Efficacy, Safety and Immunogenicity Study of GSK Biologicals' Candidate Malaria Vaccine (SB257049) Evaluating Schedules With or Without Fractional Doses, Early Dose 4 and Yearly Doses, in Children 5-17 Months of Age

GlaxoSmithKline1,500 enrolled

Overview

The study intends to establish proof of concept for a fractional dose schedule under conditions of natural exposure in children 5-17 months old at first vaccination. The study also aims to establish the role of third dose spacing in a fractional dose schedule, describe the effect of an earlier full fourth dose at Month 14 and describe the effect of multiple fractional or full yearly doses.

The current study intends to establish proof of concept (POC) for a fractional dose schedule under conditions of natural exposure. The study will be conducted in children 5-17 months old at first vaccination living in areas of mid to high malaria transmission, in line with the age group recommended by the World Health Organization (WHO) for the implementation of the RTS,S/AS01E vaccine. Results from this study will be critical in informing future possibilities for the development of vaccine-based strategies which, in combination with other interventions, may contribute to the malaria elimination agenda.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

NONE

Enrollment

1,500

Conditions

Malaria

Interventions

Eligibility

Sex: ALLMin age: 5 MonthsMax age: 17 MonthsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Participants' parent(s)/LAR(s) who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g. return for follow-up visits). * Signed or thumb-printed and witnessed informed consent obtained from the parent(s)/LAR(s) of the participant prior to performance of any study specific procedure. Where parent(s)/LAR(s) are illiterate, the consent form will be countersigned by an independent witness. * A male or female between, and including, five and 17 months of age at the time of the first vaccination. * Healthy participants as established by medical history and clinical examination before entering into the study. * Previously received three documented doses of diphtheria, tetanus, pertussis, hepatitis B vaccine (DTPHepB), and at least three doses of oral polio vaccine. Exclusion Criteria: * Child in care. * Use of a drug or vaccine that is not approved for that indication (by one of the following regulatory authorities: Food and Drug Administration \[FDA; USA\] or European Union member state or WHO \[with respect to prequalification\]) other than the study vaccines during the period starting 30 days before the first dose of study vaccines (Day -29 to Day 0), or planned use during the study period. * Any medical condition that in the judgment of the investigator would make intramuscular injection unsafe. * Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immune-modifying drugs during the period starting six months prior to the first vaccine dose. For corticosteroids, this will mean prednisone (0.5 mg/kg/day (for pediatric participants) or equivalent. Inhaled and topical steroids are allowed. * Planned administration/administration of a vaccine not foreseen by the study protocol in the period starting seven days before each dose and ending seven days after each dose of vaccine administration. * Concurrently participating in another clinical study, at any time during the study period, in which the participant has been or will be exposed to an investigational or a non-investigational vaccine/product (pharmaceutical product or device). * Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required). * Family history of congenital or hereditary immunodeficiency. * History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccines. * History of anaphylaxis post-vaccination. * History of any, or documented, serious adverse reaction to rabies vaccination. * Contraindication to rabies vaccination (Rabipur is contraindicated in participants with history of a severe hypersensitivity to any of the ingredients in the vaccine. Note that the vaccine contains polygeline and residues of chicken proteins, and may contain traces of neomycin, chlortetracycline and amphotericin B). * Major congenital defects. * Serious chronic illness. * Children with a past history of a neurological disorder or atypical febrile seizure (a febrile seizure is atypical if it meets one of the following criteria: not associated with fever; lasts \> 5 minutes; focal (not generalized); followed by transient or persistent neurological abnormality; occurs in a child \< 6 months of age). * Acute disease and/or fever at the time of enrolment. Fever is defined as temperature ≥ 37.5°C/99.5°F for oral, axillary or tympanic route, or ≥ 38.0°C/100.4°F for rectal route. Participants with a minor illness (such as mild diarrhea, mild upper respiratory infection) without fever may, be enrolled at the discretion of the investigator. * Administration of immunoglobulins and/or any blood products during the period starting three months before the first dose of study vaccine or planned administration during the study period. * Moderate or severe malnutrition at screening defined as weight for age or weight for height Z-score \< -2. * Hemoglobin concentration \< 8 g/dl at screening. * Same sex twins (to avoid misidentification). * Maternal death. * Prior receipt of an investigational malaria vaccine.

