(Reuters) – Drug developer Minerva Neurosciences Inc said on Friday its experimental drug for schizophrenia did not meet the main goal of a late-stage study, sending its shares down nearly 66% in early trade.

The drug, roluperidone, did not show statistically significant difference from the placebo in reducing disease symptoms after 12 weeks of treatment, although it was well tolerated during the course of the study, the company said.

Minerva intends to consult with the U.S. Food and Drug Administration about the next steps of development, it said in a statement.

Schizophrenia, which affects about 2.4 million adults in the United States, is a chronic mental disorder that causes distortion in thoughts, hallucinations, and feelings of fright and paranoia.

Existing anti-psychotic drugs in the market include Rexulti from Danish drugmaker H. Lundbeck A/S and Japan’s Otsuka Pharmaceutical Co Ltd, as well as Allergan Plc’s Vraylar, Johnson & Johnson’s Invega and Intra-Cellular Therapies’ Caplyta.

(Reporting by Manojna Maddipatla and Trisha Roy in Bengaluru; Editing by Anil D’Silva)