Dupilumab in patients with chronic spontaneous urticaria (LIBERTY-CSU CUPID): Two randomized, double-blind, placebo-controlled, phase 3 trials.

BACKGROUND: Chronic spontaneous urticaria (CSU) is a chronic inflammatory disease characterized by recurrent pruritic wheals (hives) and/or angioedema. Patients with CSU could remain symptomatic despite standard-of-care H1 antihistamines (H1-AH) or anti-IgE (omalizumab) treatment. Dupilumab blocks IL-4/IL-13 signaling and is approved for multiple type 2/atopic indications. OBJECTIVE: We conducted two phase 3, randomized, placebo-controlled, double-blind trials comparing dupilumab with placebo in patients with symptomatic CSU despite H1-AH. METHODS: In LIBERTY-CSU CUPID Study A, patients were omalizumab-naive (n = 138, aged ≥6 years). In Study B, patients were omalizumab-intolerant/incomplete responders (n = 108, aged ≥12 years). The primary end point was either change from baseline over 7 days in the Urticaria Activity Score (UAS7) or Itch Severity Score (ISS7) at week 24, with the other as a key secondary end point, depending on regional regulatory requirements. Studies were pooled for safety assessment. RESULTS: In Study A, UAS7 and ISS7 improved with dupilumab versus placebo (difference -8.5 [95% CI, -13.2 to -3.9; P = .0003] and -4.2 [95% CI, -6.6 to -1.8; P = .0005]). In Study B, tested at α = 0.043 after interim analysis, UAS7 improved (difference -5.8 [95% CI, -11.4 to -0.3; P = .0390]), with a numerical trend in ISS7 (difference -2.9 [95% CI, -5.7 to -0.07; nominal P = .0449, not significant]). Pooled safety data were consistent between dupilumab and placebo and with the known dupilumab safety profile. CONCLUSIONS: Dupilumab reduced urticaria activity by reducing itch and hives severity in omalizumab-naive patients with CSU uncontrolled with H1-AH. Although the primary end point for Study B was not met, dupilumab effects were small in patients who were omalizumab-intolerant/incomplete responders.

Dupilumab in CRSwNP: Responder Analysis Using Clinically Meaningful Efficacy Outcome Thresholds.

OBJECTIVES/HYPOTHESIS: Dupilumab, a fully human monoclonal antibody that blocks the shared interleukin (IL)-4/IL-13 receptor component, significantly improved outcomes for patients with chronic rhinosinusitis with nasal polyps (CRSwNP) in the SINUS-24 and SINUS-52 studies. This post hoc analysis evaluated dupilumab's effect on patient-reported symptoms and objective outcome measures using thresholds of clinically meaningful within-patient change from baseline. METHODS: Patients with CRSwNP receiving subcutaneous dupilumab or placebo every 2 weeks in SINUS-24/SINUS-52 were analyzed. Patients recorded severity of nasal congestion (NC), loss of smell (LoS), and anterior/posterior rhinorrhea (each within range 0-3) daily. Total Symptom Score (TSS) was calculated as a composite severity score (0-9) for these symptoms. Objective measures included University of Pennsylvania Smell Identification Test (UPSIT; 0-40), nasal polyps score (NPS; 0-8), and Lund-Mackay computed tomography score (LMK-CT; 0-24). Thresholds of within-patient change in scores from baseline at weeks 24 and 52 considered clinically meaningful were ≥1.0 (NC, LoS), ≥3.0 (TSS), ≥8.0 (UPSIT), ≥1.0 (NPS), and ≥5.0 (LMK-CT). RESULTS: A total of 724 and 303 patients were included in the week 24 and 52 analyses, respectively. Responder rates were significantly higher with dupilumab versus placebo at week 24 for NC (64% vs. 24%), LoS (63% vs. 14%), TSS (62% vs. 15%), UPSIT (54% vs. 6%), NPS (63% vs. 14%), and LMK-CT (59% vs. 3%); all P < .0001. Results were consistent at week 52. CONCLUSION: Significantly greater proportions of dupilumab-treated patients with CRSwNP compared with placebo demonstrated clinically meaningful improvements in patient-reported sinonasal symptoms and objective outcomes. LEVEL OF EVIDENCE: 2 Laryngoscope, 132:259-264, 2022.

