Dose Escalation, Randomized Controlled Trial to Evaluate the Safety, Immunogenicity and Efficacy of Intravenously Administered Attenuated Plasmodium Falciparum Sporozoite Vaccine (PfSPZ Vaccine) in Tanzanian Adults
Malaria, Plasmodium Falciparum Malaria
About this trial
This is an interventional prevention trial for Malaria focused on measuring Malaria, Plasmodium falciparum malaria, PfSPZ Vaccine, PfSPZ Challenge, Controlled human malaria infection (CHMI)
Eligibility Criteria
Inclusion Criteria:
- Healthy male aged between 18 - 35 years.
- Good health status based on history and clinical examination.
- Long term or permanent resident in or near Dar-es-Salaam.
- Able and willing to complete the study visit schedule over the one year follow up period, including the hospitalizations required for protocol compliance.
- Able and willing to complete the informed consent process conducted in English.
- Demonstrate understanding of the study and procedures by answering 20 questions from the Protocol & Study Procedures Understanding Checklist correctly with a maximum of two attempts.
- Agrees to inform study doctor of medical conditions and contraindications for participation in the study.
- Agrees to provide contact information to the study team for a household member who will serve as an emergency contact during trial participation.
- Willing to be attended by a study doctor and take medications, which may be prescribed by a study doctor, during study participation.
- Reachable (24/7) by mobile phone during the whole study period.
- Agrees not to participate in another study during the study period.
- Agrees not to donate blood during the study period.
- Willing to undergo HIV, hepatitis B and hepatitis C testing.
- Willing to undergo controlled human malaria infection (CHMI).
Exclusion Criteria:
- History of malaria in the past 5 years.
- Positive for malaria by thick blood smear at screening.
- Plans to travel outside the Dar-es-Salaam or Coast Region in first 12 months of the study.
- Previous receipt of an investigational malaria vaccine.
- Antibodies to parasites or selected parasite protein(s) above acceptable cut off established for the site
- History of arrhythmias or prolonged QT-interval or other cardiac disease or clinically significant abnormalities in electrocardiogram (ECG) at screening.
- History or indication of a history of drug or alcohol abuse interfering with normal social function.
- Use of chronic immunosuppressive drugs, antibiotics, or other immune modifying drugs within three months of study enrollment (inhaled and topical corticosteroids are allowed).
- Ongoing condition that could interfere with the interpretation of the study results or compromise the health of the volunteer.
- History of diabetes mellitus or cancer.
- Body Mass Index (BMI) below 18 or above 30 kg/m2.
- Any clinically significant deviation from the normal range in biochemistry or hematology blood tests or in urine analysis or electrolytes.
- Positive HIV, Hepatitis B virus or Hepatitis C virus tests.
- Participation in any other clinical study within 30 days prior to study enrollment.
- Known hypersensitivity, allergy, or other contra-indications to Coartem® or Malarone® including treatment taken by the volunteer that interferes with Coartem® or Malarone®.
- Any confirmed or suspected immunosuppressive or immunodeficient condition, including asplenia.
- Heterozygous or homozygous for sickle cell or homozygous for alpha thalassemia.
- Glucose-6-phosphate dehydrogenase deficiency
- Psychiatric condition that precludes compliance with the protocol; past or present psychoses; disorder requiring lithium; or within five years prior to enrollment, history of suicide plan or attempt.
- Any medical, psychiatric, social condition, or occupational reason that, in the judgment of the investigator, is a contraindication to protocol participation or impairs the volunteer's ability to give informed consent, increases the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study or impair interpretation of the study data.
- History of 3 or more other immunizations within the six months before administration of the first dose of vaccine.
- Clinically active tuberculosis
Sites / Locations
- Bagamoyo Research and Training Center, Ifakara Health Institute, Kingani Estate, PO Box 74
Arms of the Study
Arm 1
Arm 2
Arm 3
Arm 4
Arm 5
Arm 6
Arm 7
Experimental
Experimental
Placebo Comparator
Experimental
Placebo Comparator
Experimental
Placebo Comparator
Group 1
Group 2(A)
Group 2(B)
Group 3(A)
Group 3(B)
Group 4
Group 5
Three volunteers will receive 3 ascending doses of PfSPZ Vaccine by IV administration four weeks apart. The three doses are 3x10^4, 1.35x10^5, and 2.7x10^5 PfSPZ. This is the safety group that will be inoculated first before all others for demonstration of safety and will be followed up for assessment of safety after the completion of the three doses. The follow up will be at weeks 1, 2, 4, 8 and 24 after completion of vaccination. Volunteers in Group 1 will not undergo CHMI. Group 1 is unblinded.
