APA: Successor to Effexor Effective Against Anxiety in Depression

SAN DIEGO, May 23 -- The novel serotonin-norepinephrine reuptake inhibitor desvenlafaxine succinate (Pristiq) was significantly superior to placebo in the treatment of anxiety symptoms in depression, results of a pooled analysis showed.

In seven randomized, placebo controlled studies, patients on desvenlafaxine had significantly greater improvement from baseline to week eight, compared with placebo, on anxiety items of the 17-item Hamilton Depression Rating Scale, reported Karen A. Tourian, M.D., and colleagues from Wyeth, maker of Pristiq.

Patients also showed significantly greater improvement in total score on the Covi Anxiety Scale, they said at the American Psychiatric Association meeting here.

"Despite the exclusion of any anxiety disorder at baseline and the low mean baseline anxiety scores among the study population," the investigators said, "patients treated with desvenlafaxine had significantly better anxiety scores at end point than those treated with placebo."

Desvenlafaxine is a metabolite and follow-on compound of venlafaxine (Effexor), a blockbuster antidepressant whose patent protection will expire in 2008. The new drug received an approvable letter from the FDA in January of this year, but has not yet received the final go-ahead.

In the pooled analysis, the investigators looked at seven randomized, double-blind, placebo-controlled, eight-week trials in which desvenlafaxine was pitted against placebo.

All of the studies enrolled adult outpatients diagnosed with major depressive disorder according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. Patients were excluded from the studies if any anxiety disorder was the primary diagnosis.

A total of 1,186 patients in the seven studies were randomized to receive desvenlafaxine at doses ranging from 100 mg a day to 400 mg a day. An additional 797 patients were randomly assigned to placebo. All the studies lasted eight weeks.

For the pooled analysis, the primary efficacy outcomes measured were the 17-item Hamilton Rating Scale for Depression (HAM-D17) item 10 (Anxiety/Psychic), total score on the Covi Anxiety Scale (included in six of the seven trials).

Patients with a Covi Anxiety score greater than 9, or who had a Covi score that exceeded their score on the Raskin Depression Scale total score were excluded from study enrollment.

In an intent-to-treat analysis, the investigators measured changes from baseline using a mixed-effects model for repeated measures analysis. These included the fixed, categorical effects of treatment, and adjusted for protocol, visit, and the treatment-by-visit interaction, as well as the continuous, fixed covariate of baseline score.

They also conducted secondary analyses evaluating changes from baseline to end point using analysis of covariance with the last observation carried forward (last observation is used when there is missing data on HAM-D17 or Covi Anxiety scale at end of study), and observed cases analyses (subjects are omitted from the analysis if missing data at end of study).

Treatment differences on the HAM-D17 Anxiety/Psychic item were statistically significant at all time points evaluated (P