Fig. 3From: Designs for adding a treatment arm to an ongoing clinical trialExample of adding a single experimental treatment arm to a two-arm trial comparing treatment 1 to control. The first dashed vertical line represents when the new treatment arm (treatment 2) is added to the trial. The second dashed vertical line represents when all treatments finish recruiting. The allocation ratio is adapted when treatment 2 is added and all treatments finish recruiting simultaneously. The allocation ratios and sample sizes in each stage for each treatment are displayedBack to article page