Global benefit-risk assessment in designing clinical trials and some statistical considerations of the method.

When characterizing a therapy, the efficacy and the safety are two major aspects under consideration. In prescribing a therapy to a patient, a clinician puts the two aspects together and makes a decision based on a consolidated thought process. The global benefit-risk (GBR) measures proposed by Chuang-Stein et al. (Stat. Med. 1991; 10:1349-1359) are useful in facilitating the thinking, and creating the framework for making statistical comparisons based on benefit-risk point of view. This article describes how a GBR linear score was defined and used as the primary outcome measure in a clinical trial design. The robustness of the definitions of 'benefit' and 'risk' are evaluated using different criteria. The sensitivity of the pre-specified weights is also analyzed using alternative weights; one of those was determined by the relative to an identified distribution integral transformation approach (Biometrics 1958; 14:18-38). Statistical considerations are illustrated using pooled data from clinical trials studying antidepressant. The pros and cons for using GBR assessments in the setting of clinical trials are discussed.

A randomized, double-blind comparison of duloxetine and venlafaxine in the treatment of patients with major depressive disorder.

BACKGROUND: Clinical trials assessing antidepressant therapies typically include separate assessments of efficacy (benefit) and adverse events (risk). Global benefit-risk (GBR) assessment allows the simultaneous evaluation of both efficacy and adverse events. The objective was to compare the serotonin and norepinephrine reuptake inhibitors (SNRIs) duloxetine and venlafaxine using GBR assessment. METHODS: Data were combined from two similarly designed, multicenter, randomized, double-blind, parallel group studies in which patients with major depressive disorder were randomized to either duloxetine 60 mg/day or venlafaxine extended release (XR) 150 mg/day (75 mg/day for the first 2 weeks) for a 6-week fixed dosing period followed by an additional 6 weeks of treatment in which the dose could be increased up to 120 mg/day for duloxetine and 225 mg/day for venlafaxine. Patients completing the study (or receiving study drug for 2 weeks or more) were eligible to enter a taper period where the dose of study drug was gradually reduced over 1-2 weeks prior to drug discontinuation. The primary outcome measure (defined a priori) was the GBR comparison of duloxetine 60 mg/day and venlafaxine XR 150 mg/day after 6 weeks of treatment. In the GBR analysis, benefit was defined as remission at endpoint [17-item Hamilton Depression Rating Scale (HAMD17) 7]. Risk was defined by four categories: patients having either no adverse events (AEs), AEs with no severity rating greater than moderate, AEs with at least one severity rating of severe, or having discontinued with a reason of self-reported adverse event (regardless of any AE severity). Additional efficacy measures included HAMD17 total score and subscales, HAMA, CGI-S, and PGI-I. Safety and tolerability were assessed via analysis of reasons for discontinuation, treatment-emergent adverse events (TEAEs), discontinuation-emergent adverse events, and changes in vital signs, weight, and laboratory analytes. RESULTS: There were no significant differences between duloxetine 60 mg/day and venlafaxine 150 mg/day as measured by GBR assessment at the end of 6 weeks (-1.418 vs. -1.079, P = 0.217) or 12 weeks (-0.349 vs. -0.121, P = 0.440), nor were there significant differences between treatment groups on the majority of efficacy measures. Significantly more venlafaxine-treated patients (74.5%) completed 12 weeks of treatment compared with duloxetine-treated patients (64.8%, P =.006). Nausea was the most common treatment-emergent adverse event (TEAE) for both drugs, and was significantly higher with duloxetine 60 mg/day compared to venlafaxine 150 mg/day during the first 6 weeks of treatment (43.6% vs. 35.0%, P0.05). During the taper period, significantly more venlafaxine-treated patients reported discontinuation-emergent adverse events (DEAEs) than duloxetine-treated patients. From a safety perspective, significantly more venlafaxine-treated patients (n = 4) than duloxetine-treated patients (n=0, P =.047) experienced sustained elevations of systolic blood pressure during the fixed dosing period. Otherwise, there were few significant differences in safety measures found between treatment groups during 6 and 12 weeks of therapy. CONCLUSIONS: Duloxetine 60 mg/day and venlafaxine XR 150 mg/day have similar benefit-risk profiles on the basis of a comparison utilizing GBR assessment. The implications of the more subtle differences between these drugs, as well as for interpreting the GBR assessment, are discussed.

