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Dose Escalation PfSPZ-CVac

Sanaria PfSPZ Challenge With Pyrimethamine Chemoprophylaxis (PfSPZ-CVac Approach): Phase 1 Dose Escalation Trial to Determine Safety and Development of Protective Efficacy After Exposure to Only Pre-erythrocytic Stages of Plasmodium Falciparum

Status
Completed
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03083847
Enrollment
55
Registered
2017-03-20
Start date
2017-06-05
Completion date
2019-06-26
Last updated
2021-06-01

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Malaria

Keywords

Malaria, Parasitemia, Immune, Responses, Sporozoites

Brief summary

Background: People get malaria from bites from infected mosquitos. Researchers are studying a vaccine strategy. They will give people malaria parasites by injecting them with live infectious malaria parasites with antimalarial medications and then see if this strategy prevents malaria infection while off antimalarial medications. Objective: To see if combining a high dose of live, infectious malaria parasites (known as Sanaria PfSPZ Challenge) and two FDA approved drugs that kill malaria parasites (pyrimethamine \[PYR\] OR chloroquine \[CQ\]) is safe and can provide people protection against malaria. Eligibility: Healthy adults ages 18-50 who: * are not pregnant or breastfeeding or planning on becoming pregnant while in the study * are not infected with HIV, Hepatitis B or Hepatitis C * have reliable early morning access to the NIH Clinical Center * are able to come to the outpatient clinic frequently, sometimes daily * have not been diagnosed with malaria within the past 10 years Design: * Participants will be screened with medical history and physical exam. They will have heart, blood, and urine tests. * Participants will have blood drawn for tests at most visits. * Participants will keep track of their temperature and symptoms during some sections of the study. * Participants will join one part of the study. Part 1 is one month: * Participants will get the parasites by an injection into a vein on day 1 and receive antimalarial medications. * They will have daily visits on days 7-14 * They will take another antimalarial at visits on days 15-17. * The final visit will be on day 29. Part 2 is seven months: * For the first 3 months, participants will get the parasite injection into a vein for 3 injections in total. Each injection will occur once per month while taking an antimalarial drug. * They will have daily visits on days 7-14 after the first injection, and on days 7-11 after the second and third injection. * They will have a final (fourth) injection around month 6 without any antimalarial medication. * After this fourth injection, participants may have up to 21 daily visits from day 7 after injection until end of study. Part 3 is one month: * Participants will get the parasites by injection into a vein on day 1 without antimalarial medications. * They will have visits almost every day starting day 7 from injection. * They will take an antimalarial medication when they are diagnosed with malaria * They will return for final end of study visit on days 27-29.