Trial monitoring via a futility criterion for interim results on a count data endpoint and a continuous endpoint.

Assumptions made at design stage regarding the true treatment effect, background event rate and other factors may not always hold. Thus, long-term and large-scale studies may be designed with an interim analysis in order that the trials may be stopped early due to futility to save resource. There are many considerations of trial conducts for this type of trials. In this paper, we use a mock study to illustrate systematically the thinking and procedures for trial monitoring with a futility criterion for the interim results on a count data endpoint and a continuous endpoint. We focus on the discussions of blinded trial monitoring, the probability of meeting the futility criterion, conditional power/probability of success, Bayesian inference, potential delayed treatment effect and subgroup analysis. The experience should be applicable to future studies with similar features.

Dupilumab improves health-related quality of life in patients with chronic rhinosinusitis with nasal polyposis.

BACKGROUND: Chronic rhinosinusitis with nasal polyposis (CRSwNP) negatively affects health-related quality of life (HRQoL). In a previously reported randomized clinical trial (NCT01920893), addition of dupilumab to mometasone furoate in patients with CRSwNP refractory to intranasal corticosteroids (INCS) significantly improved endoscopic, radiographic, and clinical endpoints and patient-reported outcomes. The objective of this analysis was to examine the impact of dupilumab treatment on HRQoL and productivity using secondary outcome data from this trial. METHODS: Following a 4-week mometasone furoate nasal spray run-in, patients were randomized to commence subcutaneous dupilumab (600 mg loading dose, then 300 mg once weekly for 15 weeks [n = 30], or matched placebo [n = 30]). Outcomes included scores on the CRS disease severity visual analog scale (VAS), 22-item Sino-Nasal Outcome Test (SNOT-22), 5-dimension EuroQoL (EQ-5D) general health status VAS, and 36-item Short-Form Health Survey (SF-36) for HRQoL and nasal polyp-related healthcare resource use questionnaires. RESULTS: Following 16 weeks of treatment, the proportion of patients with moderate-to-severe CRSwNP (VAS > 3-10) decreased from 86.2% to 21.4% with dupilumab and 88.0% to 84.2% with placebo. Dupilumab (vs placebo) resulted in significantly greater improvement in HRQoL, based on SNOT-22, SF-36, and EQ-5D VAS scores. The dupilumab group had a significantly lower adjusted annualized mean number of sick leave days (0.09, vs 4.18 with placebo, P = .015) and significantly greater improvement (vs placebo) in the SNOT-22 item "reduced productivity." CONCLUSIONS: In adults with CRSwNP refractory to treatment with INCS alone, the addition of dupilumab reduced disease severity, significantly improved HRQoL, and improved productivity.

Dupilumab reduces opacification across all sinuses and related symptoms in patients with CRSwNP.

