Clinical Research Directory

Inclusion Criteria: 1. Participant provides written informed consent. 2. Male or female patients ≥18 years undergoing myeloablative allo-HCT for a hematologic malignancy or myeloproliferative disorder. 3. Participant is able to ingest the SYN-004 dosage form (size 0 hard capsule). Exclusion Criteria: 1. Allergy(ies) to MER, PIP, TAZO, or FEP. 2. History of allergy to SYN-004 or its components. 3. Admitted for HCT and started on MER, PIP/TAZO, or FEP prior to enrollment in the present study. 4. Currently enrolled in another interventional clinical study or received an investigational drug or device within 30 days or within a time period consistent with a washout period of 5 half-lives before signing the Informed Consent Form, whichever is longer. 5. Recipients of umbilical cord blood transplantation. 6. Underlying condition requiring HCT is not in remission (per International Working Group definitions), except for myelodysplastic syndrome and lymphoma, as long as these conditions are chemotherapy responsive. 7. Creatinine clearance \<60 mL/min/1.73 m² by Cockroft-Gault calculation. 8. Cardiac ejection fraction \<50%. 9. Cirrhosis, bilirubin \>1.5x upper limit of normal, or AST/ALT \>2.5x upper limit of normal. 10. History of veno-occlusive disease (VOD) or hepatic sinusoidal obstructive syndrome (SOS). 11. DLCO and/or FEV1 ≤80% of normal. 12. Chronic HIV or HBV infection. 13. Invasive fungal infection not responding to treatment at time of HCT. 14. Known active bacterial or viral infection at time of HCT. 15. CDI in the preceding 6 months. 16. Unable to comply with study protocol as determined by primary investigator. 17. Active gastrointestinal (GI) bleeding at time of HCT. 18. Prior colectomy or short gut syndrome. 19. Pregnant or breast feeding.