Review of local injection of anti-TNF for perianal fistulising Crohn's disease

Background Perianal fistulising Crohn's disease (PFCD) affects a third of Crohn's disease patients and represents a disabling phenotype with poor outcome. The anti-tumour necrosis factor alpha (TNF) therapies have been shown to maintain clinical remission in a third of patients after 1 year of treatment. Maintenance therapy with systematic administration schedules confers greatest benefit, but exposes patients to risks/side effects of continued systemic use and led to consideration of local drug delivery (first described in 2000). In this review, we analyse all published articles on local anti-TNF therapy in the treatment of PFCD. Methods The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to systematically search Medline and Embase using the medical subject headings 'fistula', 'anus', 'Crohn disease', 'infliximab' and 'adalimumab'. This was combined with free text searches, e.g. 'local injection' and 'Crohn's perianal disease'. Studies/abstracts describing local injection treatment with anti-TNF were included in this review. Results Six pilot studies including a total of 92 patients were included in this review. Outcomes reported were mostly clinical and included 'complete/partial response' to therapy and short-term results varied between 40 and 100%. There were no significant adverse events and the local injections were well tolerated. Conclusions There is paucity of data assessing this treatment modality. Local anti-TNF therapy appears safe, but outcome reporting is heterogeneous, subjective and long-term data are unavailable. Our review suggests a potential role may be in those in whom systemic treatment is contraindicated and calls for standardised reporting of outcomes in this field to enable better data interpretation.