2022 |
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![]() | Dídac Macià, Joseph J. Campo, Gemma Moncunill, Chenjerai Jairoce, Augusto J. Nhabomba, Maximilian Mpina, Hermann Sorgho, David Dosoo, Ousmane Traore, Kwadwo Asamoah Kusi, Nana Aba Williams, Amit Oberai, Arlo Randall, Hèctor Sanz, Clarissa Valim, Kwaku Poku Asante, Seth Owusu-Agyei, Halidou Tinto, Selidji Todagbe Agnandji, Simon Kariuki, Ben Gyan, Claudia Daubenberger, Benjamin Mordmüller, Paula Petrone, Carlota Dobaño Strong off-target antibody reactivity to malarial antigens induced by RTS,S/AS01E vaccination is associated with protection. Journal Article In: JCI insight, vol. 7, iss. 10, 2022, ISSN: 2379-3708. Abstract | BibTeX | Tags: *Adaptive immunity, *Antigen, *Epidemiology, *Immunology, *Infectious disease, *Malaria, *Malaria Vaccines, *Malaria/prevention & control, Antibodies, Antigens, Child, Falciparum/prevention & control, Humans, Immunoglobulin G, Infant, Protozoan, Vaccination | Links: @article{nokey, The RTS,S/AS01E vaccine targets the circumsporozoite protein (CSP) of the Plasmodium falciparum (P. falciparum) parasite. Protein microarrays were used to measure levels of IgG against 1000 P. falciparum antigens in 2138 infants (age 6-12 weeks) and children (age 5-17 months) from 6 African sites of the phase III trial, sampled before and at 4 longitudinal visits after vaccination. One month postvaccination, IgG responses to 17% of all probed antigens showed differences between RTS,S/AS01E and comparator vaccination groups, whereas no prevaccination differences were found. A small subset of antigens presented IgG levels reaching 4- to 8-fold increases in the RTS,S/AS01E group, comparable in magnitude to anti-CSP IgG levels (~11-fold increase). They were strongly cross-correlated and correlated with anti-CSP levels, waning similarly over time and reincreasing with the booster dose. Such an intriguing phenomenon may be due to cross-reactivity of anti-CSP antibodies with these antigens. RTS,S/AS01E vaccinees with strong off-target IgG responses had an estimated lower clinical malaria incidence after adjusting for age group, site, and postvaccination anti-CSP levels. RTS,S/AS01E-induced IgG may bind strongly not only to CSP, but also to unrelated malaria antigens, and this seems to either confer, or at least be a marker of, increased protection from clinical malaria. | ||
2021 |
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Journal Articles |
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![]() | Yeka Adoke, Rella Zoleko-Manego, Serge Ouoba, Alfred B Tiono, Grace Kaguthi, Juv^encio Eduardo Bonzela, Tran Thanh Duong, Alain Nahum, Marielle Bouyou-Akotet, Bernhards Ogutu, Alphonse Ouedraogo, Fiona Macintyre, Andreas Jessel, Bart Laurijssens, Mohammed H Cherkaoui-Rbati, Cathy Cantalloube, Anne Claire Marrast, Rapha"el Bejuit, David White, Timothy N C Wells, Florian Wartha, Didier Leroy, Afizi Kibuuka, Ghyslain Mombo-Ngoma, Daouda Ouattara, Ir`ene Mugenya, Bui Quang Phuc, Francis Bohissou, Denise P Mawili-Mboumba, Fredrick Olewe, Issiaka Soulama, Halidou Tinto, FALCI Study Group A randomized, double-blind, phase 2b study to investigate the efficacy, safety, tolerability and pharmacokinetics of a single-dose regimen of ferroquine with artefenomel in adults and children with uncomplicated Plasmodium falciparum malaria Journal Article In: Malar. J., vol. 20, no. 1, pp. 222, 2021, ISSN: 1475-2875, (PMID: 34011358 PMCID: PMC8135182). Abstract | BibTeX | Tags: Adamantane/administration & dosage/analogs & derivatives, Adolescent, Adult, Aged, Aminoquinolines/administration & dosage, Benin, Burkina Faso, C580Y, Child, Combination treatment, Double-Blind