Phase 3 Infant Safety & Immunogenicity Trial of MVA-BN® in DRC

Summary

This Phase 3 double-blinded, randomized study aims to evaluate the safety and immunogenicity of the two-dose MVA-BN mpox vaccine regimen, administered subcutaneously, in infants and children aged 4 to 24 months in the Democratic Republic of the Congo (DRC), a population at high risk of mpox infection and complications. The study will compare the safety and immunogenicity of a full-dose regimen versus a half-dose regimen in this population. A hierarchical testing strategy will be applied as follows: first, non-inferiority of the full-dose regimen in infants/children (4-24 months old) will be evaluated against the full-dose regimen in adults from the POX-MVA-045 study. If non-inferiority is demonstrated, the immunogenicity of the half dose in infants/children (4-24 months old) will subsequently be tested for non-inferiority vs the full dose in adult. The trial will be conducted in Boende, Tshuapa Province, DRC. The trial plans to enroll 344 male and female infants/children, who will be randomized to receive two doses of the MVA-BN vaccine administered 28 days apart. Participants in Child Group 1 (N=172) will receive the standard vaccine dose (0.5 mL), while those in Child Group 2 (N=172) will receive half the standard dose (0.25 mL), with both groups following the same dosing schedule. This study builds on positive safety and immunogenicity data from prior trials that support the use of the standard dose regimen in younger children. However, considering the developmental differences in the immune systems of infants and young children/adolescents, it aims to evaluate whether a half-dose regimen can provide similar immunogenicity while potentially reducing reactogenicity. The findings will offer valuable insights into the optimal dosing strategy for this age group, balancing safety and immunogenicity to inform future vaccination recommendations.

Timeline

Start

2025-05-29

Primary completion

2026-06-30

Completion

2027-05

Publications

• Background Lemey G, Lariviere Y, Zola TM, Maketa V, Matangila J, Mitashi P, Vermeiren P, Thys S, De Bie J, Muhindo HM, Ravinetto R, Van Damme P, Van Geertruyden JP. Algorithm for the support of non-related (serious) adverse events in an Ebola vaccine trial in the Democratic Republic of the Congo. BMJ Glob Health. 2021 Jun;6(6):e005726. doi: 10.1136/bmjgh-2021-005726.
• Background Zola Matuvanga T, Lariviere Y, Lemey G, De Bie J, Milolo S, Meta R, Esanga E, Vermeiren PP, Thys S, Van Geertruyden JP, Van Damme P, Maketa V, Matangila J, Mitashi P, Muhindo-Mavoko H. Setting-up an Ebola vaccine trial in a remote area of the Democratic Republic of the Congo: Challenges, mitigations, and lessons learned. Vaccine. 2022 May 31;40(25):3470-3480. doi: 10.1016/j.vaccine.2022.04.094. Epub 2022 May 9.
• Background Puri A, Pollard AJ, Schmidt-Mutter C, Laine F, PrayGod G, Kibuuka H, Barry H, Nicolas JF, Lelievre JD, Sirima SB, Kamala B, Manno D, Watson-Jones D, Gaddah A, Keshinro B, Luhn K, Robinson C, Douoguih M; EBL4001 Study Group. Long-Term Clinical Safety of the Ad26.ZEBOV and MVA-BN-Filo Ebola Vaccines: A Prospective, Multi-Country, Observational Study. Vaccines (Basel). 2024 Feb 17;12(2):210. doi: 10.3390/vaccines12020210.
• Background Lariviere Y, Zola T, Stoppie E, Maketa V, Matangila J, Mitashi P, De Bie J, Muhindo-Mavoko H, Van Geertruyden JP, Van Damme P. Open-label, randomised, clinical trial to evaluate the immunogenicity and safety of a prophylactic vaccination of healthcare providers by administration of a heterologous vaccine regimen against Ebola in the Democratic Republic of the Congo: the study protocol. BMJ Open. 2021 Sep 28;11(9):e046835. doi: 10.1136/bmjopen-2020-046835.
• Background Poland GA, Kennedy RB, Tosh PK. Prevention of monkeypox with vaccines: a rapid review. Lancet Infect Dis. 2022 Dec;22(12):e349-e358. doi: 10.1016/S1473-3099(22)00574-6. Epub 2022 Sep 15.
• Background Beeson AM, Haston J, McCormick DW, Reynolds M, Chatham-Stephens K, McCollum AM, Godfred-Cato S. Mpox in Children and Adolescents: Epidemiology, Clinical Features, Diagnosis, and Management. Pediatrics. 2023 Feb 1;151(2):e2022060179. doi: 10.1542/peds.2022-060179.
• Background Sanchez Clemente N, Coles C, Paixao ES, Brickley EB, Whittaker E, Alfven T, Rulisa S, Agudelo Higuita N, Torpiano P, Agravat P, Thorley EV, Drysdale SB, Le Doare K, Muyembe Tamfum JJ. Paediatric, maternal, and congenital mpox: a systematic review and meta-analysis. Lancet Glob Health. 2024 Apr;12(4):e572-e588. doi: 10.1016/S2214-109X(23)00607-1. Epub 2024 Feb 21.
• Background Bunge EM, Hoet B, Chen L, Lienert F, Weidenthaler H, Baer LR, Steffen R. The changing epidemiology of human monkeypox-A potential threat? A systematic review. PLoS Negl Trop Dis. 2022 Feb 11;16(2):e0010141. doi: 10.1371/journal.pntd.0010141. eCollection 2022 Feb.
• Tshilumba SM, Ruiz PM, Matuvanga TZ, Lemey G, Kimbulu P, Azoum MA, Salloum M, Kasereka G, Mitashi F, Bikioli F, Muteba D, Bisumba A, Van Damme P, Muhindo-Mavoko H, Jordan E, Van Geertruyden JP, Maketa V, Mitashi P, Lariviere Y. Protocol for a phase 3, randomized, double-blind clinical trial evaluating the safety and immunogenicity of the MVA-BN(R) vaccine against mpox in children aged 4 to less than 24 months in the Democratic Republic of the Congo: Data to guide future paediatric vaccination strategies. Vaccine. 2026 Jun 29;89:128890. doi: 10.1016/j.vaccine.2026.128890. Online ahead of print.

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