Abstract: The randomised, controlled trial (RTC) is considered the gold
standard for the assessment of the effect of any therapeutic intervention.
However, rare diseases carry several issues in terms of population size,
life-threatening nature of the condition and lack of other available
treatments, which basically render this approach not always feasible.
Alternative methodological approaches are being developed to better suit the
need of an orphan drug development.
Keywords: Randomised, controlled trial, population size, rare disorder