SAN ANTONIO, TX—Vilazodone may be an effective treatment option for adults with major depressive disorder (MDD) regardless of sex, age, MDD history, or baseline symptom severity, research presented at the U.S. Psychiatric & Mental Health Congress has shown.

The results, from a post hoc analysis of 4 randomized, double-blind, placebo-controlled trials, found that relative to placebo, “vilazodone significantly reduced depression symptoms in subgroups of patients categorized by demographics, disease history, and symptom severity,” noted Susan G. Kornstein, MD, Professor, Psychiatry and Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, and colleagues.

Vilazodone, a selective serotonin reuptake inhibitor and 5-HT1A receptor partial agonist, is approved in the United States for the treatment of MDD in adults.

Previously, the 4 clinical trials had established the efficacy of this agent vs. placebo based on change from baseline in total score at the end of double-blind treatment at Week 8 or 10 using the Montgomery-Åsberg Depression Rating Scale (MADRS).

To determine the effects of vilazodone in reducing symptoms of depression across different patient subgroups, the investigators conducted a post-hoc analysis of pooled data from these trials.

Three of the studies administered vilazodone 40mg daily or placebo to patients for 8 weeks; in the fourth study, vilazodone 20mg daily, vilazodone 40mg daily, or placebo were given for 10 weeks.

The post-hoc analyses in the intent-to-treat (ITT) population included 2,218 patients, all of whom had received 1 or more doses of study treatment and had 1 or more post-baseline total score on MADRS. A total of 1,254 patients had received vilazodone and 964, placebo. Effect sizes were estimated using Cohen’s d calculation.

Three subgroups of patients were defined using demographics, MDD history, and symptom severity. For demographics, patients were categorized by sex (men, women) and age (<45, ≥45–<60, and ≥60 years). MDD history included duration of illness (<2, ≥2–<10, and ≥10 years), whether episodes were recurrent (yes or no), and duration of the current episode (≤6, >6–≤12, and >12 months). Baseline MADRS total score denoted symptom severity (<30, ≥30, and ≥35 [very severe]).

Patient demographics and baseline characteristics were similar between treatment groups. In the vilazodone arm, 57.6% were female, as were 57.0% in the placebo arm; 74.4% and 73.4% were white and mean age was 40.6 years and 41.5 years, respectively. A total of 36.9% and 38.1% in the vilazodone and placebo arms had MDD duration ≥10 years, with the majority (74.4% and 74.3%) having recurrent MDD. Current episode duration was ≤6 months in 51.8% and 51.7% of patients, respectively; mean MADRS total score of ≥30 was noted in 64.9% and 65.1%.

At Week 8 in the pooled ITT population, the least square mean changes from baseline in MADRS total score was -15.2 for vilazodone and -11.7 for placebo (P < .001).

Dr. Korstein noted that the largest effect sizes for vilazodone vs. placebo were in the age ≥60 years (d=0.82), MDD duration ≥10 years (d=0.40), current episode duration <12 months (d=0.42), MADRS total score ≥30 (d=0.41), and MADRS total score ≥35 (d =0.43) groups.

MADRS response at end of treatment was 34.4% for placebo and 49.0% for vilazodone (OR 1.8; 95% CI, 1.5–2.2; P<0.001), which was clinically meaningful for all subgroups based on a number needed to treat of ≤10.