BACKGROUND: Chronic rhinosinusitis with nasal polyposis (CRSwNP) is associated with substantial sinus opacification. In a phase 2a study (NCT01920893), dupilumab, a fully human anti-IL-4Rα monoclonal antibody, improved outcomes in CRSwNP refractory to intranasal corticosteroids. We evaluated dupilumab’s effect on sinus opacification in relation to effects on nasal polyp burden, symptoms, and health-related quality of life (HRQoL) in patients with CRSwNP. METHODOLOGY: 16-week randomized, double-blind, placebo-controlled, parallel-group study in 60 adults with CRSwNP. Patients received weekly subcutaneous dupilumab 300-mg or placebo and daily mometasone furoate nasal spray. Sinus opacification was assessed using standard and Zinreich-modified Lundâ€"Mackay (zLMK) scoring. Correlation was assessed between zLMK score and CRSwNP endpoints, including nasal polyp score (NPS), SNOT-22, daily symptom scores, and UPSIT smell-test score. RESULTS: Baseline characteristics were similar across treatment groups. Mean plus/minus SD baseline LMK scores of 18.7 plus/minus 5.5 (placebo) and 18.6 plus/minus 5.0 (dupilumab) indicated severe disease with extensive opacification involving all sinuses. Baseline LMK and LMK scores correlated with NPS severity and loss of sense of smell (daily symptoms; SNOT-22 smell/taste; loss of sense of smell [UPSIT]). At Week 16, dupilumab-treated patients had significantly improved sinus opacification measured by LMK in all individual sinuses vs placebo. Dupilumab also showed similar efficacy with zLMK, with only small differences from LMK, and correlated with SNOT22 smell/taste. The most common adverse events were nasopharyngitis, injection-site reactions, and headache. CONCLUSIONS: In patients with CRSwNP, baseline LMK showed extensive sinus opacification and correlated with symptoms, HRQoL, and hyposmia. Dupilumab treatment reduces opacification across all sinuses and related symptoms in patients with CRSwNP.

Efficacy and safety of dupilumab in patients with severe chronic rhinosinusitis with nasal polyps (LIBERTY NP SINUS-24 and LIBERTY NP SINUS-52): results from two multicentre, randomised, double-blind, placebo-controlled, parallel-group phase 3 trials.

BACKGROUND: Patients with chronic rhinosinusitis with nasal polyps (CRSwNP) generally have a high symptom burden and poor health-related quality of life, often requiring recurring systemic corticosteroid use and repeated sinus surgery. Dupilumab is a fully human monoclonal antibody that inhibits signalling of interleukin (IL)-4 and IL-13, key drivers of type 2 inflammation, and has been approved for use in atopic dermatitis and asthma. In these two studies, we aimed to assess efficacy and safety of dupilumab in patients with CRSwNP despite previous treatment with systemic corticosteroids, surgery, or both. METHODS: LIBERTY NP SINUS-24 and LIBERTY NP SINUS-52 were two multinational, multicentre, randomised, double-blind, placebo-controlled, parallel-group studies assessing dupilumab added to standard of care in adults with severe CRSwNP. SINUS-24 was done in 67 centres in 13 countries, and SINUS-52 was done in 117 centres in 14 countries. Eligible patients were 18 years or older with bilateral CRSwNP and symptoms despite intranasal corticosteroid use, receiving systemic corticosteroids in the preceding 2 years, or having had sinonasal surgery. Patients in SINUS-24 were randomly assigned (1:1) to subcutaneous dupilumab 300 mg or placebo every 2 weeks for 24 weeks. Patients in SINUS-52 were randomly assigned (1:1:1) to dupilumab 300 mg every 2 weeks for 52 weeks, dupilumab every 2 weeks for 24 weeks and then every 4 weeks for the remaining 28 weeks, or placebo every 2 weeks for 52 weeks. All patients were randomly assigned centrally with a permuted block randomisation schedule. Randomisation was stratified by asthma or non-steroidal anti-inflammatory drug-exacerbated respiratory disease status at screening, previous surgery at screening, and country. Patients with or without comorbid asthma were included. Coprimary endpoints were changes from baseline to week 24 in nasal polyp score (NPS), nasal congestion or obstruction, and sinus Lund-Mackay CT scores (a coprimary endpoint in Japan), done in an intention-to-treat population. Safety was assessed in a pooled population of both dupilumab groups in SINUS-52 up to week 24 and the dupilumab group in SINUS-24 and the placebo groups in both studies until week 24. The trials are complete and registered at ClinicalTrials.gov, NCT02912468 and NCT02898454. FINDINGS: Between Dec 5, 2016, and Aug 3, 2017, 276 patients were enrolled in SINUS-24, with 143 in the dupilumab group and 133 in the placebo group receiving at least one study drug dose. Between Nov 28, 2016, and Aug 28, 2017, 448 patients were enrolled in SINUS-52, with 150 receiving at least one dose of dupilumab every 2 weeks, 145 receiving at least one dose of dupilumab every 2 weeks for 24 weeks and every 4 weeks until week 52, and 153 receiving at least one dose of placebo. Dupilumab significantly improved the coprimary endpoints in both studies. At 24 weeks, least squares mean difference in NPS of dupilumab treatment versus placebo was -2·06 (95% CI -2·43 to -1·69; p<0·0001) in SINUS-24 and -1·80 (-2·10 to -1·51; p<0·0001) in SINUS-52; difference in nasal congestion or obstruction score was -0·89 (-1·07 to -0·71; p<0·0001) in SINUS-24 and -0·87 (-1·03 to -0·71; p<0·0001) in SINUS-52; and difference in Lund-Mackay CT scores was -7·44 (-8·35 to -6·53; p<0·0001) in SINUS-24 and -5·13 (-5·80 to -4·46; p<0·0001) in SINUS-52. The most common adverse events (nasopharyngitis, worsening of nasal polyps and asthma, headache, epistaxis, and injection-site erythema) were more frequent with placebo. INTERPRETATION: In adult patients with severe CRSwNP, dupilumab reduced polyp size, sinus opacification, and severity of symptoms and was well tolerated. These results support the benefits of adding dupilumab to daily standard of care for patients with severe CRSwNP who otherwise have few therapeutic options. FUNDING: Sanofi and Regeneron Pharmaceuticals.

