A Study to Test the Safety and Efficacy of MK-8998 in Acutely Psychotic Participants With Schizophrenia (MK-8998-004)

A Phase IIa, Randomized, Multicenter, Double-Blind, Active Comparator- and Placebo-Controlled, Clinical Trial to Study the Safety and Efficacy of MK8998 in Acutely Psychotic Patients With Schizophrenia

A study to evaluate the safety and efficacy of treatment with MK-8998 as compared to placebo and olanzapine for acutely psychotic patients with schizophrenia. The primary hypothesis is that in participants undergoing an acute psychotic episode of schizophrenia, MK-8998 6 to 8 mg twice daily is superior to placebo in the treatment of symptoms of schizophrenia as measured by the mean change from baseline in the Positive and Negative Syndrome Scale (PANSS) total score at Week 4.

Inclusion Criteria:

• Patient's age is 18 to 55
• Patient meets DSM-IV/DSM-IV-TR criteria for a primary diagnosis of schizophrenia
• The duration of the patients schizophrenia diagnosis must be greater than 1 year
• Patient has an acute exacerbation of psychotic symptoms (of at least 3 days but no longer than 6 weeks) and marked deterioration of function

Exclusion Criteria:

• Patient currently has a clinically significant neurological, metabolic, hepatic, renal, hematological, pulmonary, cardiovascular, gastrointestinal, and/or urological disorder that would pose a risk to the patient in the opinion of the investigator if they were to participate in the study or that might confound the results of the study
• The patient has evidence of acute hepatitis, clinically significant chronic hepatitis, or impaired hepatic function
• The patient has a chronic organic disease of the central nervous system (other than schizophrenia) such as, tumors, inflammation, active seizure disorder, vascular disorder, Parkinson's disease, Alzheimer's disease or other forms of dementia, myasthenia gravis, or other degenerative processes. In addition, patients must not have a history of mental retardation or persistent neurological symptoms attributable to serious head injury
• Patient has a history of alcohol/drug dependence within 3 months or alcohol/drug abuse within 1 month of screening. Exceptions include caffeine and nicotine abuse/dependence
• Patient has a history of hypersensitivity to olanzapine OR poor response to olanzapine in the last 2 years OR intolerable side effects due to olanzapine OR patients current psychotic relapse occurred while consistently taking a therapeutic dose (10 mg or more) of olanzapine OR olanzapine is medically contradicted
• Patient is refractory to antipsychotic treatment