Safety, Tolerability and Pharmacodynamics of SYNB1020

Phase 1

Terminated

Brief Summary: This Phase 1b/2a, randomized, double-blind, placebo-controlled study was designed to evaluate the safety, tolerability, and pharmacodynamics of SYNB1020 in hepatic insufficiency and cirrhosis patients with hyperammonemia, with dosing of the investigational medicinal product (IMP) administered in an inpatient unit and subsequent outpatient follow-up for SYNB1020 clearance in two study parts.

Detailed Description: 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.

Recruitment & Eligibility

Inclusion Criteria

Age ≥ 18 to < 75 years
Females must have been of non-childbearing potential
Able and willing to complete informed consent process
Available for and agreed to all study procedures
Screening laboratory evaluations within defined acceptable limits or judged to be not clinically significant by the Investigator
Diagnosis of chronic, stable, hepatic insufficiency with features of cirrhosis due to any etiology
Evidence of elevated portal hypertension by either liver stiffness measurement, the presence of abdominal or esophageal varices, splenomegaly or ascites (Part 2 only)
Elevated venous ammonia (Part 2 only)

Key

Exclusion Criteria

Body mass index < 18.5 or ≥ 40 kg/m^2
Administration or ingestion of an investigational drug within 8 weeks or 5 half-lives, whichever was longer, prior to screening or current enrollment in an investigational study
Allergy to ranitidine or intolerance to any of the excipients (glycerol, CS Health Easy Fiber)
Any condition, prescription medication or over-the-counter product that may possibly have affected absorption of medications or nutrients
Dependence on drugs of abuse
Apart from chronic liver disease, any acute or chronic medical, surgical, psychiatric, or social condition including history of cerebrovascular disease (stroke, transient ischemic attack) or dementia, or laboratory abnormality that may have increased the subject risk associated with study participation, compromised adherence to study procedures and requirements, confounded interpretation of the safety, kinetics, or PD results, and, in the judgment of the Investigator, made the subject inappropriate for enrollment
Current or past hepatic encephalopathy of Grade 2 or higher requiring hospitalization
Child-Turcotte-Pugh score > 9
History of liver transplant

Arm && Interventions

Group	Intervention	Description
Part 2: Placebo	Placebo	Subjects randomized to receive control in Part 2 received matching placebo (100 mL masking solution) administered orally TID given immediately after meals from Days 1 through 6.
Part 1: SYNB1020	SYNB1020	Part 1 comprised a sentinel open-label cohort of subjects enrolled sequentially to receive SYNB1020, which was administered orally at a dose of 5 × 10\^11 colony-forming units (CFU) 3 times daily (TID) given immediately after meals from Days 1 through 6.
Part 2: SYNB1020	SYNB1020	Subjects randomized to receive SYNB1020 in Part 2 received SYNB1020 administered orally at a dose of 5 × 10\^11 CFU TID given immediately after meals from Days 1 through 6.

Primary Outcome Measures

Name	Time	Method
Number of Participants With Treatment-Emergent Adverse Events	Up to 70 days	Toxicity was graded in accordance with the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE), version 4.03, as follows: Grade 1 (mild/asymptomatic; no intervention); Grade 2 (moderate; minimal intervention); Grade 3 (severe/medically significant; hospitalization indicated; disabling); Grade 4 (life-threatening; urgent intervention required). Adverse events (AEs) were reported based on clinical laboratory tests, vital sign and weight measurements, physical examinations, and any other medically indicated assessments, including subject interviews, from the time informed consent was signed through the end of the safety follow-up period. AEs were considered to be treatment emergent adverse events (TEAEs) if they occurred or worsened in severity after the first dose of study treatment. TEAEs were considered treatment-related if relationship to study drug was possibly related, probably related, definitely related, or a missing relationship.

Secondary Outcome Measures

Name	Time	Method
Daily Fasting Spot Venous Ammonia	Up to 9 days	Fasting spot venous ammonia was collected at baseline (Day -2) and at the time of discharge from the inpatient unit (Day 7).
Number of Participants With Clearance of SYNB1020 From Feces	Up to 65 days	SYNB1020 transit through the gastrointestinal tract was measured with qualitative and quantitative polymerase chain reaction (PCR) fecal assays from fecal samples collected at baseline, daily during the dosing period (Days 1 through 6), at the time of discharge from the inpatient unit (Day 7), and at follow-up visits beginning 7±1 days after the last dose and continuing biweekly until a subject had a negative SYNB1020 fecal test. SYNB1020 clearance reflects a test value of below the limit of quantitation (BLQ) occurring after the indicated number of days following the last dose of study treatment.

Locations (5): Southern California Research Center
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Coronado, California, United States
Inland Empire Liver Foundation
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Rialto, California, United States
Texas Liver Institute
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San Antonio, Texas, United States
Medical University of South Carolina
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Charleston, South Carolina, United States
McGuire VA Medical Center
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Richmond, Virginia, United States