To model the cost and consequences of desvenlafaxine and venlafaxine in the second-line outpatient treatment of major depressive disorder (MDD) from the payer (National Health System) perspective in Spain.

The model (a Markov simulation) follows a cohort of MDD patients through 1 year after failure of first-line treatment with a Selective-Serotonin-Reuptake-Inhibitor (SSRI) and estimates outcome measures (% in remission and depression-free days) accrued and costs incurred during outpatient treatment of MDD. Selected comparator is venlafaxine because its actual generic price. The model also considers drug treatment switching beyond the second-line of therapy (3rd line) or changing to another drugs in 4th-line in cases of patient discontinuation or lack of remission according with outcomes from STAR-D trial. Efficacy of drugs was extracted from clinical trial published. The model generates outcomes and cost from the NHS in year 2014.

Due to fewer discontinuations, desvenlafaxine was associated with numerically more depression-free days and a higher percentage of patients in remission versus venlafaxine: 1.7 days and 0.5% more in remission. Also, healthcare costs were a little bit lower with desvenlafaxine than with venlafaxine: €1,114 vs. €1,166 (-52€).

In patients who have not responded to a first-line SSRI therapy, desvenlafaxine-50mg was clinically similar in effectiveness but a less costly option (about 5% lower) compared with venlafaxine for the second-line treatment of MDD patients from a payer (NHS) perspective in Spain.