Working to find a new PKU treatment

All Study Participants Receive at No Cost:


Close care and monitoring throughout the study


Investigational drug or placebo


All study-related visits


Compensation for participation, including travel and study-related activities

The Investigational Drug: SYNB1618


SYNB1618, a modified probiotic


Given orally as a liquid


Designed to break down phenylalanine in the diet


Has been approved for safety testing by the FDA

If you choose to take part in this study, you will be randomly assigned (like flipping a coin) to receive either the investigational drug or a placebo.

What is a placebo?

A placebo looks like the investigational drug but does not contain any active ingredients.

Neither you nor the study team will know if you're receiving the investigational drug or the placebo.

This is to make sure that the results are not tainted due to you or the study team knowing which participants had the investigational drug and which did not.


Study Schedule (19 Weeks in Duration):

The study doctor will examine you, perform tests, and ask questions to find out if you are eligible to take part in the study.

You will learn more about the study. If you decide to take part, you will sign the Informed Consent Form.

Two days before you start treatment, you will enter the study center so the study team can perform some more tests and ask you questions about your health.

You will be randomly assigned into a group on your first day of treatment.

You will receive the investigational drug or placebo for 7 days. You will need to stay at the study site during this time.

On your last day, the study team will perform some last tests and ask you questions.

Every week for up to 8 weeks after your treatment, you'll be in contact with the study site to answer some questions. You will also provide weekly stool samples to the study site.