A new fully liquid presentation of MenACWY-CRM conjugate vaccine: Results from a multicentre, randomised, controlled, observer-blind study

Re-randomization tests as sensitivity analyses to confirm immunological noninferiority of an investigational vaccine: Case study

Here we present as case study how re-randomization tests were performed in two randomized, controlled clinical trials as sensitivity analyses, as recommended by the United States Food and Drug Administration in the context of adaptive randomization. This was done to confirm primary conclusions on immunological noninferiority of an investigational new fully liquid presentation of a quadrivalent cross-reacting material conjugate meningococcal vaccine (MenACWY-CRM), over its licensed lyophilized/liquid presentation. In two phase 2b studies (Study #1: NCT03652610; Study #2: NCT03433482), noninferiority of the fully liquid presentation of MenACWY-CRM to the licensed presentation was assessed and demonstrated for immune responses against meningococcal serogroup A (MenA), the only vaccine component modified from lyophilized to liquid in the new presentation. The original vaccine assignment algorithm, with a minimization procedure accounting for center or center within age strata, was used to re-randomize participants belonging to the fully liquid and licensed vaccine groups while keeping antibody responses, covariates and entry order as observed. Test statistics under re-randomization were generated according to the ANCOVA model used in the primary analysis. To confirm immunological noninferiority following re-randomization, the corresponding p-values had to be <0.025. For both studies and all primary objective evaluations, the re-randomization p-values were well below 0.025 (0.0004 for Study #1; 0.0001 for the two co-primary endpoints in Study #2). Re-randomization tests performed to comply with a regulatory request confirmed the primary conclusions of immunological noninferiority for the MenA of the fully liquid compared to the licensed vaccine presentation.

Fully Liquid MenACWY-CRM Vaccine: Results from an Integrated Safety Analysis

INTRODUCTION

The currently licensed quadrivalent MenACWY-CRM conjugate vaccine presentation consists of two vials (lyophilized MenA and liquid MenCWY) to be reconstituted before injection. A new fully liquid, single-vial formulation has been developed to simplify administration and prevent reconstitution errors. We present pooled safety data from two randomized, controlled, observer-blind phase 2b clinical trials, in which the fully liquid presentation was compared with the licensed presentation.

METHODS

This is a post hoc analysis of two studies, in which safety data from participants aged 10-40 years who received one dose of either liquid MenACWY-CRM (1337 participants; MenACWY liquid group) or licensed MenACWY-CRM (1332 participants; MenACWY licensed group) were pooled. Frequencies were calculated for solicited adverse events (AEs) during 7 days post-vaccination and unsolicited AEs, including medically attended AEs and serious AEs (SAEs), during the 6-month safety follow-up period. Analysis results are presented by vaccine group, overall and by age category (10-17 and 18-40 years).

RESULTS

Overall, AEs solicited for collection during the first 7 days after vaccination were reported by similar percentages of participants (69.2%, MenACWY liquid; 68.2%, MenACWY licensed), and were generally mild/moderate in intensity. Solicited local AEs were reported by 46.0% of the MenACWY liquid group and 43.5% of the MenACWY licensed group and solicited systemic AEs by 55.2 and 54.1%, respectively. During the 6-month post-vaccination period, unsolicited AEs were reported by 32.2 and 31.2% of the MenACWY liquid group and MenACWY licensed group, respectively, and medically attended AEs by 18.6 and 17.3%, respectively. Overall, 14 participants in each group (1.0 and 1.1%, respectively) reported SAEs, none of which was considered vaccine-related by the investigator. The safety profiles of both MenACWY-CRM presentations were similar for each age group and overall.

CONCLUSIONS

This pooled analysis shows the safety profile of fully liquid MenACWY-CRM is comparable with that of the currently licensed vaccine presentation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT03652610 (August 29, 2018), NCT03433482 (14 February 2018).

Development of a New Solid-Phase Extraction Base Method for Free Saccharide Content Estimation of Meningococcal Conjugate Vaccines

GlaxoSmithKline (GSK) is currently developing a fully liquid presentation to ease the administration of the licensed quadrivalent conjugate vaccine (Menveo) against meningococcal serogroup A, C, W, and Y (MenACWY) infections. Herein, we report a new method for determining the free saccharide (FS) content of CRM₁₉₇-MenACWY conjugated antigens, with the aim of improving accuracy and reproducibility. Mathematical models have been used to support technical knowledge in reducing the need for experimental development. This results in an improved, faster, and platform-based technique for FS separation with one single pretreatment applicable to all antigens of the multivalent meningococcal vaccine.