Immunotherapy: its efficacy depends on the microbiota

Among patients with metastatic melanoma being treated with ipilimumab, only some respond favorably to this cancer treatment, which works by activating the immune system. Some of them also have side effects, in particular enterocolitis, whose symptoms are similar to those of chronic inflammatory bowel diseases, in which the microbiota plays a major role. In order to understand these differences in treatment response, French researchers, whose studies were published in the Annals of Oncology, analyzed the intestinal microbiota of 26 patients. The results suggest that patients hosting a majority of Faecalibacterium bacteria respond better to treatment than those with a microbiota rich in Bacteroides.

This is a discovery that, in the future, could enable the identification of patients who are likely to benefit from ipilimumab and is a major step in the concept of personalized therapy, through the modulation of the microbiota via the administration of probiotics or prebiotics or by fecal transplant.