Here is the design of a clinical trial:

Official Title: An Open-label, Active-Controlled, Safety, and Efficacy Study of Oral Baricitinib in Patients From 2 Years to Less Than 18 Years Old With Active Juvenile Idiopathic Arthritis-Associated Uveitis or Chronic Anterior Antinuclear Antibody-Positive Uveitis

Included conditions:
- Uveitis

Study Armgroups:
- {'label': 'Baricitinib', 'type': 'EXPERIMENTAL', 'description': 'Participants ≥9 to \\<18 years of age were administered 4 milligrams (mg) baricitinib once daily (QD). Participants \\<9 years of age were administered 2 mg baricitinib QD.\n\nParticipants \\<6 years of age received an oral suspension. Participants ≥6 to \\<12 years of age had the option of receiving an oral suspension. Participants \\>12 years of age were supplied tablets.', 'interventionNames': ['Drug: Baricitinib']}
- {'label': 'Adalimumab', 'type': 'ACTIVE_COMPARATOR', 'description': 'Participants received adalimumab administered subcutaneously (SC) once every 2 weeks. The dose was based on body weight: 20 mg every 2 weeks for participants weighing \\<30 kilograms (kg), or 40 mg every 2 weeks for participants weighing ≥30 kg.', 'interventionNames': ['Drug: Adalimumab']}

Interventions:
- {'type': 'DRUG', 'name': 'Baricitinib', 'description': 'Administered orally', 'armGroupLabels': ['Baricitinib'], 'otherNames': ['LY3009104']}
- {'type': 'DRUG', 'name': 'Adalimumab', 'description': 'Administered SC', 'armGroupLabels': ['Adalimumab']}

Primary Outcomes:
- {'measure': 'Part A: Percentage of Responders for Baricitinib at Week 24', 'description': 'Response was defined according to the Standardization of Uveitis Nomenclature (SUN) criteria as a 2-step decrease in the level of inflammation (anterior chamber cells) or decrease to zero through week 24, in the eye most severely affected at baseline.', 'timeFrame': 'Week 24'}

Please estimate the sample size based on the assumption: 
The study aims to detect a true baricitinib treatment response rate of >57% with >80% probability.
Sample size {14}
        The study will enroll at least 20 and up to 40 patients who have had an inadequate response or intolerance to MTX (MTX-IR) and/or bDMARDs (bDMARD-IR) as follows: approximately 30 patients in total will be treated with baricitinib, and at least 10 patients will be treated with adalimumab. At least 20 patients who are MTX-IR (but not bDMARD-IR) will be randomized in a 1:1 ratio to either open-label baricitinib or adalimumab; at least 10 patients will be randomized to baricitinib, and at least 10 patients will be randomized to adalimumab (Fig. 1). Approximately 20 additional patients who are MTX-IR or bDMARD-IR will be treated with baricitinib. Patients who are bDMARD-IR will only receive open-label baricitinib to avoid retreatment with a bDMARD. With a total sample size of 30 in the baricitinib arm, and assuming an observed response rate of 66.7%, the study will be able to detect a true baricitinib treatment response rate of >57% with >80% probability. The observed response rate of 66.7% is based on the assumption that 20 out of 30 patients in the baricitinib arm will achieve the primary endpoint. The response rate threshold of 57% was chosen to match the response rate observed for patients with JIA-uveitis treated with adalimumab in the SYCAMORE study [6].