Poster Presentation First Malaria World Congress 2018

A phase Ia/b study to assess the safety and immunogenicity of placental malaria vaccine candidate: Preliminary results of the PRIMALVAC trial (#381)

Amadou T. Konate 1 , Laura Richert 2 , Arnaud Chêne 3 , Jean Philippe Semblat 3 , Gwenaelle Roguet 4 , Nadine Bernhamouda 5 , Mathilde Bahuaud 6 , Nicolas Havelange 7 , Alexis Kuppers 8 , Cecilia Campion 2 , Valérie Boilet 2 , Sonia Gueguen 8 , Pierre Loulergue 4 , Odile Leroy 7 , Frederic Batteux 6 , Eric Tartour 5 , Nicola K. Viebig 7 , Rodolphe Thiebaut 2 , Sodiomon Bienvenu Sirima 1 , Odile Launay 4 , Benoît Gamain 3
  1. Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou, KADIOGO, Burkina Faso
  2. EUCLID/F-CRIN, Université, CHU Bordeaux, INSERM, Bordeaux Population Health Research Center, UMR1219, Bordeaux, France
  3. INSERM U1134, Université Paris Diderot Sorbonne Paris-Cité, Paris, France
  4. Université Paris Descartes, Sorbonne Paris-Cité; INSERM CIC 1417; Assistance Publique Hôpitaux de Paris, CIC Cochin-Pasteur, Paris, France
  5. INSERM U970, Université Paris Descartes Sorbonne Paris-Cité, Hôpital Européen Georges Pompidou, Paris, France
  6. Université Paris Descartes, Sorbonne Paris-Cité AP-HP, Département d'Immunologie Biologique, Groupe Hospitalier Cochin Broca Hôtel-Dieu, Paris, France
  7. European Vaccine Initiative, Heidelberg, Germany
  8. INSERM PRC, Paris, France

Introduction: Adhesion of P. falciparum-infected erythrocytes (PEs) to placental chondroitin-4-sulfate (CSA) has been linked to the severe placental malaria (PM) outcomes. Evidences strongly support the VAR2CSA variant surface antigen mediating PEs CSA-binding phenotype as the leading candidate for a PM vaccine. This study was conducted to assess the safety and immunogenicity of 3 different dosages (20µg, 50µg and 100µg) of the recombinant VAR2CSA protein (PRIMVAC), formulated with Alhydrogel or GLA-SE administered at day 0, 28 and 56.

 Methods: A randomized double-blind phase Ia/Ib dose-escalation vaccine trial was conducted in healthy adult women. Within 4 sequential cohorts, volunteers were randomized to 2 arms (PRIMVAC adjuvanted with Alhydrogel or GLA-SE) in the first phase conducted in France and then to 3 arms (PRIMVAC with Alhydrogel or GLA-SE or placebo) in Burkina Faso. Enrolled volunteers were observed for at least 1 hour following each vaccination then seen at 1 day and 7 days later for safety evaluations. Serious adverse events (SAE) were recorded throughout the study duration. Routine clinical laboratory safety analyses were performed prior first injection and at each subsequent visit.

 Results: A total of 68 subjects were recruited in the four study cohorts. No SAE was reported in any of the cohort A volunteers and enrollment in cohort B started. A Data Safety Monitoring Board (DSMB) reviewed the safety data for cohorts A (20µg) and B (50µg) before the trial was initiated in Burkina Faso. The DSMB also reviewed the safety data in Burkina to authorize the progression from the cohort C (50µg) to cohort D (100µg). Last vaccination of the last subject occurred in September 2017.

 Conlusion: This was the first placental malaria vaccine trial conducted in France and Burkina. No serious adverse events have been recorded. Preliminary safety and immunogenicity results will be presented.