Value and Power Adjusted Sample Size Re-estimation (CVPA-SSR) algorithm to adjust the critical value cutoff used in the final Z-test and the power critical value used in the interim SSR formula to preserve the nominal Type I error rate and the desired power. We conduct simulations for trials with single-arm and two-arm internal pilots to confirm that the CVPA-SSR algorithm does preserve the nominal Type I error rate and the desired power. We investigate the robustness of the CVPA-SSR algorithm for trials with single-arm and two-arm internal pilots when the assumptions used in designing the trial are incorrect. No Type I error inflation is observed but significant over- or under-powering of the trial occurs when the treatment effect used to design the trial is misspecified

Relationships Between Clinical Scales and Binge Eating Days in Adults with Moderate to Severe Binge Eating Disorder in Two Phase III Studies

OBJECTIVES: In two Phase III studies, lisdexamfetamine dimesylate (LDX) reduced binge eating (BE) days/week in adults with moderate to severe binge eating disorder (BED) and was associated with improvement based on the Clinical Global Impressions-Improvement (CGI-I) scale. In this study, post hoc analyses examined the relationships between clinical observations and clinical rating scales in individuals with BED. CLINICAL TRIAL REGISTRATION: NCT01718483 (ClinicalTrials.gov/ct2/show/NCT01718483); NCT01718509(ClinicalTrials.gov/ct2/show/NCT01718509). METHODS: Two 12-week, double-blind, placebo-controlled studies randomized (1:1) adults meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, BED criteria and with protocol-defined moderate to severe BED (study 1, N=383; study 2, N=390) to placebo or dose-optimized LDX (50 or 70 mg). Assessments included the number of BE days/week, CGI-Severity (CGI-S) and CGI-I scores, and Yale-Brown Obsessive Compulsive Scale modified for Binge Eating (Y-BOCS-BE) total scores. For these post hoc analyses, data were pooled across studies and treatment arms. Statistical assessments included Spearman correlations and equipercentile linking analyses (ELA). Reported P-values are nominal (descriptive and not adjusted for multiplicity). RESULTS: At baseline, nominally significant correlations with CGI-S scores were reported for BE days/week (r=0.374; Pr=0.319; Pr=0.647; Pr=0.741; P CONCLUSION: These post hoc analyses suggest that indices of global disease severity and improvement positively correlate with BE behavior and with obsessive and compulsive features of BED, measured by the Y-BOCS-BE, supporting the clinical relevance of BED treatment outcomes

Functional impairment outcomes in clinical trials of different ADHD medications:post hoc responder analyses and baseline subgroup analyses

Several recent phase 3 clinical trials of attention-deficit/hyperactivity disorder (ADHD) medications have used the Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P). Here, we assess WFIRS-P response in individual patients in two pivotal trials of lisdexamfetamine dimesylate (LDX) and guanfacine extended release (GXR). We also analysed pooled WFIRS-P data from seven phase 3 studies of ADHD medications to shed light on factors associated with baseline functional impairment. The proportion of patients with a change in WFIRS-P score that exceeded the minimal important difference (MID) criteria for response was greater for LDX than placebo in the Family, Learning and School, and Risky Activities domains, and was greater for GXR than placebo in the Social Activities, Learning and School, and Family domains. Responders had significantly worse baseline scores in all WFIRS-P domains (all p < 0.001) than non-responders. In the pooled analyses, baseline WFIRS-P scores in all domains were significantly worse in participants with oppositional defiant disorder (ODD) than in those without ODD. Having combined type or hyperactive-impulsive type ADHD, being enrolled into a study in Europe, being male and being younger also had modest negative effects on baseline WFIRS-P scores. The present analysis of WFIRS-P response shows that previously reported group-level improvements in WFIRS-P functional impairment score translated into clinically relevant improvements in many individual participants. Functional impairment is a diverse and subjective construct that is influenced by multiple factors. Optimal management of individuals with ADHD should involve monitoring improvements in functioning and quality of life, as well as symptomatic improvement

Correlations Between Clinical Trial Outcomes Based on Symptoms, Functional Impairments, and Quality of Life in Children and Adolescents With ADHD

OBJECTIVE: To assess relationships between treatment-associated changes in measures of ADHD symptoms, functional impairments, and health-related quality of life in children and adolescents with ADHD. METHOD: Pearson correlation coefficients were calculated post hoc for changes from baseline to endpoint in outcomes of one randomized, placebo- and active-controlled trial of lisdexamfetamine (osmotic-release methylphenidate reference) and one of guanfacine extended-release (atomoxetine reference). RESULTS: Changes in ADHD Rating Scale IV (ADHD-RS-IV) total score generally correlated moderately with changes in Child Health and Illness Profile-Child Edition: Parent Report Form (CHIP-CE:PRF) Achievement and Risk Avoidance ( r ≈ .4), but weakly with Resilience, Satisfaction, and Comfort ( r ≈ .2); and moderately with Weiss Functional Impairment Rating Scale-Parent (WFIRS-P) total score ( r ≈ .5). CHIP-CE: PRF Achievement and Risk Avoidance correlated moderately to strongly with WFIRS-P total score ( r ≈ .6). CONCLUSION: The ADHD-RS-IV, CHIP-CE:PRF, and WFIRS-P capture distinct but interconnected aspects of treatment response in individuals with ADHD