Detailed description

Human studies have shown that immunization by the bite Plasmodium falciparum (Pf) sporozoite(SPZ)-infected mosquitoes under drug coverage with chloroquine, an approach called chemoprophylaxis with sporozoites (CPS) or infection treatment vaccination (ITV), can provide high level, long term protection against homologous controlled human malaria infection (CHMI). The Sanaria PfSPZ chemoprophylaxis vaccination (PfSPZ CVac) approach duplicates this with an injectable SPZ regimen. In both approaches, whether mosquitoes or syringes are used for SPZ administration, when chloroquine is used as the chemoprophylactic agent, transient, limited, asexual erythrocytic stage is seen in the majority of participants. Thus the question remains whether the significant protective efficacy seen can be achieved with pre-erythrocytic (sporozoite/liver stage) exposure only. Previously, we performed a phase 1 study to investigate the safety, tolerability, immunogenicity, and protective efficacy of Sanaria PfSPZ CVac with chloroquine (sporozoites, liver, and blood stage) or pyrimethamine with chloroquine (sporozoites and liver stage only) to further describe stage specific sterile protection (NIAID protocol #15-I-0169). In this study, we demonstrated that pyrimethamine is safe to administer, well tolerated, and can prevent subpatent and patent parasitemia (qPCR and blood smear negative) 100% of the time during Sanaria PfSPZ CVac. The study also duplicated the results previously reported with Sanaria PfSPZ CVac with chloroquine in terms of safety profile and protective efficacy against homologous CHMI. Although a combination of Sanaria PfSPZ- CVac with pyrimethamine and PfSPZ Challenge at 51,200 PfSPZ did not provide a significant protection level against homologous CHMI, we demonstrated that some subjects did develop protective immunity without any evidence of blood stage exposure during PfSPZ-CVac. Building on these results and taking the lessons learned from other pre-erythrocytic vaccine studies and models that have shown the importance of reaching a minimal antigen threshold required for the development of sterile immunity, this proposed study will assess the safety, tolerability, immunogenicity, and protective efficacy of increasing the dose of Sanaria PfSPZ Challenge sporozoites while receiving the same, or, if needed to successfully prevent parasitemia, a higher dose of pyrimethamine. Unlike the first study, however, pyrimethamine will be administered by itself as the partner drug, and will not be co-administered with chloroquine. The efficacy of PfSPZ-CVac with pyrimethamine will be assessed against CHMI with homologous parasites (Arm 2a) and CHMI with heterologous parasites (Arm 2b). Additionally, we will explore the impact of increasing the dose of Sanaria PfSPZ Challenge sporozoites while receiving chloroquine alone prophylaxis. The efficacy of PfSPZ-CVac with chloroquine will be assessed only against CHMI with heterologous parasites (Arm 3), as protection against homologous parasites has now been shown in two separate trials. It will thus be possible to compare the efficacy of the two partner drugs against heterologous CHMI. The results of this study will contribute to understanding the targets and mechanisms of immunity against Pf malaria infection and how the degree of exposure to the parasite (pre-erythrocytic or erythrocytic stage only or both) impacts these responses and subsequent protective efficacy.

Interventions

Chloroquine has been widely used for treatment and prophylaxis of malaria since 1946 (Most, London et al. 1984). It was the treatment of choice for uncomplicated malaria for decades because it was safe, well tolerated, affordable and highly effective for the treatment of malaria. However, increasing spread of chloroquine- resistant Pf over the last two decades has severely limited its use (Wellems 2002). Chloroquine phosphate is U.S Food and Drug Administration (FDA) approved for suppressive treatment (prophylaxis) and for acute attacks of malaria due to P. vivax, P. malariae, P. ovale, and susceptible strains of Pf.

DRUGPyrimethamine

Pyrimethamine is a folic acid antagonist that has been commonly used as antimalarial drug for both treatment and prevention of malaria, usually in combination with sulfadoxine in adults, pregnant women, and children worldwide (Organization April 2013 (rev. January2014)

BIOLOGICALSanaria PfSPZ Challenge

Sanaria Inc has manufactured two strains of Sanaria PfSPZ Challenge: NF54 and 7G8. The Sanaria PfSPZ Challenge contains fully infectious PfSPZ purified from the salivary glands of Anopheles stephensi mosquitoes raised under aseptic conditions. The infectious PfSPZ are formulated in cryoprotectant to maintain potency for an extended period. Sanaria PfSPZ Challenge (NF54) is known to be susceptible to chloroquine, pyrimethamine, atovaquone, artesunate, but not mefloquine. Sanaria PfSPZ Challenge (7G8) is known to be susceptible to mefloquine, atovaquone, artemether and artesunate but not to chloroquine or pyrimethamine.

Sponsors

Sanaria Inc.
CollaboratorINDUSTRY
National Institute of Allergy and Infectious Diseases (NIAID)
Lead SponsorNIH

