Points to consider for analyzing efficacy outcomes in long-term extension clinical trials.

This article focuses on 2 objectives in the analysis of efficacy in long-term extension studies of chronic diseases: (1) defining and discussing estimands of interest in such studies and (2) evaluating the performance of several multiple imputation methods that may be useful in estimating some of these estimands. Specifically, 4 estimands are defined and their clinical utility and inferential ramifications discussed. The performance of several multiple imputation methods and approaches were evaluated using simulated data. Results suggested that when interest is in a binary outcome derived from an underlying continuous measurement, it is preferable to impute the underlying continuous value that is subsequently dichotomized rather than to directly impute the binary outcome. Results also demonstrated that multivariate Gaussian models with Markov chain Monte Carlo imputation and sequential regression have minimal bias and the anticipated confidence interval coverage, even in settings with ordinal data where departures from normality are a concern. These approaches are further illustrated using a long-term extension study in psoriasis.

Nonparametric covariate adjustment in estimating hazard ratios.

In randomized clinical trials with time-to-event outcomes, the hazard ratio is commonly used to quantify the treatment effect relative to a control. The Cox regression model is commonly used to adjust for relevant covariates to obtain more accurate estimates of the hazard ratio between treatment groups. However, it is well known that the treatment hazard ratio based on a covariate-adjusted Cox regression model is conditional on the specific covariates and differs from the unconditional hazard ratio that is an average across the population. Therefore, covariate-adjusted Cox models cannot be used when the unconditional inference is desired. In addition, the covariate-adjusted Cox model requires the relatively strong assumption of proportional hazards for each covariate. To overcome these challenges, a nonparametric randomization-based analysis of covariance method was proposed to estimate the covariate-adjusted hazard ratios for multivariate time-to-event outcomes. However, empirical evaluations of the performance (power and type I error rate) of the method have not been studied. Although the method is derived for multivariate situations, for most registration trials, the primary endpoint is a univariate outcome. Therefore, this approach is applied to univariate outcomes, and performance is evaluated through a simulation study in this paper. Stratified analysis is also investigated. As an illustration of the method, we also apply the covariate-adjusted and unadjusted analyses to an oncology trial.

To adjust or not to adjust for baseline when analyzing repeated binary responses? The case of complete data when treatment comparison at study end is of interest.

The benefits of adjusting for baseline covariates are not as straightforward with repeated binary responses as with continuous response variables. Therefore, in this study, we compared different methods for analyzing repeated binary data through simulations when the outcome at the study endpoint is of interest. Methods compared included chi-square, Fisher's exact test, covariate adjusted/unadjusted logistic regression (Adj.logit/Unadj.logit), covariate adjusted/unadjusted generalized estimating equations (Adj.GEE/Unadj.GEE), covariate adjusted/unadjusted generalized linear mixed model (Adj.GLMM/Unadj.GLMM). All these methods preserved the type I error close to the nominal level. Covariate adjusted methods improved power compared with the unadjusted methods because of the increased treatment effect estimates, especially when the correlation between the baseline and outcome was strong, even though there was an apparent increase in standard errors. Results of the Chi-squared test were identical to those for the unadjusted logistic regression. Fisher's exact test was the most conservative test regarding the type I error rate and also with the lowest power. Without missing data, there was no gain in using a repeated measures approach over a simple logistic regression at the final time point. Analysis of results from five phase III diabetes trials of the same compound was consistent with the simulation findings. Therefore, covariate adjusted analysis is recommended for repeated binary data when the study endpoint is of interest.

A multiple-imputation-based approach to sensitivity analyses and effectiveness assessments in longitudinal clinical trials.

