Efficacy and Safety of SYNB1618 and SYNB1934 in Adult Patients With Phenylketonuria

This is an open-label, dual-arm Phase 2 study; all participating PKU patients will receive active study drug, SYNB1618 or SYNB1934. This study is evaluating a dose-ramp regimen consisting of 4 dose levels of SYNB1618 or SYNB1934 over 15 days of treatment. This study has been designed with the flexibility of being able to be conducted either at the clinical site or by a home healthcare professional at an alternative location (e.g., patient's home, hotel). Patients will be screened for eligibility and complete a customized diet run-in period prior to starting the 15-day dose ramp ('treatment period'). During the treatment period patients will be required to adhere to the same customized diet menus as in the diet run-in period. The efficacy of SYNB1618 SYNB1934 will be assessed in this study by measuring the reduction of the area under the curve (AUC) for plasma D5-phenylalanine (D5-Phe) as well as the reduction of plasma Phe levels. Safety will be monitored by documentation of adverse events (AEs), clinical laboratory measurements, vital signs, and physical examinations.