A new indication for treatment-resistant depression in adults has been added to the olanzapine/fluoxetine combination pill (Symbyax), the drugmaker Eli Lilly announced.

The combination drug was the first approved by the FDA for bipolar disorder in 2003, and is now the first okayed for treatment-resistant depression.

It is approved for use in adults with major depressive disorder who have not responded to two separate trials of different antidepressants during their current episode, according to the updated label information.

Information has also been added to the labels of olanzapine (Zyprexa) and fluoxetine indicating that the two drugs can be used in combination for the acute treatment of bipolar disorder and treatment-resistant depression.

Clinicians can prescribe the single-pill option or the two drugs in separate pills.

The approval of the treatment-resistant depression indication for the combination pill was made on the basis of data from one pivotal trial, three supportive studies, and one inconclusive trial using doses ranging from 6 to 18 mg for olanzapine and 25 to 50 mg for fluoxetine, Eli Lilly said.

An analysis of all five studies together showed a significant reduction in depressive symptoms from baseline with the combination pill compared with both fluoxetine ( P =0.015) and olanzapine ( P =0.007) alone.

There were also significantly greater remission rates with the combination ( P ≤0.05), the drugmaker said.

Adverse events reported more frequently in patients taking the olanzapine/fluoxetine combination were weight gain, increased appetite, dry mouth, somnolence, and fatigue.