It is important to understand the effects of a drug as actually taken (effectiveness) and when taken as directed (efficacy). The primary objective of this investigation was to assess the statistical performance of a method referred to as placebo multiple imputation (pMI) as an estimator of effectiveness and as a worst reasonable case sensitivity analysis in assessing efficacy. The pMI method assumes the statistical behavior of placebo- and drug-treated patients after dropout is the statistical behavior of placebo-treated patients. Thus, in the effectiveness context, pMI assumes no pharmacological benefit of the drug after dropout. In the efficacy context, pMI is a specific form of a missing not at random analysis expected to yield a conservative estimate of efficacy. In a simulation study with 18 scenarios, the pMI approach generally provided unbiased estimates of effectiveness and conservative estimates of efficacy. However, the confidence interval coverage was consistently greater than the nominal coverage rate. In contrast, last and baseline observation carried forward (LOCF and BOCF) were conservative in some scenarios and anti-conservative in others with respect to efficacy and effectiveness. As expected, direct likelihood (DL) and standard multiple imputation (MI) yielded unbiased estimates of efficacy and tended to overestimate effectiveness in those scenarios where a drug effect existed. However, in scenarios with no drug effect, and therefore where the true values for both efficacy and effectiveness were zero, DL and MI yielded unbiased estimates of efficacy and effectiveness.

Comparison of several multiple imputation strategies for repeated measures analysis of clinical scales: to truncate or not to?

We evaluated via a simulation study several strategies for imputing missing ordinal outcomes in a longitudinal clinical trial, contrasting methods that involve truncation of imputed values outside plausible ranges with those that do not. Our aim was to identify a preferred imputation strategy for estimating treatment difference at study endpoint. Plausible data were simulated via resampling of existing placebo data sets and adding treatment effect; then different imputation strategies were evaluated under missingness at random (MAR) and varying dropout rates. Our conclusion is that imputation methods based on rounding and truncation lead to larger bias than strategies based on simple methods based on (nontruncated) multivariate normal distribution.

The challenges of evaluating dose response in flexible-dose trials using marginal structural models.

Assessing dose response from flexible-dose clinical trials is problematic. The true dose effect may be obscured and even reversed in observed data because dose is related to both previous and subsequent outcomes. To remove selection bias, we propose marginal structural models, inverse probability of treatment-weighting (IPTW) methodology. Potential clinical outcomes are compared across dose groups using a marginal structural model (MSM) based on a weighted pooled repeated measures analysis (generalized estimating equations with robust estimates of standard errors), with dose effect represented by current dose and recent dose history, and weights estimated from the data (via logistic regression) and determined as products of (i) inverse probability of receiving dose assignments that were actually received and (ii) inverse probability of remaining on treatment by this time. In simulations, this method led to almost unbiased estimates of true dose effect under various scenarios. Results were compared with those obtained by unweighted analyses and by weighted analyses under various model specifications. The simulation showed that the IPTW MSM methodology is highly sensitive to model misspecification even when weights are known. Practitioners applying MSM should be cautious about the challenges of implementing MSM with real clinical data. Clinical trial data are used to illustrate the methodology.

Duloxetine for the treatment of recurrent major depressive disorder in elderly patients: treatment outcomes in patients with comorbid arthritis.

BACKGROUND: Evaluation and treatment of major depression (MDD) in elderly patients is frequently complicated by the presence of comorbid medical conditions, which can reduce the effect of depression treatment, leading to lower rates of depressive-symptom improvement and higher rates of relapse. OBJECTIVE: The authors investigated results of antidepressant concurrent with arthritis pain treatment in elderly patients. METHOD: Patients age 65 and over with recurrent MDD were stratified by arthritis status and randomized to duloxetine (a dual reuptake-inhibitor of serotonin and norepinephrine) or placebo treatment for 8 weeks (duloxetine, N=117; placebo, N=55). RESULTS: Duloxetine significantly reduced MDD symptom severity in elderly patients with and without arthritis, and produced significant reduction in several pain measures in those patients with comorbid arthritis. DISCUSSION: The magnitude and time-course of depressive symptom improvement did not differ significantly between patients with and without arthritis. Some studies have suggested that the severity of pain in arthritis patients may be linked to depression severity.

The significance of treating somatic symptoms on functional outcome improvement in patients with major depressive disorder: a post hoc analysis of 2 trials.

