How gut bacteria change the way colorectal cancer drugs work

Metabolism of cancer chemotherapeutics by the human gut microbiome

['FUNDING_R01'] · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · NIH-11212153

Testing whether common gut bacteria change how colorectal cancer drugs like 5‑FU and capecitabine work and cause side effects for people treated with these medicines.

Quick facts

Phase['FUNDING_R01']
Study typeNih_funding
SexAll
SponsorUNIVERSITY OF CALIFORNIA, SAN FRANCISCO (nih funded)
Locations1 site (SAN FRANCISCO, UNITED STATES)
Trial IDNIH-11212153 on ClinicalTrials.gov

What this research studies

Researchers will study bacteria from the human gut to find which species, genes, and enzymes can break down fluoropyrimidine drugs such as 5‑FU and capecitabine. They will use lab assays and engineered mouse models, including germ‑free and xenograft mice, to see how those bacterial activities change drug levels and tumor responses. The team plans to identify specific bacterial taxa (for example, Anaerostipes) that inactivate these drugs and measure downstream effects on drug pharmacokinetics and pharmacodynamics. Findings are intended to help explain why some patients get more benefit or more toxicity from these common colorectal cancer medicines.

Who could benefit from this research

Good fit: People receiving 5‑FU or capecitabine for colorectal cancer would be the most directly relevant patients for results and any future clinical follow‑up.

Not a fit: Patients not treated with fluoropyrimidine drugs or those with cancers unrelated to these medications are unlikely to benefit directly from this project.

Why it matters

Potential benefit: If successful, this work could point to tests or microbiome interventions that predict or reduce side effects and improve how well fluoropyrimidine drugs work for individual patients.

How similar studies have performed: Prior human and laboratory studies suggest the gut microbiome can influence chemotherapy effects, but detailed mechanistic and causal evidence in mouse models is still limited.

Where this research is happening

SAN FRANCISCO, UNITED STATES

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.

View on NIH RePORTER →

Conditions: Anti-Cancer Agents

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.