Bifidobacterium longum

Bifidobacterium longum was among bacterial species enriched in responders (objective response or stable disease >12 months) to FMT plus pembrolizumab in a Phase 2 trial of 15 PD-1-refractory advanced melanoma patients (NCT03341143), confirming its previously reported association with favorable anti-PD-1 response in human melanoma.

PMID: 33542131

D008545 Melanoma H00038 Melanoma

Bifidobacterium longum was among 8 commensal species significantly enriched in pre-treatment stool of metastatic melanoma anti-PD-1 responders (n=16) versus non-responders (n=26) by integrated 16S rRNA, shotgun metagenomic, and qPCR analysis (P<0.05, permutation test); fecal microbiota from responding patients conveyed improved tumor control and augmented CD8+ T cell infiltration in germ-free mouse recipients.

PMID: 29302014

D007167 Immunotherapy D008545 Melanoma D061026 Programmed Cell Death 1 Receptor H00038 Melanoma

Bifidobacterium longum 35624–based probiotic administration to germ-free mice colonized with an ICB complete responder's microbiota significantly impaired antitumor response to anti-PD-L1 therapy, resulting in significantly larger tumors compared to sterile water control (P=0.04 by likelihood ratio test in linear mixed model; n=4–5 per group), with concomitant reduction in gut microbiome alpha diversity (inverse Simpson index).

PMID: 34941392

D000082082 Immune Checkpoint Inhibitors D008546 Melanoma, Experimental D019936 Probiotics H00038 Melanoma

B. longum 35624–based probiotic administration significantly reduced the frequency of IFN-γ–positive CD8+ cytotoxic T cells in the tumor microenvironment of anti-PD-L1–treated melanoma-bearing germ-free mice (P=0.03 by supervised flow cytometry analysis; n=6 per group), indicating suppression of intratumoral cytotoxic T cell responses as a mechanism of impaired ICB efficacy.

PMID: 34941392

D008546 Melanoma, Experimental D019936 Probiotics D013601 T-Lymphocytes H00038 Melanoma