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NCT Number: NCT07686835

Dietary Fiber to Induce Gut Microbiota-mediated Response to Immunotherapy in Melanoma.

Previous research has shown that a higher fiber intake may have a beneficial effect on the intestinal health and improve the effectiveness of immunotherapy, but this is not certain. The objective of this double-blinded randomized clinical trial is to analyze, whether increased dietary fiber intake by patients with metastatic melanoma will increase the relative amount of Bifidobacterium, which in turn stimulates immune cell activity and improves the response to immunotherapy.

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Key information

Conditions

Melanoma (Skin) Stage IV Melanoma Melanoma (Skin Cancer) Melanoma Advanced Melanoma Metastatic Neoplasms Neoplasms by Histologic Type Neoplasms by Site Neoplasms, Germ Cell and Embryonal Neoplasms, Nerve Tissue Neuroectodermal Tumors Neuroendocrine Tumors Nevi and Melanomas Skin Diseases Skin Neoplasms Skin and Connective Tissue Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Medical Oncology, Nijmegen, Gelderland, Netherlands

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Histologically confirmed cutaneous melanoma classified as irresectable stage III or stage IV disease
  • Measurable disease according to RECIST 1.1 criteria
  • Age ≥ 18 years
  • Starting standard-of-care treatment with ICI in first line
  • Written informed consent must be given
  • Able to read and understand Dutch or English
  • Able to comply with study procedures (e.g. willing to provide fecal samples)

Exclusion criteria

  • Symptomatic brain metastases
  • Received prior immunotherapy; previous (neo)adjuvant treatment is allowed if the last administration is at least 6 months ago
  • Use of systemic immunosuppressive medications
  • Use of laxatives up to 1 week prior to start of ICI
  • Use of supplements that alter bowel function or gut microbiota such as fibers/prebiotics, probiotics, synbiotics, or postbiotics up to 1 month prior to start of ICI
  • Use of antibiotics up to 1 months prior to start of ICI
  • Use of proton pumps inhibitors (PPI's) up to 3 months prior to start of ICI
  • Pregnant or lactating
  • Current participation in another clinical trial requiring the use of study medication
  • Has a known allergy to plants such as lettuce, sage, tarragon, chicory, artichoke, chamomile, daisy, or sunflower.
  • Has a medical history of gastrointestinal resection (appendectomy is allowed)
  • Has active inflammatory bowel disease

Treatment and study plan

Dried chicory roots

Dietary Supplement

The dried chicory roots are implemented using a dosage of 22.5 gram/day resulting in 18.5 gram additional fibers a day.

Other names: Dietary fibers, fiber, Vezel

Placebo

Dietary Supplement

The control arm will receive 12.4 grams of placebo a day, isocaloric to the intervention.

Other names: Placebo control, Control

Primary outcomes

  1. An increase in the relative abundance of Bifidobacterium in fecal samples.

    Time frame: From baseline (T0) to 3-4 weeks (T1) after start ICI

    The primary endpoint of this study is defined as a ≥5% (e.g. from 3% to 8%) increase in the relative abundance of Bifidobacterium in fecal samples between baseline (T0) and follow-up (T1) and significant differences between the experimental arm and the control arm.

Secondary outcomes

  1. Fecal microbiota composition

    Time frame: Measurement at baseline (T0), 3-4 weeks (T1), 3-4 months (T2), and 6-7 months (T3) after start ICI

    Study the baseline and on-treatment gut microbiota composition of patients with melanoma treated with ICI +/- additional dietary fiber.

  2. Radiological response rate to ICI

    Time frame: From baseline (T0) to the first date of documented progression or date of death from any cause, wichever came first, assesed up to 5 year.

    Evaluate radiological response rates to ICI +/- additional dietary fiber, assessed by CT/PET scan per RECIST 1.1 defined as; the date of randomization to the date of disease progression or death, respectively.

  3. Progression free survival (PFS)

    Time frame: From baseline (T0) to the first date of documented progression or date of death from any cause, wichever came first, assesed up to 5 year.

    Evaluate progression-free survival defined as; the date of randomization to the date of disease progression or death, respectively.

  4. Overall survival (OS)

    Time frame: From baseline (T0) on, survival follow-up will be continued after study completion for a maximal of 5 years in accordance with standard-of-care follow-up.

    Evaluate overall survival to ICI +/- additional dietary fiber defined as; the date from randomization to date of death, respectively.

  5. Evaluate the gastro-intestinal side effects of additional dietary fiber intake

    Time frame: From start intervention at baseline (T0) until the end of wash-out period at 6-7 months (T3) after start ICI.

    Evaluate the gastro-intestinal side effects of additional dietary fiber intake, according to CTCAE common criteria v 5.0.

Other outcomes

  1. Habitual dietary intake (Food Frequency Questionnaire)

    Time frame: At baseline (T0) and at 3-4 months (T2)

    Nutritional intake is measured using a semi-quantitative Food Frequency Questionnaire (FFQ). Scores are calculated using the Dutch National Food Consumption tables. The FFQ will be used to evaluate habitual diet and fiber intake.

  2. Physical activity level (Short QUestionnaire to ASsess Health-enhancing physical activity)

    Time frame: At baseline (T0) and at 3-4 months (T2)

    Physical activity is measured using the Short QUestionnaire to ASsess Health-enhancing physical activity (SQUASH). The questions in the SQUASH are pre-structured in commuting, leisure time, household and work/school activities. Scores will be assigned to the different reported activities base on intensities in MET and translated to minutes of physical activity.

  3. Sleep quality and duration (Pittsburgh Sleep Quality Index)

    Time frame: At baseline (T0) and at 3-4 months (T2)

    Sleep quality is measured with the Pittsburgh Sleep Quality Index (PSQI), a 19-item questionnaire with scores ranging from 0-21. A score above 5 indicates bad sleep quality.

  4. Bristol Stool Scale (BSS)

    Time frame: Measurement at baseline (T0), 3-4 weeks (T1), 3-4 months (T2), and 6-7 months (T3) after start ICI

    Stool consistency is measured using the Bristol Stool Scale (BSS)

  5. Circulating tumor DNA (ctDNA)

    Time frame: Measurement at baseline (T0), 3-4 weeks (T1), 3-4 months (T2), and 6-7 months (T3) after start ICI

    ctDNA levels will be analysed to evaluate circulating tumor DNA.

  6. Short-Chain Fatty Acids

    Time frame: Measurement at baseline (T0), 3-4 weeks (T1), 3-4 months (T2), and 6-7 months (T3) after start ICI

    Fecal and Plasma SCFA's levels will be evaluated.

  7. Sequencing mRNA in circulating immune cells

    Time frame: Measurement at baseline (T0), 3-4 weeks (T1), 3-4 months (T2), and 6-7 months (T3) after start ICI

    (m)RNA will be sequenced to evaluate the transcription/gene expression in circulating immune cells.

  8. Tumor infiltration

    Time frame: Pretreatment

    Archived tumor tissue, previous to baseline (T0):

    Pre-interventional tumor tissue will be requested for immune cell analyses using multiplex immunohistochemistry.

Study contacts

Contact information is provided by the study sponsor or research team.

Isabel Ossekoppele, MS

CONTACT

[email protected]

Kalijn Bol, dr.

CONTACT

[email protected]

+31 243618800

Sponsors and collaborators

Lead sponsor

Radboud University Medical Center

Other

Collaborators

  • Wageningen University and Research

Registry information

Acronym: FIGURE-IM

Important dates

Study start
2026
Primary completion
2028
Study completion
2029
First posted
Jul 7, 2026
Registry last updated
Jul 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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