Immunogenicity and safety of meningococcal group A, C, W and Y tetanus toxoid conjugate vaccine: review of clinical and real-world evidence

Randomized trial showing persistence of hSBA titers elicited by a pentavalent meningococcal MenABCWY vaccine for up to 4 years following a primary series and safety and immunogenicity of a booster dose

BACKGROUND

Vaccination against 5 prominent meningococcal serogroups (A/B/C/W/Y) is necessary for broad disease protection. We report immunopersistence through 4 years after a 2-dose (6-month interval) pentavalent MenABCWY primary vaccine series and safety and immunogenicity of a booster administered 4 years after primary vaccination.

METHODS

This randomized, active-controlled, observer-blinded study was conducted in the United States and Europe. In stage 1, healthy MenACWY vaccine-naive or -experienced 10- to 25-year-olds were randomized 1:2 to receive MenABCWY and placebo or MenB-fHbp and MenACWY-CRM. Eligible participants were randomly selected to participate in stage 2, which was an open-label immunopersistence and booster extension. Immunogenicity was assessed through serum bactericidal antibody using human complement (hSBA) assays with serogroups A/C/W/Y (MenA/C/W/Y) and 4 primary serogroup B (MenB) test strains. Immunogenicity endpoints included hSBA seroprotection rates through 48 months after primary vaccination and 1 month after the booster. Safety endpoints included booster reactogenicity events and adverse events (AEs).

RESULTS

Of 1379 eligible participants, 353 entered stage 2; 242 completed the 48-month blood draw after primary vaccination and 240 completed the booster vaccination phase. MenA/C/W/Y seroprotection rates remained high for 4 years following a 2-dose MenABCWY primary series (MenACWY-naive, 62.0 %-100.0 %; MenACWY-experienced, 98.7 %-100.0 %) and trended higher than those after a single MenACWY-CRM dose (MenACWY-naive, 38.1 %-95.2 %; MenACWY-experienced, 89.7 %-100.0 %). Corresponding seroprotection rates against MenB remained stable and generally higher than baseline (MenABCWY, 18.2 %-36.6 %; MenB-fHbp, 16.2 %-31.9 % across strains). Following a booster, seroprotection rates against all 5 serogroups were ≥ 93.8 % across groups. Most booster dose reactogenicity events were mild or moderate in severity, and AEs were infrequent.

CONCLUSIONS

Immune responses remained high for MenA/C/W/Y and above baseline for MenB through 4 years after the MenABCWY primary series, with robust responses for all 5 serogroups observed following a booster. The MenABCWY booster had an acceptable safety and tolerability profile consistent with the primary series. NCT03135834.

Immunogenicity and safety of a pentavalent meningococcal ABCWY vaccine in adolescents and young adults: an observer-blind, active-controlled, randomised trial

BACKGROUND

Meningococcal serogroups A, B, C, W, and Y cause nearly all meningococcal disease, and comprehensive protection requires vaccination against all five serogroups. We aimed to assess the immunogenicity and safety of a pentavalent MenABCWY vaccine comprising two licensed vaccines-meningococcal serogroup B-factor H binding protein vaccine (MenB-FHbp) and a quadrivalent meningococcal serogroup ACWY tetanus toxoid conjugate vaccine (MenACWY-TT)-compared with two doses of MenB-FHbp and a single dose of quadrivalent meningococcal serogroup ACWY CRM197-conjugate vaccine (MenACWY-CRM) as the active control. We previously reported the primary safety and immunogenicity data relating to the two-dose MenB-FHbp schedule. Here we report secondary outcomes and ad-hoc analyses relating to MenABCWY immunogenicity and safety.

