Trial Outcomes & Findings for A Study to Evaluate the Efficacy, Immunogenicity and Safety in a Sporozoite Challenge Model of a Fractional Booster Dose of GSK Biologicals' Candidate Malaria Vaccine Administered to Previously Vaccinated Healthy Malaria-naïve Adults (NCT NCT03824236)

Last Updated: 2020-08-14

Results Overview

Occurrence of P. falciparum parasitemia (defined by a positive blood slide) following sporozoite challenge. Post-challenge, parasitemia was determined by microscopy of Giemsa-stained thick blood films (smear). Microscopy was performed on thick smears using a validated standard operation procedure. P. falciparum infection was defined as asexual blood stage P. falciparum parasite density greater than (\>) 0 detected by blood slide reading. For the analysis of proportion affected (relative risk), all subjects included in the analysis were considered at risk of infection and no censoring or elimination was applied for subjects not completing the entire protocol-defined post-challenge follow-up (Day 50 - 28 days post challenge).

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

61 participants

Primary outcome timeframe

During the sporozoite challenge dose follow-up period (from Day 22 up to Day 50)

Results posted on

2020-08-14

Participant Flow

Participant milestones

Participant milestones
Measure	P-Fx Group Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Overall Study STARTED	25	24	12
Overall Study COMPLETED	25	24	11
Overall Study NOT COMPLETED	0	0	1

Reasons for withdrawal

Reasons for withdrawal
Measure	P-Fx Group Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Overall Study Lost to Follow-up	0	0	1

Baseline Characteristics

A Study to Evaluate the Efficacy, Immunogenicity and Safety in a Sporozoite Challenge Model of a Fractional Booster Dose of GSK Biologicals' Candidate Malaria Vaccine Administered to Previously Vaccinated Healthy Malaria-naïve Adults

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group n=12 Participants Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.	Total n=61 Participants Total of all reporting groups
Age, Continuous	35.7 Years STANDARD_DEVIATION 10.2 • n=5 Participants	35.5 Years STANDARD_DEVIATION 10.1 • n=7 Participants	31.7 Years STANDARD_DEVIATION 10.8 • n=5 Participants	34.8 Years STANDARD_DEVIATION 10.2 • n=4 Participants
Sex: Female, Male Female	10 Participants n=5 Participants	10 Participants n=7 Participants	4 Participants n=5 Participants	24 Participants n=4 Participants
Sex: Female, Male Male	15 Participants n=5 Participants	14 Participants n=7 Participants	8 Participants n=5 Participants	37 Participants n=4 Participants
Race/Ethnicity, Customized AMERICAN INDIAN OR ALASKA NATIVE	1 Participants n=5 Participants	1 Participants n=7 Participants	0 Participants n=5 Participants	2 Participants n=4 Participants
Race/Ethnicity, Customized ASIAN	2 Participants n=5 Participants	1 Participants n=7 Participants	2 Participants n=5 Participants	5 Participants n=4 Participants
Race/Ethnicity, Customized BLACK OR AFRICAN AMERICAN	7 Participants n=5 Participants	11 Participants n=7 Participants	4 Participants n=5 Participants	22 Participants n=4 Participants
Race/Ethnicity, Customized OTHER, Not specified	0 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants	1 Participants n=4 Participants
Race/Ethnicity, Customized WHITE	15 Participants n=5 Participants	11 Participants n=7 Participants	5 Participants n=5 Participants	31 Participants n=4 Participants

PRIMARY outcome

Timeframe: During the sporozoite challenge dose follow-up period (from Day 22 up to Day 50)

Population: Analysis was performed on Per-Protocol Set which included all subjects fulfilling eligibility criteria, who received or not the Fx dose of study vaccine according to protocol, did not report any underlying medical condition influencing the efficacy response, underwent P. falciparum challenge and had available data concerning outcome measures.

