Here is the design of a clinical trial:

Official Title: Randomized Clinical Trial to Compare Efficacy and Safety of Repeated Courses of Rituximab to That of Maintenance Mycophenolate Mofetil Following Single Course of Rituximab in Maintaining Remission Over 24 Months Among Children With Steroid Dependent Nephrotic Syndrome

Included conditions:
- Steroid-Dependent Nephrotic Syndrome

Study Armgroups:
- {'label': 'Repeated Courses of Rituximab Only', 'type': 'EXPERIMENTAL', 'description': 'First course Course Rituximab at Randomization. Prophylactic 2nd and 3rd course rituximab re-administration will be done at 8 months and 16 months of follow-up if B cell count normalize.', 'interventionNames': ['Drug: Rituximab']}
- {'label': 'Rituximab and Mycophenolate Mofetil', 'type': 'ACTIVE_COMPARATOR', 'description': 'First course Course Rituximab at Randomization. Addition of Maintenance Mycophenolate Mofetil from 4 Month onwards.', 'interventionNames': ['Drug: Rituximab', 'Drug: Mycophenolate Mofetil']}

Interventions:
- {'type': 'DRUG', 'name': 'Rituximab', 'description': 'First course Course Rituximab at Randomization.', 'armGroupLabels': ['Repeated Courses of Rituximab Only', 'Rituximab and Mycophenolate Mofetil']}
- {'type': 'DRUG', 'name': 'Mycophenolate Mofetil', 'description': 'Addition of Maintenance Mycophenolate Mofetil from 4 Month onwards', 'armGroupLabels': ['Rituximab and Mycophenolate Mofetil']}

Primary Outcomes:
- {'measure': 'The primary endpoint is the time to first relapse or death (whichever occurs first) till end of study (follow-up phase of 24 months)', 'timeFrame': '24 months'}

Please estimate the sample size based on the assumption: 
Power of 90%, two-sided alpha level of 5%, and a drop-out rate of 10%.
Sample size/ power calculation
          The sample size calculation is based on the primary endpoint, time to first relapse or death (whichever occurs first), using log-rank test to compare the event times of arm A and B. An event rate of 25% after 24âmonths in arm A and 5% in arm B was assumed (hazard ratioâ=â0.178) [12â14, 17â22]. Assuming an individual follow-up time of 24âmonths, in total 95 patients (15 events) are required to prove efficacy with a power of 90% and a two-sided alpha level of 5% for the log-rank test. To account for major protocol violations and drop-outs an assumed drop-out rate of 10% yields a total of 100 patients to be randomized [23, 24].