Efficacy of duloxetine and selective serotonin reuptake inhibitors: comparisons as assessed by remission rates in patients with major depressive disorder.

It has been proposed that serotonin and norepinephrine reuptake inhibitors (SNRIs) may result in higher remission rates of major depressive disorder than therapy with selective serotonin reuptake inhibitors (SSRIs). To test this hypothesis, a meta-analysis of individual patient data (N = 1833) was performed for the complete set of 6 phase II/III studies that compared duloxetine (fixed doses; range, 40-120 mg/d) with 2 SSRIs (paroxetine or fluoxetine; 20 mg/d) in outpatients with major depressive disorder. Remission was defined as an end point score of less than or equal to 7 on the 17-item Hamilton Rating Scale for Depression (HAMD17); alternate outcome criteria were also examined, as were remission rates among the 1044 patients with moderate-to-severe depression (HAMD17 total score greater than or equal to 19). The HAMD17 remission rates were 40.3% (351/871), 38.3% (162/423), and 28.4% (144/507) for duloxetine, the 2 SSRIs, and placebo, respectively. Both active treatments were superior to placebo; the difference between duloxetine and SSRIs was not statistically significant. Similar findings were observed for alternate outcomes. Duloxetine therapy was significantly more effective than therapy with the 2 SSRIs for patients with more severe depression, with remission rates of 35.9% (183/510) versus 28.6% (70/245) (P = 0.046). A secondary analysis of dose-response relationships indicated that this advantage was not attributable to the studies using higher doses of duloxetine. Thus, whereas duloxetine and the 2 SSRIs were comparably efficacious overall, therapy with the serotonin and norepinephrine reuptake inhibitor resulted in a significantly higher remission rate among patients with moderate-to-severe depression.

Duloxetine for the treatment of fibromyalgia in women: pooled results from two randomized, placebo-controlled clinical trials.

BACKGROUND: To assess the efficacy (in particular, in pain, functional impairment, and quality of life) and safety and tolerability (incidence of adverse events, discontinuation rates, changes in laboratory findings, and vital signs) of duloxetine in female patients with fibromyalgia. METHODS: Data were pooled from two placebo-controlled clinical trials of similar design (randomized, 12-week, and double-blind), comparing duloxetine 60 mg a day (q.d.) or 60 mg twice daily (b.i.d.) (n = 326) with placebo (n = 212), in women who met the American College of Rheumatology criteria for primary fibromyalgia. RESULTS: Compared with the patients receiving placebo, duloxetine-treated female patients demonstrated a significantly greater improvement in the Brief Pain Inventory (BPI) average pain severity score and in the Fibromyalgia Impact Questionnaire (FIQ) total score, beginning at week 1 and continuing through week 12 (p < 0.001). Duloxetine was superior to placebo on all efficacy measures, including mean tender point threshold, Clinical Global Impression of Severity, Patient Global Impression of Improvement, and average interference from pain scores. The duloxetine-treated group was superior to placebo on all quality of life and functional measures, including each domain of the Medical Outcomes Study Short Form-36 (SF-36). A direct treatment effect of duloxetine on pain reduction was demonstrated and shown to be independent of secondary improvement in mood (based on BPI average pain score). Significantly more duloxetine-treated patients reported treatment-emergent adverse events (296 [90.8%] duloxetine-treated and 165 [77.8%] placebo-treated, p < 0.001). Rates of serious adverse events were similar between duloxetine-treated and placebo-treated patients. CONCLUSIONS: The pooled results of these studies demonstrate that duloxetine is a safe and efficacious treatment for both the pain and functional impairment associated with fibromyalgia in female patients, while significantly improving quality of life.

Duloxetine for patients with diabetic peripheral neuropathic pain: a 6-month open-label safety study.

