Addition of Antibiotics to Upfront Treatment Regimen for Colorectal Cancer

The film gives the main points. The full list below is copied from the registry; the study team makes the final decision.

• Age18 Years to no maximum
• SexAll
• Healthy volunteersNo

You may be able to join if

• Diagnosis of stage IV colorectal cancer
• Measurable disease by Response evaluation criteria in solid tumors (RECIST) 1.1 criteria
• Planned first-line treatment with a 5FU-based doublet chemotherapy regimen for colon cancer, specifics of the regimen at the discretion of the treating physician Note: Patients who have received adjuvant therapy >6 months prior are eligible
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-2
• Absolute neutrophil count (ANC) ≥1,500 cells/μL
• Platelet count ≥100,000 cells/μL
• Hemoglobin ≥8 g/dL Note: The use of transfusion or other intervention to achieve hemoglobin ≥8 g/dL is acceptable.
• Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5 × upper limit of normal (ULN) Note: Patients with documented liver metastases: AST and ALT ≤5 × ULN
• Serum creatinine ≤1.5 x ULN or calculated creatinine clearance ≥40 mL/min using the Cockcroft-Gault equation: (140 - age) × body weight/plasma creatinine × 72 (× 0.85 if female)
• Radiographically measurable disease by RECIST 1.1
• Nonpregnant and not actively breastfeeding
• Sexually active patients of childbearing potential and their partners must agree to use medically acceptable form of contraception, per treating investigator, throughout the study Patients should continue to use medically acceptable methods of contraception after study treatment ends, following the guidance for their specific chemotherapy regimen.
• Childbearing potential excludes:
• Age > 50 years and naturally amenorrhoeic for > 1 year OR previous hysterectomy or bilateral salpingo-oophorectomy
• Patients on a pre-existing daily aspirin regimen may participate in the study without interrupting this regimen.
• Patients with a contraindication to aspirin may participate in the study. These patients will not be required to take aspirin as part of the study treatment.

You cannot join if

• Total colectomy
• Diagnosed with Cockayne Syndrome
• Using disulfiram, tizanidine, or theophylline and unable to stop taking these medications for the length of the microbiome modulation therapy
• On methotrexate doses of 15 mg/week or more
• History of allergic reaction to ciprofloxacin, metronidazole, or aspirin
• Fuss course of antibiotics in the 30 days before chemotherapy start Note: Full course is defined as ≥5 doses with an intent to treat a defined infection. Use of antibiotics intended for prophylaxis at the time of surgery is allowed
• Corrected QT interval (QTc) >480 on baseline ECG
• Diagnosed with a malabsorptive syndrome
• Inability to swallow tablets

This is how the treatment is meant to work. Whether it helps, and how safe it is, is what this trial is testing.

Treatments listed in the registry

• Standard of Care Chemotherapy + Metronidazole, ciprofloxacin, aspirin (Drug): Metronidazole, ciprofloxacin, aspirin is initiated Cycle 1 Day 1 of chemotherapy. May be initiated any time from 7 days before Cycle 1 Day 1 up to and including Cycle 1 Day 3

Randomized · Parallel · masking: None

Main goals

• Best response by analysis using Response Evaluation Criteria in Solid Tumors (Up to 5 years)

Other goals

• Estimate the overall survival (OS) of patients with colorectal cancer (CRC) treated with a 5FU-based treatment regimen with or without the addition of MBMT.
• Estimate the progression free survival (PFS) of patients with CRC treated with a 5FU-based treatment regimen with or without the addition of the MBMT
• Assess the tolerability of the study antibiotic regimen
• Assess the tolerability of the study aspirin regimen for the duration of chemotherapy
• Evaluate the safety of MBMT in addition to a 5FU-based treatment regimen

Planned enrollment: 97 (estimated).

• Virginia Cancer Institute (VCI), Richmond, Virginia
• Virginia Commonwealth University, Richmond, Virginia

Site status as of Oct 30, 2026. Check the live record before contacting a site.

• ClinicalTrials.gov NCT06728072

Registry record reviewed as fetched Oct 30, 2026, last updated by the sponsor Aug 17, 2026. Public record; not medical advice.