Identifying optimal treatments for patients living with rare diseases is challenging due to the small numbers of individuals affected. One design used to address this challenge is known as the small n, sequential, multiple assignment, randomized trial (snSMART). To investigate the efficacy of an active drug measured by a continuous outcome tested at a low and high dose compared to placebo, we propose a new two-stage snSMART design. In stage 1, patients are randomized to...