Neoadjuvant Immune Checkpoint Blockade + a Prebiotic Food-enriched Dietary Intervention to Optimize Immune Response in Melanoma: NEO-PreFED

Eligibility Criteria

• 1. Age ≥ 18 years old.
• 2. Body mass index (BMI) 18.5-45 kg/m2
• 3. English-speaking
• 4. ECOG performance status of 0 or 1
• 5. Histologically confirmed resectable stage IIIB-D or oligometastatic Stage IV cutaneous melanoma or locally invasive/advanced mucosal melanoma as determined by multidisciplinary review
• 6. Planned initiation of standard-of-care neoadjuvant Ipilimumab + Nivolumab or Nivolumab + Relatlimab
• 7. Measurable disease per RECIST 1.1
• 8. WOCP must have negative UPT within 1 week of beginning dietary intervention.
• 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.
• 11. Archival tissue specimen or planned to undergo tumor biopsy as part of standard of care treatment.
• 1. Uveal melanoma
• 2. History of inflammatory bowel disease, total colectomy, or bariatric surgery
• 3. Currently taking steroids \> Prednisone 10 mg/day or equivalent
• 4. Medical contraindications to the Intervention Diet as determined by the treating physician.
• 5. Self-reported major dietary restrictions, including but not limited to relevant food allergies, celiac disease, or diets such as vegan, ketogenic, extended fasting.
• 6. Insulin-dependent diabetes or conditions requiring bile-acid sequestrants
• 7. Unable or unwilling to undergo study procedures.
• 8. IV antibiotic use in the past month or oral antibiotic use in past 2 weeks
• 9. Regularly taking supplements containing prebiotics, fiber and/or probiotics, and unable/unwilling to discontinue for the purpose of the study
• 10. Current smoker or heavy drinker (defined as \>14 drinks per week) or current illicit drug use
• 11. Currently pregnant, planning to become pregnant, or lactating
• 12. Concurrent malignancy requiring systemic therapy other than hormonal therapy
• 13. Cognitively impaired adults