Overview

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.

Eligibility

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