Open-label treatment with desvenlafaxine in postmenopausal women with major depressive disorder not responding to acute treatment with desvenlafaxine or escitalopram.

Background: Preliminary clinical evidence indicates that menopausal status might impact on the efficacy of certain classes of antidepressants.

Objective: The aim of this study was to evaluate open-label desvenlafaxine treatment (administered as desvenlafaxine succinate) in postmenopausal women who did not achieve clinical response to acute, double-blind treatment with desvenlafaxine or escitalopram.

Study Design: This phase IIIb, multicentre study included a 6-month open-label extension phase of patients who did not respond in the initial 8-week, randomized, double-blind acute phase.

Patients: Postmenopausal women aged 40-70 years with a primary diagnosis of major depressive disorder were recruited. PRIMARY INTERVENTION: Non-responders to acute treatment with double-blind desvenlafaxine or escitalopram received flexible-dose, open-label desvenlafaxine 100-200 mg/day for the 6-month extension phase.

Main Outcome Measure: The primary efficacy assessment was the 17-item Hamilton Rating Scale for Depression (HAM-D(17)) total score. Secondary efficacy outcome measures were the Clinical Global Impressions-Improvement (CGI-I) and -Severity scales, Hamilton Rating Scale for Anxiety, Quick Inventory of Depressive Symptomatology-Self-Report, Visual Analogue Scale-Pain Intensity and the Montgomery-Åsberg Depression Rating Scale (MADRS). Secondary health assessments were the Changes in Sexual Functioning Questionnaire, 5-Dimension EuroQoL Index, Health State Today, Menopause Rating Scale, Sheehan Disability Scale, treatment response (≥ 50% decrease in total HAM-D(17) and MADRS score from acute-phase baseline and CGI-I total score ≤ 2), HAM-D(17) remission (total score ≤ 7) and safety. Descriptive statistics were used to summarize outcomes.

Results: The efficacy analysis included 123 patients (desvenlafaxine/desvenlafaxine = 64; escitalopram/desvenlafaxine = 59). At final evaluation of the open-label extension phase, mean reductions from acute-phase baseline in HAM-D(17) total scores were -11.33 for the desvenlafaxine/desvenlafaxine group and -11.41 for the escitalopram/desvenlafaxine group. HAM-D(17) response or remission after 6 months of open-label extension phase desvenlafaxine treatment were achieved in 56-58% and 41-48% of patients, respectively. The results of the other secondary efficacy outcome measures and other definitions of treatment response were generally consistent with the primary analyses. The observed adverse events were similar to those reported during previous desvenlafaxine clinical trials.

Conclusions: Postmenopausal women with major depressive disorder who did not respond to acute, double-blind treatment with escitalopram or desvenlafaxine achieved modest, continued improvement with long-term, open-label desvenlafaxine therapy. Further interpretation of these findings is limited by aspects of the study design (i.e. open-label, non-placebo-controlled) and the lack of randomized comparison groups in the extension phase, which prevents statistical assessment of the efficacy of longer term treatment with desvenlafaxine. Clinicaltrials.gov identifier: NCT00406640.