Malaria remains a major health challenge, particularly in sub-Saharan Africa, where children under five face the greatest risk of mortality. In a bid to develop effective solutions, a clinical trial in Burkina Faso assessed the safety and immunogenicity of the BK-SE36/CpG malaria vaccine in healthy adults and children.
25 October 2023
As part of the GHIT-funded SEmalvac2 project, a phase 1b clinical trial took place in Ouagadougou, Burkina Faso with 135 participants aged 21-45 years, 5-10 years, and 12-24 months receiving three vaccine doses at specific intervals. The vaccine is a recombinant blood-stage antigen, based on the Plasmodium falciparum serine repeat antigen5 (SE36), adsorbed to aluminium hydroxide gel to yield BK-SE36, and administered alongside synthetic oligodeoxynucleotides bearing CpG motifs (CpG-ODN (K3)).
This study built upon the encouraging results obtained with BK-SE36 in malaria-exposed children[1] and with BK-SE36/CpG in healthy malaria-naïve Japanese adults[2] and aimed at evaluating if CpG-ODN (K3) can improve vaccine immunogenicity in the target population.
This study found that the vaccine was safe, well tolerated and generated higher antibody titres after the third dose, with stronger immune responses observed in younger cohorts. The vaccine also predominantly elicited antibodies against peptides in intrinsically unstructured regions of SE36 which have been previously identified as protective epitopes[3]. These findings pave the way for further proof-of-concept studies to evaluate BK-SE36/CpG’s efficacy in preventing malaria.
In conclusion, the trial's outcomes suggest that the use of the CpG adjuvant could help overcome immune tolerance and that BK-SE36/CpG is well-tolerated and immunogenic, bringing us one step closer to the development of a malaria vaccine that can protect vulnerable populations in malaria-endemic regions.
Read the full manuscript:
Ouédraogo Alphonse, Bougouma Edith Christiane, Palacpac Nirianne Marie Q., Houard Sophie, Nebie Issa, Sawadogo Jean, Berges Gloria D., Soulama Issiaka, Diarra Amidou, Hien Denise, Ouedraogo Amidou Z., Konaté Amadou T., Kouanda Seni, Myoui Akira, Ezoe Sachiko, Ishii Ken J., Sato Takanobu, D’Alessio Flavia, Leroy Odile, Tiono Alfred B., Cousens Simon, Horii Toshihiro, Sirima Sodiomon B. (2023). Safety and immunogenicity of BK-SE36/CpG malaria vaccine in healthy Burkinabe adults and children: a phase 1b randomised, controlled, double-blinded, age de-escalation trial
Frontiers in Immunology ➡️ doi.org/10.3389/fimmu.2023.1267372
See more about SEMALVAC2 project: https://www.euvaccine.eu/malaria-vaccines/SEmalvac2
[1] European Vaccine Initiative. EVI [Internet]. Blood-stage malaria vaccine candidate BK-SE36 shown to be safe and immunogenic in children; 2022 Sep 5 [cited 2023 Oct 25]. Available from: https://www.euvaccine.eu/post/blood-stage-malaria-vaccine-candidate-bk-se36-shown-to-be-safe-and-immunogenic-in-children
[2] Ezoe S, Palacpac NMQ, Tetsutani K, Yamamoto K, Okada K, Taira M, Nishida S, Hirata H, Ogata A, Yamada T, Yagi M, Edula JR, Oishi Y, Tougan T, Ishii KJ, Myoui A, Horii T. First-in-human randomised trial and follow-up study of Plasmodium falciparum blood-stage malaria vaccine BK-SE36 with CpG-ODN(K3). Vaccine. 2020 Oct 27;38(46):7246-7257. doi: 10.1016/j.vaccine.2020.09.056. Epub 2020 Oct 2. PMID: 33012605.
[3] Yagi M, Bang G, Tougan T, Palacpac NM, Arisue N, Aoshi T, Matsumoto Y, Ishii KJ, Egwang TG, Druilhe P, Horii T. Protective epitopes of the Plasmodium falciparum SERA5 malaria vaccine reside in intrinsically unstructured N-terminal repetitive sequences. PLoS One. 2014 Jun 2;9(6):e98460. doi: 10.1371/journal.pone.0098460. PMID: 24886718; PMCID: PMC4041889.
This project has received funding from Global Health Innovative Technology Fund (GHIT) and Nobelpharma.
Photo credit: Photo by Gustavo Fring (www.pexels.com)