Immunogenicity of Sarilumab Monotherapy in Patients with Rheumatoid Arthritis Who Were Inadequate Responders or Intolerant to Disease-Modifying Antirheumatic Drugs.

INTRODUCTION: This open-label study evaluated the immunogenicity, safety, and efficacy of sarilumab monotherapy in patients with active, moderate-to-severe rheumatoid arthritis (RA) and inadequate response or intolerance to prior conventional synthetic disease-modifying antirheumatic drugs. METHODS: Adults with RA (n = 132) were randomized to receive subcutaneous sarilumab (150 [n = 65] or 200 mg [n = 67]) every 2 weeks (q2w) for 24 weeks. Endpoints included incidence of antidrug antibodies (ADAs) at week 24, safety, and efficacy. RESULTS: Persistent ADAs occurred in eight patients (12.3%) receiving sarilumab 150 mg q2w, seven of whom (10.8%) had neutralizing antibodies (NAbs), and in four patients (6.1%) receiving sarilumab 200 mg q2w, two of whom (3.0%) had NAbs; all exhibited low antibody titers. Infections and neutropenia were the most common adverse events (AEs). There were three serious AEs, no reports of anaphylaxis, and few hypersensitivity reactions (e.g., rash) with no notable differences in hypersensitivity reactions in ADA-positive patients relative to ADA-negative patients. Changes in absolute neutrophil count, alanine aminotransferase level, and platelet count were consistent with interleukin-6 signaling blockade and in agreement with previous observations. At week 24, overall American College of Rheumatology 20%/50%/70% improvement criteria responses were 73.8%/53.8%/29.2%, respectively, with sarilumab 150 mg q2w and 71.6%/50.7%/29.9% with sarilumab 200 mg q2w. No patients with an ADA-positive response showed loss of efficacy. CONCLUSIONS: ADA titers were low and persistent ADAs and NAbs occurred relatively infrequently in both sarilumab dose groups. ADA did not meaningfully impact the safety or efficacy of either dose of sarilumab over 24 weeks. TRIAL REGISTRATION: ClinicalTrials.gov, identifier NCT02121210. FUNDING: Sanofi Genzyme and Regeneron Pharmaceuticals, Inc. Plain language summary available for this article.

Sample size calculations for comparing two groups of count data.

A sample size formula for comparing two groups of count data is derived using the method of moments by matching the first and second moments of the distribution of the count data, and it does not need any further distributional assumption. Compared to sample size formulas derived using a likelihood-based approach or using simulations, the proposed sample size formula applies to count data following any distribution in addition to the negative binomial distribution. The proposed sample size formula can be used even when the study is analyzed with a likelihood-based approach. Because asymptotically, the method of moments is no more efficient than likelihood-based approaches, the proposed sample size formula can be viewed as an upper bound of the required sample size by likelihood-based approaches to start the study. Applications of the sample size formula are illustrated using an asthma study design.

