CREAM study: Clinical correlation between immunotherapy-RElated clinical outcome and intestinal microbiote in metastatic patients.

TPS215Background: It's known that composition of intestinal flora can influence the development of inflammatory gastrointestinal diseases, even though the association of inflammation with specific intestinal microbes is still unknown, because the inflammation and its treatment can change the composition of microbiote. Some bacterial species are essential to maintain the mucosal physiological tolerance, although species such as Bacteroides, Clostridium and Faecalibacterium can induce the up-regulation of T-cells and stimulate the production of anti-inflammatory cytokines. Innovative therapies such as anti-CTLA-4 antibody and inhibitors of the PD-1 receptor are particularly involved in the up-regulation of lymphocyte system: among their side effects, the most relevant are those immune-mediated such as hypophysitis, thyroiditis and colitis. In particular this last one usually occurs within 16weeks from the start of treatment: about one third of patients develop intestinal inflammation of any grade as a resul...