Study design

Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes

Inclusion criteria

* INCLUSION CRITERIA: * Age greater than or equal to 18 and less than or equal to 50 years. * In good general health and without clinically significant medical history * Malaria comprehension exam completed, passed (a score of greater than or equal to 80% or per investigator s discretion) and reviewed prior to enrollment * Reliable access to the clinical trial center and availability to participate for duration of study * Females of childbearing potential must be willing to use reliable contraception (as defined below) from 21 days prior to study day -2 to 28 days following last Sanaria PfSPZ Challenge exposure * Subject to the judgment and discretion of the PI, female participants who meet ANY ONE of the criteria listed immediately below, may not be required to take any additional measures to avoid pregnancy. Such participants will be counseled on risks at the time of consent and at appropriate points (e.g. when pregnancy testing occurs) during the study: * Females who have had their uterus, and/or BOTH ovaries removed * Females who have had BOTH fallopian tubes surgically 'tied' or removed * Females who are above the age of 45 and have spontaneously had no menses at any point during the past 12 or more consecutive months (i.e. have reached menopause) * Females who, in the conservative and reasonable judgment of the PI (e.g. due to sexual orientation or serious life choice (such as being celibate clergy or transgender), during the entire trial will NOT participate in any potentially reproductive sexual contact * Females who, in the conservative and reasonable judgment of the PI, are in a monogamous stable relationship with a male who has undergone vasectomy at least 4 months prior or another procedure/medical condition that deems the male sterile * Subject to the judgment and discretion of the PI, female participants who DO NOT meet ANY of the criteria listed above, will be appropriately counseled on reproductive risks and pregnancy avoidance, and will be required to adhere to the following measures and agree to 2 methods of pregnancy prevention as noted below: * CATEGORY 1: a highly effective hormonal method to prevent pregnancy \[e.g. CONSISTENT, CONTINUOUS use of contraceptive pill, patch, ring, implant or injection\], and/or IUD or equivalent * IN ADDITION TO CATEGORY 2: a barrier method to be used at the time of potentially reproductive sexual activity (e.g. \[male/female condom, 'cap,' or diaphragm\] + spermicide).

Exclusion criteria

* Currently is breast-feeding (if female). * Pregnancy as determined by a positive urine or serum human choriogonadotropin (beta- hCG) test at any point during the study (if female). * Recent travel to a malaria endemic area within 5 years of enrollment (Endemic areas are defined per the CDC website. Factors such as but not limited to use of antimalaria prophylaxis during travel, length of stay, activities during the travel, history of illnesses within 30 days of travel will be considered to determine the likelihood that the subject was exposed to malaria) * Planned travel to a malaria endemic area (as defined by the Center for Disease Control) during the study period * Reported history of confirmed malaria diagnosis on peripheral blood smear or by clinical history in the past 10 years. * Hemoglobin, WBC, platelets, ALT, and creatinine outside of local lab normal range (subjects may be included at the investigator s discretion for not clinically significant values outside of normal range) * Abnormal urinalysis as defined by positive urine glucose, protein, and red blood cells. Subject can be included if investigator determine the abnormality is not clinically significant . * BMI \< 17 or BMI \> 35 * Anticipated use during the study period, or use within the following periods prior to enrollment: * Investigational malaria vaccine within the last five years * Malaria chemoprophylaxis within 6 months * Chronic systemic immunosuppressive medications (\>14 days) within 6 months (e.g.cytotoxic medications, oral/parental corticosteroids \>0.5 mg/kg/day prednisone or equivalent). Corticosteroid nasal spray for allergic rhinitis and topical corticosteroids for mild, uncomplicated dermatitis are allowed. * Blood products or immunoglobulins within 6 months * Systemic antibiotics with antimalarial effects within 30 days (such as clindamycin, doxycycline) * Investigational or non-registered product or vaccine within 30 days * Receipt of a live vaccine within 28 days or a killed vaccine within the 14 days prior to Sanaria PfSPZ Challenge * Medications known to interact with pyrimethamine and/or chloroquine (for the main and pilot study participants ONLY), atovaquone, proguanil (ALL participants) * Reported history of: * Sickle cell disease, sickle cell trait, or other hemoglobinopathies * Splenectomy or functional asplenia * Systemic anaphylaxis * Any allergic reactions to study drugs (pyrimethamine, chloroquine) or NSAIDs, atovaquone, proguanil * Documented history of chronic or active neurologic disease (including seizures, uncontrolled migraine headaches) * Psoriasis or porphyria * Ocular diseases including retinopathy or visual field defects * Clinically significant medical condition, physical examination findings, other clinically significant abnormal laboratory results, or past medical history that may have clinically significant implications for current health status and participation in the study in the opinion of the Investigator. A clinically significant condition or process includes but is not limited to: * A process that would affect the immune response, or requires medication that affects the immune response * Any contraindication to repeated phlebotomy * A condition or process in which signs or symptoms could be confused with reactions to malaria challenge and/or infection, including dermatologic abnormalities at the site of sporozoite inoculation * A chronic or subclinical condition which could be exacerbated by administration of any of the PfSPZ-CVac components or malaria infection * History of, or known active cardiac disease including: (1) prior myocardial infarction (heart attack); (2) angina pectoris; (3) congestive heart failure; (4) valvular heart disease; (5) cardiomyopathy; (6) pericarditis; (7) stroke or transient ischemic attack; (8) exertional chest pain or shortness of breath; or ( 9) other heart conditions under the care of a doctor * Clinically significant ECG findings, as determined by the expert study cardiologist * Moderate or high risk for coronary heart disease (CHD) based on NHANES I cardiovascular risk assessment * Acute illness at the time of enrollment * Infection with HIV, Hepatitis B, Hepatitis C * Psychiatric condition that precludes compliance with the protocol including but not limited to: * Psychosis within the past 3 years * Ongoing risk for suicide, or history of suicide attempt or gesture within the past 3 years * Suspected or known current alcohol or drug abuse as defined by the American Psychiatric Association in the DSM V at the discretion of the PI * Clinical trial staff and/or Sanaria Inc. employees with direct involvement in the conduct of the trial are excluded from participation. * Participating in other clinical trials involving investigational interventions or off label medication use during the study period (excluding participation in the optional long term follow up visits). Participation in other trials such as observational or imaging studies will be discussed with the investigators. * Any other finding that, in the judgment of the Investigator, would interfere with, or serve as a contraindication to, protocol adherence, assessment of safety or reactogenicity, or a subject s ability to give informed consent, or increase the risk of having an adverse outcome from participating in the study.