Dupilumab reduces local type 2 pro-inflammatory biomarkers in chronic rhinosinusitis with nasal polyposis.

BACKGROUND: Chronic rhinosinusitis with nasal polyposis (CRSwNP) is a type 2-mediated inflammatory disease associated with significant clinical, social, and economic burdens and high unmet therapeutic need. Dupilumab, a fully human monoclonal antibody targeting the interleukin-4 receptor α (IL-4Rα) subunit, demonstrated efficacy and acceptable safety in CRSwNP and other type 2 diseases (eg, atopic dermatitis and asthma). We now report the local effects of dupilumab on type 2 inflammatory biomarkers in nasal secretions and nasal polyp tissues of patients with CRSwNP in a randomized, placebo-controlled, phase 2 trial (NCT01920893). METHODS: Cytokines, chemokines, and total immunoglobulin E (IgE) levels were measured using immunoassay techniques in nasal secretions and nasal polyp tissue homogenates of CRSwNP patients receiving dupilumab 300 mg or placebo weekly for 16 weeks. RESULTS: With dupilumab, type 2 biomarker concentrations decreased in nasal secretions (least squares mean area under the curve from 0 to 16 weeks for the change from baseline) vs placebo for eotaxin-3 (-30.06 vs -0.86 pg/mL; P = 0.0008) and total IgE (-7.90 vs -1.86 IU/mL; P = 0.022). Dupilumab treatment also decreased type 2 biomarker levels in nasal polyp tissues at Week 16 vs baseline for eosinophilic cationic protein (P = 0.008), eotaxin-2 (P = 0.008), eotaxin-3 (P = 0.031), pulmonary and activation-regulated chemokine (P = 0.016), IgE (P = 0.023), and IL-13 (P = 0.031). CONCLUSIONS: Dupilumab treatment reduced multiple biomarkers of type 2 inflammation in nasal secretions and polyp tissues of patients with CRSwNP, demonstrating that antagonism of IL-4Rα signaling suppresses IL-4-/IL-13-dependent processes, such as mucosal IgE formation, as well as the expression of chemokines attracting inflammatory cells to the nasal mucosa.

Two years of sarilumab in patients with rheumatoid arthritis and an inadequate response to MTX: safety, efficacy and radiographic outcomes.

Objectives: To examine 2-year safety, efficacy and radiographic outcomes of sarilumab in adults with RA and inadequate response to MTX (MTX-IR). Methods: In the randomized, placebo-controlled MOBILITY trial, MTX-IR patients received subcutaneous sarilumab (150 or 200 mg) or placebo every 2 weeks (q2w) plus MTX for up to 1 year. Upon study completion, patients could enrol in the open-label, long-term extension study (EXTEND, NCT011046652), in which all patients received sarilumab 200 mg q2w plus MTX. Dose reduction to 150 mg q2w was allowed for abnormal laboratory findings and per investigator's discretion. Results: Of 1197 patients participating in MOBILITY, 901 entered EXTEND. Over the 2-year period, treatment-emergent adverse events (TEAEs) and serious AEs occurred at rates of 279.6 events per 100 patient-years and 16.6 events per 100 patient-years, respectively. The most common TEAEs were neutropenia, injection site erythema, increased alanine aminotransferase and upper respiratory tract infections. After 1 year in the open-label, long-term extension, disease activity reached similar levels regardless of initial treatment. Modified total Sharp scores at year 1 were maintained through year 2. Best radiographic outcomes were observed in patients initially randomized to sarilumab 200 mg q2w. After dose reduction, 89.4% of patients continued the study through 2 years. Conclusion: Sarilumab safety through year 2 was consistent with IL-6 receptor blockade. Clinical response was similar irrespective of initial treatment, and radiographic progression stabilized. Patients initiated on sarilumab 200 mg q2w had the best radiographic outcomes. Dose reduction allowed most patients to continue with the study.