BACKGROUND: Functional impairment is associated with major depressive disorder (MDD), and patients with MDD often present with somatic symptoms. OBJECTIVE: To examine the relationships between improved global functioning and core depressive symptoms as well as painful and nonpainful somatic symptoms in patients with MDD. METHOD: This post hoc analysis of 2 identical trials compared the efficacy of duloxetine with that of paroxetine or placebo as treatment of MDD. In the trials, patients with DSM-IV-defined MDD received duloxetine 80 mg/day (N = 188), duloxetine 120 mg/day (N = 196), paroxetine 20 mg/day (N = 183), or placebo (N = 192) for 8 weeks. The Sheehan Disability Scale (SDS), Maier subscale of the 17-item Hamilton Rating Scale for Depression, 21-item Somatic Symptom Inventory, and Visual Analog Scale for overall pain were used to measure functional impairment, core symptoms of depression, and nonpainful and painful somatic symptoms, respectively. Baseline-to-endpoint mean changes in SDS total and subdomains were measured using analysis of variance with last-observation-carried-forward Pearson partial correlations, and path analysis was used to assess the significance of associations and relative contributions of improvement in global functional impairment, depression, and somatic symptoms. The trials were conducted from November 2000 to July 2002. RESULTS: The difference between antidepressant treatment and placebo in SDS total and subdomains was significant (p < .001). At baseline and in change from baseline to endpoint, associations between global functional impairment and core depressive and somatic symptoms were all significant (p < .05). Path analysis demonstrated improvement of functional impairment attributed to treatment effect as 37.0% (core depressive symptoms), 13.0% (nonpainful somatic symptoms), and 11.0% (painful somatic symptoms). CONCLUSION: In patients with MDD, over a third of functional improvement associated with antidepressant therapy was mediated through improvement in core depressive symptoms. In addition, a significant proportion of functional improvement, although to a lesser degree, was associated with the treatment of both nonpainful and painful somatic symptoms.

The impact of missing data and how it is handled on the rate of false-positive results in drug development.

In drug development, a common choice for the primary analysis is to assess mean changes via analysis of (co)variance with missing data imputed by carrying the last or baseline observations forward (LOCF, BOCF). These approaches assume that data are missing completely at random (MCAR). Multiple imputation (MI) and likelihood-based repeated measures (MMRM) are less restrictive as they assume data are missing at random (MAR). Nevertheless, LOCF and BOCF remain popular, perhaps because it is thought that the bias in these methods lead to protection against falsely concluding that a drug is more effective than the control. We conducted a simulation study that compared the rate of false positive results or regulatory risk error (RRE) from BOCF, LOCF, MI, and MMRM in 32 scenarios that were generated from a 2(5) full factorial arrangement with data missing due to a missing not at random (MNAR) mechanism. Both BOCF and LOCF inflated RRE were compared to MI and MMRM. In 12 of the 32 scenarios, BOCF yielded inflated RRE compared with eight scenarios for LOCF, three scenarios for MI and four scenarios for MMRM. In no situation did BOCF or LOCF provide adequate control of RRE when MI and MMRM did not. Both MI and MMRM are better choices than either BOCF or LOCF for the primary analysis.

Improvements in psoriasis within different body regions vary over time following treatment with ixekizumab.

BACKGROUND: Ixekizumab is a high-affinity monoclonal antibody that selectively targets interleukin-17 A. OBJECTIVE: Examine the efficacy of ixekizumab in clearing psoriasis within different body regions. METHODS: Data from 3 placebo- (PBO) or PBO- and etanercept (ETN)-controlled trials were integrated. Patients with moderate-to-severe psoriasis were randomized to 12 weeks of PBO (UNCOVER-1, -2, -3, N = 792; UNCOVER-2, -3, N = 361), 50 mg ETN twice weekly (N = 740), or 80 mg ixekizumab every 2 (IXE Q2W; N = 1169; N = 736) or 4 weeks (IXE Q4W; N = 1165; N = 733) after a 160-mg starting dose. RESULTS: Mean percent improvements in regional Psoriasis Area and Severity Index (PASI) were noted at Week 1 and increased through Week 12 in the IXE Q2W (approved dosing regimen) group for each body region. Week 12 improvements were 91.4% (head/neck); 92.8% (trunk); 89.9% (arms); and 88.7% (legs) (all regions p < .001 vs. PBO). Mean regional PASI improvements at Week 12 were ≥84.2% for ixekizumab versus ≤70.9% for ETN in all regions (p < .001). Scaling and thickness reduced faster than erythema. CONCLUSIONS: Within 12 weeks of ixekizumab treatment, all signs of psoriasis across all body regions reached clinically meaningful improvements, with the head/neck and trunk responding quicker than psoriasis of the arms and legs, especially with reduced scaling and thickness.

