Phase 3 Efficacy and Durability of Ampreloxetine for the Treatment of Symptomatic nOH in Participants With Multiple System Atrophy

Inclusion Criteria: * Participant is male or female and at least 30 years old. * Participant has a diagnosis of possible or probable MSA of the Parkinsonian subtype (MSA-P) or cerebellar subtype (MSA-C) according to The Gilman Criteria (2008). * Participant has a diagnosis of possible or probable MSA of the Parkinsonian subtype (MSA-P) or cerebellar subtype (MSA-C) confirmed by the Enrollment Steering Committee (ESC). * Participant must meet the diagnostic criteria of nOH, as demonstrated by a sustained reduction in BP of ≥20 mmHg (systolic) or ≥10 mmHg (diastolic) within 3 min of standing as part of orthostatic standing test or being tilted up ≥60o from a supine position as determined by a tilt-table test. * Participant must score ≤4 on UMSARS Part IV at Visit 1 (Screening). * Participant must score at least a 4 on the OHSA item 1 at Visit 2 (Day 1). * Participant must be willing to not take any prohibited medications during the study. * If participant is female, the participant must not be pregnant, breastfeeding, or planning a pregnancy during the course of the study. A woman of childbearing potential must have a documented negative pregnancy test at screening. * During the study and for 30 days after receiving the last dose of the study drug, females of childbearing potential or males capable of fathering children must agree to use highly effective birth control measures (failure rate \<1% when used consistently and correctly) or agree to abstain from sexual intercourse.…