Randomization and Masking
Assignment to treatment groups within each cohort for the randomized portion of the study was determined by a computer-generated random sequence using an Interactive Web-Response System to assign identical glass vials containing either the elamipretide or a placebo, which consisted of the same formulation without elamipretide. Participants were stratified by the subclassification of the specific sequence alteration causing their PMM, as determined by the adjudication committee formed to review and confirm eligibility for study enrollment.