Differential antidepressant symptom efficacy: placebo-controlled comparisons of duloxetine and SSRIs (fluoxetine, paroxetine, escitalopram).

OBJECTIVE: To test the hypothesis that in patients with major depressive disorder (MDD), the response for specific Hamilton Depression Rating Scale items will differ for duloxetine compared with selective serotonin reuptake inhibitors (SSRIs) and that patterns of response will differ based on symptom severity at baseline. METHOD: Data were pooled from all Lilly-sponsored clinical trials where duloxetine was compared with placebo and an SSRI in patients with MDD: 7 randomized, double-blind, fixed-dose, 8-week studies of duloxetine (n = 1,133) versus SSRI (n = 689) versus placebo (n = 641). Duloxetine doses were 40, 60, 80 and 120 mg/day. SSRI doses were 10 mg/day (escitalopram) and 20 mg/day (fluoxetine and paroxetine). RESULTS: Compared to SSRI-treated patients, duloxetine-treated patients had a significantly greater (p < or = 0.05) reduction in the 17-item Hamilton Depression Rating Scale (HAMD17) total score and HAMD17 items of work and activities, psychomotor retardation, genital symptoms and hypochondriasis. Differences favoring the SSRIs approached significance for middle insomnia (p = 0.057) and late insomnia (p = 0.06), with effect sizes at least twice the magnitude of the corresponding effect sizes for duloxetine. Similarly, the advantage for duloxetine versus the SSRIs approached significance for general somatic symptoms (p = 0.056), with an effect size twice that observed for the SSRIs. The HAMD17 total score difference was driven mostly by patients with lower baseline MDD severity (HAMD17 total score < or = 19), where the HAMD17 effect size advantage for duloxetine over combined SSRIs was statistically significant (p = 0.031). CONCLUSION: Potentially important differences in symptom response patterns were found between duloxetine and the combined SSRIs depending on symptom severity, and different HAMD17 items responded differently to duloxetine compared with SSRIs. Understanding these differences may be useful in tailoring antidepressant therapy for individual patients.

Evidence for the efficacy of duloxetine in treating mild, moderate, and severe depression.

Clinicians need to know whether duloxetine is effective in patients across a broad range of depressive symptoms and depression severity. Data were pooled from nine randomized, double-blind, placebo-controlled studies in major depressive disorder (total N=2227) comparing duloxetine (40-120 mg/day) with placebo for 8-9 weeks. Patients were retrospectively stratified by baseline score on the HAMD17 into mild (< or =19; n=682), moderate (n=1099), or severe (> or =25; n=446) groups. Duloxetine produced significantly greater baseline-to-endpoint mean change than placebo in HAMD17 total score, Maier and retardation subscales, and the Clinical Global Impressions-Severity of Illness scale in all three cohorts. Significant improvement was seen in HAMD17 items 1 (depressed mood), 3 (suicide), 7 (work and activities), and 10 (psychic anxiety) regardless of severity. The HAMD17 anxiety subscale and items 13 (somatic symptoms-general) and 15 (hypochondriasis) showed significant improvement only in moderately and severely ill patients. Significant improvement in the HAMD17 Maier subscale was seen in all groups by week 1. In all three groups, placebo was significantly superior to duloxetine at early visits on HAMD17 item 12 (somatic symptoms-GI). Mildly and severely ill patients exhibited significant reduction in visual analog scale overall pain severity at the study endpoint. The studies contained fewer patients with very mild or very severe illness, limiting our ability to draw conclusions in these patient populations. Duloxetine demonstrated superior efficacy in the treatment of major depressive disorder, when compared with placebo, regardless of the baseline severity of depressive symptoms, although effect sizes were largest in the most severely depressed patients.

Attrition in randomized controlled clinical trials: methodological issues in psychopharmacology.

