Alkermes Plc /zigman2/quotes/205084517/composite ALKS +5.88% announced positive results Thursday for a trial of its ALKS 3831 treatment for schizophrenia. The Phase 3 trial dubbed Enlighten-2 was designed to evaluate the treatment's favorable weight profile compared to olanzapaine, an antipsychotic agent that has been shown to be effective in treating the disease, but limited in clinical use because it causes patients to gain a lot of weight. ALKS 3831 met its primary endpoint of lower weight gain from baseline at six months. The company is now planning to submit a New Drug Application to the U.S. Food and Drug Administration in mid-2019. "Significant unmet patient need remains in schizophrenia despite the number of treatment options available. A new agent that offers the robust efficacy of olanzapine but with a favorable weight profile that stabilizes within weeks of treatment initiation would be an important and differentiated addition to the treatment armamentarium for schizophrenia," said Christoph Correll, M.D., Professor of Psychiatry and Molecular Medicine at Hofstra Northwell School of Medicine in a statement. Weight gain is a common metabolic side effect of antipsychotic medications, a major challenge for the roughly 2.4 million American adults who suffer from schizophrenia, a chronic brain disorder that is marked by symptoms such as hallucinations and delusions along with depression and social withdrawal. Alkermes shares were halted premarket for the news, but have fallen 32.6% in 2018, while the S&P 500 /zigman2/quotes/210599714/realtime SPX +1.95% has gained 2.6%.