Bexsero, currently awaiting regulatory approval, produced robust immunity against disease-causing strains of Neisseria meningitidis serogroup B (MenB) in trials in infants, toddlers and adolescents. No vaccines are currently available to prevent this type of meningococcal infection.
"The rapid disease progression and flu-like symptoms of MenB can be difficult to recognise, particularly in infants, making prevention through vaccination the most effective way to control this disease," said Jamie Findlow, Deputy Head of the Health Protection Agency’s Vaccine Evaluation Unit in Manchester.
An open-label Phase IIb study randomised more than 1800 infants to receive Bexsero at 2, 4 and 6 months or at 2, 3 and 4 months, with or without routine vaccination (pneumococcal conjugate and DTaP-IPV-Hib-hepatitis B). The majority of infants given Bexsero, in either dose schedule with or without routine vaccines, achieved a human serum bactericidal antibody titre ≥1:5 against the MenB antigens tested. Bexsero did not markedly affect the responses to the routine vaccines and its tolerability profile was comparable to those of the routine vaccines.
An open-label extension study enrolled more than 1500 toddlers who had received a three-dose primary series of Bexsero at 2, 4 and 6 months. Children were randomised to receive either a fourth (booster) dose of Bexsero at the same time as the measles, mumps, rubella, and varicella vaccine (MMR-V), or Bexsero at 12 months followed by MMR-V at 13 months. Again, Bexsero was highly immunogenic against all vaccine antigens tested and did not affect immune responses to MMR-V. Adverse events, notably fever, were not increased by the concomitant use of Bexsero and MMR-V.
The extension study also showed that a catch-up schedule of two doses of Bexsero two months apart was sufficient to elicit protective immune responses in previously unvaccinated toddlers aged 12 or 13 months.
Finally, in an observer-blind study, more than 1600 adolescents aged 11–17 years were randomised to receive one to three doses of Bexsero or placebo, one month apart. The vaccine induced robust immune responses and had an acceptable tolerability profile following one, two or three doses.
Bexsero has been developed by Novartis.