Here is the design of a clinical trial:

Official Title: Efficacy and Safety of Rituximab in the First Episode of Pediatric Idiopathic Nephrotic Syndrome

Included conditions:
- Steroid-Sensitive Nephrotic Syndrome

Study Armgroups:
- {'label': 'Intervention/treatment', 'type': 'EXPERIMENTAL', 'interventionNames': ['Drug: Rituximab']}

Interventions:
- {'type': 'DRUG', 'name': 'Rituximab', 'description': 'Rituximab (375 mg/m2) will be given as a single intravenous infusion after remission', 'armGroupLabels': ['Intervention/treatment']}

Primary Outcomes:
- {'measure': '1-year relapse-free survival rate', 'description': 'The rate of no relapse within 1 year', 'timeFrame': '1-year period after randomization'}

Please estimate the sample size based on the assumption: 
The study assumes a 10% dropout rate, 80% power, and a two-sided alpha level of 0.05.
Sample size
        The present study design is an exploratory single-arm study. The sample size is based on the expected rate of the primary efficacy endpoint and the anticipated size of the effect of RTX treatment. According to previous literature, the 1-year relapse-free survival rate is approximately 30% in children with the first episode of SSNS after standardised prednisone/prednisolone treatment.6 Based on this previous study,6 we estimated that a sample size of 44, with the assumption of a 10% dropout rate, would provide 80% power to detect a 20% increase in the relapse-free rate between the traditional method and RTX treatment at a two-sided alpha level of 0.05.