Supplementary Material for: Pyoderma Gangrenosum and Interleukin Inhibitors: A Semi-Systematic Review

Background: Pyoderma gangrenosum (PG) is a rare ulcerating skin disease associated with multiple comorbidities and increased mortality. In recent decades, newer biologics such as interleukin inhibitors have been used to treat PG; however, the literature is scarce, consisting predominantly of case reports and caseseries. The aim of our review was to evaluate the effectiveness and safety of interleukin inhibitors for the treatment of PG in adults. Summary: A literature search was conducted using search terms related to PG and interleukin inhibitors in databases such as PubMed, Embase, Scopus, Web of Science, and Cochrane Library. The study eligibility criteria included patients diagnosed with PG, over the age of 18, and treated with an interleukin inhibitor. Our study included 60 papers describing 81 patients fulfilling the eligibility criteria. The treatment with interleukin inhibitors resulted in 70% (95% CI 59–80%) response and 57% (95% CI 45–68%) complete response rates, and few (4%) mild adverse events, hence supporting the off-label use for the treatment of recalcitrant PG in adults. The response and complete response rates were 59% (17/29) and 38% (11/29) for anakinra, 64% (7/11) and 55% (6/11) for canakinumab, and 79% (27/34) and 71% (24/34) for ustekinumab, respectively. Limitations include publication bias that might have overestimated the efficacy as successful cases responding to treatment are more likely to be reported than nonresponding cases. Additionally, the heterogeneity of the treatment groups does not allow conclusions of superiority or inferiority of the different interleukin inhibitors to be drawn. Further studies are needed to investigate the efficacy of the different interleukin inhibitors and to investigate the importance of underlying disease for treatment response.