Prebiotic Food-enriched Diet (PreFED) to Enhance the Microbiome and Response to First-line Immunotherapy in Unresectable Melanoma

To learn about the possible effects of a prebiotic food-enriched diet (PreFED) targeting the gut microbiome in participants with melanoma who are starting immune checkpoint blockade (ICB) therapy.

Primary Objectives

• Evaluate the effect of dietary intervention on the abundance of Faecalibacterium in stool samples from baseline to 12 weeks

Secondary Objectives

* Determine the best overall response rate (BORR) to PreFED + ICB regimens and landmark ORR at 12 weeks (intervention) and 24 weeks (maintenance)
* Determine progression-free survival (PFS) and overall survival (OS) with PreFED + ICB regimens
* Compliance and adherence to the dietary intervention at 12 weeks and maintenance at 24 weeks
* Determine the safety (diet-related AEs) and tolerability (GSRS-IBS) of the dietary intervention at 12 weeks and maintenance at 24 weeks
* Assess the rate of immune related adverse events in patients on ICB regimens receiving dietary intervention at 12 weeks and maintenance at 24 weeks
* Assess the effects of dietary intervention on systemic and tumor immunity
* Assess the effect of dietary intervention on overall gut microbiome composition and networks at 12 weeks and maintenance at 24 weeks
* Assess the effects of dietary intervention on gut metabolic output and systemic metabolism at 12 weeks and maintenance at 24 weeks
* Assess the effects of dietary interventions on quality of life and other patient reported outcomes (PROs) at 12 weeks and maintenance at 24 weeks

Eligibility Criteria:
Inclusion Criteria:

* Age ≥18 years old
* Able to self-complete study assessments monitoring diet and gastrointestinal symptom burden
* Body mass index (BMI) 18.5-45 kg/m2
* ECOG performance status of 0 or 1
* Histologically confirmed stage III/IV, unresectable cutaneous or mucosal melanoma. Asymptomatic brain metastases are allowed.
* Planned initiation of 1st line standard-of-care approved immune checkpoint blockade (anti-PD1 +/- anti-CTLA4 or anti-LAG3 inhibitors) in the metastatic setting (prior ICB in adjuvant setting is allowed if last exposure ≥ 6 months prior). Prior targeted therapy is also allowed.
* Returning to MD Anderson for restaging and follow-up (ICB treatment may occur locally)
* WOCP must have negative UPT within 1 week of beginning dietary intervention.
* Self-reported willingness to eat the provided foods (with some tailoring to their food preferences)
* Self-reported willingness to comply with scheduled visits, undergo venipuncture, provide stool samples.

Exclusion Criteria:

* Uveal melanoma previous ICB treatment in the metastatic setting
* History of inflammatory bowel disease, total colectomy, or bariatric surgery.
* Currently taking steroids \> Prednisone 10 mg/day or equivalent
* Medical contraindications to the Intervention Diet as determined by the treating physician.
* Self-reported major dietary restrictions, including but not limited to relevant food allergies, celiac disease, or diets such as vegan, ketogenic, extended fasting.
* Insulin-dependent diabetes or condition requiring bile acid sequestrants
* Unable or unwilling to undergo study procedures.
* IV antibiotic use in the past month or oral antibiotic use in past 2 weeks.
* Regularly taking supplements containing prebiotics, fiber and/or probiotics, and unable/unwilling to discontinue for the purpose of the study.
* Current smoker or heavy drinker (defined as \>14 drinks per week) or current illicit drug use.
* Currently pregnant, planning to become pregnant, or lactating.
* Concurrent malignancy requiring systemic therapy other than hormonal therapy.
* Cognitively impaired adults