Method, Drug Combinations, Exposure–response, Falciparum/prevention & control, Female, Ferroquine, Ferrous Compounds/administration & dosage, Gabon, Humans, Infant, Kelch-13 mutation, Kenya, Malaria, Male, Metallocenes/administration & dosage, Middle Aged, Mozambique, Parasite clearance, Peroxides/administration & dosage, Pharmacokinetics/pharmacodynamics, Plasmodium falciparum/drug effects, Preschool, resistance, Uganda, Vietnam, Vomiting, Young Adult | Links: @article{Adoke2021-el, BACKGROUND: For uncomplicated Plasmodium falciparum malaria, highly efficacious single-dose treatments are expected to increase compliance and improve treatment outcomes, and thereby may slow the development of resistance. The efficacy and safety of a single-dose combination of artefenomel (800 mg) plus ferroquine (400/600/900/1200 mg doses) for the treatment of uncomplicated P. falciparum malaria were evaluated in Africa (focusing on children $łeq$ 5 years) and Asia. METHODS: The study was a randomized, double-blind, single-dose, multi-arm clinical trial in patients aged > 6 months to 5 years and 20 Asian patients. None of the treatment arms met the target efficacy criterion for PCR-adjusted ACPR at Day 28 (lower limit of 95% confidence interval [CI] > 90%). PCR-adjusted ACPR at Day 28 [95% CI] in the PP Set ranged from 78.4% [64.7; 88.7%] to 91.7% [81.6; 97.2%] for the 400 mg to 1200 mg ferroquine dose. Efficacy rates were low in Vietnamese patients, ranging from 20 to 40%. A clear relationship was found between drug exposure (artefenomel and ferroquine concentrations at Day 7) and efficacy (primary endpoint), with higher concentrations of both drugs resulting in higher efficacy. Six distinct kelch-13 mutations were detected in parasite isolates from 10/272 African patients (with 2 mutations known to be associated with artemisinin resistance) and 18/20 Asian patients (all C580Y mutation). Vomiting within 6 h of initial artefenomel administration was common (24.6%) and associated with lower drug exposures. CONCLUSION: The efficacy of artefenomel/ferroquine combination was suboptimal in African children aged $łeq$ 5 years, the population of interest, and vomiting most likely had a negative impact on efficacy. Trial registration ClinicalTrials.gov, NCT02497612. Registered 14 Jul 2015, https://clinicaltrials.gov/ct2/show/NCT02497612?term=NCT02497612&draw=2&rank=1. | ||
![]() | Mehreen S Datoo, Magloire H Natama, Athanase Somé, Ousmane Traoré, Toussaint Rouamba, Duncan Bellamy, Prisca Yameogo, Daniel Valia, Moubarak Tegneri, Florence Ouedraogo, Rachidatou Soma, Seydou Sawadogo, Faizatou Sorgho, Karim Derra, Eli Rouamba, Benedict Orindi, Fernando Ramos Lopez, Amy Flaxman, Federica Cappuccini, Reshma Kailath, Sean Elias, Ekta Mukhopadhyay, Andres Noe, Matthew Cairns, Alison Lawrie, Rachel Roberts, Innocent Valéa, Hermann Sorgho, Nicola Williams, Gregory Glenn, Louis Fries, Jenny Reimer, Katie J Ewer, Umesh Shaligram, Adrian V S Hill, Halidou Tinto Efficacy of a low-dose candidate malaria vaccine, R21 in adjuvant Matrix-M, with seasonal administration to children in Burkina Faso: a randomised controlled trial Journal Article In: Lancet, vol. 397, no. 10287, pp. 1809–1818, 2021, ISSN: 1474-547X 0140-6736, (Copyright © 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved. PMID: 33964223 PMCID: PMC8121760). Abstract | BibTeX | Tags: Adjuvants, Burkina Faso, Double-Blind Method, Falciparum/prevention & control, Female, Hepatitis B Surface Antigens, Humans, Immunogenicity, Immunologic/administration & dosage, Infant, Malaria, Malaria Vaccines/therapeutic use, Malaria/prevention & control, Male, Nanoparticles/administration & dosage, Proportional