Attrition is a ubiquitous problem in randomized controlled clinical trials (RCT) of psychotropic agents that can cause biased estimates of the treatment effect, reduce statistical power, and restrict the generalizability of results. The extent of the problem of attrition in central nervous system (CNS) trials is considered here and its consequences are examined. The taxonomy of missingness mechanisms is then briefly reviewed in order to introduce issues underlying the choice of data analytic strategies appropriate for RCTs with various forms of incomplete data. The convention of using last observation carried forward to accommodate attrition is discouraged because its assumptions are typically inappropriate for CNS RCTs, whereas multiple imputation strategies are more appropriate. Mixed-effects models often provide a useful data analytic strategy for attrition as do the pattern-mixture and propensity adjustments. Finally, investigators are encouraged to consider asking participants, at each assessment session, the likelihood of attendance at the subsequent assessment session. This information can be used to eliminate some of the very obstacles that lead to attrition, and can be incorporated in data analyses to reduce bias, but it will not eliminate all attrition bias.

Duloxetine efficacy for major depressive disorder in male vs. female patients: data from 7 randomized, double-blind, placebo-controlled trials.

OBJECTIVE: A number of studies have suggested potential gender differences in the efficacy of antidepressant medications. Pooled data from double-blind, placebo-controlled studies were utilized to compare the efficacy of duloxetine in the treatment of major depressive disorder (MDD) in male and female patients. METHOD: Efficacy data were pooled from 7 randomized, double-blind, placebo-controlled clinical trials of duloxetine. These studies represent all available data from U.S. acute-phase, placebo-controlled studies of duloxetine for the treatment of MDD. Patients (aged > or = 18 years) meeting DSM-IV criteria for MDD received duloxetine (40-120 mg/day; men, N = 318; women, N = 578) or placebo (men, N = 242; women, N = 484) for up to 9 weeks. Efficacy measures included the 17-item Hamilton Rating Scale for Depression (HAM-D17) total score, HAM-D17 subscales (core, Maier, anxiety, retardation, sleep), the Clinical Global Impressions-Severity of Illness scale (CGI-S) and Patient Global Impression of Improvement scale (PGI-I), the Quality of Life in Depression Scale (QLDS), and Visual Analog Scales (VAS) for pain. The first patient visit was February 1, 1999, and the last patient visit was November 27, 2002. RESULTS: In both male and female patients, duloxetine produced significantly greater improvement in HAM-D17, CGI-S, and PGI-I when compared with placebo (p < .05). Treatment-by-gender interactions did not reach statistical significance, indicating that the magnitude of duloxetine's treatment effects did not differ significantly between male and female patients. However, there was a trend for female patients to show a more robust response than male patients to both duloxetine and placebo. On the basis of VAS assessments of pain severity, duloxetine-treated female patients appeared to exhibit greater improvement than male patients, while women receiving placebo had smaller responses than placebo-treated men. Improvements in quality of life were significantly greater for both men (p = .006) and women (p = .001) receiving duloxetine than placebo and showed no significant difference by gender. CONCLUSION: In this analysis of pooled data, the efficacy of duloxetine did not differ significantly in male and female patients.

Duloxetine in the treatment of major depressive disorder: comparisons of safety and efficacy in U.S. Hispanic and majority Caucasian patients.

