Safety, Tolerability and Pharmacodynamics of SYNB1020

In Part 1, a sentinel open-label cohort of subjects with cirrhosis and Model for End-Stage Liver Disease (MELD) score \<12 was admitted to an inpatient facility for a run-in diet, baseline assessments, IMP administration, safety monitoring, and collection of blood, urine, and stool samples for evaluation of safety, tolerability, and pharmacokinetic (PK) and pharmacodynamic (PD) evaluations. Subjects in Part 1 were enrolled sequentially to receive SYNB1020. Once the safety and tolerability were established in Part 1, enrollment was opened to subjects in Part 2. Part 2 comprised a randomized, double-blind, placebo-controlled study in subjects with cirrhosis and hyperammonemia. Subjects were permitted to be pre-screened for eligibility based on medical history and a single fasting spot venous ammonia measurement. Eligible subjects with elevated fasting spot venous ammonia then underwent full screening within 7 days of pre-screening. Eligible subjects were admitted to an inpatient facility for a run-in diet and 24-hour ammonia profile, and those with an elevated 24-hour ammonia area under the curve (AUC) (\>1.2 × the upper limit of normal \[ULN\]) proceeded with computer-generated randomization in a 1:1 ratio to receive either SYNB1020 or matching placebo. Randomization was followed by IMP administration, safety monitoring, and collection of blood, urine, and stool samples for PK and PD evaluations.