UNLOCKED: A Phase 2, Open-label Trial With KB195 in Subjects With a Urea Cycle Disorder

Key Inclusion Criteria: * Signed informed consent and willing to comply with protocol-specified procedures. * Has any confirmed UCD other than N-acetyl glutamatesynthase (NAGS) deficiency. * Is male or female, 12 to 70 years of age (inclusive) * If ≥ 18 years old, has a BMI ≥20.0 and \< 40.0 kg/m2. If \< 18 years old, has a BMI between 5th percentile and 95th percentile and weight greater than 5th percentile according to age, sex and regionally appropriate growth chart * Has evidence of poorly controlled disease on the current standard of care (SOC) * If NBT is part of SOC, is on a stable dose and regimen for at least 4 weeks before Screening and the dose is expected to remain stable during the study * Is willing to maintain a stable diet throughout the course of study and is willing to continue usual exercise routine. * If taking probiotics or prebiotics, is on a stable dose regimen for at least 4 weeks before Screening and the dose and regimen are expected to remain stable during the study * Has a negative urine screen for drugs of abuse at Screening * If male or female of child bearing potential, agree with use effective method of contraception for the duration of the study and 90 days after last dose of study product Key Exclusion Criteria: * Is at a high risk for metabolic decomposition. * Has had a substantive change in diet or any other aspect of UCD management within 4 weeks before the Screening Visit * Has used a systemic anti-infective within 4 weeks before the Screening Visit, or use is anticipated during the study * Has been diagnosed with Citrullinemia Type II * Is receiving any systemically administered immunosuppressant medication on a chronic basis * Has changed the use of or dose of any drug or other compound to modulate GI motility within 4 weeks before the Screening Visit, or the use or dose is expected change during the course of the study * Has a history of or active GI or liver disease * Has a prior solid organ transplantation including liver transplantation, or is anticipated to receive a liver transplant during study participation * Has used an investigational drug, product, or device within 30 days before the Screening Visit * Has a contraindication, sensitivity, or known allergy to the study drug * Is considered, in the opinion of the PI, to likely be a poor attendee or unlikely for any reason to be able to comply with the study drug procedures