P318 Intra-dermal with topical imiquimod pre-treatment versus intra-muscular hepatitis B vaccination in inflammatory bowel disease patients: a double-blind randomized controlled trial

Background

Patients with inflammatory bowel disease (IBD) are often immunocompromised and at risk of various opportunistic infections including viral hepatitis. Vaccination is recommended to prevent hepatitis B infection, but efficacy with conventional intra-muscular hepatitis B vaccination in IBD patients is suboptimal. Intra-dermal vaccination has been shown to be an effective way in augmenting immune response in poor vaccine responders. In addition, topical imiquimod, a synthetic agonist of toll-like receptor 7, has been shown to further boost the immunogenicity when applied to the injection site before intra-dermal vaccination. Our study compared the efficacy of intra-dermal hepatitis B vaccination with topical imiquimod with conventional intra-muscular hepatitis B vaccination in IBD patients.

Methods

This is a double-blind, randomized-controlled trial. IBD patients with no evidence of active or past infection nor history of vaccination i.e. negative serology to all HBsAg/Anti-HBc/Anti-HBs were recruited. They were randomized in 1:1 ratio to receive either intra-dermal recombinant hepatitis B vaccine with topical imiquimod pre-treatment to site of injection (ID) or intra-muscular recombinant hepatitis B vaccine with topical aqueous cream (IM). Same dose (20mcg) of vaccine (Engerix B, Glaxo Smith Klein) was administered to both groups at 0, 1, 6 month.  The primary outcome was the sero-protection rate at 12-month, defined as percentage of recruited subjects with anti-HBs titre ≥ 10 mIU/mL. 

Results

104 patients (mean age 46; 68% male; 50% Crohn’s and 50% UC) were enrolled, with 53 received ID and 51 received IM vaccine. The percentage of patients using steroids, immunomulators and biologics at the time of randomization was 15, 55 and 22 %, respectively. Baseline demographic, disease characteristic, and laboratory parameter were comparable between the ID and IM groups. Sero-protection rate at 12-month was significantly higher in the ID arm compared to the IM arm (91% vs. 69%, P=0.005; Figure). Percentage of good responders at 12 month (anti-HBs titre > 100 mIU/mL) was also higher in the ID arm than in the IM (77% vs 59%, P=0.042). Multivariate analysis showed that use of ID vaccine (OR 4.45, 95% CI 1.40-14.47) and a higher albumin level (OR 1.30, 95% CI 1.06-1.58) are associated with better sero-protection rate. There was no significant difference in adverse effects reported in (64% in ID vs 55% in IM; Table). 

Figure 

Table Adverse events