Venlafaxine Hydrochloride (Page 12 of 14)

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 capsule was 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 Differencea (95% CI)

Study 1

Ven XR (75 to 225 mg) Placebo

91.1 86.7

-31(2.22) -19.9 (2.22)

11.2 (-5.3, -17.1) –

Study 2

Ven XR (75 to 225 MG) Placebo

90.8 87.4

-32.8 (2.69) -22.1 (2.66)

-10.7 (-3.7,-17.6) –

Study 3

Ven XR (75 to 225 MG) Placebo

83.2 83.6

-36 (2.35) -19.1 (2.40)

-16.9(-22.6, -11.2) -12.7 (-6.5, -19)

Study 4

Ven XR (75 to 225 mg) Placebo

86.2 86.1

-35 (2.64) -22.2 (2,47)

-14.6 (-21.8, -7.4) –

Study 5

Ven XR 75 mg

91.8

-38.1 (3.16)

-14.6 (-21.8, -7.4)

Ven XR (150 to 225 mg)

86.2

-37.6 (3.05)

-14.1 (-21.3, -6.9)

Placebo

89.3

-23.5 (3.08)

14.4 Panic Disorder

The efficacy of venlafaxine hydrochloride extended-release capsules as a treatment for Panic Disorder (PD) was established in two double-blind, 12-week, multicenter, placebo-controlled studies in adult outpatients meeting DSM-IV criteria for PD, with or without agoraphobia. Patients received fixed doses of 75 or 150 mg per day in one study (study 1) and 75 or 225 mg per day in the other study (study 2).

Efficacy was assessed on the basis of outcomes in three variables: (1) percentage of patients free of full- symptom panic attacks on the Panic and Anticipatory Anxiety Scale (PAAS); (2) mean change from baseline to endpoint on the Panic Disorder Severity Scale (PDSS) total score; and (3) percentage of patients rated as responders (much improved or very much improved) on the Clinical Global Impressions (CGI) Improvement scale. In these two studies, venlafaxine hydrochloride extended-release capsule was statistically significantly more effective than placebo (for each fixed dose) on all three endpoints, but a dose-response relationship was not clearly established.

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.

In a longer term study (study 3), adult outpatients meeting DSM-IV criteria for PD who had responded during a 12-week open phase with venlafaxine hydrochloride extended-release capsules (75 to 225 mg per day) were randomly assigned to continue the same venlafaxine hydrochloride extended-release capsules dose (75, 150, or 225 mg) or switch to placebo for observation for relapse under double-blind conditions. Response during the open phase was defined as ≤ 1 full-symptom panic attack per week during the last 2 weeks of the open phase and a CGI Improvement score of 1 (very much improved) or 2 (much improved). Relapse during the double-blind phase was defined as having 2 or more full-symptom panic attacks per week for 2 consecutive weeks or having discontinued due to loss of effectiveness as determined by the investigators during the study. Randomized patients were in response status for a mean time of 34 days prior to being randomized. In the randomized phase following the 12 week open-label period, patients receiving continued venlafaxine hydrochloride extended-release capsules experienced a statistically significantly longer time to relapse.

Table 20 Panic Disorder Studies
a Odds ratio (drug to placebo) in terms of probability of free of full-symptom panic attacks based on logistic regression model.
95%CI: 95% confidence interval without adjusting for multiple dose arms.
* Doses statistically significantly superior to placebo.

Study Number

Treatment Group

Primary Efficacy Measure: Whether Free of Full-symptom Panic Attacks

Percent of patients Free of Full symptom panic attack

Adjusted Odds Ratioa to placebo

Adjusted Odds Ratioa 95% Confidence Interval

Study 1

Ven XR 75 mg* Ven XR 150 mg* Placebo

54.1% (85/157) 61.4% (97/158) 34.4% (53/154)

2. 268 3.035 —

(1.43, 3.59) (1.91, 4.82) —

Study 2

Ven XR 75 mg* Ven XR 225 mg* Placebo

64.1% (100/156) 70% (112/160) 46.5% (73/157)

2.350 2.890 —

(1.46, 3.78) (1.80, 4.64) —

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