Sarilumab plus methotrexate improves patient-reported outcomes in patients with active rheumatoid arthritis and inadequate responses to methotrexate: results of a phase III trial.

BACKGROUND: Sarilumab is a human monoclonal antibody directed against the alpha subunit of the interleukin-6 receptor complex. In the MOBILITY phase III randomized controlled trial (RCT), sarilumab + methotrexate (MTX) treatment resulted in clinical improvements at 24 weeks that were maintained at 52 weeks in adults with rheumatoid arthritis (RA), who have inadequate response to MTX (MTX-IR). These analyses indicate the effects of sarilumab + MTX versus placebo on patient-reported outcomes (PROs) in this RCT. METHODS: Patients (n = 1197) were randomized to receive placebo, sarilumab 150 or 200 mg subcutaneously + MTX every 2 weeks for 52 weeks; after 16 weeks, patients without ≥20 % improvement from baseline in swollen or tender joint counts on two consecutive assessments were offered open-label treatment. PROs included patient global assessment of disease activity (PtGA), pain, health assessment questionnaire disability index (HAQ-DI), Short Form-36 Health Survey (SF-36), and functional assessment of chronic illness therapy-fatigue (FACIT-F). Changes from baseline at weeks 24 and 52 were analyzed using a mixed model for repeated measures. Post hoc analyses included percentages of patients reporting improvements equal to or greater than minimal clinically important differences (MCID) and normative values in the FACIT-F and SF-36. Pearson correlation between observed PRO scores and clinical measures of disease activity was tested at week 24. RESULTS: Both doses of sarilumab + MTX vs placebo + MTX resulted in improvement from baseline by week 24 in PtGA, pain, HAQ-DI, SF-36 and FACIT-F scores (p < 0.0001) that was clinically meaningful, and persisted until week 52. In post hoc analyses, the percentages of patients with improvement equal to or greater than the MCID across all PROs were greater with sarilumab than placebo (p < 0.05), with differences ranging from 11.6 to 26.2 %, as were those reporting equal to or greater than normative scores. CONCLUSIONS: In this RCT in patients with MTX-IR RA, sarilumab + MTX resulted in sustained improvement in PROs that were clinically meaningful, greater than placebo + MTX, and complement the previously reported clinical efficacy and safety of sarilumab. TRIAL REGISTRATION: ClinicalTrials.gov. NCT01061736 . February 2, 2010.

Sarilumab Plus Methotrexate in Patients With Active Rheumatoid Arthritis and Inadequate Response to Methotrexate: Results of a Phase III Study.

OBJECTIVE: To evaluate the efficacy and safety of sarilumab in combination with methotrexate (MTX) for the treatment of rheumatoid arthritis (RA). METHODS: Adults with moderate-to-severe RA and an inadequate response to MTX were randomized (1:1:1) to receive sarilumab (doses of 150 mg or 200 mg) or placebo every 2 weeks in conjunction with weekly MTX for 52 weeks. Co-primary end points were the proportion of patients achieving American College of Rheumatology 20% (ACR20) improvement responses at week 24, change from baseline in the Health Assessment Questionnaire (HAQ) disability index (DI) at week 16, and change from baseline in the modified Sharp/van der Heijde score (SHS) of radiographic damage at week 52. RESULTS: Baseline characteristics were similar among the groups. For all 3 co-primary end points, the sarilumab 150 mg and 200 mg groups demonstrated statistically significant improvements as compared with the placebo group (ACR20 response rate at week 24, 58.0%, 66.4%, and 33.4%, respectively [P < 0.0001]; least squares mean change in HAQ DI at week 16, -0.53, -0.55, and -0.29, respectively [P < 0.0001]; and mean change in SHS at week 52, 0.90, 0.25, and 2.78, respectively [P < 0.0001]). The most common treatment-emergent adverse event was infection. In the sarilumab 150 mg, sarilumab 200 mg, and placebo groups, the incidence of serious infections was 2.6%, 4.0%, and 2.3%, respectively. Elevations in alanine aminotransferase levels >3-fold the upper limit of normal occurred in 9.5%, 8.0%, and 2.1% of patients, respectively; in 24 patients, this led to discontinuation of treatment. Elevated total cholesterol levels were observed in 36.8%, 43.0%, and 18.3% of patients, respectively. In patients receiving 150 mg and 200 mg sarilumab, neutrophil counts of 0.5 to <1.0 × 10(9) /liter were observed in 5.1% and 7.8% of patients, respectively, while neutrophil counts of <0.5 × 10(9) /liter were observed in 0.9% and 0.7% of patients, respectively; none of the patients receiving placebo experienced changes in neutrophil counts. CONCLUSION: In RA patients treated with sarilumab (150 mg or 200 mg every 2 weeks) in combination with MTX, both doses provided sustained clinical efficacy, as shown by significant improvements in symptomatic, functional, and radiographic outcomes. Sarilumab was generally well tolerated. The adverse events observed in this study were consistent with the effects of interleukin-6 signaling blockade.