Design outcomes

Primary

MeasureTime frameDescription
Number of Participants With P.Falciparum Blood Stage Infection14 days post PfSPZ Challenge injectionParticipants with P. falciparum blood stage infection defined as detection of P. falciparum parasites by qPCR (real time NIH qPCR and sensitive retrospective Laboratory of Malaria Immunology & Vaccinology (LMIV) qPCR) following Sanaria® PfSPZ Challenge (NF54) via direct venous injection (DVI).
Number of Participants Requiring Treatment With Additional Anti-malarial Medication12 days post PfSPZ Challenge injectionIncidence of a clinical malaria diagnosis occurring after PfSPZ-Cvac challenge requiring treatment with atovaquone/proguanil (Malarone).
Number of Participants With Local and Systemic Adverse Events (AEs)7 monthsParticipants who had one or more episodes of related or/and unrelated adverse events (AEs). An AE is defined as any untoward medical occurrence temporarily associated with the subject's participation in research, whether or not considered related or not. Refer to adverse event table for specific AE.
Number of Participants With Serious Adverse Events (SAEs)7 monthsParticipants who had one or more episodes of serious adverse events (SAEs). SAE is defined as a life-threatening reaction or event that results in death.

Countries

United States

Participant flow

Recruitment details

Contingency arms for a higher PYR dose (75mg instead of 50mg) were not enrolled as criteria were not met for their inclusion (50mg of PYR prevented detectable parasitemia in all enrolled arms). The PYR contingency arms that were not enrolled were labelled 1c, 1e, and 1f in the protocol.

Pre-assignment details

121 participants were screened; 55 participants were assigned to an arm; 66 participants did not meet screening criteria; one subject was consented to two arms, but started on only a control arm. Participants in each Pilot phase were independent; no participant was enrolled in more than one arm or period in either the pilot or main phases.

