Desvenlafaxine vs. placebo in the treatment of persistent depressive disorder

Pharmacotherapy of non-major persistent depressive disorder (PDD) is little studied. We report a study of the serotonin-norepinephrine reuptake inhibitor (SNRI) desvenlafaxine (DVLX) for PDD.

Non-psychotic, non-bipolar outpatients aged 20-65 having PDD without concurrent major depression (MDD) were randomized double-blind to desvenlafaxine or placebo for 12 weeks. All had Hamilton Depression Rating Scale (HDRS-24) score ≥ 12. Open-label DVLX was offered for 12 weeks following the acute trial.

Seventy-one subjects having mean baseline HDRS-24 20.27 ± 4.77 were eligible, of whom post-RZ data was available for all 59 randomized. The primary 12 week analysis did not differentiate DVLX-treated subjects' mean HDRS scores from those on placebo (6.53 ± 3.98 vs. 8.24 ± 4.96, F = 3.33, df = 1, p = .07). Several secondary analyses yielded statistically significant results, including Responder, CGI and QIDS.

As the primary analysis did not reach statistical significance, this is a negative study which does not support the use of DVLX for non-major PDD. Nevertheless, statistically significant secondary analyses suggest the overall negative result could be due to sample size or sampling, suggesting further studies of this medication might be appropriate in this population.