Sample size determination in two-sided distribution-free treatment versus control multiple comparisons.

The problem of power and sample size determination for distribution-free multiple comparison tests of K treatments versus a control group is addressed. We define the power as the probability of correctly rejecting one specified or all K hypotheses, corresponding to the per-pair and all-pairs power, respectively. The power formulas are derived for both joint ranking and pairwise ranking mechanism for general multiple comparison problems, followed by explicit form of these formulas when the single-step, step-down, or step-up adjustments are applied. The proposed power and sample size calculation methods apply to scenarios both when the underlying distributions are known and when they are unknown but a pilot study is available. Numerical methods via quasi-Monte Carlo integration and Monte Carlo integration are assessed. Our simulation studies show the accuracy of the power and sample size calculation formulas. We recommend the Monte Carlo integration as the calculation algorithm. An example from a mouse peritoneal cavity study is used to demonstrate the application of the methods.

A comparison of bias-corrected covariance estimators for generalized estimating equations.

Although asymptotically the sandwich covariance estimator is consistent and robust with respect to the selection of the working correlation matrix, when the sample size is small, its bias may not be negligible. This article compares the small sample corrections for the sandwich covariance estimator as well as the inferential procedures proposed by Mancl and DeRouen ( 2001 ), Kauermann and Carroll ( 2001 ), Fay and Graubard ( 2001 ), and Fan et al. ( 2012 ). Simulation studies show that when using a maximum likelihood method to estimate the covariance parameters and using the between-within method for the denominator degrees of freedom when making inference, the Kauermann and Carroll method is preferred in the investigated balanced logistic regression and the Mancl and DeRouen and Fan et al. methods are preferred in the investigated proportional odds model. A collagen-induced arthritis study is employed to demonstrate the application of the methods.

A note on power and sample size calculations for the Kruskal-Wallis test for ordered categorical data.

Although the Kruskal-Wallis test has been widely used to analyze ordered categorical data, power and sample size methods for this test have been investigated to a much lesser extent when the underlying multinomial distributions are unknown. This article generalizes the power and sample size procedures proposed by Fan et al. ( 2011 ) for continuous data to ordered categorical data, when estimates from a pilot study are used in the place of knowledge of the true underlying distribution. Simulations show that the proposed power and sample size formulas perform well. A myelin oligodendrocyte glycoprotein (MOG) induced experimental autoimmunce encephalomyelitis (EAE) mouse study is used to demonstrate the application of the methods.

Vitamin D intake and cardiovascular mortality in the NHANES I epidemiological follow-up study cohort.