Outcome measures

Outcome measures
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group n=11 Participants Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Number of Subjects Reporting Plasmodium Falciparum (P. Falciparum) Parasitemia (Defined by a Positive Blood Slide) Following Sporozoite Challenge (in All Study Groups Versus Infectivity Controls)	12 Participants	11 Participants	11 Participants

SECONDARY outcome

Timeframe: During the sporozoite challenge period starting at Day 22 (after the vaccine dose administered at Day 1), up to Day 50

For the analyses of time to onset of parasitemia (Kaplan-Meyer and log-rank), time at risk started on first day of challenge. Time at risk was censored on Day 50 (28 days post challenge), drop-out date, start date of anti-malarial treatment or date meeting an endpoint, whichever occured first. Time-at-risk was calculated as: censor date - date challenge + 1.

Outcome measures

Outcome measures
Measure	P-Fx Group n=12 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=11 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group n=11 Participants Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Time to Onset of P. Falciparum Parasitemia (Defined by a Positive Blood Slide) Following Sporozoite Challenge	14.6 Days Standard Deviation 1.9	14.1 Days Standard Deviation 1.6	11.6 Days Standard Deviation 0.9

SECONDARY outcome

Timeframe: At Day 1, prior to challenge (Day 22), 28 days post-challenge (Day 50) and at study end (Day 190)

Population: Analysis was performed on Per-Protocol Set which included all subjects fulfilling eligibility criteria, who received the Fx dose according to protocol, underwent P. falciparum challenge and had available immunogenicity data concerning outcome measures. Analysis was not performed on the Infectivity Control Group (no Fx dose being administered).

Anti-CS antibody concentrations are presented as Geometric Mean Concentrations (GMCs), expressed in Enzyme-linked immunosorbent assay Unit per milliliter (EU/mL). The cut-off for the assay was equal to 1.9 EU/mL. GMC calculations are performed by taking the inverse logarithm of the mean of the log concentration transformations. Antibody concentrations below the cut-off of the assay will be given an arbitrary value of half the cut-off of the assay for the purpose of GMC calculation.

Outcome measures

Outcome measures
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Anti- Circumsporozoite (CS) Repeat Region Antibody Concentrations Day 1	32.8 EU/mL Interval 24.5 to 44.1	7.2 EU/mL Interval 3.9 to 13.4	—
Anti- Circumsporozoite (CS) Repeat Region Antibody Concentrations Day 22	87.3 EU/mL Interval 67.0 to 113.9	37.3 EU/mL Interval 23.4 to 59.5	—
Anti- Circumsporozoite (CS) Repeat Region Antibody Concentrations Day 50	77.8 EU/mL Interval 59.5 to 101.8	25.7 EU/mL Interval 15.3 to 43.2	—
Anti- Circumsporozoite (CS) Repeat Region Antibody Concentrations Day 190	49.7 EU/mL Interval 37.7 to 65.7	12.7 EU/mL Interval 6.9 to 23.4	—

SECONDARY outcome

Timeframe: At Day 1, prior to challenge (Day 22), 28 days post-challenge (Day 50) and at study end (Day 190)

Anti-HBs IgG antibody concentrations are presented as Geometric Mean Concentrations (GMCs), expressed in milli-International Unit per milliliter (mIU/mL). The cut-off for the assay was equal to 6.2 mIU/mL. GMC calculations are performed by taking the inverse logarithm of the mean of the log concentration transformations. Antibody concentrations below the cut-off of the assay will be given an arbitrary value of half the cut-off of the assay for the purpose of GMC calculation.

Outcome measures

Outcome measures
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Anti-Hepatitis B (HBs) Immunoglobulin G (IgG) Antibody Concentrations Day 1	7788 mIU/mL Interval 4822.8 to 12576.4	6608.1 mIU/mL Interval 3147.2 to 13874.8	—
Anti-Hepatitis B (HBs) Immunoglobulin G (IgG) Antibody Concentrations Day 22	25344.5 mIU/mL Interval 16377.3 to 39221.5	29271.3 mIU/mL Interval 18417.1 to 46522.4	—
Anti-Hepatitis B (HBs) Immunoglobulin G (IgG) Antibody Concentrations Day 50	21203.1 mIU/mL Interval 14058.2 to 31979.2	19894.8 mIU/mL Interval 11569.4 to 34211.1	—
Anti-Hepatitis B (HBs) Immunoglobulin G (IgG) Antibody Concentrations Day 190	11593.9 mIU/mL Interval 7446.0 to 18052.6	9092.5 mIU/mL Interval 4652.8 to 17768.4	—

SECONDARY outcome

Timeframe: Within 7 days after vaccination (day of vaccination and 6 subsequent days) in the booster vaccination groups

Population: Analysis was performed on Intent-To-Treat Set, which included all subjects from the P-Fx and NP-Fx groups who received the Fx dose of the study vaccine and with the symptoms sheet documented.

