A phase II randomised, double-blinded, placebo-controlled study to

INTERVENTION: Product Name: BI 409306 Product Code: BI 409306 Pharmaceutical Form: Film‐coated tablet Current Sponsor code: BI 409306 Other descriptive name: BI 409306 Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 10‐ Pharmaceutical form of the placebo: Film‐coated tablet Route of administration of the placebo: Oral use Product Name: BI 409306 Product Code: BI 409306 Pharmaceutical Form: Film‐coated tablet Current Sponsor code: BI 409306 Other descriptive name: BI 409306 Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 25‐ Pharmaceutical form of the placebo: Film‐coated tablet Route of administration of the placebo: Oral use Product Name: BI 409306 Product Code: BI 409306 Pharmaceutical Form: Film‐coated tablet Current Sponsor code: BI 409306 Other descriptive name: BI 409306 Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 50‐ Pharmaceutical form of the placebo: Film‐coated tablet Route of administration of the placebo: Oral use CONDITION: Patients with schizophrenia on stable antispychotic treatment ; MedDRA version: 18.1 Level: LLT Classification code 10039634 Term: Schizophrenia residual System Organ Class: 100000004873 Therapeutic area: Psychiatry and Psychology [F] ‐ Mental Disorders [F03] PRIMARY OUTCOME: Main Objective: The objective of the study is to investigate the efficacy, safety and; tolerability of four different doses of BI 409306 compared to placebo; given for 12 weeks in patients with schizophrenia on stable; antipsychotic treatment. Primary end point(s): 1: Change from baseline in cognitive function as measured by the Cambridge Neuropsychological Test Automated Battery (CANTAB) after 12 weeks of treatment; ; 2: Occurrence of (S)AEs (including the abnormalities of physical examination, vital signs, ECG test and laboratory tests); ; 3: Occurrence of Protocol‐specified AESI (adverse events of special interest); ; 4: Dramatic worsening of disease state as assessed by PANSS; ; 5: Suicidality as assessed by C‐SSRS; Secondary Objective: Not applicable Timepoint(s) of evaluation of this end point: 1: 12 weeks; ; 2: up to 20 weeks; ; 3: up to 20 weeks; ; 4: 12 weeks; ; 5: 12 weeks; SECONDARY OUTCOME: Secondary end point(s): 1: Change from baseline in everyday functional capacity as measured by Schizophrenia Cognition Rating Scale (SCoRS) global ratings after 12 weeks of treatment ; ; 2: Change from baseline in the composite score of Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) after 12 weeks of treatment ; ; 3: Change from baseline in Clinical Global Impressions ‐Severity (CGI‐S) scale score after 12 weeks of treatment ; ; 4: Patient Global Impressions ‐Improvement (PGI‐I) scale score measured after 12 weeks of treatment ; ; 5: Change from baseline in PANSS negative symptom factor score after 12 weeks of treatment (for subset of patients diagnosed with negative symptom) ; ; 6: Change in psychopathology symptoms as assessed by PANSS ; Timepoint(s) of evaluation of this end point: 1: 12 weeks ; ; 2: 12 weeks ; ; 3: 12 weeks ; ; 4: 12 weeks ; ; 5: 12 weeks ; ; 6: 12 weeks ; INCLUSION CRITERIA: Patients with established diagnoses of schizophrenia (per Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM‐5)) with the following clinical features: a) Clinically stable and are in the residual (non‐acute) phase of their illness for at least 8 weeks b) Current antipsychotic and concomitant psychotropic medications must meet the criteria below: b)‐3 Maintained on current concomitant psychotropic medications other than anticholinergics, antiepileptics and lithium, and on curr b)‐1 Maintained on current atypical (second generation) antipsychotic medications (in any approved dosage form) other than Clozapine and on current dose for at least 8 weeks prior to randomisation, and/or b)‐2 Maintained on current typical (first generation) antipsychotic medications and on current dose for at least 6 months, optionally combined with anticholinergics if treated with a stable dose for at least 6 months prior to randomisation, and/or