Intervention: ICLEPERTIN
Trial phase: Phase 2
SMILES: C[C@@H](Oc1ccc(S(C)(=O)=O)cc1C(=O)N1C[C@@H]2C[C@]2(c2cc(C(F)(F)F)on2)C1)C(F)(F)F
Sex: All
Age groups: Adult
Healthy volunteers: No
Participants at risk: 99
Group description: Patients administered once daily (in the morning) two tablets of 5 milligram (mg) of BI 425809 (total BI 425809 dose= 10 mg) orally for 12 weeks. Concomitantly patients received non-pharmacological adjunctive computerized cognitive training (CCT).
Eligibility criteria:
Inclusion Criteria:

Signed and dated written informed consent in accordance with ICH Harmonized Tripartite Guideline for Good Clinical Practice (ICH-GCP) and local legislation prior to admission to the trial.
Male or female patients who are 18-50 years (inclusive) of age at time of consent.

Established schizophrenia (as per DSM-5) with the following clinical features:

Outpatient, with no hospitalization for worsening of schizophrenia within 3 months prior to randomization
Psychiatrically stable without symptom exacerbation within 3 months prior to randomization
PANSS score ≤ 5 on positive items P1, P3-P7 and ≤ 4 on positive item P2 at Visit 1, and confirmed at Visit 2

Patients must be on stable antipsychotic treatment; also, current antipsychotic medications and concomitant anticholinergics, antiepileptics, lithium and allowed antidepressants must meet the criteria below:

Patients must take 1 and may take up to 2 antipsychotics (typical and/or atypical), except for clozapine
Patients must be stable on current antipsychotics, anticholinergics, antiepileptics, lithium and allowed antidepressants for at least 3 months prior to randomization and be on current dose for at least 30 days prior to randomization o Patients on Long-Acting Injectable (LAI) antipsychotics should be on the same medication and dose for at least 3 months prior to randomization
Women of childbearing potential (WOCBP)2 must be ready and able to use highly effective methods of birth control per Non-Clinical Safety Studies for the Conduct of Human Clinical Trials and Marketing Authorization for Pharmaceuticals (ICH M3 (R2)) that result in a low failure rate of less than 1% per year when used consistently and correctly. A list of contraception methods meeting these criteria is provided in Section 4.2.2.3. Such methods should be used throughout the trial, and for a period of at least 35 days after last trial drug intake, and the patient must agree to periodic pregnancy testing during participation in the trial.
Patients must demonstrate their ability to properly use the CCT device and program, as well as be compliant with CCT run-in (defined as completing at least 2 hours per week for two weeks, totalling 4 hours CCT, during the screening period)3.
Patients must be able to comply with all protocol procedures, in the investigator's opinion.
Patients must have a study partner who will preferably be consistent throughout the study. It is recommended that the study partner should interact (in-person or telephone) with the subject at least 2 times a week.

Exclusion Criteria:

Patients who have a categorical diagnosis of another current major psychiatric disorder on the Mini-International Neuropsychiatric Interview (M.I.N.I.).
Diseases of the central nervous system (CNS) that may impact the assessment of the cognitive tests as per investigator's opinion. A movement disorder due to antipsychotic treatment not currently controlled with anti- EPS treatment or another movement disorder (e.g. Parkinson´s disease).
Patients with a history of participating in any formal cognitive remediation program for 10 or more training sessions.

Patients who were treated with any of the following medications within the last 6 months prior to randomization:

Bitopertin, BI 409306, encenicline or other investigational drug testing effects on cognition in schizophrenia
Clozapine (atypical antipsychotic medication)
Sarcosine, cycloserine, serine and glycine
Stimulants (e.g. methylphenidate, dextroamphetamine, modafinil)
Tricyclic antidepressants
Patients receiving any other investigational drug (other than a potential cognitive enhancing drug) within 30 days or 6 half-lives (whichever is longer) prior to randomization. For investigational LAI antipsychotics, the last injection must be at least 3 months or two administration cycles (i.e. 6 months if administration is every 3 months) prior to randomization, whichever is longer.
Patients who have participated in a clinical trial with repeated assessments (i.e. a single assessment is not exclusionary) with the MATRICS Consensus Cognitive Battery (MCCB) within the last 6 months prior to randomization.
Patients who required a change in ongoing benzodiazepine or sleep medication dose or regimen within the last 30 days prior to randomization.
Patients with known active infection with SARS-CoV-2 within the last 30 days prior to randomization.
Other exclusion criteria apply