Solicited local AEs assessed are erythema, pain and swelling. Any occurrence of AE regardless of intensity grade are reported. Any Erythema or any Swelling symptom = any symptom recorded with a surface diameter greater than 0 millimeter.

Outcome measures

Outcome measures
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Number of Subjects With Any Solicited Local Adverse Events (AEs) in the Booster Vaccination Groups Erythema	8 Participants	4 Participants	—
Number of Subjects With Any Solicited Local Adverse Events (AEs) in the Booster Vaccination Groups Pain	11 Participants	10 Participants	—
Number of Subjects With Any Solicited Local Adverse Events (AEs) in the Booster Vaccination Groups Swelling	4 Participants	4 Participants	—

SECONDARY outcome

Timeframe: Within 7 days after vaccination (day of vaccination and 6 subsequent days) in the booster vaccination groups

Solicited general AEs assessed are fatigue, gastrointestinal symptoms (nausea, vomiting, diarrhea and/or abdominal pain), headache and fever. Any occurrence of symptom regardless of intensity grade and relationship to the vaccination. Fever was defined as temperature equal or greater than 37.5 °C (preferably oral route measure).

Outcome measures

Outcome measures
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Number of Subjects With Any Solicited General AEs in the Booster Vaccination Groups Fatigue	7 Participants	4 Participants	—
Number of Subjects With Any Solicited General AEs in the Booster Vaccination Groups Gastrointestinal symptoms	2 Participants	0 Participants	—
Number of Subjects With Any Solicited General AEs in the Booster Vaccination Groups Headache	6 Participants	5 Participants	—
Number of Subjects With Any Solicited General AEs in the Booster Vaccination Groups Fever	3 Participants	0 Participants	—

SECONDARY outcome

Timeframe: Up to 21 days after booster vaccination period (day of vaccination and 20 subsequent days), after booster vaccination

Population: Analysis was performed on Intent-To-Treat Set, which included all subjects from the P-Fx and NP-Fx groups who received the Fx dose of the study vaccine.

An unsolicited adverse event is any untoward medical occurrence in a clinical investigation subject, temporally associated with use of a medicinal product, whether or not considered related to the medicinal product. An unsolicited adverse event is any event reported in addition to those solicited during the clinical study and any solicited symptom with onset outside the specified period of follow-up for solicited symptoms.

Outcome measures

Outcome measures
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Number of Subjects With Any Unsolicited AEs After Vaccination, in the Booster Vaccination Groups	5 Participants	1 Participants	—

SECONDARY outcome

Timeframe: Within 29 days after challenge (day of challenge and 28 subsequent days)

Population: Analysis was performed on Intent-To-Treat Set, which included all subjects who received at least one dose of study vaccine. All challenged infectivity controls were also included in this analysis.

An adverse event is any untoward medical occurrence in a clinical investigation subject, temporally associated with use of a medicinal product, whether or not considered related to the medicinal product.

Outcome measures

Outcome measures
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group n=12 Participants Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Number of Subjects With Any Unsolicited AEs After Challenge, in All Study Groups	19 Participants	19 Participants	12 Participants

SECONDARY outcome

Timeframe: From Day 1 up to study conclusion (Day 190)

AEs of specific interest are potential immune-mediated diseases (pIMDs) and meningitis. pIMDs are a subset of AEs that include autoimmune diseases and other inflammatory and/or neurologic disorders of interest which may or may not have an autoimmune etiology.