METHODS

We did an observer-blind, active-controlled trial at 68 sites in the USA, Czech Republic, Finland, and Poland. Healthy individuals (aged 10-25 years) who had or had not previously received a MenACWY vaccine were randomly assigned (1:2) using an interactive voice or web-based response system, stratified by previous receipt of a MenACWY vaccine, to receive 0·5 mL of MenABCWY (months 0 and 6) and placebo (month 0) or MenB-FHbp (months 0 and 6) and MenACWY-CRM (month 0) via intramuscular injection into the upper deltoid. All individuals were masked to group allocation, except staff involved in vaccine dispensation, preparation, and administration; and protocol adherence. Endpoints for serogroups A, C, W, and Y included the proportion of participants who achieved at least a four-fold increase in serum bactericidal antibody using human complement (hSBA) titres between baseline and 1 month after each vaccination. For serogroup B, secondary endpoints included the proportion of participants who achieved at least a four-fold increase in hSBA titres from baseline for each of four primary test strains and the proportion of participants who achieved titres of at least the lower limit of quantitation against all four test strains combined at 1 month after the second dose. Endpoints for serogroups A, C, W, and Y were assessed in the modified intent-to-treat (mITT) population, which included all randomly assigned participants who received at least one vaccine dose and had at least one valid and determinate MenB or serogroup A, C, W, or Y assay result before vaccination up to 1 month after the second dose, assessed in ACWY-experienced and ACWY-naive participants separately. Secondary endpoints for serogroup B were analysed in the evaluable immunogenicity population, which included all participants in the mITT population who were randomly assigned to the group of interest, received all investigational products as randomly assigned, had blood drawn for assay testing within the required time frames, had at least one valid and determinate MenB assay result after the second vaccination, and had no important protocol deviations; outcomes were assessed in both ACWY-experienced and ACWY-naive populations combined. Non-inferiority of MenABCWY to MenACWY-CRM and MenB-FHbp was determined using a -10% non-inferiority margin for these endpoints. Reactogenicity and adverse events were assessed among all participants who received at least one vaccine dose and who had available safety data. This trial is registered with Clinicaltrials.gov, NCT03135834, and is complete.

FINDINGS

Between April 24 and November 10, 2017, 1610 participants (809 MenACWY-naive; 801 MenACWY-experienced) were randomly assigned: 544 to receive MenABCWY and placebo (n=272 MenACWY-naive; n=272 MenACWY-experienced) and 1066 to receive MenB-FHbp and MenACWY-CRM (n=537 MenACWY-naive; n=529 MenACWY-experienced). Among MenACWY-naive or MenACWY-experienced MenABCWY recipients, 75·5% (95% CI 69·8-80·6; 194 of 257; serogroup C) to 96·9% (94·1-98·7; 254 of 262; serogroup A) and 93·0% (88·4-96·2; 174 of 187; serogroup Y) to 97·4% (94·4-99·0; 224 of 230; serogroup W) achieved at least four-fold increases in hSBA titres against serogroups ACWY after dose 1 or 2, respectively, in ad-hoc analyses. Additionally, 75·8% (71·5-79·8; 320 of 422) to 94·7% (92·1-96·7; 396 of 418) of MenABCWY and 67·4% (64·1-70·6; 563 of 835) to 95·0% (93·3-96·4; 782 of 823) of MenB-FHbp recipients achieved at least four-fold increases in hSBA titres against MenB strains after dose 2 in secondary analyses; 79·9% (334 of 418; 75·7-83·6) and 74·3% (71·2-77·3; 605 of 814), respectively, achieved composite responses. MenABCWY was non-inferior to MenACWY-CRM (single dose) and to MenB-FHbp in ad-hoc analyses based on the proportion of participants with at least a four-fold increase in hSBA titres from baseline and (for MenB-FHbp only) composite responses. Reactogenicity events after vaccination were similarly frequent across groups, were mostly mild or moderate, and were unaffected by MenACWY experience. No adverse events causing withdrawals were related to the investigational product. Serious adverse events were reported in four (1·5%; 0·4-3·7) MenACWY-naive individuals in the MenABCWY group versus six (2·2%; 0·8-4·8) among MenACWY-experienced individuals in the MenABCWY group and 14 (1·3%; 0·7-2·2) in the active control group (MenACWY-experienced and MenACWY-naive individuals combined); none of these were considered related to the investigational product.