OBJECTIVE: To evaluate new pharmacotherapies for the treatment of major depressive disorder (MDD) in Hispanic Americans, the largest ethnic minority group in the United States. METHOD: Efficacy and safety data were pooled from 7 double-blind, placebo-controlled clinical trials of duloxetine conducted from February 1999 through November 2002. English-speaking patients (aged > or = 18 years) meeting DSM-IV criteria for MDD received duloxetine (40-120 mg/ day; Hispanic, N = 58; Caucasian, N = 748) or placebo (Hispanic, N = 62; Caucasian, N = 594) for up to 9 weeks. Efficacy measures included the 17-item Hamilton Rating Scale for Depression (HAM-D-17) total score, HAM-D-17 subscales, the Clinical Global Impressions-Severity of Illness scale, the Patient Global Impression of Improvement scale, and the Visual Analog Scales for pain. Safety was assessed using discontinuation rates, treatment-emergent adverse events, vital signs, and laboratory analyses. Three sets of data were analyzed using different pooling strategies, including exploratory analyses with 470 subjects (Hispanic, N = 51; Caucasian, N = 419) receiving the recommended dose of 60 mg. RESULTS: No evidence for a differential effect of duloxetine in Hispanic and Caucasian patients was found in efficacy outcomes. Discontinuation rates due to adverse events among duloxetine-treated patients were 14.0% for Hispanics and 17.0% for Caucasians, compared with 3.2% and 5.7%, respectively, for placebo-treated patients (p = .671). The type of adverse events and their individual rate of occurrence did not differ significantly between Hispanic and Caucasian patients. Mean changes from baseline for pulse, blood pressure, weight, and laboratory analytes were small and showed no significant differences between Hispanic and Caucasian patients. CONCLUSION: In this analysis of pooled data, no evidence for a differential effect of duloxetine in Hispanic and majority Caucasian patients was found in efficacy or safety outcomes.

Duloxetine for the treatment of major depressive disorder: a closer look at efficacy and safety data across the approved dose range.

OBJECTIVE: This analysis focuses on efficacy and safety data obtained from studies of duloxetine for the treatment of major depressive disorder (MDD) within the approved dose range of 40-60 mg/day. METHOD: Efficacy and safety data were obtained from the acute phase portions of four randomized, double-blind, placebo-controlled clinical trials in patients meeting DSM-IV criteria for MDD. In Studies 1 and 2, patients were randomized to duloxetine 60 mg once daily (QD) (n=123 [Study 1]; n=128 [Study 2]) or placebo (n=122 [Study 1]; n=139 [Study 2]) for 9 weeks. In Studies 3 and 4, patients were randomized to duloxetine 20 mg twice daily (BID) (n=91 [Study 3]; n=86 [Study 4]) or placebo (n=90 [Study 3]; n=89 [Study 4]) for 8 weeks. Efficacy measures included the 17-item Hamilton Rating Scale for Depression (HAMD17) total score (primary outcome), HAMD17 subscales, the Clinical Global Impression of Severity (CGI-S) and Patient Global Impression of Improvement (PGI-I) scales, and Visual Analog Scales (VAS) for pain. Safety assessments included rates of discontinuation due to adverse events, spontaneously reported treatment-emergent adverse events, and changes in vital signs. RESULTS: In both studies of duloxetine 60 mg QD, mean change in HAMD17 total score was significantly greater in duloxetine-treated patients compared with placebo (Study 1, p<.001; Study 2, p=.024). At a dose of 20 mg BID, duloxetine demonstrated significant superiority over placebo on the HAMD17 total score in one of the two studies (Study 4, p=.034). Probabilities of remission among patients receiving duloxetine 60 mg QD were 44.2% in Study 1 (p<.001 vs. placebo) and 43.0% in Study 2 (NS), while for patients receiving duloxetine 20 mg BID the probabilities of remission were 27.2% in Study 3 (NS) and 36.1% in Study 4 (NS). Across the six assessed VAS measures of pain severity and interference, the main effect of treatment for duloxetine 60 mg QD was significantly superior to placebo on 7 of the 12 outcomes in Studies 1 and 2, while duloxetine 20 mg BID was not superior to placebo on any of the 12 outcomes in Studies 3 and 4. The rate of discontinuation due to adverse events was 13.1% among patients receiving duloxetine 60 mg QD, and 11.9% at a dose of 20 mg BID. The most frequently reported treatment-emergent adverse events at both doses included nausea, headache, dry mouth, dizziness, and insomnia. The incidence of treatment-emergent nausea among patients receiving duloxetine 60 mg QD was 37.8%, compared with 16.4% among patients receiving 20 mg BID. CONCLUSION: Duloxetine provides safe and effective acute phase treatment of MDD at doses of 40-60 mg/day. Compared with placebo, the 60 mg QD dose was more consistently effective than the 20 mg BID dose. However, the incidence of certain treatment-emergent adverse events is likely to be lower at the 40 mg dose.

