A Study to Test the Benefit of Vitamin B5 in Patients With Melanoma

This single-center, single-cohort study aims to investigate the effectiveness of oral calcium pantothenate (C-PAN) in raising plasma pantothenic acid levels in melanoma patients. Conducted at Princess Margaret Cancer Centre, the study will enroll 12 eligible subjects with locally unresectable or metastatic melanoma undergoing first-line standard of care (SOC) with combined immune checkpoint inhibitor (ICI) therapy, Nivolumab and Ipilimumab. Additionally, the study will explore changes in immune cell subsets, metabolomics, and gut microbiome to understand the impact of pantothenate/CoA pathway manipulation on ICI efficacy and immune-mediated colitis prevention. Patients will initially receive a run-in period of C-PAN at a dose of 2000 mg daily for 3 to 7 days, alongside approved SOC drugs. Subsequently, patients will continue with the maintenance dose of 2000 mg daily, starting on the same day as the first cycle of combined ICI. This maintenance dose will be continued until the occurrence of unacceptable toxicity, disease progression by iRECIST criteria, or for a maximum duration of 1 year, whichever comes first, unless there are specific criteria indicating the discontinuation of C-PAN. For all subjects, radiologic imaging to assess response to treatment will be performed as per standard practice (ideally every 8 to 12 weeks, with first assessment at week 9). Fecal samples will be collected from all subjects at baseline (1st sample), at week 9 following the start of ICI, and at study completion or discontinuation. An additional fecal sample will be collected in case of development of immune-related colitis or immune-related diarrhea. Standard laboratory investigations for immunotherapy will be collected as per institutional practice. Blood samples for biomarkers will be collected at various time points.