Interim analysis showed inadequate efficacy of bifeprunox

The primary purpose of the study is to evaluate the efficacy of bifeprunox in the maintenance phase of schizophrenia compared to placebo.

Schizophrenia is a serious and disabling mental disorder that affects approximately 1% of the world's population. There are a number of antipsychotic drugs in use but none is ideal, in particular because their safety profile is complex and their effectiveness is limited. In particular, after having overcome acute exacerbations many patients continue to experience significant symptoms that prevent an adequate functioning. In the current study, patients suffering from schizophrenia and currently in a post-acute maintenance phase of the disease will be included. Non-treatment resistant patients will be included in the study, since they have partially responded to their current antipsychotic treatment but still have clinically significant symptoms and/or impairment of functioning in their daily life. The study is a 12-month study with an initial 12-week placebo-controlled, quetiapine-referenced phase. After this initial 12-week phase, the patients allocated to placebo will be switched to bifeprunox. In the final non-inferiority analysis of the 12-month data, the results from this study will be combined with the data from a similar study (11915A).

Inclusion Criteria:

Main inclusion criteria

• The subject has a primary diagnosis of schizophrenia
• The subject experiences clinically significant symptoms
• The subject's medication remained stable for 8 weeks prior to screening
• The subject is currently in the post-acute maintenance phase of his/her disease

Exclusion Criteria:

Main exclusion criteria

• The subject is at significant risk of suicide
• The subject is treatment resistant
• The subject has experienced an acute exacerbation within 8 weeks prior screening
• The subject is unlikely to comply with the protocol
• The subject has a current diagnosis or a history of substance abuse