High-fiber diet effects on gut bacteria, metabolism, and the tumor immune environment in people with solid tumors

Effects of High-Fiber Diet on Gut Microbiota, Metabolism, and Immune Microenvironment in Solid Tumor Patients: A Clinical Study

This study will test whether a high-fiber diet can change gut bacteria, metabolism, and immune activity in adults with solid tumors such as colorectal cancer.

Quick facts

• Phase: Phase 1
• Study type: Interventional
• Enrollment: 25 (estimated)
• Ages: 18 Years to 75 Years
• Sex: All
• Sponsor: West China Hospital (Academic / other)
• Drugs / interventions: chemotherapy, immunotherapy
• Locations: 1 site (Chengdu, Sichuan)
• Trial ID: NCT07477522 on ClinicalTrials.gov

What this trial studies

This phase 1 interventional study at West China Hospital will put eligible adults with solid tumors on a prescribed high-fiber diet and collect blood, stool, and tumor samples to measure changes in the gut microbiome, metabolic markers, and the tumor immune microenvironment. Participants must be 18–80 years old with pathologically confirmed solid tumors, at least one measurable lesion by RECIST v1.1, ECOG 0–1, adequate nutrition (NRS-2002 <3, BMI ≥18.5), and able to eat or receive enteral nutrition. Investigators will compare baseline and post-diet samples to identify microbial shifts, metabolic changes, and immune cell or cytokine alterations. As a phase 1 effort the primary focus is on safety, tolerability, and biological effects rather than demonstrating clinical benefit.

Who should consider this trial

Good fit: Adults 18–80 with confirmed solid tumors (for example colorectal cancer), at least one measurable lesion, ECOG 0–1, NRS-2002 <3, BMI ≥18.5, and able to eat or receive enteral nutrition are ideal candidates.

Not a fit: Patients with poor performance status, severe malnutrition, non-solid hematologic cancers, inability to eat, or who cannot attend study visits are unlikely to receive benefit from this dietary intervention.

Why it matters

Potential benefit: If successful, this approach could improve treatment responses or reduce side effects by favorably altering the gut microbiome and tumor immune environment.

How similar studies have performed: Early clinical and preclinical studies indicate diet and fiber can modify the microbiome and may boost immune responses, but human data showing clear clinical benefit in solid tumors are limited and preliminary.

Eligibility criteria

Inclusion Criteria:

* (1) Sign a written informed consent form before any study - related procedures are carried out.

  (2) Males or females, aged 18 - 80 years old. (3) Diagnosed with solid tumors by pathological tissue biopsy. (4) According to the RECIST v1.1 (Response Evaluation Criteria in Solid Tumors Version 1.1) criteria, there is at least 1 measurable lesion (lesions previously treated with local therapies such as radiotherapy cannot be regarded as measurable lesions).

  (5) ECOG (Eastern Cooperative Oncology Group Performance Status) score of 0 - 1.

  (6) NRS - 2002 (Nutritional Risk Screening 2002) score \< 3. (7) BMI (Body Mass Index) ≥ 18.5 (can be adjusted appropriately according to the actual situation).

  (8) Patients who can eat orally or through a feeding tube and can tolerate enteral nutrition.

  (9) Sufficient organ function, and the subjects need to meet the following laboratory indicators: In the absence of granulocyte - colony - stimulating factor use in the past 14 days, the absolute neutrophil count ≥ 1.5×10⁹/L.

Platelets ≥ 75×10⁹/L. In the absence of blood transfusion or erythropoietin use in the past 7 days, hemoglobin ≥ 8 g/dL.

Serum albumin ≥ 3.0 g/dL. Total bilirubin ≤ 1.5× the upper limit of normal (ULN). Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT) ≤ 2.5×ULN. In case of liver metastasis, ALT and/or AST ≤ 5×ULN, and total bilirubin ≤ 3×ULN. In case of liver or bone metastasis, Alkaline Phosphatase (AKP) ≤ 5×ULN.

Creatinine clearance rate ≥ 50 mL/min (calculated according to the Cockcroft - Gault formula) or serum creatinine ≤ 1.5×ULN.

International Normalized Ratio (INR) ≤ 1.5×ULN, Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT) ≤ 1.5×ULN.

Urine protein \< 2+ (if urine protein ≥ 2+, a 24 - hour urine protein quantification can be performed, and subjects with a 24 - hour urine protein quantification \< 2.0 g can be enrolled).

(10) Women of child - bearing potential must agree to avoid sexual intercourse (heterosexual intercourse) or use a reliable and effective contraceptive method from the signing of the informed consent form until at least 6 months after the last administration of the study drug. In addition, the serum HCG (Human Chorionic Gonadotropin) test must be negative within 3 days before the start of the study treatment, and the subject must be non - lactating. A female patient is considered to be of child - bearing potential if she is post - menopausal but has not reached the post - menopausal state (non - menstrual period ≥ 12 consecutive months, and no other causes are found except menopause) and has not undergone sterilization surgery (such as hysterectomy, bilateral tubal ligation, or bilateral oophorectomy).

(11) If there is a risk of pregnancy, all subjects (regardless of male or female) need to use a contraceptive method with an annual failure rate of less than 1% throughout the treatment period until 120 days after the last administration of the study drug (or 180 days after the last administration of the chemotherapy drug)

Exclusion Criteria:

* (1) Patients with cognitive impairment or mental illness who are unable to understand the study content.

  (2) Patients with central nervous system or meningeal metastases. (3) Patients with clinically symptomatic moderate or severe ascites (that is, those who require therapeutic paracentesis within 2 weeks before the start of study treatment; patients with only a small amount of ascites shown on imaging and no clinical symptoms can be enrolled).

  (4) Patients with uncontrolled or moderate to severe pleural effusion and pericardial effusion.

  (5) Patients with severe diarrhea, intractable vomiting, severe malabsorption syndrome, paralytic and mechanical intestinal obstruction; tracheoesophageal fistula, gastrointestinal perforation or gastrointestinal fistula, or abdominal abscess; patients with extra - gastrointestinal bleeding with a CTCAE (Common Terminology Criteria for Adverse Events) grade 3 or above within 6 months before the start of study treatment or grade 2 or above within 3 months (such as abnormal vaginal bleeding, hematemesis).

  (6) Patients known to be allergic to the active ingredients or excipients of the study drug.

  (7) Patients with poorly controlled diabetes. (8) Patients with poorly controlled hypertension (systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg under routine antihypertensive treatment), with a history of hypertensive crisis or hypertensive encephalopathy.

  (9) Patients with severe cardiovascular and cerebrovascular diseases, including cerebrovascular accident (CVA), transient ischemic attack (TIA), myocardial infarction, and major vascular diseases within 6 months before enrollment (including but not limited to aortic aneurysms requiring surgical repair or recent arterial thrombosis); patients with poorly controlled clinical symptoms or heart diseases, such as unstable angina pectoris, NYHA (New York Heart Association) heart failure grade II or above, left ventricular ejection fraction \< 50% on color Doppler echocardiography, or severe arrhythmias that cannot be controlled by drug treatment.

  (10) Pregnant or lactating women. (11) Other situations considered by the investigator as inappropriate for enrollment.

Where this trial is running

Chengdu, Sichuan

• West China Hospital — Chengdu, Sichuan, China (Recruiting)

Study contacts

• Study coordinator: Jingwen Wei

Conditions Colorectal Cancer; Diet Habits; High-fibre Diet; high-fibre diet