Here is the design of a clinical trial:

Official Title: Lengthening Adalimumab Dosing Interval in Quiescent Crohn's Disease Patients

Included conditions:
- Crohn Disease in Remission
- Crohn Disease

Study Armgroups:
- {'label': 'Intervention group', 'type': 'EXPERIMENTAL', 'description': 'Lengthening adalimumab dosing interval: The adalimumab injection interval during maintenance therapy (40 mg sc / 2 weeks) will be extended through a stepwise disease activity guided manner to 3 weeks and subsequently - after 24 weeks - to 4 weeks. If a step-down leads to recurrence of disease activity patients will return to the preceding effective dosing interval.', 'interventionNames': ['Other: Lengthening adalimumab dosing interval']}
- {'label': 'Control group', 'type': 'NO_INTERVENTION', 'description': 'Standard care: patients will continue adalimumab maintenance treatment of 40mg per 2 weeks. Treatment decisions are made at the discretion of the treating physician.'}

Interventions:
- {'type': 'OTHER', 'name': 'Lengthening adalimumab dosing interval', 'description': 'Lengthening adalimumab dosing interval from 2 weeks to 3 weeks and -later- to 4 weeks.', 'armGroupLabels': ['Intervention group'], 'otherNames': ['Lengthening Humira dosing interval', 'Longer adalimumab interval', 'Longer Humira interval', 'Adalimumab dose reduction', 'Humira dose reduction']}

Primary Outcomes:
- {'measure': 'Cumulative incidence of persistent disease flares.', 'description': 'A persistent flare is defined as two of three of the following criteria persisting for \\> 8 weeks, despite dose escalation of adalimumab; FC \\>250 µg/g, CRP≥10 mg/L, HBI ≥5. Non-inferiority is reached if the difference in cumulative incidence of persistent flares not exceeds the non-inferiority margin of 15%.', 'timeFrame': 'From the date of randomization up to week 48.'}

Please estimate the sample size based on the assumption: 
One-sided testing is used with an alpha of 0.05 (Zα=1.64), power 1-beta 0.8 (Zβ=0.84), and a randomisation ratio of 2:1 intervention versus control. A 10% drop-out rate is also accounted for.
Sample size
        The null hypothesis in non-inferiority studies is that the intervention is inferior compared with the control arm by more than the non-inferiority margin. The alternative hypothesis is that the intervention is not worse than the control by more than the non-inferiority margin. Therefore, if the null hypothesis is rejected, the alternative hypothesis that the intervention is non-inferior is accepted.34 Based on an extrapolation of data from the DRESS study and results from a real-life CD cohort in Leuven, an estimated 15% of patients will experience the primary outcome (persistent flare) in the control arm. In the Leuven cohort, 41/156 (26%) patients discontinued adalimumab due to loss of response, despite adalimumab dose escalation.21 35 The latter 26% was adjusted to an expected 15% for our cohort because the follow-up time in our cohort concerns 12 rather than 20 months, and our cohort is a preselected cohort of patients in long and stable remission rather than a cross-sectional cohort. In non-inferiority analyses, one-sided testing is used. Applying one sided testing, an alpha of 0.05 (ZÎ±=1.64), power 1-beta 0.8 (ZÎ²=0.84), a non-inferiority margin of 15% and randomisation ratio of 2:1 intervention versus control resulted in n=105âand n=53 for intervention and control arm, respectively. Accounting for a 10% drop-out, 174 patients have to be included in total.
        A non-inferiority margin of 15% means a maximum difference in persistent flare of 15% between the usual care and intervention group. We believe this strikes an acceptable balance between the potential harms of flare, and the benefits of dose reduction (fewer injections, potential for reduced risk of side effects and cost-savings). The large Nor-Switch trial also used a non-inferiority margin of 15% for disease worsening during follow-up.36 Based on this example, discussions in our study-group and approval of the protocol by the Dutch Organisation for Health Research and Development, we believe this margin is appropriate. The DRESS study used a non-inferiority margin of 20%. Although side effects/SAEs of adalimumab seem comparable in RA versus IBD, rheumatologists probably accept a higher proportion of flares because there are more alternative biological therapies available, thus a loss of effect of one biological therapy might be given less weight in RA.6