Participants by arm

ArmCount
Main (2a):3 Doses of 2x10^5 PfSPZ Challenge+Pyrimethamine+NF54
Main Phase - 3 monthly doses of 2x10\^5 sporozoites of PfSPZ Challenge + pyrimethamine on days 2 and 3 post injection + homologous controlled human malaria infection (CHMI) with 3.2x10\^3 PfSPZ Challenge (NF54) at 12 weeks after third injection
9
Main (2b):3 Doses of 2x10^5 PfSPZ Challenge+Pyrimethamine+7G8
Main Phase - 3 monthly doses of 2x10\^5 sporozoites of PfSPZ Challenge + pyrimethamine on days 2 and 3 post injection + heterologous CHMI with 3.2x10\^3 PfSPZ Challenge (7G8) at 12 weeks after third injection
10
Main (3):3 Doses of 2x10^5 PfSPZ Challenge+Chloroquine+7G8
Main Phase - 3 monthly doses of 2x10\^5 sporozoites of PfSPZ Challenge + weekly chloroquine (1000mg given 2 days prior to injections and 500mg given 5 days post injection and weekly thereafter until 5 days post third injection) + heterologous controlled human malaria infection (CHMI) with 3.2x10\^3 PfSPZ Challenge (7G8) at 12 weeks after third injection
10
Main Phase (4a) - Infectivity Control: NF54 (Homologous) CHMI
Main Phase - Infectivity Control with one dose of 3.2x10\^3 sporozoites of PfSPZ Challenge (NF54) (homologous) controlled human malaria infection (CHMI)
4
Main Phase (4b) - Infectivity Control: 7G8 (Heterologous) CHMI
Main Phase - Infectivity Control with 3.2x10\^3 sporozoites of PfSPZ Challenge 7G8 (heterologous) controlled human malaria infection (CHMI)
8
Pilot (1a):1 Injection of 5x10^4 PfSPZ Challenge+Pyrimethamine
Pilot Phase - 1 injection of 5x10\^4 sporozoites of PfSPZ Challenge (NF54) with 50mg of pyrimethamine dosed on days 2 and 3 after injection
2
Pilot (1b):1 Injection of 1x10^5 PfSPZ Challenge+Pyrimethamine
Pilot Phase - 1 injection of 1x10\^5 sporozoites of PfSPZ Challenge (NF54) with 50mg of pyrimethamine dosed on days 2 and 3 after injection
2
Pilot (1d):1 Injection of 2x10^5 PfSPZ Challenge+Pyrimethamine
Pilot Phase - 1 injection of 2x10\^5 sporozoites of PfSPZ Challenge (NF54) with 50mg of pyrimethamine dosed on days 2 and 3 after injection
4
Pilot (5a): 1 Injection of 1x10^5 PfSPZ Challenge+Chloroquine
Pilot Phase - 1 injection of 1x10\^5 sporozoites of PfSPZ Challenge (NF54) with 1000mg of chloroquine (loading dose) 2 days prior to injections and 500mg (maintenance dose) 5 days post injection
2
Pilot (5b): 1 Injection of 2x10^5 PfSPZ Challenge+Chloroquine
Pilot Phase - 1 injection of 2x10\^5 sporozoites of PfSPZ Challenge (NF54) with 1000mg of chloroquine (loading dose) 2 days prior to injections and 500mg (maintenance dose) 5 days post injection
4
Total55

Withdrawals & dropouts

PeriodReasonFG000FG001FG002FG003FG004FG005FG006FG007FG008FG009
MainAdverse Event0000000200
MainPhysician Decision0000010000
MainPregnancy0000000100
MainWithdrawal by Subject0000001100

