Magnitude and durability of ProC6C-AlOH/Matrix-Mtm vaccine-induced malaria transmission-blocking antibodies in Burkinabe adults from a Phase 1 randomized trial

ProC6C is a multi-stage malaria vaccine designed to disrupt parasite transmission and prevent infection by incorporating three parasite proteins (Pfs230-Pro, Pfs48/45-6C, and CSP) in a single vaccine antigen. The Phase 1 clinical trial (PACTR202201848463189) conducted in Burkina Faso, showed ProC6C-...

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Main Authors: Mohammad Naghizadeh, Kazutoyo Miura, Ebenezer Addo Ofori, Carole Long, Issaka Sagara, Alfred B. Tiono, Jordan Plieskatt, Michael Theisen
Format: Article
Language:English
Published: Taylor & Francis Group 2025-12-01
Series:Human Vaccines & Immunotherapeutics
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Online Access:https://www.tandfonline.com/doi/10.1080/21645515.2025.2488075
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author Mohammad Naghizadeh
Kazutoyo Miura
Ebenezer Addo Ofori
Carole Long
Issaka Sagara
Alfred B. Tiono
Jordan Plieskatt
Michael Theisen
author_facet Mohammad Naghizadeh
Kazutoyo Miura
Ebenezer Addo Ofori
Carole Long
Issaka Sagara
Alfred B. Tiono
Jordan Plieskatt
Michael Theisen
author_sort Mohammad Naghizadeh
collection DOAJ
description ProC6C is a multi-stage malaria vaccine designed to disrupt parasite transmission and prevent infection by incorporating three parasite proteins (Pfs230-Pro, Pfs48/45-6C, and CSP) in a single vaccine antigen. The Phase 1 clinical trial (PACTR202201848463189) conducted in Burkina Faso, showed ProC6C-AlOH/Matrix-M was safe, well tolerated, immunogenic and generated a functional antibody response to all three constituent antigens at the primary output (D70). As magnitude and durability are central to an efficacious malaria vaccine, analysis was expanded past the initial endpoint, to determine transmission-blocking antibodies (anti-Pfs230 and anti-Pfs48/45-6C) present through D180. Analysis of transmission-reducing activity (TRA) showed 7/20 samples remained biologically active at D180. To identify immune biomarkers for high levels of TRA, the Pfs48/45-6C IgG concentration (calculated relative to the transmission-blocking mAb TB31F) was compared among TRA positive and negative individuals. The magnitude of anti-Pfs48/45-6C IgG had an excellent predictive accuracy (area under the receiver operating curve [ROC AUC] >0.8) with a threshold of 8.7 μg/ml for significant TRA. Additionally, there was significant correlation of TRA and anti-Pfs48/45 epitope I IgG concentration but not significant correlation for anti-Pfs230-Pro IgG, suggesting that vaccine-induced anti-Pfs48/45-6C IgG is the main predictor of TRA. This finding was corroborated by the observation that complement had no effect on TRA in the standard membrane feeding assay (SMFA). Collectively, these efforts confirm the transmission-blocking attributes of ProC6C and suggest that an alternative dosing regimen be evaluated in future clinical trials to improve longevity of functional transmission-reducing antibodies.
