Impact of a Prebiotic Food-enriched Diet (PreFED) in Combination With Ipilimumab/Nivolumab Combination Immune Checkpoint Blockade (ICB) in ICB-refractory Melanoma Patients

Eligibility Criteria

• 1. Age ≥ 18 years old
• 2. English-speaking
• 3. Body mass index (BMI) 18.5-45 kg/m2
• 4. ECOG performance status of 0 or 1
• 5. Histologically confirmed stage III/IV, unresectable cutaneous melanoma. Asymptomatic brain metastases are allowed.
• 6. Prior treatment with anti-PD1 or anti-PD-1 + anti-LAG3 agents and documented disease progression either while on these agents or after stopping therapy without intervening therapy.
• 7. Planned initiation of standard-of-care Ipilimumab 3 mg/kg + Nivolumab 1 mg/kg
• 8. Measurable disease per RECIST 1.1
• 9. Self-reported willingness to eat the provided foods (with some tailoring to their food preferences)
• 10. Self-reported willingness to comply with scheduled visits, undergo venipuncture, provide stool samples.
• 1. Prior treatment with anti-CTLA4
• 2. Mucosal or uveal melanoma
• 3. Concurrent malignancy requiring systemic therapy other than hormonal therapy.
• 4. History of inflammatory bowel disease, total colectomy, or bariatric surgery
• 5. Currently taking steroids \> Prednisone 10 mg/day or equivalent
• 6. IV antibiotic use in the past month or oral antibiotic use in past 2 weeks
• 7. Regularly taking supplements containing prebiotics, fiber and/or probiotics, and unable/unwilling to discontinue for the purpose of the study.
• 8. Medical contraindications to the Intervention Diet as determined by the treating physician.
• 9. Self-reported major dietary restrictions, including but not limited to relevant food allergies, celiac disease, or diets such as vegan, ketogenic, extended fasting.
• 10. Insulin-dependent diabetes or conditions requiring bile-acid sequestrants.
• 11. Current smoker or heavy drinker (defined as \>14 drinks per week) or current illicit drug use.
• 12. Currently pregnant, planning to become pregnant, or lactating.
• 13. Cognitively impaired adults