Safety and Immunogenicity of SUM-101 Malaria Vaccine in Children and Infants Living in Burkina Faso

Experimental design: Phase Ib, age de-escalation and dose-escalation study. A total of 39 participants will be enrolled, consisting of healthy children (18 months-5 years) and infants (5-17 months) residing in Sabou health district or in Banfora health district, Burkina Faso. The participants will be divided into three groups. Two doses of MSP1 (25μg and 10μg) and two doses of GLA-SE (2μg and 1μg) will be evaluated.

Group 1 will be the first cohort enrolled to assess safety in children before the vaccination of infants commences. There will be no control arm, therefore, all participants in Group 1 will receive three doses of SUM-101 vaccine on D0, D28 and D56 in an open-label design.

Groups 2 and 3 will consist of the target population (infants aged 5-17 months) who will be randomised into A) a vaccine arm (12 participants) and B) a control arm (3 participants). Vaccination of Groups 2 and 3 will be conducted in a double-blinded manner. All participants in Groups 2 and 3 will receive three doses of either SUM-101 vaccine or Verorab® (rabies vaccine) on D0, D28 and D56.

Because this is the first time SUM-101 is administered to children and infants, the vaccinations will be staggered with regular safety reviews. A dose of 25μg MSP1+2μg GLA-SE will be used in children in Group 1. This choice is based on the good safety and tolerability data obtained in malaria naïve adults in Germany using this dose. Subject to favourable safety data from children, a lower dose of 10μg MSP1 with 1μg or 2μg of GLA-SE will be used in infants in Groups 2A and 3A. As an additional safety measure, the first 3 participants enrolled in Group 1 will be sentinels who will be vaccinated in an open-label manner. To ensure blinding, the first 4 participants enrolled in Groups 2 and 3 will be sentinels who will be vaccinated with either SUM-101 or control vaccine. The sentinel participants will be vaccinated one at a time (not at the same time) at least 72 hours before the remaining participants are vaccinated.

For the children cohort, the trial will be an open-label uncontrolled trial (with no control group), as the cohort of children will be used as a transition group between adults and infants. Tolerance and safety in adults have already been demonstrated in previous trials in Germany and Tanzania. The safety of the lowest dose used in adults will be evaluated in children in an open-label manner (without a control group, in a staggered fashion with a sentinel approach and a review of the data by the Data Safety Monitoring Board -DSMB-) to ensure a safe transition to the target group of the study, the infant population, where the vaccine will also be administered in a staggered fashion with a sentinel approach. Adjuvant doses are informed by safety and immunogenicity data from previous SUM-101 clinical trials and as recommended by the adjuvant manufacturer and another clinical trial (NCT04607408).

The principal investigator (PI) will review the safety data of the sentinel participants and decide whether to proceed with the vaccination of the other participants according to pre-defined safety criteria. In case of any product-related safety concerns, the decision will be made by the DSMB. The DSMB will review safety data and decide whether to transition from vaccination of children (Group 1) to infants (Group 2 and 3). Additional DSMB meetings will be scheduled at the end of the follow up period.

The duration of involvement in the study from enrolment will be approximately 24 weeks. The screening period will be approximately 4 weeks. The vaccination phase of the study takes 8 weeks for each participant, and the post-vaccination follow-up lasts for up to 12 weeks after the third vaccination.

Inclusion criteria

• Resident in the study area villages and participant's parent(s)/legal guardian anticipate being available for vaccination and follow-up for following last dose of vaccination.
• Z-score of weight-for-age within ±2SD.

Exclusion criteria

• Clinically significant skin disorder (psoriasis, contact dermatitis etc.), immunodeficiency, cardiovascular disease, respiratory disease, endocrine disorder, liver disease, renal disease, gastrointestinal disease, neurological illness, major congenital defects, malnutrition requiring hospital admission and anaemia.
• History of allergic reaction, significant IgE-mediated event, or anaphylaxis to immunisation.
• Clinically significant laboratory abnormality as judged by the study investigator.
• History of blood transfusion.
• Administration of immunoglobulins and/or any blood products within the three months preceding the planned administration of the vaccine candidate.
• Previous vaccination with experimental malaria vaccines.
• Participation in another research study/clinical trial involving receipt of an investigational medicinal product or planned use during the study period.
• Any confirmed or suspected immunosuppressive or immunodeficient state, including HIV infection (no HIV testing); asplenia; recurrent, severe infections and chronic immunosuppressant medication (For corticosteroids, this will mean prednisone, or equivalent, 0.5 mg/kg/day. Inhaled and topical steroids are allowed).
• Any significant disease, disorder or situation which, in the opinion of the Investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant´s ability to participate in the trial.