Outcomes

Primary Outcomes

Incidence of Clinical Malaria Meeting the Primary Case Definition

The primary case definition is: Plasmodium (P.) falciparum asexual parasitemia greater than (\>)5000 parasites/microliters (μl) and presence of fever (axillary temperature greater than or equal to \[≥\]37.5°C) at the time of presentation and occurring in a child who is unwell and brought for treatment to a healthcare facility. The incidence is expressed as a person year rate for each group (n/T), representing the number of events (n) reported over the risk period, which was counted in days and expressed as person years at risk (T). The objective of this endpoint was to demonstrate the superiority of a Fx012-14-mFxD Group compared to a standard schedule of RTS,S/AS01E with three full doses (R012-20+R012-14 Group) in terms of vaccine efficacy. This analysis was reported for the R012-20+R012-14 Group (Pooled group) because the interventional strategy (1st dose at Month 0, 2nd dose at Month 1, 3rd dose at Month 2) was the same for both the R012-20 group and the R012-14 group until Month 14.

Time frame: From Month 2.5 to Month 14

Secondary Outcomes

Incidence of Clinical Malaria Meeting the Primary and Secondary Case Definitions of the Fx012-14-mFxD Group Versus the R012-20 Group

The primary case definition is P. falciparum asexual parasitemia \> 5000 μl and presence of fever (axillary temperature ≥ 37.5°C) at the time of presentation and occurring in a child who is unwell and brought for treatment to a healthcare facility. The secondary case definition is P. falciparum asexual parasitemia \> 0 and presence of fever (axillary temperature ≥ 37.5°C) at the time of presentation or history of fever within 24 hours of presentation and occurring in a child who is unwell and brought for treatment to a healthcare facility. The incidence of clinical malaria for primary and secondary case definition is expressed as n/T, representing the n reported over the risk period, which was counted in days and expressed as T.

Time frame: From Month 0 to Month 50

Incidence of Clinical Malaria Meeting the Primary and Secondary Case Definitions of the Fx012-14-mFxD Group Versus the R012-14-mD Group

Time frame: From Month 0 to Month 50

The Prevalence of P. Falciparum Infections Defined by Positive Blood Slide at Each Cross-sectional Survey

Prevalence of P. falciparum infections of each RTS,S/AS01E schedule at cross-sectional visits. As specified in the statistical analysis plan, a graphical presentation of the prevalence over time was analyzed for this outcome measure and only the percentage values were reported to depict the prevalence of P. falciparum infections.

Time frame: Monthly from Month 0 to Month 20 and every 3 months thereafter until Study End (Month 50)

Incidence of P. Falciparum Infections Defined by Positive Blood Slide

The incidence of P. falciparum infections is expressed as n/T, representing the n reported over the risk period, which was counted in days and expressed as T. Assessment of vaccine efficacy (VE) against first or only episodes of incident P. falciparum infections defined by positive blood slide over the entire study period (Month 0 to Month 50) was not done after the Month 21 Interim analysis since it was assumed that almost all children would have already contracted malaria at least once.

Time frame: Month 0 to Month 14

Number of Seropositive Participants for Anti-circumsporozoite (Anti-CS) Antibodies

A seropositive participant is defined as a participant with antibody concentrations ≥ 0.5 ELISA units per milliliter (EU/mL).

Time frame: Before Dose 1, one month post-Dose 2, before and one month post-Dose 3, before and one month after Dose 4, before and one month after each yearly dose and at Study End (Month 50)

Number of Seropositive Participants for Anti-hepatitis B (Anti-HB) Antibodies

A seropositive participant is defined as a participant with antibody concentrations ≥ 10 milli-international units per milliliter (mIU/mL).

Time frame: Before Dose 1, one month post-Dose 2, before and one month post-Dose 3, before and one month after Dose 4, before and one month after each yearly dose and at Study End (Month 50)

Antibody Concentrations for Anti-CS

The antibody concentrations were calculated as geometric mean concentrations (GMCs) and expressed as EU/mL.

Time frame: Before Dose 1, one month post-Dose 2, before and one month post-Dose 3, before and one month after Dose 4, before and one month after each yearly dose and at Study End (Month 50)

Antibody Concentrations for Anti-HB

The antibody concentrations were calculated as GMCs and expressed as mlU/mL.

Time frame: Before Dose 1, one month post-Dose 2, before and one month post-Dose 3, before and one month after Dose 4, before and one month after each yearly dose and at Study End (Month 50)

Number of Participants With Any, Fatal and Related Serious Adverse Events (SAEs)

SAEs assessed included any untoward medical occurrences that resulted in death, were life-threatening, required hospitalization or prolongation of hospitalization or resulted in disability/incapacity. Related SAEs= Any SAE related to investigational vaccine or related to study participation or to a GSK concomitant medication/vaccine as assessed by the investigator. Fatal SAEs= Any SAEs leading to death.