Outcome measures

Outcome measures
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group n=12 Participants Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Number of Subjects With AEs of Specific Interest (Potential Immune-mediated Diseases [pIMDs] and Meningitis), in All Study Groups	0 Participants	0 Participants	0 Participants

SECONDARY outcome

Timeframe: From Day 1 up to study conclusion (Day 190)

An SAE is any untoward medical occurrence that results in death, is life threatening, requires hospitalization or prolongation of hospitalization, results in disability/incapacity or is a congenital anomaly/birth defect in the offspring of a study subject.

Outcome measures

Outcome measures
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group n=12 Participants Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Number of Subjects With Serious Adverse Events (SAEs) (Any, Fatal or Related to Investigational Vaccine) During the Whole Study Period, in All Study Groups Any SAEs	2 Participants	0 Participants	0 Participants
Number of Subjects With Serious Adverse Events (SAEs) (Any, Fatal or Related to Investigational Vaccine) During the Whole Study Period, in All Study Groups Related SAEs	0 Participants	0 Participants	0 Participants
Number of Subjects With Serious Adverse Events (SAEs) (Any, Fatal or Related to Investigational Vaccine) During the Whole Study Period, in All Study Groups Fatal SAEs	0 Participants	0 Participants	0 Participants

SECONDARY outcome

Timeframe: At screening, Day(D)1, D8, D22 (day of first parasitemia) and D50 (28 days post-challenge) for the booster vaccination groups; and at screening, D22 (day of first parasitemia) and D50 (28 days post-challenge) for the infectivity control subjects

Biochemistry (Alanine Aminotransferase \[ALT\], Aspartate Aminotransferase \[AST\] and Creatinine) and hematological (Hemoglobin, Platelets, White Blood Cells \[WBC\] decrease and WBC increase) laboratory values were presented according to toxicity grading scales and tabulated by group. Grading scale adapted from FDA guidance for industry: toxicity grading scale for healthy adult and adolescent volunteers enrolled in preventive vaccine clinical trials (September 2007).

