The small molecule drug bifeprunox mesilate (formerly DU127090) was discovered by and underwent early development at Solvay Pharmaceuticals, of the Solvay group. The drug is being developed for the treatment of psychosis and mood disorders, such as schizophrenia. In contrast to fi rst-generation atypical antipsychotic drugs, which act via dopamine D2 receptor antagonism, drugs such as bifeprunox act as partial D2 agonists.