VENLAFAXINE HYDROCHLORIDE (Page 12 of 13)

14.2 Generalized Anxiety Disorder

The efficacy of venlafaxine hydrochloride extended-release capsules as a treatment for Generalized Anxiety Disorder (GAD) was established in two 8-week, placebo-controlled, fixed-dose studies (75 to 225 mg per day), one 6-month, placebo-controlled, flexible-dose study (75 to 225 mg per day), and one 6-month, placebo-controlled, fixed-dose study (37.5, 75, and 150 mg per day) in adult outpatients meeting DSM-IV criteria for GAD.

In one 8-week study, venlafaxine hydrochloride extended-release capsules demonstrated superiority over placebo for the 75, 150, and 225 mg per day doses as measured by the Hamilton Rating Scale for Anxiety (HAM-A) total score, both the HAM-A anxiety and tension items, and the Clinical Global Impressions (CGI) scale. However, the 75 and 150 mg per day doses were not as consistently effective as the highest dose (study 1). A second 8-week study evaluating doses of 75 and 150 mg per day and placebo showed that both doses were more effective than placebo on some of these same outcomes; however, the 75 mg per day dose was more consistently effective than the 150 mg per day dose (study 2). A dose-response relationship for effectiveness in GAD was not clearly established in the 75 to 225 mg per day dose range studied.

Two 6-month studies, one evaluating venlafaxine hydrochloride extended-release capsules doses of 37.5, 75, and 150 mg per day (study 3) and the other evaluating venlafaxine hydrochloride extended-release capsules doses of 75 to 225 mg per day (study 4), showed that daily doses of 75 mg or higher were more effective than placebo on the HAM-A total, both the HAM-A anxiety and tension items, and the CGI scale during 6 months of treatment. While there was also evidence for superiority over placebo for the 37.5 mg per day dose, this dose was not as consistently effective as the higher doses.

Examination of gender subsets of the population studied did not reveal any differential responsiveness on the basis of gender.

Table 18: Generalized Anxiety Disorder Studies

SD: standard deviation; SE: standard error; LS Mean: least-squares mean; CI: confidence interval.

a Difference (drug minus placebo) in least-squares mean change from baseline

* Doses statistically significantly superior to placebo.

Study Number Treatment Group Primary Efficacy Measure: HAM-A Score
Mean Baseline Score (SD) LS Mean Change from Baseline (SE) Placebo Subtracted Difference a (95% CI)
Venlafaxine Hydrochloride Extended-Release Capsules 75 mg 24.7 -11.1 (0.95) -1.5 (-3.8, 0.8)
Study 1 Venlafaxine Hydrochloride Extended-Release Capsules 150 mg 24.5 -11.7 (0.87) -2.2 (-4.5, 0.1)
Venlafaxine Hydrochloride Extended-Release Capsules 225 mg 23.6 -12,1 (0.81) -2.6 (-4.9, -0.3)
Placebo 24.1 -9.5 (0.85)
Venlafaxine Hydrochloride Extended-Release Capsules 75 mg 23.7 -10.6 (0.82) -2.6 (-4.6, -0.5)
Study 2 Venlafaxine Hydrochloride Extended-Release Capsules 150 mg 23.0 -9.8 (0.86) -1.7 (-3.8, 0.3)
Placebo 23.7 -8.0 (0.73)
Venlafaxine Hydrochloride Extended-Release Capsules 37.5 mg 26.6 (0.4) -13.8 -2.8 (-5.1, -0.6)
Study 3 Venlafaxine Hydrochloride Extended-Release Capsules 75 mg 26.3 (0.4) -15.5 -4.6 (-6.9, -2.3)
Venlafaxine Hydrochloride Extended-Release Capsules 150 mg 26.3 (0.4) -16.4 -5.5 (-7.8, -3.1)
Placebo 26.7 (0.5) -11.0
Study 4 Venlafaxine Hydrochloride Extended-Release Capsules 75-225 mg 25.0 -13.4 (0.79) -4.7 (-6.6, -2.9)
Placebo 24.9 -8.7 (0.70)

14.3 Social Anxiety Disorder (also known as Social Phobia)

The efficacy of venlafaxine hydrochloride extended-release capsules as a treatment for Social Anxiety Disorder (SAD) was established in four double-blind, parallel-group, 12-week, multicenter, placebo-controlled, flexible-dose studies (studies 1-4) and one double-blind, parallel-group, 6-month, placebo-controlled, fixed/flexible-dose study, which included doses in a range of 75 to 225 mg per day in adult outpatients meeting DSM-IV criteria for SAD (study 5).

In these five studies, venlafaxine hydrochloride extended-release capsules were statistically significantly more effective than placebo on change from baseline to endpoint on the Liebowitz Social Anxiety Scale (LSAS) total score. There was no evidence for any greater effectiveness of the 150 to 225 mg per day group compared to the 75 mg per day group in the 6-month study.

Examination of subsets of the population studied did not reveal any differential responsiveness on the basis of gender. There was insufficient information to determine the effect of age or race on outcome in these studies.

Table 19: Social Anxiety Disorder Studies

SD: standard deviation; SE: standard error; LS Mean: least-squares mean; CI: confidence interval.

a Difference (drug minus placebo) in least-squares mean change from baseline

* Doses statistically significantly superior to placebo.

Study Number Treatment Group Primary Efficacy Measure: LSAS Score
Mean Baseline Score (SD) LS Mean Change from Baseline (SE) Placebo Subtracted Difference a (95% CI)
Study 1 Venlafaxine Hydrochloride Extended-Release Capsules (75-225 mg) 91.1 -31.0 (2.22) 11.2 (-5.3, -17.1)
Placebo 86.7 -19.9 (2.22)
Study 2 Venlafaxine Hydrochloride Extended-Release Capsules (75-225 MG) 90.8 -32.8 (2.69) -10.7 (-3.7,-17.6)
Placebo 87.4 -22.1 (2.66)
Study 3 Venlafaxine Hydrochloride Extended-Release Capsules (75-225 MG) 83.2 -36.0 (2.35) -16.9(-22.6, -11.2)
Placebo 83.6 -19.1 (2.40) -12.7 (-6.5, -19.0)
Study 4 Venlafaxine Hydrochloride Extended-Release Capsules (75-225 mg) 86.2 -35.0 (2.64) -14.6 (-21.8, -7.4)
Placebo 86.1 -22.2 (2,47)
Venlafaxine Hydrochloride Extended-Release Capsules 75 mg 91.8 -38.1 (3.16) -14.6 (-21.8, -7.4)
Study 5 Venlafaxine Hydrochloride Extended-Release Capsules (150-225 mg) 86.2 -37.6 (3.05) -14.1 (-21.3, -6.9)
Placebo 89.3 -23.5 (3.08)

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