The human microbiota corresponds to an extremely rich and varied set of microorganisms that colonize our various epitheliums from birth, including the intestine, lungs and skin, where they interact continuously with our immune system. Changes in microbial composition and function, termed dysbiosis, have been linked to alterations in immune responses and to disease development, such as psoriasis. Recent research has shown that the gut microbiota can condition the therapeutic response to checkpoint inhibitors and that fecal microbiota transplant overcomes resistance to these therapy, suggesting a direct role for the microbiota in the ability to shape a therapeutic immune response. Antibiotic exposure during the course of cancer therapy negatively correlates with patients' response to anti-PD-1 treatment response, thus highlighting the link between the enrichment of specific microbial taxa in intestines and the response to immunotherapy. This observation suggests that treatments capable of modulating microbial networks and promoting specific bacterial clades may modulate the host's immune response. Hence, beyond their expected effect in the targeted tissue, part of the therapeutic effect of drugs could rely on this mechanism. In psoriasis patients, observational studies suggest that gut microbiome is altered differently after the use of anti-IL17 or anti-IL23 biologic agents.
Main objective: To determine the evolution of microbial composition of fecal samples issued to patients who responded to a biologic agent (IL-17 inhibitors, IL-23 inhibitors) and have stopped their treatment for 2 to 4 weeks before the index date, at baseline and 6 months or clinical relapse after treatment discontinuation
Design of the study: Prospective french multicentre observational cohort study
Population of study participants: Patients with psoriasis in remission after IL23i or IL17inhibitor treatments and who have stopped their medication for 2 to 4 weeks.
Number of participants included: 50 adult patients considered in remission and have stopped for at least 2 weeks and a maximum of 4 weeks, one of the following biologic agent: secukinumab, ixekizumab, brodalumab, bimekizumab, guselkumab, tildrakizumab, or risankizumab
