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P438 Prospective, randomized clinical trial comparing the efficacy of two vaccines against hepatitis B virus (HBV) in inflammatory bowel disease (IBD) patients

M. Chaparro*1, J. Gordillo2, E. Domènech3, M. Esteve4, M. Barreiro de-Acosta5, A. Villoria6, E. Iglesias-Flores7, M. Blasi2, J.E. Naves8, O. Benítez9, L. Nieto5, X. Calvet10, V. García-Sánchez7, J.R. Villagrasa11, A.C. Marín1, M. Ramas1, I. Moreno12, J.P. Gisbert1

1Hospital Universitario de La Princesa, IIS-IP and CIBERehd, Gastroenterology Unit, Madrid, Spain, 2Hospital Santa Creu i Sant Pau, Gastroenterology Unit, Barcelona, Spain, 3Hospital Universitari Germans Trias i Pujol and CIBERehd, Gastroenterology Unit, Badalona, Spain, 4Hospital Universitario Mutua de Terrassa, Gastroenterology Unit, Terrassa, Spain, 5Complejo Hospitalario Universitario de Santiago, Gastroenterology Unit, Santiago de Compostela, Spain, 6Hospital de Sabadell and CIBERehd, Gastroenterology Unit, Sabadell, Spain, 7Hospital Universitario Reina Sofía, Gastroenterology Unit, Córdoba, Spain, 8Hospital Universitario Germans Trias i Pujol and CIBERehd, Gastroenterology Unit, Barcelona, Spain, 9Hospital Universitario Mutua de Terrassa and CIBERehd. , Gastroenterology Unit, Terrassa, Spain, 10Hospital de Sabadell. Corporació Sanitària Universitària Parc Taulí and CIBERehd, Gastroenterology Unit, Sabadell, Spain, 11Hospital Universitario de La Princesa and IIS-IP , Preventive medicine unit, Madrid, Spain, 12Hospital Universitario de La Princesa and IIS-IP , Fundación de Investigación Biomédica, Madrid, Spain

Background

Background: Aims: To compare the success rate between two HBV vaccines in IBD patients: the traditional (Engerix ® ) and a new vaccine with an adjuvant (Fendrix®). Secondary aim was to identify predictor factors of response to the vaccine

Methods

IBD patients with negative HBV serology and without previous vaccination against HBV were included in this multicenter study (EUDRA CT number: 2010-023947-14), and randomized 1:1 to receive Fendrix® or double doses of Engerix® at months 0, 1, 2 and 6. Anti-HBs concentration was measured 2 months after the 3rd and 4th doses

Results

173 patients were included: 28% under immunosuppressants, and 35% under anti-TNF. 54% of patients received Engerix® and 46% Fendrix®; the main characteristics of patients (age, gender, type of IBD and treatment) were similar between the 2 groups. Overall, 43% of patients had response (pre-defined as anti-HBs ≥100 IU/l) after the first 3 doses (165 patients have received 3 doses up to now), and 71% after the completion of the vaccination (161 have completed the vaccination). 47% of patients that did not respond after the 3th dose, responded to the 4th vaccine administration (p<0.0001). The response rate after the 4 doses was 75% (95%CI, 63-84%) with Fendrix® vs. 67% (56-77%) with Engerix® (p=0.3; however, the statistical power for this comparison was only 30%); considering anti-HBs ≥10 IU/l (the standard threshold to define response), the success rate was marginally higher with Fendrix® than with Engerix® (88% [78-94%) vs. 77% [66-85%], p=0.06). In patients under anti-TNF, the response rate (anti-HBs ≥ 100 IU/l) after the 4 doses was 67% (47-83%) with Fendrix® vs. 45% (27-64%) with Engerix® (p=0.09); and considering anti-HBs ≥ 10 IU/l, the success rate was 80% (61-82%) with Fendrix® and 58% (39-75%) with Engerix® (p=0.06). In the multivariate analysis, older age (OR=0.9, p<0.0001), and the treatment with immunosuppressants (OR=0.12, p<0.01) or anti-TNFs (OR=0.09, p<0.0001) were associated with a lower the response rate to the vaccination. The type of vaccine -Engerix® or Fendrix®- was not associated with the response to the vaccination (OR=1.8, 95%CI=0.8-4). The frequencies of IBD flaring ups during the study period were similar in patients receiving Fendrix® and Engerix® (17% vs. 22%)

Conclusion

We could not demonstrate a statistically significant higher response rate of Fendrix® (single dose) over Engerix® (double dose) in IBD patients, although a beta error cannot be excluded. A 4-dose vaccine schedule significantly increases (over 40%) the response compared with a 3-dose regimen. Older age and the immunosuppressive and anti-TNF treatment impaired the success rate of the vaccine. The risk of flaring up is not increased with one vaccine compared to the other