Safety and immunogenicity of HBAI20 Hepatitis B vaccine in healthy naïve and non-responding adults.

Approximately 5% of the healthy adult population respond inadequately to the commercial recombinant hepatitis B vaccines. As the recombinant vaccines all have an aluminium-based adjuvant, we tried to enhance the immune response by adding a cytokine-based adjuvant. This new adjuvant AI20, containing 20g recombinant human IL-2 attached to 20g aluminium hydroxide, was added to HBVaxPro (c)-10g (HBAI20). In a double-blind randomized controlled trial (RCT), 24 naive subjects were randomized to receive either HBAI20 or commercial HBVaxPro (c)-10g vaccine. In an open-label study, 10 nonresponders received HBAI20 vaccine. All participants received 3 vaccinations (0, 1 and 6months). In the RCT, the occurrence of any adverse events or severe events was similar between the trial arms. At month 7, all naive participants were seroprotected; moreover, 92% in the HBAI20 group had protective antibodies 10days after the second vaccination vs 58% in the HBVaxPro (c)-10g group, P=.16. In the open-label study, no serious adverse events were noted. The HBAI20 vaccine was able to elicit protective anti-HBs titres in 90% of nonresponders, 1month after the third vaccination. According to these results, the new HBAI20 vaccine seems safe, well-tolerated and may promote more rapid protection against hepatitis B infection.