The PRIMM study, a multicenter cohort study conducted in Netherlands and UK, shows a positive linear association between a Mediterranean dietary pattern that was high in whole grains, fish, nuts, fruit, and vegetables and the response to immunotherapy with immune checkpoint inhibitors in patients with advanced melanoma; results were recently published on JAMA Oncology.
Immune checkpoint blockade has revolutionized the treatment of advanced melanoma, improving survival, but many patients do not tolerate and/or respond to this treatment and durable responses are observed for 40% to 60% of patients, depending on treatment regimens, while patients experience a range of immune-related adverse events of differing severity. Since recent evidence suggests that variability in the efficacy of immune checkpoint blockade is partially explained by differences in the gut microbiome, the PRIMM study aimed to investigate associations between different dietary patterns and immune checkpoint blockade response and immune-related adverse events using a multinational prospective cohort of patients with advanced melanoma. Researchers prospectively collected dietary and clinical data from 91 patients who received immune checkpoint inhibitors between 2018 and 2021 for advanced melanoma in the UK and the Netherlands. Results revealed positive linear associations between a Mediterranean dietary pattern enriched in whole grains, fish, nuts, fruit, and vegetables and the probability of overall response rate and progression-free survival at 12 months. «A potential mechanism underlying the association between diet and immunotherapy response is the gut microbiome», authors explain. «Preclinical studies have shown immunomodulatory and antitumor activities of several nutrients, including fiber, polyphenols, and antioxidants, that are mediated via the gut microbiome. The Mediterranean diet has been associated with an increased abundance of bacteria producing single chain fatty acids that have been shown to be predictive of immunotherapy response in several studies. This cohort study suggests that the Mediterranean dietary pattern is associated with a higher probability of progression-free survival and overall response rate in patients receiving immune checkpoint blockade for advanced melanoma. These findings suggest a potential role for diet in improving responses to immune checkpoint blockade treatment outcomes», authors conclude.