PKU Treatment with SYNB1618 – Phase II

Study of the Efficacy and Safety of SYNB1618 in Subjects with Phenylketonuria

Protocol Description

The purpose of this multi-center study is to determine whether SYNB1618 may be helpful in controlling phenylalanine (Phe) levels in patients with phenylketonuria (PKU), a rare genetic disorder. SYNB1618 is a type of probiotic that has been genetically modified to quickly break down Phe into non-toxic molecules. In people with PKU, an enzyme that does not work properly causes an accumulation of Phe, a protein, which can lead to intellectual disability and central nervous system problems. People with PKU must follow a restrictive diet to avoid foods containing Phe.

Study Level: Phase II

Eligibility Criteria

Subject to certain exclusion criteria, this study is enrolling adult participants who have classic PKU.
Males and Females: Ages 18 and older


Following initial screening, participants will be given special dietary instructions, which will be initiated 2 weeks prior to the dosing period and maintained throughout the course of the study. During the 2-week dosing period, participants will take the study drug up to three times a day, with dose levels increased every few days. Study visits will be scheduled for examinations and testing, and participants will be contacted by members of the study team by telephone in the intervals between visits.
Visits: 6
Duration: Up to 95 days

Status: Open to Enrollment

Source(s) of Support


Primary Investigator

Gerard Vockley, MD, PhD

Contact Information

For more information about the study or enrollment, please contact: 
Jessica Lindenberger, MSN, CRNP, FNP-C