Here is the design of a clinical trial:

Official Title: The Efficacy, Safety and Cost-effectiveness of Hydroxychloroquine, Sulfasalazine, Methotrexate Triple Therapy in Preventing Relapse Among Patients With Rheumatoid Arthritis Achieving Clinical Remission or Low Disease Activity

Included conditions:
- Recurrence (Disease Attribute)

Study Armgroups:
- {'label': 'A', 'type': 'EXPERIMENTAL', 'description': 'Maintenance treatment group', 'interventionNames': ['Drug: Entanercept', 'Drug: MTX']}
- {'label': 'B', 'type': 'EXPERIMENTAL', 'description': 'Combination treatment group', 'interventionNames': ['Drug: Entanercept', 'Drug: HCQ', 'Drug: MTX']}
- {'label': 'C', 'type': 'EXPERIMENTAL', 'description': 'Single drug group', 'interventionNames': ['Drug: Entanercept', 'Drug: MTX']}

Interventions:
- {'type': 'DRUG', 'name': 'Entanercept', 'description': 'Both Entanercept and MTX were given to patients for 60weeks (Week0-Week60).', 'armGroupLabels': ['A', 'B', 'C'], 'otherNames': ['MTX']}
- {'type': 'DRUG', 'name': 'HCQ', 'description': 'Combination of HCQ+SSZ+MTX were given to patients for 60weeks (Week0-Week60).Entanercept was given to patients for 12 weeks (Week0-Week12).', 'armGroupLabels': ['B'], 'otherNames': ['SSZ', 'MTX', 'TFP']}
- {'type': 'DRUG', 'name': 'MTX', 'description': 'MTX was given to patients for 60weeks (Week0-Week60). Entanercept was given to patients for 12 weeks (Week0-Week12).', 'armGroupLabels': ['A', 'B', 'C'], 'otherNames': ['Entanercept']}

Primary Outcomes:
- {'measure': 'the rate of recurrence', 'timeFrame': '60 weeks'}

Please estimate the sample size based on the assumption: 
A power of 0.8 and a significance level of 0.05 (two-sided) were used. The dropout rate is estimated to be 20%.
Sample size estimation
          According to the study purposes, a superiority design was considered appropriate. Our hypothesis is that the relapse rate in group A (triple therapy group) will be lower than that in group C (MTX monotherapy group) in 60Â weeks after randomization.
          Sample size was calculated by PASS 11.0. It was reported that for patients with established RA achieving CR or LDA by TNFi combined with MTX, 24% to 85% suffered from disease relapse after discontinuation of TNFi [4â7]. When combined csDMARDs preserved after TNFi removed, the rate of relapse was 51.2â58% [4, 7]. We assume that adding HCQâ+âSSZ 3Â months before the removal of TNFi may somehow decrease the relapse. Accordingly, we expect the relapse rate as 50% in patients in triple therapy group, and 74% in MTX monotherapy group. With a power of 0.8 and a significance level of 0.05 (two-sides), using a 1:1:1 treatment allocation of enrollment, to detect the difference of relapse rate between the two groups, the required sample size is 61 for each group. Given the estimated dropout rate of 20%, we intend to recruit a total of 240 subjects (80 for each group).
          We assume that the relapse rate may be similar between group A and group B (TNFi maintenance therapy group), and the cost-effectiveness may be better in group A than in group B. The relapse rate and cost-effective comparison between group A and group B will be exploratory and there was no relevant research hypothesis, so the sample size was not calculated by it.