Group 2: Two sub groups: 2A and 2B. Grp 2A (n=20) receives 5 vaccinations IV of 1.35x10^5 PfSPZ Vaccine; 4 doses at 4 wk intervals; 5th dose at 8 wks after 4th dose. Grp 2 starts 1 wk after Grp 1 has completed 2nd dose; and received clearance from Safety Monitoring Committee (SMC). Grp 2 starts with 4 volunteers (3 safety + 1 placebo control to maintain blinding) receiving their first doses (at each dosing time point) before the remaining 20 volunteers in Grp 2. The remaining 20 volunteers start inoculations 48 hrs after first 4 safety volunteers at each dosing time point. Three weeks after last immunization, Grp 2 will undergo the first CHMI by IV injection of 3.2x10^3 PfSPZ Challenge (NF54). 24 weeks after the last immunization, volunteers from Grp 2 who underwent the first CHMI and did not become infected will have a second CHMI by IV injection of 3.2x10^3 PfSPZ Challenge (NF54).
Group 2: Two sub groups: 2A and 2B. Grp 2B (n=4) receives 5 placebo injections of normal saline (NS) by IV administration; 4 doses at 4 wk intervals; 5th dose at 8 wks after 4th dose. Grp 2 starts 1 wk after Grp 1 has completed 2nd dose; and received clearance from Safety Monitoring Committee (SMC). Grp 2 starts with 4 volunteers (3 safety + 1 placebo control to maintain blinding) receiving their first doses (at each dosing time point) before the remaining 20 volunteers in Grp 2. The remaining 20 volunteers start inoculations 48 hrs after first 4 safety volunteers at each dosing time point. Three weeks after last placebo injection, Grp 2 will undergo the first CHMI by IV injection of 3.2x10^3 PfSPZ Challenge (NF54).
Group 3: Two sub groups: 3A and 3B. Grp 3A (n=20) receives 5 vaccinations IV of 2.7x10^5 PfSPZ Vaccine; 4 doses at 4 wk intervals; 5th dose at 8 wks after 4th dose. Grp 3 starts 1 wk after Grp 1 has completed 3rd dose; and received clearance from Safety Monitoring Committee (SMC). Grp 3 starts with 4 volunteers (3 safety + 1 placebo control to maintain blinding) receiving their first doses (at each dosing time point) before the remaining 20 volunteers in Grp 3. The remaining 20 volunteers start inoculations 48 hrs after first 4 safety volunteers at each dosing time point. Three weeks after last immunization, Grp 3 will undergo the first CHMI by IV injection of 3.2x10^3 PfSPZ Challenge (NF54). 24 weeks after the last immunization, volunteers from Grp 3 who underwent the first CHMI and did not become infected will have a second CHMI by IV injection of 3.2x10^3 PfSPZ Challenge (NF54).
Group 3: Two sub groups: 3A and 3B. Grp 3B (n=4) receives 5 placebo injections of normal saline (NS) by IV administration; 4 doses at 4 wk intervals; 5th dose at 8 wks after 4th dose. Grp 3 starts 1 wk after Grp 1 has completed 3rd dose; and received clearance from Safety Monitoring Committee (SMC). Grp 3 starts with 4 volunteers (3 safety + 1 placebo control to maintain blinding) receiving their first doses (at each dosing time point) before the remaining 20 volunteers in Grp 3. The remaining 20 volunteers start inoculations 48 hrs after first 4 safety volunteers at each dosing time point. Three weeks after last placebo injection, Grp 3 will undergo the first CHMI by IV injection of 3.2x10^3 PfSPZ Challenge (NF54).
The fourth group will include 6 volunteers who will be unblinded and will receive 5 vaccinations of 2.7 x 10^5 PfSPZ Vaccine by IV administration. Four vaccinations at 4 weeks intervals of 2.7x10^5 PfSPZ will be given and the fifth dose will be administered 8 weeks after the 4th. Volunteers from Group 4 will start their vaccinations 48 hours after the four safety volunteers from Group 3 have received their first dose, at each dosing time point. This group will participate in only one CHMI assessment at 24 weeks to assess duration of protection at 24 weeks.
The 5th group will be divided into 3 sub groups 5A, 5B, 5C, who will be screened and recruited to serve as unblinded controls for the 1st and 2nd CHMI at 3 and 24 weeks. They will participate only in the screening and 4 weeks follow up of the 1st and 2nd CHMI assessments. Group 5A (n=2) will be challenged at the time of the 3-week CHMI of Group 2. Group 5B (n=2) will be challenged at the time of the 3-week CHMI of Group 3. Groups 5A and 5B will supplement the 4 NS- injected volunteers as infectivity controls, totaling 6 altogether. Group 5C (n=6) will be challenged at the time of the 24-week CHMI for Groups 3 and 4.