Dietary fiber improves outcomes for melanoma patients receiving ICB therapy, study finds

Melanoma patients who consume a diet high in fiber had a better response to checkpoint inhibitor immunotherapy (ICB), compared to patients with a low-fiber diet, according to new research.

In an observational study, led by the University of Texas and the National Institutes of Health and published in Science, researchers gained early insights as to how diet-related factors may influence the immune response.

Patients reporting a combination of high fiber consumption and no use of over-the counter probiotic supplements gained the most noticeable benefit.

Researchers assessed the fecal microbiota profiles, dietary habits, and commercially available probiotic supplement use in melanoma patients and performed parallel preclinical studies. Higher dietary fiber was associated with significantly improved progression-free survival in 128 patients on ICB, with the most pronounced benefit observed in patients with sufficient dietary fiber intake and no probiotic use. The study includes data from 438 melanoma patients.

Findings were repeated in preclinical models, demonstrating impaired treatment response to anti-programmed cell death 1 (anti-PD-1)-based therapy in mice receiving a low-fiber diet or probiotics, with a lower frequency of interferon-γ-positive cytotoxic T cells in the tumor microenvironment. Together, this data has clinical implications for patients receiving ICB for cancer.

Jennifer Wargo, MD led the study. Approximately 80 scientists took part in the research.