Baseline characteristics

CharacteristicTotalMain (2a):3 Doses of 2x10^5 PfSPZ Challenge+Pyrimethamine+NF54Main (3):3 Doses of 2x10^5 PfSPZ Challenge+Chloroquine+7G8Main (2b):3 Doses of 2x10^5 PfSPZ Challenge+Pyrimethamine+7G8Main Phase (4a) - Infectivity Control: NF54 (Homologous) CHMIMain Phase (4b) - Infectivity Control: 7G8 (Heterologous) CHMIPilot (1a):1 Injection of 5x10^4 PfSPZ Challenge+PyrimethaminePilot (1b):1 Injection of 1x10^5 PfSPZ Challenge+PyrimethaminePilot (1d):1 Injection of 2x10^5 PfSPZ Challenge+PyrimethaminePilot (5a): 1 Injection of 1x10^5 PfSPZ Challenge+ChloroquinePilot (5b): 1 Injection of 2x10^5 PfSPZ Challenge+Chloroquine
Age, Categorical
<=18 years
0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants
Age, Categorical
>=65 years
0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants
Age, Categorical
Between 18 and 65 years
55 Participants9 Participants10 Participants10 Participants4 Participants8 Participants2 Participants2 Participants4 Participants2 Participants4 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
5 Participants1 Participants0 Participants1 Participants1 Participants1 Participants0 Participants0 Participants0 Participants1 Participants0 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
50 Participants8 Participants10 Participants9 Participants3 Participants7 Participants2 Participants2 Participants4 Participants1 Participants4 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
Asian
3 Participants0 Participants0 Participants2 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants1 Participants
Race (NIH/OMB)
Black or African American
11 Participants1 Participants3 Participants3 Participants1 Participants1 Participants1 Participants0 Participants0 Participants0 Participants1 Participants
Race (NIH/OMB)
More than one race
2 Participants1 Participants0 Participants1 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
2 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants1 Participants1 Participants0 Participants0 Participants
Race (NIH/OMB)
Unknown or Not Reported
1 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants1 Participants0 Participants
Race (NIH/OMB)
White
36 Participants7 Participants7 Participants4 Participants3 Participants7 Participants1 Participants1 Participants3 Participants1 Participants2 Participants
Sex: Female, Male
Female
25 Participants5 Participants5 Participants4 Participants2 Participants4 Participants0 Participants2 Participants2 Participants0 Participants1 Participants
Sex: Female, Male
Male
30 Participants4 Participants5 Participants6 Participants2 Participants4 Participants2 Participants0 Participants2 Participants2 Participants3 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
EG003
affected / at risk
EG004
affected / at risk
EG005
affected / at risk
EG006
affected / at risk
EG007
affected / at risk
EG008
affected / at risk
EG009
affected / at risk
deaths
Total, all-cause mortality
0 / 20 / 20 / 40 / 20 / 40 / 90 / 100 / 100 / 40 / 8
other
Total, other adverse events
2 / 22 / 23 / 42 / 24 / 48 / 99 / 1010 / 104 / 48 / 8
serious
Total, serious adverse events
0 / 20 / 20 / 40 / 20 / 40 / 90 / 102 / 100 / 40 / 8

Outcome results

Primary

Number of Participants Requiring Treatment With Additional Anti-malarial Medication

Incidence of a clinical malaria diagnosis occurring after PfSPZ-Cvac challenge requiring treatment with atovaquone/proguanil (Malarone).

Time frame: 12 days post PfSPZ Challenge injection

ArmMeasureValue (NUMBER)
Pilot (1a):1 Injection of 5x10^4 PfSPZ Challenge+PyrimethamineNumber of Participants Requiring Treatment With Additional Anti-malarial Medication0 participants
Pilot (1b): 1 Dose of 1x10^5 PfSPZ Challenge + PyrimethamineNumber of Participants Requiring Treatment With Additional Anti-malarial Medication0 participants
Pilot (1d): 1 Dose of 2x10^5 PfSPZ Challenge + PyrimethamineNumber of Participants Requiring Treatment With Additional Anti-malarial Medication0 participants
Primary

Number of Participants With Local and Systemic Adverse Events (AEs)

Participants who had one or more episodes of related or/and unrelated adverse events (AEs). An AE is defined as any untoward medical occurrence temporarily associated with the subject's participation in research, whether or not considered related or not. Refer to adverse event table for specific AE.

