Points to consider for clinical trials of the gastrointestinal tract in systemic sclerosis.

The pathogenesis of gastrointestinal tract involvement in SSc is not fully understood. However, gastrointestinal signs and symptoms are very common. Trials to test therapies, with rare exceptions, should be double-blind, randomized trials with either active therapy or placebo as comparators. Trial duration will vary dependent on the anticipated therapy and should usually be 6-24 weeks long, although some motility trials may need to be 52 weeks. As in any well-controlled trial, inclusion and exclusion criteria should encourage relatively uniform patients with sufficiently active disease to discern response, importantly considering disease duration. Previous therapy, co-morbid conditions, potentially confounding and/or concomitant therapy should be considered. Outcome measures should include both objective/semi-objective and subjective measures, although validated measures are not frequent and design needs to consider using only validated measures. Unvalidated measures can be included to validate them for future use. A full analysis plan should be completed before study commencement, including the method to account for missing data.