INTERPRETATION

MenABCWY immune responses were robust and non-inferior to MenACWY-CRM and MenB-FHbp administered separately, and MenABCWY was well tolerated. The favourable benefit-risk profile supports further MenABCWY evaluation as a simplified schedule compared with current adolescent meningococcal vaccination programmes.

FUNDING

Pfizer.

Comparing the meningococcal serogroup C immune response elicited by a tetanus toxoid conjugate quadrivalent meningococcal vaccine (MenACYW-TT) versus a quadrivalent or monovalent C tetanus toxoid conjugate meningococcal vaccine in healthy meningococcal vaccine-naïve toddlers: A randomised, controlled trial

MenACYW-TT (MenQuadfi®) is a quadrivalent meningococcal tetanus toxoid conjugate vaccine licensed in Europe for use in individuals ≥12 months. This study assessed whether serogroup C immune responses with MenACYW-TT were at least non-inferior, or superior, to those of quadrivalent meningococcal ACWY (MCV4-TT; Nimenrix®) and monovalent meningococcal C (MenC-TT; NeisVac-C®) vaccines in toddlers (12–23 months). In this modified, double-blind Phase III study (NCT03890367), 701 toddlers received one dose of MenACYW-TT (n = 230), MCV4-TT (n = 232) or MenC-TT (n = 239). Serum bactericidal assays with human (hSBA) and baby rabbit (rSBA) complement were used to measure anti-meningococcal serogroup C antibodies at baseline and 30 days post-vaccination. A sequential statistical approach was used for primary and secondary objectives. For the primary objectives, superiority of serogroup C was assessed in terms of hSBA seroprotection rates (defined as titers ≥1:8) and GMTs for MenACYW-TT compared to MCV4-TT, and rSBA GMTs compared to MenC-TT. The safety of all vaccines within 30 days post-vaccination was described. When administered as a single dose to meningococcal vaccine-naïve healthy toddlers the superiority of the MenACYW-TT serogroup C immune response versus MCV4-TT was demonstrated for hSBA GMTs (ratio 16.3 [12.7–21.0]) and seroprotection (difference 10.43% [5.68–16.20]); and versus MenC-TT in terms of rSBA GMTs (ratio 1.32 [1.06–1.64]). The safety profiles of a single dose of MenACYW-TT, MCV4-TT and MenC-TT were similar. In meningococcal vaccine-naïve toddlers, MenACYW-TT induced superior immune responses to serogroup C versus MCV4-TT in terms of hSBA seroprotection and GMTs and versus MenC-TT in terms of rSBA GMTs.

Clinical trial and postmarketing safety experience with MenACWY-TT, a meningococcal group A, C, W, and Y tetanus conjugate vaccine

BACKGROUND

The meningococcal serogroups A, C, W, and Y tetanus toxoid conjugate vaccine (MenACWY-TT; Nimenrix®; Pfizer Ltd, Sandwich, Kent, UK) is licensed in more than 80 countries worldwide for the prevention of meningococcal disease caused by serogroups A, C, W, and Y in individuals throughout their lifespans. This report summarizes safety data from the MenACWY-TT clinical development program and postmarketing experience.

METHODS

Within the clinical study program, reactogenicity data were based on 3 primary studies, including a large pooled analysis across multiple age groups, and long-term safety data were derived from 3 studies evaluating long-term antibody persistence. Postmarketing safety data through April 19, 2021, were collected and analyzed in connection with the MenACWY-TT Periodic Safety Update Report.

RESULTS

Approximately 32 million doses of MenACWY-TT have been administered worldwide, with more than 21,530 additional individuals receiving MenACWY-TT as part of clinical trials. The safety profile of MenACWY-TT was consistent between the clinical study program and the postmarketing experience, as well as with other licensed meningococcal vaccines. The most commonly observed adverse events (AEs) were pyrexia/fever, headache, injection site pain/reactions, nausea/vomiting, and fatigue; serious AEs were rare relative to the number of doses administered. Several cases of serogroup replacement/lack of efficacy were observed in the 1-year postmarketing period but did not appear to be related to MenACWY-TT use.