Hazards Models, Protozoan Proteins/immunology, Saponins/administration & dosage, Treatment Outcome, Vaccine, Vaccines, Virus-Like Particle/therapeutic use | Links: @article{Datoo2021-dk, BACKGROUND: Stalled progress in controlling Plasmodium falciparum malaria highlights the need for an effective and deployable vaccine. RTS,S/AS01, the most effective malaria vaccine candidate to date, demonstrated 56% efficacy over 12 months in African children. We therefore assessed a new candidate vaccine for safety and efficacy. METHODS: In this double-blind, randomised, controlled, phase 2b trial, the low-dose circumsporozoite protein-based vaccine R21, with two different doses of adjuvant Matrix-M (MM), was given to children aged 5-17 months in Nanoro, Burkina Faso-a highly seasonal malaria transmission setting. Three vaccinations were administered at 4-week intervals before the malaria season, with a fourth dose 1 year later. All vaccines were administered intramuscularly into the thigh. Group 1 received 5 $mu$g R21 plus 25 $mu$g MM, group 2 received 5 $mu$g R21 plus 50 $mu$g MM, and group 3, the control group, received rabies vaccinations. Children were randomly assigned (1:1:1) to groups 1-3. An independent statistician generated a random allocation list, using block randomisation with variable block sizes, which was used to assign participants. Participants, their families, and the local study team were all masked to group allocation. Only the pharmacists preparing the vaccine were unmasked to group allocation. Vaccine safety, immunogenicity, and efficacy were evaluated over 1 year. The primary objective assessed protective efficacy of R21 plus MM (R21/MM) from 14 days after the third vaccination to 6 months. Primary analyses of vaccine efficacy were based on a modified intention-to-treat population, which included all participants who received three vaccinations, allowing for inclusion of participants who received the wrong vaccine at any timepoint. This trial is registered with ClinicalTrials.gov, NCT03896724. FINDINGS: From May 7 to June 13, 2019, 498 children aged 5-17 months were screened, and 48 were excluded. 450 children were enrolled and received at least one vaccination. 150 children were allocated to group 1, 150 children were allocated to group 2, and 150 children were allocated to group 3. The final vaccination of the primary series was administered on Aug 7, 2019. R21/MM had a favourable safety profile and was well tolerated. The majority of adverse events were mild, with the most common event being fever. None of the seven serious adverse events were attributed to the vaccine. At the 6-month primary efficacy analysis, 43 (29%) of 146 participants in group 1, 38 (26%) of 146 participants in group 2, and 105 (71%) of 147 participants in group 3 developed clinical malaria. Vaccine efficacy was 74% (95% CI 63-82) in group 1 and 77% (67-84) in group 2 at 6 months. At 1 year, vaccine efficacy remained high, at 77% (67-84) in group 1. Participants vaccinated with R21/MM showed high titres of malaria-specific anti-Asn-Ala-Asn-Pro (NANP) antibodies 28 days after the third vaccination, which were almost doubled with the higher adjuvant dose. Titres waned but were boosted to levels similar to peak titres after the primary series of vaccinations after a fourth dose administered 1 year later. INTERPRETATION: R21/MM appears safe and very immunogenic in African children, and shows promising high-level efficacy. FUNDING: The European & Developing Countries Clinical Trials Partnership, Wellcome Trust, and National Institute for Health Research Oxford Biomedical Research Centre. |
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