Oral Presentation 25th International Pathogenic Neisseria Conference 2026

First clinical trial results in the Phase 2/3 study of the EuBiologics pentavalent meningococcal ACWYX conjugate vaccine compared to Nimenrix® in healthy children aged 12-23-month-old in The Gambia (140654)

Howard Her 1 , Magnus Ochoge 2 , Ama Umesi 2 , Dolapo Obayemi 2 , Selasi-Esi Asase 2 , Madikoi Danso 2 , Mary Grey-Johnson 2 , Musa Alhaji-Shehu 2 , Suleiman-Idris Ahmad 2 , Kazeem Amoo 2 , Elishia Roberts 2 , Simon Donkor 2 , Fadima Cheick Haidara 3 , Milagritos D Tapia 4 , Yeong Ok Baik 1 , Chankyu Lee 1 , JinIl Kim 1 , William P Hausdorff 5 , Niles Eaton 5 , Christina Polyak 5 , Michael Raine 5 , Ryan Tuttle 5 , Yuxiao Tang 5 , Nancy Hosken 5 , Patricia Njuguna 5 , Ray Borrow 6 , Kelly Townsend-Payne 6 , Samba O Sow 3 , Ed Clarke 2
  1. R&D Division, EuBiologics Co.Ltd, Seoul, Republic of Korea
  2. Vaccines & Immunity Theme, MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, Gambia
  3. Centre pour le Développement des Vaccins , Bamako, Mali
  4. Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
  5. Center for Vaccine Innovation and Access, PATH, Seattle, USA
  6. Vaccine Evaluation Unit, UK Health Security Agency, Manchester, Greater Manchester, United Kingdom

Background

Ensuring a sustainable supply of a low-cost multivalent meningococcal conjugate vaccine is critical to eliminating meningitis epidemics - the first goal of the WHO’s Global Roadmap for Defeating Meningitis by 2030. The first pentavalent ACWYX conjugate vaccine has been licensed and is being introduced. We provide the first clinical trial results in 12-23-month-olds, for a second pentavalent ACWYX conjugate vaccine, EuNmCV-5, that employs CRM197 as a carrier in a ready-to-use liquid formulation.

Methods

A phase 2/3 trial enrolling 4,236 healthy 9-month to 29-year-old participants across 6 cohorts is being conducted in Mali and The Gambia (PACTR 202407771418605). Cohort 2 provides the first safety and immunogenicity data for EuNmCV-5 compared to a licensed MenACWY conjugate vaccine (Nimenrix®, Pfizer) in 12-23-month-old children. Solicited adverse reactions and unsolicited adverse events were collected for 7- and 28-days after vaccination, respectively. Serious adverse events were collected for 336 days. Immunogenicity, based on serum bactericidal antibodies measured using rabbit complement (rSBA), was assessed 28-days after vaccination.

Results

Between March and June 2025, 200 eligible 12-23-month-olds were randomized (1:1) and vaccinated in The Gambia. The median age of participants was 12.3 months and 91 (45.5%) were female. Overall, 1.5% and 5.0% of toddlers had an injection-site and systemic adverse event, respectively. 47% had at least one unsolicited adverse event. No notable differences were observed in safety event rates between groups. Geometric mean titres (GMTs) were low for all serogroups at baseline. At 28-days after vaccination, GMTs ranged from 7359.3 for serogroups X and Y to 2630.0 for serogroup C following EuNmCV-5 and from 5226.6 for serogroup A to 886.0 for serogroup C following MenACWY. Seroresponse rates were above 93% following EuNmCV-5 and comparable to post-MenACWY seroresponse rates. The percentage of participants with an rSBA titre of > 1:8 ranged from 93-97% following EuNmCV-5 and from 87-91% following MenACWY. A comparable picture was seen using an rSBA titre threshold of > 1:128.

If available, additional data from Cohort 3 will be presented.

Conclusions

The initial safety and immunogenicity profile for EuNmCV-5 in 12-to-23-month-olds is comparable to that of the licensed MenACWY conjugate vaccine and supports cohort progression.