Efficacy and safety of faecal microbiota tranplantation for active peripheral psoriatic arthritis:A randomised sham-controlled trial

Background: Although causality remains to be established, targeting dysbiosis of the intestinal microbiota by faecal microbiota transplantation (FMT) has been proposed as a novel therapeutic option for treatment of extra-intestinal inflammatory diseases.1Objectives: In this proof-of-concept study, we evaluated efficacy and safety of FMT in psoriatic arthritis (PsA).2Methods: In this double-blind, parallel-group, sham-controlled, superiority trial, we randomly allocated (1:1) adults with active peripheral PsA (≥3 swollen joints) despite ongoing treatment with methotrexate to one gastroscopic-guided FMT or sham transplantation into the duodenum. The transplants (50 g faeces) came from one of four healthy, thoroughly screened, anonymous stool donors.3 The primary efficacy endpoint was the proportion of participants experiencing treatment failure (i.e., needing treatment intensification) through 26 weeks. The first key secondary endpoint was change in Health Assessment Questionnaire Disability Index (HAQ-DI) score from baseline to week 26. Safety was monitored throughout the trial. Trial registration number: NCT03058900, ClinicalTrials.gov.Results: Of 97 screened, 31 (32%) underwent randomisation (15 allocated to FMT), all received the assigned intervention, and 30 (97%) completed the 26-week clinical evaluation (Table 1). Treatment failure occurred more frequently in the FMT group than in the sham group (9 [60%] vs 3 [19%]; risk ratio, 3.20; 95% CI, 1.06 to 9.62; P=0.018). During the entire 26 weeks of observation, the rate of the treatment failures was significantly higher in the FMT than in the sham group, see figure 1. Improvement in HAQ-DI score differed between groups (0.07 vs 0.30) by 0.23 points (95% CI, 0.02 to 0.44; P=0.031) in favour of sham. No serious adverse events were observed.Conclusion: In this first interventional randomised controlled trial of FMT in immune-mediated arthritis, FMT was inferior to sham in treating active peripheral PsA. FMT did not appear to result in serious adverse events.