How gut bacteria change colon cancer medicines

Metabolism of cancer chemotherapeutics by the human gut microbiome

NIH-funded research University of California, San Francisco · NIH-11174568

This work looks at whether common gut bacteria change how colorectal cancer drugs like 5‑FU and capecitabine work or cause side effects for people with colorectal cancer.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionUniversity of California, San Francisco NIH-funded
Lab location1 site (San Francisco, United States)
Project IDNIH-11174568 on NIH RePORTER

What this research studies

The team will use lab-based biochemical and cell assays to identify which human gut bacterial species, genes, and enzymes modify 5‑fluorouracil (5‑FU) and capecitabine. Findings from those tests will be moved into controlled germ-free (gnotobiotic) and xenograft mouse experiments to measure effects on drug levels, tumor response, and toxicity. Based on preliminary data they suspect bacteria in the Anaerostipes genus may inactivate 5‑FU and are focusing on those microbes. The overall aim is to map bacterial pathways that alter drug pharmacokinetics and pharmacodynamics to inform future patient-centered studies.

Who could benefit from this research

Good fit: People with colorectal cancer who are receiving or planning to receive fluoropyrimidine chemotherapy (5‑FU or capecitabine) would be the most relevant group for follow-up patient studies.

Not a fit: Patients with cancers not treated by fluoropyrimidines or those not exposed to these drugs are unlikely to receive direct benefit from this work.

Why it matters

Potential benefit: If successful, this research could lead to tests or microbiome-targeted approaches that predict or reduce side effects and improve how well fluoropyrimidine chemotherapy works.

How similar studies have performed: Previous lab and animal studies and some correlative patient data suggest gut microbes can alter drug metabolism, but translating these findings into clinical tests or treatments is still at an early stage.

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.
Conditions Anti-Cancer Agents
Last reviewed 2026-06-13 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.