The objective of the present study was to determine whether vitamin D intake is associated with CVD mortality in a general population sample. The association between vitamin D intake and CVD mortality (ICD-9 code 410-414) rates was investigated using data from the the First National Health and Nutrition Examination Survey (NHANES I) Epidemiological Follow-up Study (NHEFS) 1971-1992. Overall, higher vitamin D intake was associated with lower CVD mortality. After adjustment for traditional risk factors for CVD, vitamin D intake showed mild but nonstatistically significant protective effects against CVD mortality with a hazard ratio for adequate as compared to low intake (with 95% confidence intervals) of 0.90 (0.74, 1.08). Hazard ratios were 0.95, 0.83, 0.88, and 1.02, in males, females, Whites, and Blacks, respectively (with 95% confidence intervals overlapping 1.0 in all cases). Thus, we did not find a statistically significant association between vitamin D intake and CVD mortality, although our findings are compatible with a mild protective effect, especially among females and Whites.

Robust small-sample inference for fixed effects in general Gaussian linear models.

Although asymptotically, the empirical covariance estimator is consistent and robust with respect to the selection of the working correlation matrix, when the sample size is small, its bias may not be negligible. This article proposes a small sample correction for the empirical covariance estimator in general Gaussian linear models. Inference for the fixed effects based on the corrected covariance matrix is also derived. A two-way analysis of variance (ANOVA) model with repeated measures, which evaluates the effectiveness of a CB1 receptor antagonist, and a four-period crossover design, which assesses the treatment effect in subjects with intermittent claudication, serve as examples to illustrate the proposed and other investigated methods. Simulation studies show that the proposed method generally performs better than other bias-correction methods, including Mancl and DeRouen (2001), Kauermann and Carroll (2001), and Fay and Graubard (2001), in the investigated balanced designs.

The central cannabinoid CB1 receptor is required for diet-induced obesity and rimonabant's antiobesity effects in mice.

Cannabinoid receptor CB1 is expressed abundantly in the brain and presumably in the peripheral tissues responsible for energy metabolism. It is unclear if the antiobesity effects of rimonabant, a CB1 antagonist, are mediated through the central or the peripheral CB1 receptors. To address this question, we generated transgenic mice with central nervous system (CNS)-specific knockdown (KD) of CB1, by expressing an artificial microRNA (AMIR) under the control of the neuronal Thy1.2 promoter. In the mutant mice, CB1 expression was reduced in the brain and spinal cord, whereas no change was observed in the superior cervical ganglia (SCG), sympathetic trunk, enteric nervous system, and pancreatic ganglia. In contrast to the neuronal tissues, CB1 was undetectable in the brown adipose tissue (BAT) or the liver. Consistent with the selective loss of central CB1, agonist-induced hypothermia was attenuated in the mutant mice, but the agonist-induced delay of gastrointestinal transit (GIT), a primarily peripheral nervous system-mediated effect, was not. Compared to wild-type (WT) littermates, the mutant mice displayed reduced body weight (BW), adiposity, and feeding efficiency, and when fed a high-fat diet (HFD), showed decreased plasma insulin, leptin, cholesterol, and triglyceride levels, and elevated adiponectin levels. Furthermore, the therapeutic effects of rimonabant on food intake (FI), BW, and serum parameters were markedly reduced and correlated with the degree of CB1 KD. Thus, KD of CB1 in the CNS recapitulates the metabolic phenotype of CB1 knockout (KO) mice and diminishes rimonabant's efficacy, indicating that blockade of central CB1 is required for rimonabant's antiobesity actions.

On sample size of the kruskal-wallis test with application to a mouse peritoneal cavity study.

As the nonparametric generalization of the one-way analysis of variance model, the Kruskal-Wallis test applies when the goal is to test the difference between multiple samples and the underlying population distributions are nonnormal or unknown. Although the Kruskal-Wallis test has been widely used for data analysis, power and sample size methods for this test have been investigated to a much lesser extent. This article proposes new power and sample size calculation methods for the Kruskal-Wallis test based on the pilot study in either a completely nonparametric model or a semiparametric location model. No assumption is made on the shape of the underlying population distributions. Simulation results show that, in terms of sample size calculation for the Kruskal-Wallis test, the proposed methods are more reliable and preferable to some more traditional methods. A mouse peritoneal cavity study is used to demonstrate the application of the methods.