Outcome measures

Outcome measures
Measure	P-Fx Group n=25 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 Participants Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group n=12 Participants Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Number of Subjects With Abnormal Laboratory Values WBC Decrease, Day 8, Grade 1	0 Participants	1 Participants	—
Number of Subjects With Abnormal Laboratory Values ALT, Screening, Grade 0	24 Participants	23 Participants	11 Participants
Number of Subjects With Abnormal Laboratory Values ALT, Screening, Grade 1	1 Participants	1 Participants	1 Participants
Number of Subjects With Abnormal Laboratory Values ALT, Day 1, Grade 0	25 Participants	23 Participants	—
Number of Subjects With Abnormal Laboratory Values ALT, Day 1, Grade 1	0 Participants	1 Participants	—
Number of Subjects With Abnormal Laboratory Values ALT, Day 8, Grade 0	24 Participants	24 Participants	—
Number of Subjects With Abnormal Laboratory Values ALT, Day 8, Grade 1	1 Participants	0 Participants	—
Number of Subjects With Abnormal Laboratory Values ALT, Day 22, Grade 0	23 Participants	23 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values ALT, Day 22, Grade 1	2 Participants	1 Participants	0 Participants
Number of Subjects With Abnormal Laboratory Values ALT, Day 50, Grade 0	23 Participants	22 Participants	10 Participants
Number of Subjects With Abnormal Laboratory Values ALT, Day 50, Grade 1	2 Participants	2 Participants	1 Participants
Number of Subjects With Abnormal Laboratory Values AST, Screening, Grade 0	25 Participants	24 Participants	11 Participants
Number of Subjects With Abnormal Laboratory Values AST, Screening, Grade 1	0 Participants	0 Participants	1 Participants
Number of Subjects With Abnormal Laboratory Values AST, Day 1, Grade 0	24 Participants	24 Participants	—
Number of Subjects With Abnormal Laboratory Values AST, Day 1, Grade 1	1 Participants	0 Participants	—
Number of Subjects With Abnormal Laboratory Values AST, Day 8, Grade 0	24 Participants	24 Participants	—
Number of Subjects With Abnormal Laboratory Values AST, Day 8, Grade 1	1 Participants	0 Participants	—
Number of Subjects With Abnormal Laboratory Values AST, Day 22, Grade 0	25 Participants	23 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values AST, Day 22, Grade 1	0 Participants	1 Participants	0 Participants
Number of Subjects With Abnormal Laboratory Values AST, Day 50, Grade 0	25 Participants	24 Participants	10 Participants
Number of Subjects With Abnormal Laboratory Values AST, Day 50, Grade 1	0 Participants	0 Participants	1 Participants
Number of Subjects With Abnormal Laboratory Values Creatinine, Screening, Grade 0	25 Participants	24 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values Creatinine, Day 1, Grade 0	25 Participants	24 Participants	—
Number of Subjects With Abnormal Laboratory Values Creatinine, Day 8, Grade 0	25 Participants	24 Participants	—
Number of Subjects With Abnormal Laboratory Values Creatinine, Day 22, Grade 0	25 Participants	24 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values Creatinine, Day 50, Grade 0	25 Participants	24 Participants	11 Participants
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Screening, Grade 0	24 Participants	23 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Screening, Grade 1	1 Participants	1 Participants	0 Participants
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Day 1, Grade 0	25 Participants	22 Participants	—
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Day 1, Grade 1	0 Participants	2 Participants	—
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Day 8, Grade 0	25 Participants	22 Participants	—
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Day 8, Grade 1	0 Participants	2 Participants	—
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Day 22, Grade 0	23 Participants	21 Participants	10 Participants
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Day 22, Grade 1	2 Participants	2 Participants	2 Participants
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Day 22, Grade 2	0 Participants	1 Participants	0 Participants
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Day 50, Grade 0	23 Participants	22 Participants	10 Participants
Number of Subjects With Abnormal Laboratory Values Hemoglobin, Day 50, Grade 1	2 Participants	2 Participants	1 Participants
Number of Subjects With Abnormal Laboratory Values Platelets, Screening, Grade 0	24 Participants	24 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values Platelets, Screening, Grade 1	1 Participants	0 Participants	0 Participants
Number of Subjects With Abnormal Laboratory Values Platelets, Day 1, Grade 0	24 Participants	24 Participants	—
Number of Subjects With Abnormal Laboratory Values Platelets, Day 1, Grade 2	1 Participants	0 Participants	—
Number of Subjects With Abnormal Laboratory Values Platelets, Day 8, Grade 0	25 Participants	24 Participants	—
Number of Subjects With Abnormal Laboratory Values Platelets, Day 22, Grade 0	24 Participants	24 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values Platelets, Day 22, Grade 1	1 Participants	0 Participants	0 Participants
Number of Subjects With Abnormal Laboratory Values Platelets, Day 50, Grade 0	25 Participants	24 Participants	11 Participants
Number of Subjects With Abnormal Laboratory Values WBC Decrease, Screening, Grade 0	24 Participants	24 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values WBC Decrease, Screening, Grade 1	1 Participants	0 Participants	0 Participants
Number of Subjects With Abnormal Laboratory Values WBC Decrease, Day 1, Grade 0	24 Participants	22 Participants	—
Number of Subjects With Abnormal Laboratory Values WBC Decrease, Day 1, Grade 1	0 Participants	2 Participants	—
Number of Subjects With Abnormal Laboratory Values WBC Decrease, Day 1, Grade 2	1 Participants	0 Participants	—
Number of Subjects With Abnormal Laboratory Values WBC Decrease, Day 8, Grade 0	25 Participants	23 Participants	—
Number of Subjects With Abnormal Laboratory Values WBC Decrease, Day 22, Grade 0	25 Participants	24 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values WBC Decrease, Day 50, Grade 0	24 Participants	23 Participants	11 Participants
Number of Subjects With Abnormal Laboratory Values WBC Decrease, Day 50, Grade 1	1 Participants	1 Participants	0 Participants
Number of Subjects With Abnormal Laboratory Values WBC Increase, Screening, Grade 0	25 Participants	24 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values WBC Increase, Day 1, Grade 0	25 Participants	24 Participants	—
Number of Subjects With Abnormal Laboratory Values WBC Increase, Day 8, Grade 0	25 Participants	24 Participants	—
Number of Subjects With Abnormal Laboratory Values WBC Increase, Day 22, Grade 0	25 Participants	24 Participants	12 Participants
Number of Subjects With Abnormal Laboratory Values WBC Increase, Day 50, Grade 0	25 Participants	24 Participants	11 Participants