Duloxetine in the treatment of major depressive disorder: comparisons of safety and tolerability in male and female patients.

BACKGROUND: While some studies have suggested sex differences in the efficacy of antidepressant medications, there have been few investigations into potential sex differences related to safety and/or tolerability. Pooled data from double-blind, placebo-controlled studies were utilized to assess the safety and tolerability of duloxetine in the treatment of major depressive disorder (MDD) in male and female patients. METHODS: Safety data were pooled from seven double-blind, placebo-controlled clinical trials of duloxetine. Patients (aged >or=18 years) meeting DSM-IV criteria for MDD received duloxetine (40-120 mg/day, male: N=318, female: N=578) or placebo (male: N=242, female: N=484) for up to 9 weeks. Safety was assessed using discontinuation rates, spontaneously reported treatment-emergent adverse events, changes in vital signs and laboratory analyses. RESULTS: Discontinuation rates due to adverse events among duloxetine-treated patients were 18.6% for males and 13.5% for females. The most common treatment-emergent adverse events in both male and female patients included nausea, headache, dry mouth, diarrhea and constipation. The only event occurring at significantly different rates in male and female patients was nausea (Breslow Day p-value=0.008), and the significant difference was driven by a placebo nausea rate that was almost three times greater in females compared with males. No significant differential sex effects were found for pulse, blood pressure or weight. No laboratory analyte had an incidence of abnormal high or low values that differed significantly between male and female patients. LIMITATIONS: This was a post-hoc analysis of pooled data from acute phase clinical trials. Plasma concentrations of duloxetine were not obtained. Adverse event rates were based on spontaneous reports and differential dose-response effects were not evaluated. CONCLUSIONS: No evidence of clinically meaningful sex differences in the safety and tolerability of duloxetine were uncovered.

The safety and tolerability of duloxetine compared with paroxetine and placebo: a pooled analysis of 4 clinical trials.

BACKGROUND: To compare the safety and tolerability of duloxetine with paroxetine and placebo in patients with major depressive disorder (MDD). METHOD: Data from four 8-week randomized, double-blind, placebo- and paroxetine-controlled studies of duloxetine for MDD (DSM-IV criteria) were pooled to compare the safety and tolerability of duloxetine 40 to 120 mg/day with paroxetine 20 mg q.d. Two of the 4 trials included a 26-week extension. RESULTS: The pooled database included 1466 patients (duloxetine, N = 736; paroxetine, N = 359; placebo, N = 371). No deaths occurred in the acute phase trials. Discontinuation rates for adverse events did not differ significantly for duloxetine, 8.0%, and paroxetine, 6.1%. Nausea was the most frequent treatment-emergent adverse event for duloxetine (duloxetine, 14.4%; paroxetine, 12.0%; placebo, 3.8%). Blood pressure and corrected QT (QTc) interval changes were modest and did not differ significantly for the 3 groups. Mean heart rate increased slightly in the duloxetine group, 1.0 beat/minute, and did differ significantly (p < .001) from that in the paroxetine group, but the change is of doubtful importance. Mean changes in laboratory analytes remained within the reference range. Emergent sexual dysfunction was significantly greater among duloxetine- and paroxetine-treated patients than placebo-treated patients (p = .007 vs. duloxetine and p < .001 vs. paroxetine); however, it was significantly lower in duloxetine-treated patients than in paroxetine-treated patients (46.4% vs. 61.4%; p = .015). During the extension phase, weight gain (≥ 7% of initial body weight) was greater in both active-treatment groups than in the placebo group (duloxetine, 10.8%; paroxetine, 13.8%; placebo, 3.1%), but the active-treatment groups did not differ. CONCLUSIONS: Duloxetine is safe and well tolerated in patients with MDD, with safety and tolerability comparable to that of paroxetine.

Duloxetine in the treatment of major depressive disorder: comparisons of safety and efficacy.

