Fendrix vs Engerix-B for Primo-Vaccination Against Hepatitis B Infection in Patients With Inflammatory Bowel Disease: A Randomized Clinical Trial.

INTRODUCTION: To compare Engerix-B and Fendrix hepatitis B virus for primo vaccination in inflammatory bowel disease (IBD). METHODS: Patients with IBD were randomized 1:1 to receive Engerix-B double dose or Fendrix single dose at months 0, 1, 2, and 6. Anti-HBs titers were measured 2 months after the third and fourth doses. Response to vaccination was defined as anti-HBs ≥100 UI/L. Anti-HBs titers were measured 2 months after the third and fourth doses and again at 6 and 12 months after the fourth dose. RESULTS: A total of 173 patients were randomized (54% received Engerix-B and 46% Fendrix). Overall, 45% of patients responded (anti-HBs ≥100 IU/L) after 3 doses and 71% after the fourth dose. The response rate after the fourth dose was 75% with Fendrix vs 68% with Engerix-B (P = 0.3). Older age and treatment with steroids, immunomodulators, or anti-tumor necrosis factor were associated with a lower probability of response. However, the type of vaccine was not associated with the response. Anti-HBs titer negativization occurred in 13% of patients after 6 months and 20% after 12 months. Anti-HBs ≥100 IU/L after vaccination was the only factor associated with maintaining anti-HBs titers during follow-up. DISCUSSION: We could not demonstrate a higher response rate of Fendrix (single dose) over Engerix-B (double dose). A 4-dose schedule is more effective than a 3-dose regimen. Older age and treatment with immunomodulators or anti-tumor necrosis factors impaired the success. A high proportion of IBD patients with protective anti-HBs titers after vaccination loose them over time. The risk of losing protective anti-HBs titers is increased in patients achieving anti-HBs <100 IU/L after the vaccination.

Kinetics of anti-hepatitis B surface antigen titers after hepatitis B vaccination in patients with inflammatory bowel disease.

BACKGROUND: Clinically significant hepatitis B (HB) virus infection has been documented among immunocompromised patients who do not maintain anti-hepatitis surface antigen (anti-HBs) concentrations ≥ 10 IU/L after an adequate response to the vaccine. The aims of the study were to understand the kinetics of anti-HBs titers over time in patients with inflammatory bowel disease (IBD) who initially responded to vaccination and to identify factors predictive of losing protective anti-HBs titers. METHODS: Patients with IBD with a response (anti-HBs > 10 IU/L at 1-3 months) to HB virus vaccination were prospectively included. Anti-HBs titers were measured at 6 and 12 months. Anti-HBs titers were considered negative if they were <10 IU/L at any time during the follow-up. The kinetics of anti-HBs titers in the long term was estimated using Kaplan-Meier curves. Cox regression analysis was performed to identify the factors predictive of losing protective anti-HBs titers. RESULTS: The sample comprised 100 patients (mean age, 42 years; 68% Crohn's disease; 49% on thiopurines; and 14% on anti-tumor necrosis factors during follow-up). The cumulative incidence of loss of anti-HBs titers was 2% after 6 months and 15% after 12 months. The incidence rate of loss of protective anti-HBs titers was 18% per patient-year. Baseline (after vaccination) anti-HBs titers were lower among patients whose titers became negative during the follow-up than among those who maintained them >10 IU/L (191 versus 515 IU/L; P < 0.001). Treatment with anti-TNFs was the only factor associated with a higher risk of loss of anti-HBs (hazard ratio = 3.1; 95% confidence interval = 1.1-8.8; P = 0.03). CONCLUSIONS: A high proportion of patients with IBD with protective anti-HBs titers after vaccination lose them over time (18% per patient-year of follow-up). The risk of losing protective anti-HBs titers is 3-fold higher among patients on anti- tumor necrosis factors therapy.