Time frame: 7 months

ArmMeasureValue (NUMBER)
Pilot (1a):1 Injection of 5x10^4 PfSPZ Challenge+PyrimethamineNumber of Participants With Local and Systemic Adverse Events (AEs)2 participants
Pilot (1b): 1 Dose of 1x10^5 PfSPZ Challenge + PyrimethamineNumber of Participants With Local and Systemic Adverse Events (AEs)2 participants
Pilot (1d): 1 Dose of 2x10^5 PfSPZ Challenge + PyrimethamineNumber of Participants With Local and Systemic Adverse Events (AEs)3 participants
Main (2a): 3 Doses of 2x10^5 PfSPZ + Pyrimethamine + NF54 CHMINumber of Participants With Local and Systemic Adverse Events (AEs)8 participants
Main (2b): 3 Doses of 2x10^5 PfSPZ + Pyrimethamine + 7G8 CHMINumber of Participants With Local and Systemic Adverse Events (AEs)9 participants
Main (3):3 Doses of 2x10^5 PfSPZ Challenge+Chloroquine+7G8Number of Participants With Local and Systemic Adverse Events (AEs)10 participants
Pilot (5a): 1 Injection of 1x10^5 PfSPZ Challenge+ChloroquineNumber of Participants With Local and Systemic Adverse Events (AEs)2 participants
Pilot (5b): 1 Injection of 2x10^5 PfSPZ Challenge+ChloroquineNumber of Participants With Local and Systemic Adverse Events (AEs)4 participants
Primary

Number of Participants With P.Falciparum Blood Stage Infection

Participants with P. falciparum blood stage infection defined as detection of P. falciparum parasites by qPCR (real time NIH qPCR and sensitive retrospective Laboratory of Malaria Immunology & Vaccinology (LMIV) qPCR) following Sanaria® PfSPZ Challenge (NF54) via direct venous injection (DVI).

Time frame: 14 days post PfSPZ Challenge injection

Population: Participants who received investigational product

ArmMeasureValue (NUMBER)
Pilot (1a):1 Injection of 5x10^4 PfSPZ Challenge+PyrimethamineNumber of Participants With P.Falciparum Blood Stage Infection0 Participants
Pilot (1b): 1 Dose of 1x10^5 PfSPZ Challenge + PyrimethamineNumber of Participants With P.Falciparum Blood Stage Infection0 Participants
Pilot (1d): 1 Dose of 2x10^5 PfSPZ Challenge + PyrimethamineNumber of Participants With P.Falciparum Blood Stage Infection0 Participants
Main (2a): 3 Doses of 2x10^5 PfSPZ + Pyrimethamine + NF54 CHMINumber of Participants With P.Falciparum Blood Stage Infection0 Participants
Main (2b): 3 Doses of 2x10^5 PfSPZ + Pyrimethamine + 7G8 CHMINumber of Participants With P.Falciparum Blood Stage Infection0 Participants
Primary

Number of Participants With Serious Adverse Events (SAEs)

Participants who had one or more episodes of serious adverse events (SAEs). SAE is defined as a life-threatening reaction or event that results in death.

Time frame: 7 months

ArmMeasureValue (NUMBER)
Pilot (1a):1 Injection of 5x10^4 PfSPZ Challenge+PyrimethamineNumber of Participants With Serious Adverse Events (SAEs)0 participants
Pilot (1b): 1 Dose of 1x10^5 PfSPZ Challenge + PyrimethamineNumber of Participants With Serious Adverse Events (SAEs)0 participants
Pilot (1d): 1 Dose of 2x10^5 PfSPZ Challenge + PyrimethamineNumber of Participants With Serious Adverse Events (SAEs)0 participants
Main (2a): 3 Doses of 2x10^5 PfSPZ + Pyrimethamine + NF54 CHMINumber of Participants With Serious Adverse Events (SAEs)0 participants
Main (2b): 3 Doses of 2x10^5 PfSPZ + Pyrimethamine + 7G8 CHMINumber of Participants With Serious Adverse Events (SAEs)0 participants
Main (3):3 Doses of 2x10^5 PfSPZ Challenge+Chloroquine+7G8Number of Participants With Serious Adverse Events (SAEs)2 participants
Pilot (5a): 1 Injection of 1x10^5 PfSPZ Challenge+ChloroquineNumber of Participants With Serious Adverse Events (SAEs)0 participants
Pilot (5b): 1 Injection of 2x10^5 PfSPZ Challenge+ChloroquineNumber of Participants With Serious Adverse Events (SAEs)0 participants

Source: ClinicalTrials.gov · Data processed: Feb 22, 2026