About the Study

SYNHOX: A phase 1 study evaluating an oral treatment for people with hyperoxaluria (HOX) after bariatric surgery
All study participants receive at no cost:

The investigational drug

Ability to attend study visits in person or, if preferred, remotely at their home with a home health professional

All study-related tests and assessments

The investigational drug: SYNB8802

Modified probiotic designed to consume oxalate in the gastrointestinal tract and potentially prevent kidney stones and kidney damage due to HOX

Oral solution

Taken up to 3 times per day with meals

Study Schedule
(approx. 6 months)


(90 days)

  • You will meet with the study team, who will run tests and assessments to find out if you are fully eligible for the study. This can occur at a study location or at your home.


Dosing Periods
(55 days)

  • Dosing Period 1 (up to 10 days): You will take gradually increasing doses of the study drug or placebo over up to 10 days.
  • Washout Period (2–4 weeks): You will stop taking the drug for 2–4 weeks.
  • Dosing Period 2 (up to 10 days): You will “crossover”; this means that if you were taking study drug in Dosing Period 1, you will take placebo. If you took placebo in Dosing Period 1, you will now take the study drug. By the end of the study, all participants will have taken the study drug for up to 10 days.
  • During these periods you will also have tests and assessments, which can either occur at a study location or at your home.


Safety Follow-Up Period
(28 days)

  • You will attend study visits at a study location or at your home to undergo tests and assessments to check on your health and well‑being.