CONCLUSION

Extensive data derived from clinical trials and postmarketing experience indicate a consistently favorable safety profile for MenACWY-TT across a wide range of age groups.

Rationale for the Development of a Pentavalent Meningococcal Vaccine: A US-Focused Review

While invasive meningococcal disease (IMD) is uncommon, it can result in serious sequelae and even death. In 2018 in the United States, the incidence of IMD per 100,000 people was 0.03 among adolescents 11-15 years of age, 0.10 among persons 16-23 years of age, and 0.83 among infants < 1 year of age. Serogroup B accounted for 86%, 62%, and 66% of cases, respectively, in those age groups. Currently, routine meningococcal vaccination covering serogroups ACWY (MenACWY) is recommended in the United States for all adolescents at 11-12 years of age, with a booster dose at 16 years of age, whereas a meningococcal serogroup B (MenB) vaccine series is recommended for persons 16-23 years of age under the shared clinical decision-making paradigm. The MenACWY vaccination program in adolescents has been successful in reducing disease burden, but does not prevent disease caused by serogroup B, which accounts for more than half of IMD cases. There are currently no approved vaccines that cover all of the most common disease-causing meningococcal serogroups, which are A, B, C, W, and Y. A pentavalent MenABCWY vaccine that is constituted from 2 licensed meningococcal vaccines-MenB-FHbp and MenACWY-TT-is being investigated in healthy persons ≥ 10-25 years of age. The addition of a MenABCWY vaccine is the next natural step in the incremental meningococcal immunization program in the United States to improve protection against the most common serogroup causing IMD, with no increase in the number of immunizations needed. With high uptake, routine use of MenABCWY could reduce IMD cases and associated mortality, the rate of long-term physical and psychosocial sequelae in survivors, and costs associated with controlling outbreaks, particularly on college campuses. A MenABCWY vaccine would also reduce the number of injections required for adolescents, potentially improving compliance.

Carbohydrate based meningococcal vaccines: past and present overview

Neisseria meningitidis is a major cause of bacterial meningitidis worldwide. Children less than five years and adolescents are particularly affected. Nearly all invasive strains are surrounded by a polysaccharide capsule, based on which, 12 N. meningitidis serogroups are differentiated. Six of them, A, B, C, W, X, and Y, cause the vast majority of infections in humans. Mono- and multi-valent carbohydrate-based vaccines against meningococcal infections have been licensed or are currently in clinical development. In this mini-review, an overview of the past and present approaches for producing meningococcal glycoconjugate vaccines is provided.

Persistence of bactericidal antibodies following primary and booster MenACWY-TT vaccination of toddlers: A review of clinical studies

The long-term persistence of antibody responses following primary vaccination with quadrivalent conjugate vaccines targeting meningococcal serogroups A, C, W, and Y (MenACWY) and the duration of protection following a booster dose have not been fully elucidated, particularly in children who received primary dosing as toddlers. This review summarizes the findings of one phase 3 and three phase 2 open-label, randomized clinical studies that assessed the long-term antibody persistence of MenACWY conjugated to tetanus toxoid as a carrier protein (MenACWY-TT) in toddlers. Following primary vaccination, antibody responses persisted for approximately 2-3 years and then decreased up to 5 years after vaccination. Geometric mean titers remained elevated for all serogroups up to 5 years after primary vaccination. In children who received a booster dose of MenACWY-TT at 4-5 years after primary dosing as toddlers, antibody responses were documented in >99% of subjects across all serogroups, with minimal decreases in antibody persistence from 2-6 years after booster vaccination. The persistence of meningococcal serogroup C (MenC) antibody responses was similar between MenACWY-TT and MenC vaccine recipients after primary and booster dosing. Together, these findings indicate that antibody responses to primary MenACWY-TT vaccination persist for 2-3 years. Additionally, these findings indicate that in subjects who receive primary MenACWY-TT vaccination as toddlers, the antibody response to booster MenACWY-TT vaccination lasts for up to 6 years and suggest that immune memory is afforded at least into early adolescence, which is an age group at increased risk of invasive meningococcal disease.