By Manojna Maddipatla

(Reuters) – Intra-Cellular Therapies Inc said on Monday its lead drug failed to meet the main goal of a late-stage study in patients with major depressive episodes associated with bipolar disorder.

The company’s shares fell 14% before the opening bell.

The treatment, lumateperone, which is being studied as a monotherapy for the condition, failed to show statistically significant improvement in the disease condition compared to placebo in the trial, the company said.

The study, conducted only in the United States, tested two doses of the treatment against placebo in 554 patients.

However, a second global study which tested the treatment in 381 patients, met the main goal of statistically greater improvement in the severity of depressive symptoms over placebo.

The treatment is also being evaluated as an add-on therapy to lithium or valproate in a third trial.

If the drug succeeds as a monotherapy only in one of the two studies, data from this third trial, expected in 2020, would need to be positive to support a successful marketing application for lumateperone, Ritu Baral of Cowen & Co said in a note prior to the results.

Overall results from the two studies will be discussed with the U.S. Food and Drug Administration (FDA) before the company takes any call on conducting further studies, Chief Executive Officer Sharon Mates said on a conference call.

“It’s too soon to tell what we’re going to do in terms of new studies, if we’ll do new studies. We do have the adjunctive study that we’ll be reading out in the near future. So we’ll see what the FDA has to say,” Mates said.

The set of studies announced on Monday would likely not be adequate for ultimate approval in bipolar, and additional work would likely be required, Brian Abrahams of RBC Capital Markets said.

The positive readout, however, maintains some hope for this indication, which is expected to contribute about $600 million to revenue by 2028, Abrahams added.

Bipolar disorder is characterized by recurrent episodes of mania and depression and affects about 2.8% of the U.S. population aged 18 and older, according to the National Institute of Mental Health.

Intra-Cellular awaits FDA approval of lumateperone as a treatment for schizophrenia.

In May, Allergan Plc’s schizophrenia treatment, Vraylar, won the FDA’s approval to treat depressive episodes of bipolar I disorder. Analysts had expected the treatment to bring in sales of about $1.36 billion by 2026.

(Reporting by Manojna Maddipatla in Bengaluru; Editing by Maju Samuel)