Here is the design of a clinical trial:

Official Title: A Phase II Randomized, Double-blinded, Placebo-controlled Parallel Group Trial to Examine the Efficacy and Safety of BI 425809 Once Daily With Adjunctive Computerized Cognitive Training Over 12 Week Treatment Period in Patients With Schizophrenia

Included conditions:
- Schizophrenia

Study Armgroups:
- {'label': 'BI 425809 10 mg + Computerized Cognitive Training', 'type': 'EXPERIMENTAL', 'interventionNames': ['Drug: BI 425809']}
- {'label': 'Placebo + Computerized Cognitive Training', 'type': 'PLACEBO_COMPARATOR', 'interventionNames': ['Drug: Placebo']}

Interventions:
- {'type': 'DRUG', 'name': 'BI 425809', 'description': 'Tablet', 'armGroupLabels': ['BI 425809 10 mg + Computerized Cognitive Training'], 'otherNames': ['iclepertin']}
- {'type': 'DRUG', 'name': 'Placebo', 'description': 'Tablet', 'armGroupLabels': ['Placebo + Computerized Cognitive Training']}

Primary Outcomes:
- {'measure': 'Change From Baseline in Neurocognitive Function as Measured by the Neurocognitive Composite Score of the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) After 12 Weeks of Treatment', 'description': 'MCCB neurocognitive composite T-score assesses 6 cognitive domains, including speed of processing, attention vigilance, working memory, verbal learning, visual learning, reasoning and problem solving. MCCB neurocognitive T-scores in the general population have a mean of 50 and standard deviation of 10. A higher T-score indicates better cognition. Change from baseline in MCCB neurocognitive composite T-score at Week 12 was modelled based on a restricted maximum likelihood (REML) based approach using a mixed model with repeated measurements (MMRM) which included the following fixed effects: categorical factor of planned treatment, visit (screening, baseline, week 6 and Week 12), planned treatment by visit interaction, continuous covariate of baseline value, baseline by visit interaction, categorical factor of age group, and continuous covariate of change from screening to baseline value. The Least Squares Mean (95 % Confidence Interval) at Week 12 is reported.', 'timeFrame': 'At screening (28 days prior to first drug drug administration), at baseline and at Weeks 6 and 12 after first drug administration.'}

Please estimate the sample size based on the assumption: 
A 10% dropout rate is assumed. The simulations were performed using R version 3.3.2.
Sample Size Calculation
          Monte Carlo simulations (10,000 simulations) were made to assess the probabilities of observing different effect sizes of BI 425809 over placebo, given the true effect sizes. Based on the simulation results, a sample size of 200 patients is sufficient to achieve the aims of this exploratory trial. Predicting a 10% dropout rate, this will result in a total of 180 evaluable patients, or 90 evaluable patients per treatment arm. If the true effect size (mean treatment difference/SD) is 0.45, there is a 64% probability that a mean difference between the treatment and placebo groups greater than 0.4 will be observed, and an 84% probability that a mean difference of at least 0.3 will be seen. On the other hand, assuming the true effect size is only 0.2, there is a 75% probability of observing a mean difference less than 0.3, and a 91% probability of observing a mean difference of at most 0.4. The simulations were performed using R version 3.3.2.