Ketogenic Dietary Intervention to Improve Response to Immunotherapy in Patients With Metastatic Melanoma and Metastatic Kidney Cancer

PRIMARY OBJECTIVE: I. To evaluate the safety and feasibility of establishing a ketogenic dietary intervention trial with longitudinal biospecimen collection in the Ohio State University Comprehensive Cancer Center (OSUCCC) cutaneous and genitourinary oncology clinics. EXPLORATORY OBJECTIVE: I. To assess whether the microbiome (binary, high versus \[vs\] low diversity) mediates the relationship between time in ketosis (days with peripheral blood beta-hydroxybutyric acid \[BHB\] \> 0.5 mM) and tumor size over the course of treatment. OUTLINE: Patients are randomized to 1 of 2 arms. ARM I: Patients undergo a ketogenic dietary intervention with personalized coaching from a dietician about the KD, which includes extensive educational and ongoing support on the KD and continuous ketone monitoring by talking to a dietician directly, with the ability to text a dietician at any time and expect a response within 12 hours over 24weeks. Patients also undergo daily blood glucose and ketone monitoring, undergo computed tomography (CT), undergo blood sample collection and may undergo stool sample collection on the study. ARM II: Patients follow a standard of care diet on the study.