BACKGROUND: Pooled data from double-blind, placebo-controlled studies were utilized to compare the safety and efficacy of duloxetine in the treatment of major depressive disorder (MDD) in African-American and Caucasian patients. METHODS: Efficacy and safety data were pooled from seven double-blind, placebo-controlled clinical trials of duloxetine. Patients (aged > or =18 years) meeting DSM-IV criteria for MDD received duloxetine (40-120 mg/day; African Americans, N=69; Caucasians, N=748) or placebo (African Americans, N=59; Caucasians, N=594) for up to nine weeks. Efficacy measures included the 17-item Hamilton Rating Scale for Depression (HAMD17) total score, the Clinical Global Impression of Severity (CGI-S) and Patient Global Impression of Improvement (PGI-I) scales, and Visual Analog Scales (VAS) for pain. Safety was assessed using discontinuation rates, spontaneously reported treatment-emergent adverse events, vital signs and laboratory analyses, RESULTS: Based upon mean changes in HAMD17, CGI-S and PGI-I scales, the magnitude of duloxetine's treatment effects did not differ significantly between African-American and Caucasian patients. Discontinuation rates due to adverse events among duloxetine-treated patients were 13.0% for African Americans and 17.0% for Caucasians. No adverse event led to discontinuation in more than one African-American patient. The most common treatment-emergent adverse events in both ethnic groups included nausea, headache, constipation, dizziness and insomnia. The rate of occurrence of these events did not differ significantly between African-American and Caucasian patients. Mean changes from baseline for pulse, blood pressure, weight and laboratory analytes were small and showed no significant differences between African-American and Caucasian patients. CONCLUSION: In this analysis of data from seven clinical trials, no convincing evidence was found to suggest that the overall safety and tolerability profile or the efficacy profile for duloxetine in this cohort of African-American patients differed from that observed in a comparator group of Caucasian patients. The results from these analyses provide supportive evidence for the efficacy and safety of duloxetine in the treatment of MDD in African-American patients.

Sexual functioning assessed in 4 double-blind placebo- and paroxetine-controlled trials of duloxetine for major depressive disorder.

OBJECTIVE: The onset or worsening of sexual dysfunction is a common treatment-emergent side effect of antidepressant medications. Post hoc analyses of pooled data from placebo-controlled studies were utilized to assess sexual functioning in patients receiving duloxetine or paroxetine. METHOD: Acute-phase data were obtained from four 8-week, double-blind, placebo- and paroxetine-controlled trials of similar design in which patients meeting DSM-IV criteria for major depressive disorder were randomly assigned to receive placebo (N = 371), duloxetine (40-120 mg/day; N = 736), or paroxetine (20 mg/day; N = 359). Pooling of data from these studies was anticipated during study design. This represented all available data from duloxetine studies in which the Arizona Sexual Experience Scale (ASEX) was administered both at baseline and endpoint. Long-term data were available from extension phases in 2 of these trials in which acute treatment responders received placebo (N = 129), duloxetine (80-120 mg/day; N = 297), or paroxetine (20 mg/day; N = 140) for an additional 26 weeks. Data were collected between March 2000 and July 2002. RESULTS: The incidence of acute treatment-emergent sexual dysfunction was significantly lower among duloxetine-treated patients compared with those receiving paroxetine (p = .015), although both rates were significantly higher than placebo (p = .007 and p < .001 for duloxetine and paroxetine, respectively). Treatment group differences in the incidence of treatment-emergent dysfunction did not vary significantly by gender. In female patients, acute treatment-emergent sexual dysfunction was significantly lower in the duloxetine treatment group compared with the paroxetine treatment group (p = .032), with both rates being significantly higher than placebo (p = .049 and p < .001 for duloxetine and paroxetine, respectively). In the somewhat smaller group of male patients, acute treatment-emergent dysfunction did not differ significantly between duloxetine and placebo treatment groups, but the incidence was significantly higher in paroxetine-treated male patients compared with male placebo patients (p = .012). The long-term incidence of treatment-emergent dysfunction did not differ significantly between duloxetine-, paroxetine-, and placebo-treated patients. CONCLUSION: In this analysis of pooled data, patients receiving duloxetine (40-120 mg/day) or paroxetine (20 mg/day) had a significantly higher incidence of acute treatment-emergent sexual dysfunction when compared with placebo patients. However, the incidence of acute treatment-emergent dysfunction for duloxetine was significantly lower than that observed for paroxetine.