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spelling doaj-art-9cb13a91c573428da28bc23f6b3c31b12025-08-20T03:05:23ZengTaylor & Francis GroupHuman Vaccines & Immunotherapeutics2164-55152164-554X2025-12-0121110.1080/21645515.2025.2488075Magnitude and durability of ProC6C-AlOH/Matrix-Mtm vaccine-induced malaria transmission-blocking antibodies in Burkinabe adults from a Phase 1 randomized trialMohammad Naghizadeh0Kazutoyo Miura1Ebenezer Addo Ofori2Carole Long3Issaka Sagara4Alfred B. Tiono5Jordan Plieskatt6Michael Theisen7Department for Congenital Disorders, Statens Serum Institut (SSI), Copenhagen, DenmarkLaboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USADepartment for Congenital Disorders, Statens Serum Institut (SSI), Copenhagen, DenmarkLaboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USAMalaria Research and Training Center, Mali-National Institute of Allergy and Infectious Diseases International Center for Excellence in Research, University of Sciences, Techniques and Technologies of Bamako, Bamako, MaliGroupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina FasoDepartment for Congenital Disorders, Statens Serum Institut (SSI), Copenhagen, DenmarkDepartment for Congenital Disorders, Statens Serum Institut (SSI), Copenhagen, DenmarkProC6C is a multi-stage malaria vaccine designed to disrupt parasite transmission and prevent infection by incorporating three parasite proteins (Pfs230-Pro, Pfs48/45-6C, and CSP) in a single vaccine antigen. The Phase 1 clinical trial (PACTR202201848463189) conducted in Burkina Faso, showed ProC6C-AlOH/Matrix-M was safe, well tolerated, immunogenic and generated a functional antibody response to all three constituent antigens at the primary output (D70). As magnitude and durability are central to an efficacious malaria vaccine, analysis was expanded past the initial endpoint, to determine transmission-blocking antibodies (anti-Pfs230 and anti-Pfs48/45-6C) present through D180. Analysis of transmission-reducing activity (TRA) showed 7/20 samples remained biologically active at D180. To identify immune biomarkers for high levels of TRA, the Pfs48/45-6C IgG concentration (calculated relative to the transmission-blocking mAb TB31F) was compared among TRA positive and negative individuals. The magnitude of anti-Pfs48/45-6C IgG had an excellent predictive accuracy (area under the receiver operating curve [ROC AUC] >0.8) with a threshold of 8.7 μg/ml for significant TRA. Additionally, there was significant correlation of TRA and anti-Pfs48/45 epitope I IgG concentration but not significant correlation for anti-Pfs230-Pro IgG, suggesting that vaccine-induced anti-Pfs48/45-6C IgG is the main predictor of TRA. This finding was corroborated by the observation that complement had no effect on TRA in the standard membrane feeding assay (SMFA). Collectively, these efforts confirm the transmission-blocking attributes of ProC6C and suggest that an alternative dosing regimen be evaluated in future clinical trials to improve longevity of functional transmission-reducing antibodies.https://www.tandfonline.com/doi/10.1080/21645515.2025.2488075Malariavaccineantibodiesdurabilityclinical trialMatrix-M
spellingShingle Mohammad Naghizadeh
Kazutoyo Miura
Ebenezer Addo Ofori
Carole Long
Issaka Sagara
Alfred B. Tiono
Jordan Plieskatt
Michael Theisen
Magnitude and durability of ProC6C-AlOH/Matrix-Mtm vaccine-induced malaria transmission-blocking antibodies in Burkinabe adults from a Phase 1 randomized trial
Human Vaccines & Immunotherapeutics
Malaria
vaccine
antibodies
durability
clinical trial
Matrix-M
title Magnitude and durability of ProC6C-AlOH/Matrix-Mtm vaccine-induced malaria transmission-blocking antibodies in Burkinabe adults from a Phase 1 randomized trial
title_full Magnitude and durability of ProC6C-AlOH/Matrix-Mtm vaccine-induced malaria transmission-blocking antibodies in Burkinabe adults from a Phase 1 randomized trial
title_fullStr Magnitude and durability of ProC6C-AlOH/Matrix-Mtm vaccine-induced malaria transmission-blocking antibodies in Burkinabe adults from a Phase 1 randomized trial
title_full_unstemmed Magnitude and durability of ProC6C-AlOH/Matrix-Mtm vaccine-induced malaria transmission-blocking antibodies in Burkinabe adults from a Phase 1 randomized trial
title_short Magnitude and durability of ProC6C-AlOH/Matrix-Mtm vaccine-induced malaria transmission-blocking antibodies in Burkinabe adults from a Phase 1 randomized trial
title_sort magnitude and durability of proc6c aloh matrix mtm vaccine induced malaria transmission blocking antibodies in burkinabe adults from a phase 1 randomized trial
topic Malaria
vaccine
antibodies
durability
clinical trial
Matrix-M
url https://www.tandfonline.com/doi/10.1080/21645515.2025.2488075
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