Background: Bivalent rLP2086 (Trumenba), 1 of 2 meningococcal serogroup B (MnB) vaccines recently approved in the United States for the prevention of MnB disease in individuals 10-25 years of age, is composed of 2 lipidated factor H binding proteins from subfamilies A and B. This study evaluated the breadth of MnB strain coverage elicited by bivalent rLP2086 measured with serum bactericidal assays using human complement (hSBAs).
Methods: hSBA responses to diverse MnB clinical strains circulating in the United States and Europe (n = 23), as well as recent US university outbreak strains (n = 4), were evaluated. Individual prevaccination and postvaccination sera from adolescents and young adults previously enrolled in phase 2 clinical studies of bivalent rLP2086 were assessed. Responders were defined by an hSBA titer ≥1:8, which is more stringent than the accepted correlate of protection (hSBA titer ≥1:4).
Results: Baseline hSBA response rates were generally low; robust increases were observed after 2 and 3 doses of bivalent rLP2086, with hSBA responses to all test strains ranging from 31.8% to 100% and 55.6% to 100%, respectively. hSBA responses to strains expressing prevalent subfamily A and B factor H binding protein variants in the United States and Europe, A22 and B24, ranged from 88.0% to 95.0% and 81.0% to 100.0%, respectively, after dose 3. Substantial responses were also observed for recent US outbreak strains.
Conclusions: Bivalent rLP2086 elicits robust hSBA responses to MnB strains expressing 14 factor H binding protein variants representing approximately 80% of MnB invasive isolates and different from vaccine antigens, suggesting that bivalent rLP2086 confers broad protection against diverse MnB disease-causing strains.