Neumora Therapeutics said its experimental drug to treat depression failed to meet the main goal of a late-stage study, sending shares of the company down 82% in premarket trading.

The study, first of the three late-stage trials, was testing the drug, navacaprant, in patients with major depressive disorder (MDD).

The drug did not reduce symptoms of the disorder when tested on a scale used to measure the severity of depressive episodes such as sadness, reduced sleep and pessimistic thoughts.

The company said it was "disappointed" by the results from the trial.

"There is a lot to investigate from the study, in particular the contrast in drug and placebo responses in depressed mood and anhedonia in female participants compared to male participants," Neumora said.

Navacaprant was shown to be safe and generally well-tolerated with no serious adverse events reported, the company said.

Neumora will provide additional updates on the development of the drug at an industry conference later this month.