Cognitive Function of Children and Adolescents with Attention-Deficit/Hyperactivity Disorder in a 2-Year Open-Label Study of Lisdexamfetamine Dimesylate

BACKGROUND: SPD489-404 was the first 2-year safety study of lisdexamfetamine dimesylate in the treatment of attention-deficit/hyperactivity disorder in children and adolescents. In accordance with advice from the European Medicines Agency, assessment of cognitive function was a predefined safety outcome in SPD489-404. OBJECTIVE: The objective of this study was to assess cognitive function over 2 years in study SPD489-404, using the Cambridge Neuropsychological Test Automated Battery (CANTAB). METHODS: Participants aged 6-17 years received dose-optimised open-label lisdexamfetamine dimesylate (30, 50 or 70 mg/day) for 104 weeks. Cognition was assessed using four CANTAB tasks; Delayed Matching to Sample (DMS), Spatial Working Memory (SWM), Stop Signal Task (SST) and Reaction Time (RTI). Key and additional variables were pre-specified for each CANTAB task; groupwise mean percentage changes in key variables from baseline of > 5% were considered potentially clinically significant. RESULTS: All 314 enrolled participants received lisdexamfetamine dimesylate and were included in the safety population, and 191 (60.8%) completed the study. No potentially clinically significant deteriorations from baseline were observed in any key CANTAB variable over the 2 years of the study. Based on predefined thresholds, potentially clinically significant improvements from baseline were observed at 6 months (DMS median reaction time, mean per cent change, - 6.6%; SWM total between-search errors, - 22.8%; SST stop signal reaction time, -18.9%), and at the last on-treatment assessment (DMS median reaction time, - 6.5%; SWM total between-search errors, - 32.6%; SST stop signal reaction time, - 25.7%). CONCLUSIONS: Lisdexamfetamine dimesylate treatment for 2 years was not associated with deterioration of cognitive function in children and adolescents with attention-deficit/hyperactivity disorder. Although improvements in some cognitive measures were observed, lack of a control group makes interpretation of the findings difficult. Further studies of the impact of stimulants on cognition are required

An old castle and other essays,

Introduction, by H.W. Nevinson.--An old castle.--As you like it.--Antony and Cleopatra.--The winter's tale.--Shakespeare the man.--The literature of the age of Queen Anne: general characteristics of the age.--The literature of the age of Queen Anne: politics, parties, and persons.--The life of Jonathan Swift.--Robert Burns.--John Ruskin.--Browning: general characteristics.--Art, love, and religion in the poetry of Robert Browning.--Arthur Hugh Clough.--A new England mystic [Bronson Alcott]Mode of access: Internet

Outcomes of high-dose levofloxacin therapy remain bound to the levofloxacin minimum inhibitory concentration in complicated urinary tract infections

Abstract Background Fluoroquinolones are a guideline-recommended therapy for complicated urinary tract infections, including pyelonephritis. Elevated drug concentrations of fluoroquinolones in the urine and therapy with high-dose levofloxacin are believed to overcome resistance and effectively treat infections caused by resistant bacteria. The ASPECT-cUTI phase 3 clinical trial (ClinicalTrials.gov, NCT01345929 and NCT01345955 , both registered April 28, 2011) provided an opportunity to test this hypothesis by examining the clinical and microbiological outcomes of high-dose levofloxacin treatment by levofloxacin minimum inhibitory concentration. Methods Patients were randomly assigned 1:1 to ceftolozane/tazobactam (1.5 g intravenous every 8 h) or levofloxacin (750 mg intravenous once daily) for 7 days of therapy. The ASPECT-cUTI study provided data on 370 patients with at least one isolate of Enterobacteriaceae at baseline who were treated with levofloxacin. Outcomes were assessed at the test-of-cure (5–9 days after treatment) and late follow-up (21–42 days after treatment) visits in the microbiologically evaluable population (N = 327). Results Test-of-cure clinical cure rates above 90% were observed at minimum inhibitory concentrations ≤4 μg/mL. Microbiological eradication rates were consistently >90% at levofloxacin minimum inhibitory concentrations ≤0.06 μg/mL. Lack of eradication of causative pathogens at the test-of-cure visit increased the likelihood of relapse by the late follow-up visit. Conclusions Results from this study do not support levofloxacin therapy for complicated urinary tract infections caused by organisms with levofloxacin minimum inhibitory concentrations ≥4 μg/mL. Trial registration ClinicalTrials.gov, NCT01345929 and NCT0134595

Additional file 1: of A randomised, double-blind, placebo-controlled phase 1 study of the safety, tolerability and pharmacodynamics of volixibat in overweight and obese but otherwise healthy adults: implications for treatment of non-alcoholic steatohepatitis

Inclusion and exclusion criteria. (PDF 65 kb

Additional file 1: of Outcomes of high-dose levofloxacin therapy remain bound to the levofloxacin minimum inhibitory concentration in complicated urinary tract infections

List of Institutional Review Boards (IRB) and Independent Ethics Committees (IEC). (DOCX 13 kb