OBJECTIVE: Duloxetine is a relatively balanced and potent reuptake inhibitor of both serotonin and norepinephrine. Because these neurotransmitters play a role in pain inhibition, duloxetine was considered a possible treatment for diabetic peripheral neuropathic pain (DPNP). This study assessed the 6-month safety and tolerability of duloxetine in patients with DPNP; evaluation of efficacy was a secondary objective. DESIGN: In this 28-week, open-label study, in the clinical setting, 449 patients with DPNP were randomized (3:1) to receive duloxetine 60 mg twice daily (BID) (N = 334) or duloxetine 120 mg once daily (QD) (N = 115). Comprehensive safety evaluations including laboratory analyses and electrocardiograms were performed for all patients. Efficacy measures included the Brief Pain Inventory (BPI) and Clinical Global Impression of Severity (CGI-S) scales. RESULTS: Protocol completion rates were 63.8% and 62.6% for the 60 mg BID and 120 mg QD groups, respectively (P = 0.823). Discontinuations were primarily due to adverse events, 20.1% for 60 mg BID and 27.0% for 120 mg QD (P = 0.149). Heart rate increased slightly in both treatment groups (P

Duloxetine versus routine care in the long-term management of diabetic peripheral neuropathic pain.

INTRODUCTION: Duloxetine hydrochloride is a dual reuptake inhibitor of both serotonin and norepinephrine. In the present open-label study, the safety of duloxetine at a fixed-dose of 60 mg twice daily (BID) for up to 52 weeks was evaluated and compared to routine care in the therapy of patients diagnosed with diabetic peripheral neuropathic pain (DPNP). METHODS: Patients who completed a 13-week, double-blind, duloxetine and placebo acute therapy period were rerandomly assigned in a 2:1 ratio to therapy with duloxetine 60 mg BID (N=161) or routine care (N=76) for an additional 52 weeks. Routine care consisted primarily of gabapentin, amitriptyline, and venlafaxine. The study included male or female outpatients 18 years of age or older with a diagnosis of DPNP caused by type 1 or type 2 diabetes. RESULTS: A higher percentage of routine care-treated patients experienced 1 or more serious adverse events. No statistically significant therapy-group difference was observed in the overall incidence of treatment-emergent adverse events (TEAEs). The TEAEs reported by 10% or more of duloxetine 60 mg BID-treated patients were nausea, and by the routine care-treated patients were peripheral edema, pain in the extremity, somnolence, and dizziness. Duloxetine did not appear to adversely affect glycemic control, lipid profiles, nerve function, or the course of DPNP. There were no statistically significant therapy-group differences observed in the 36-item Short-Form Health Survey subscales or in the EuroQol 5-Dimension Questionnaire. CONCLUSIONS: In this study, duloxetine was safe and well tolerated compared to routine care in the long-term management of patients with DPNP.

A randomized, double-blind, placebo-controlled trial of duloxetine in the treatment of women with fibromyalgia with or without major depressive disorder.

This was a 12-week, randomized, double-blind, placebo-controlled trial to assess the efficacy and safety of duloxetine, a selective serotonin and norepinephrine reuptake inhibitor, in 354 female patients with primary fibromyalgia, with or without current major depressive disorder. Patients (90% Caucasian; mean age, 49.6 years; 26% with current major depressive disorder) received duloxetine 60 mg once daily (QD) (N=118), duloxetine 60 mg twice daily (BID) (N=116), or placebo (N=120). The primary outcome was the Brief Pain Inventory average pain severity score. Response to treatment was defined as >or=30% reduction in this score. Compared with placebo, both duloxetine-treated groups improved significantly more (P<0.001) on the Brief Pain Inventory average pain severity score. A significantly higher percentage of duloxetine-treated patients had a decrease of >or=30% in this score (duloxetine 60 mg QD (55%; P<0.001); duloxetine 60 mg BID (54%; P=0.002); placebo (33%)). The treatment effect of duloxetine on pain reduction was independent of the effect on mood and the presence of major depressive disorder. Compared with patients on placebo, patients treated with duloxetine 60 mg QD or duloxetine 60 mg BID had significantly greater improvement in remaining Brief Pain Inventory pain severity and interference scores, Fibromyalgia Impact Questionnaire, Clinical Global Impression of Severity, Patient Global Impression of Improvement, and several quality-of-life measures. Both doses of duloxetine were safely administered and well tolerated. In conclusion, both duloxetine 60 mg QD and duloxetine 60 mg BID were effective and safe in the treatment of fibromyalgia in female patients with or without major depressive disorder.