After filing patents on a decades-old antipsychotic, Aneurotech BV is laying plans for a U.S. phase IIIb trial of the drug as an adjunctive therapy in major depressive disorder. The study will assess the effects of ANT-01, a low dose of pipamperone, a selective antagonist of both the serotonin 5-HT2A and D4 dopamine receptors, which has been on the market in some countries in Europe and elsewhere for more than 40 years.