Clinical value of early partial symptomatic improvement in the prediction of response and remission during short-term treatment trials in 3369 subjects with bipolar I or II depression.

Objective: To evaluate the clinical value of early partial symptomatic improvement in predicting the probability of response during the short-term treatment of bipolar depression.

Methods: Blinded data from 10 multicenter, randomized, double-blind, placebo-controlled trials in bipolar I or II depression were used to determine if early improvement (≥20% reduction in depression symptom severity after 14 days of treatment) predicted later short-term response or remission. Sensitivity, specificity, efficiency, and positive and negative predictive values (PPV, NPV) were calculated using an intent to treat analysis of individual and pooled study data.

Results: 1913 patients were randomized to active compounds (aripiprazole, lamotrigine, olanzapine/olanzapine-fluoxetine, and quetiapine), and 1456 to placebo. In the pooled positive studies, early improvement predicted response and remission with high sensitivity (86% and 88%, respectively), but rates of false positives were high (53% and 59%, respectively). Pooled negative predictive values for response/remission (i.e. confidence in knowing the drug will not result in response or remission) were 74% and 82%, respectively, with low rates of false negatives (14% and 12%, respectively).

Conclusion: Early improvement in an individual patient does not appear to be a reliable predictor of eventual response or remission due to an unacceptably high false positive rate. However, the absence of early improvement appears to be a highly reliable predictor of eventual non-response, suggesting that clinicians can have confidence in knowing when a drug is not going to work during short-term treatment. Patients who fail to demonstrate early improvement within the first two weeks of treatment may benefit from a change in therapy.