Clinical Study on High-fiber Diet and Short-term Fasting in Melanoma Under Immunotherapy With Checkpoint Inhibition

The treatment of melanoma has improved significantly in recent years. A modern form of cancer treatment known as immunotherapy with checkpoint inhibitors plays a key role in this. These drugs help the immune system better recognize and fight cancer cells. Nevertheless, it remains a challenge to maximize treatment effectiveness while minimizing side effects. One possible approach to influencing treatment efficacy and tolerability is diet. A high-fiber diet, as recommended by the German Nutrition Society, increases the effectiveness of immunotherapy, in part through its influence on gut bacteria (the gut microbiota). Initial studies also show that short-term fasting (i.e., eating nothing or very little for a limited period) reduces the side effects of immunotherapy in mouse models and improves the tolerability of chemotherapy in humans. This study investigates the feasability of a study on short-term fasting, in addition to a high-fiber diet in patiens with melanoma undergoing immunotherapy. 40 participants will follow a high-fiber diet based on the recommendations of the German Nutrition Society. Additionally, half of the participants will undergo periodic cycles of short-term fasting of 72h with each immunotherapy. Another 20 participants will not undergo any intervention and serve as a control group. The goal is to determine whether this study concept is feasible. Exploratory outcomes include, quality of life, fatigue, tolerability of the therapy, impact on disease progression, immune system (flow cytometry) and gut bacteria (microbiome). The results are intended to help understand whether targeted dietary measures can support the effectiveness of modern cancer treatments.

Inclusion Criteria: * Histologically or cytologically confirmed stage IIB-IIIC melanoma * Indication for immune checkpoint inhibition as monotherapy as determined by the tumor board * No prior systemic melanoma therapy * ECOG 0 or 1 * ≥ 18 years of age Exclusion Criteria: * Pregnancy or breastfeeding * Underweight (BMI ≤19.5) * Pre-existing eating disorder * Severe internal medical conditions (e.g., renal insufficiency with creatinine \> 2 mg/dL) or secondary malignancy * Current vegan diet or prolonged fasting (≤ 4 days) within the last 6 months * Use of antibiotics within 4 weeks prior to the start of the study intervention