Adverse Events

P-Fx Group

Serious events: 2 serious events

Other events: 21 other events

Deaths: 0 deaths

NP-Fx Group

Serious events: 0 serious events

Other events: 22 other events

Deaths: 0 deaths

Infectivity Control Group

Serious events: 0 serious events

Other events: 12 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	P-Fx Group n=25 participants at risk Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	NP-Fx Group n=24 participants at risk Healthy subjects, between and including 18 and 55 years of age, vaccinated with RTS,S/AS01 vaccine (different doses/formulations) and not protected following the first challenge at the time of the MALARIA-092 study (NCT03162614), who received, in the current study, a fractional (Fx) booster dose of RTS,S/AS01E 12 months after completion of the vaccination course in the Malaria-092 study, and underwent sporozoite challenge.	Infectivity Control Group n=12 participants at risk Healthy subjects, between and including 18 and 55 years of age, who did not receive, in the current study, any immunization but underwent sporozoite challenge.
Injury, poisoning and procedural complications Hypobarism	4.0% 1/25 • Number of events 1 • Solicited AEs were collected within the 7-day post-booster period. Unsolicited AEs were collected within the 21-day post-booster or within the 29-day post-challenge period. SAEs were collected from Day 1 up to study conclusion (Day 190).	0.00% 0/24 • Solicited AEs were collected within the 7-day post-booster period. Unsolicited AEs were collected within the 21-day post-booster or within the 29-day post-challenge period. SAEs were collected from Day 1 up to study conclusion (Day 190).	0.00% 0/12 • Solicited AEs were collected within the 7-day post-booster period. Unsolicited AEs were collected within the 21-day post-booster or within the 29-day post-challenge period. SAEs were collected from Day 1 up to study conclusion (Day 190).
Injury, poisoning and procedural complications Injury	4.0% 1/25 • Number of events 1 • Solicited AEs were collected within the 7-day post-booster period. Unsolicited AEs were collected within the 21-day post-booster or within the 29-day post-challenge period. SAEs were collected from Day 1 up to study conclusion (Day 190).	0.00% 0/24 • Solicited AEs were collected within the 7-day post-booster period. Unsolicited AEs were collected within the 21-day post-booster or within the 29-day post-challenge period. SAEs were collected from Day 1 up to study conclusion (Day 190).	0.00% 0/12 • Solicited AEs were collected within the 7-day post-booster period. Unsolicited AEs were collected within the 21-day post-booster or within the 29-day post-challenge period. SAEs were collected from Day 1 up to study conclusion (Day 190).
Injury, poisoning and procedural complications Road traffic accident	4.0% 1/25 • Number of events 1 • Solicited AEs were collected within the 7-day post-booster period. Unsolicited AEs were collected within the 21-day post-booster or within the 29-day post-challenge period. SAEs were collected from Day 1 up to study conclusion (Day 190).	0.00% 0/24 • Solicited AEs were collected within the 7-day post-booster period. Unsolicited AEs were collected within the 21-day post-booster or within the 29-day post-challenge period. SAEs were collected from Day 1 up to study conclusion (Day 190).	0.00% 0/12 • Solicited AEs were collected within the 7-day post-booster period. Unsolicited AEs were collected within the 21-day post-booster or within the 29-day post-challenge period. SAEs were collected from Day 1 up to study conclusion (Day 190).

Other adverse events

Additional Information

GSK Response Center

GlaxoSmithKline

Phone: 866-435-7343

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee GSK agreements may vary with individual investigators, but will not prohibit any investigator from publishing. GSK supports the publication of results from all centers of a multi-center trial but requests that reports based on single site data not precede the primary publication of the entire clinical trial.
Publication restrictions are in place

Restriction type: OTHER