Urea Cycle Disorders, Inborn

Phase 1/2 Study of KRRO-121 is a randomized, placebo-controlled study in Healthy Volunteers (Phase 1 SAD and MAD) and Study Participants with Urea Cycle Disorders (Phase 2). The primary objective of the study is to evaluate the safety of KRRO-121.

Ornithine Transcarbamylase (OTC) deficiency, the most common urea cycle disorder, is an inherited metabolic disorder caused by a genetic defect in a liver enzyme responsible for detoxifying of ammonia. Individuals with OTC deficiency can develop elevated levels of ammonia in the blood, potentially resulting in severe consequences, including cumulative and irreversible neurological damage, coma, and death. The most severe form presents shortly after birth and occurs more commonly in boys than girls. This is a Phase 1/2/3, open-label, multicenter study evaluating the safety, efficacy, and dose of ECUR-506 in male babies with neonatal-onset OTC deficiency. The primary objective is to evaluate the safety, tolerability, and efficacy of up to three dose levels of ECUR-506 following intravenous (IV) administration of a single dose.

This LTFU is being conducted to assess long-term safety and durability of response in participants dosed with IP in a parent protocol, and to collect longitudinal natural history in enrolled but not dosed participants who also participated in a parent protocol.