An Extension Study to Evaluate the Long-term Efficacy and Safety of Oxabact in Patients With Primary Hyperoxaluria

Inclusion Criteria: 1. Signed informed consent (as applicable for the age of the subject). 2. Participation in and completion of study OC5-DB-02. 3. Subjects who had received vitamin B6 during OC5-DB-02 study should maintain a stable dose. Subjects not receiving vitamin B6 during OC5-DB-02 must be willing to refrain from initiating pyridoxine during study participation. Exclusion Criteria: 1. Inability to swallow size 4 capsules. 2. Use of antibiotics to which O. formigenes is sensitive. 3. Current treatment with a separate ascorbic acid preparation. 4. Pregnant or lactating women (or women who are planning to become pregnant). 5. Women of childbearing potential who are not using adequate contraceptive precautions. 6. Presence of a medical condition that the Investigator considers likely to make the subject susceptible to adverse effect of study treatment or unable to follow study procedures or any condition that is likely to interfere with the study drug mechanism of action (such as abnormal GI function). 7. Participation in any interventional study of another investigational product, biologic, device, or other agent or not willing to forego other forms of investigational treatment during this study.