A Phase 1 interventional study of Plasmodium falciparum malaria parasite in Malaria,Falciparum, sponsored by U.S. Army Medical Research and Development Command. Completed at 1 site in United States. Open to participants aged 18 Years to 50 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2021-03-30.
Sponsored by U.S. Army Medical Research and Development Command · Phase 1, Interventional, and Screening
Objectives:
Primary:
Secondary:
This is a single center, open label CHMI study. CHMI will consist of exposure to Plasmodium falciparum sporozoites through the bites of infected mosquitoes. After the challenge, subjects will be evaluated daily for the development of malaria infection using a blood smear. Unless previously diagnosed and fully treated, subjects will be required to stay in a hotel for a maximum of 12 nights starting on or around the evening of Day 7 post challenge.
All subjects diagnosed with malaria infection based on smears will be prescribed a standard malaria treatment regimen to begin on the day that parasitemia is detected. Subjects who do not become parasitemic (via smear) by Day 19 will be empirically treated for malaria.
After the hotel phase, all challenged subjects will have a final scheduled follow-up visit on Day 28 (±7 days).
1,299 studies on the registry are indexed under Malaria; 86 are open to participants now.
This study's enrollment of 12 is below the median of 220 across 1,027 interventional studies indexed under Malaria.
Browse Malaria studies →U.S. Army Medical Research and Development Command is the lead sponsor of 151 studies on the registry; 8 are open to participants now.
Of its 23 completed or terminated interventional studies of FDA-regulated products, 16 (70%) have results posted.
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To be eligible for this study, you must meet ALL of the following conditions:
Exclusion Criteria:
You must not have any of the following:
Controlled Human Malaria Infection (CHMI) will consist of exposure to Plasmodium falciparum sporozoites through the bites of infected mosquitoes. Beginning 5 days after the challenge, subjects will be evaluated daily for the development of malaria infection using a blood smear.
Biological: Plasmodium falciparum malaria parasite
Laboratory cultured Plasmodium falciparum strain 3D7 delivered via the bite of 5 infected mosquitoes with salivary gland scores of at least 2+ (11-100 sporozoites observed).
To Characterize the Infectivity of a New Lot of Plasmodium Falciparum Strain 3D7 Developing Parasitemia Within the Standard WRAIR CHMI Model.
Number of challenged subjects exposed to the new lot of Plasmodium falciparum strain 3D7 parasites developing parasitemia (defined as 2 unambiguous malaria parasites on a single smear).
Time frame: Within 2 weeks
Diagnostic Efficacy; Time to Parasitemia by Blood Smear Method After the P Falciparum Challenge
Time to parasitemia by blood smear method after the P falciparum challenge. Time to parasitemia is defined as the time from CHMI to a first positive malaria parasite result. Parasitemia was defined as the presence of 2 unambiguous malaria parasites on a single smear. Beginning on Day 1 after their challenge, subjects were seen and evaluated daily by a study investigator and blood was drawn for determination of parasitemia by qPCR. Beginning on Day 5 and through Day 19 after their challenge, blood from these daily draws was utilized to generate blood smears to evaluate the development of malaria infection. In addition to smears, subjects were also evaluated for the presence of parasitemia via qPCR. In addition to smears, subjects were also evaluated for the presence of parasitemia via qPCR. However, only blood smears were used for diagnosis during this trial and evaluation of treatment success.
Time frame: Within 2-3 weeks
Diagnostic Efficacy; Time to Parasitemia (Days) by qPCR Method After the P Falciparum Challenge
Time to parasitemia by qPCR method after the P falciparum challenge. Time to parasitemia is defined as the time from CHMI to a first positive malaria parasite result. Parasitemia was defined as the presence of 2 unambiguous malaria parasites on a single smear. On Day 0, subjects were evaluated by qPCR once prior to challenge, to establish a baseline. Beginning on Day 1 through Day 19 after their challenge, subjects were seen and evaluated daily by a study investigator and blood was drawn for determination of parasitemia by qPCR. Beginning on Day 5 and going through Day 19 after their challenge, blood from these daily draws was utilized to generate blood smears to evaluate the development of malaria infection. In addition to smears, subjects were also evaluated for the presence of parasitemia via qPCR. However, only blood smears were used for diagnosis during this trial and evaluation of treatment success.
Time frame: Within 2-3 weeks
Diagnostic Efficacy; Quantification of Parasite Clearance Time (PCT) by Blood Smear and qPCR Methods After Initiation of Antimalarial Treatment
Time to Clearance was determined for all subjects for both smear and qPCR. Time to Clearance was defined as the time (in Days) from malaria diagnosis to confirmed clearance of parasitemia. Confirmed clearance of parasitemia by malaria smear was defined as the observation of 3 sequential negative (no parasites observed) daily smears. Confirmed clearance of parasitemia by qPCR was defined as 2 sequential daily (approximately 24 hours apart) negative qPCR assay results. For clarity, the day of the final test in each sequence (smear, PCR) was used as the day of confirmed clearance for calculation purposes.
Time frame: Within 6 weeks
| Milestone | Infective Controls |
|---|---|
| Started | 12 |
| Completed | 12 |
| Not completed | 0 |
Number of challenged subjects exposed to the new lot of Plasmodium falciparum strain 3D7 parasites developing parasitemia (defined as 2 unambiguous malaria parasites on a single smear).
| Participants | Infective Controls |
|---|---|
| 9 Days post-challenge | 0 |
| 10 Days post-challenge | 1 |
| 11 Days post-challenge | 5 |
| 12 Days post-challenge | 5 |
| 13 Days post-challenge | 0 |
| 14 Days post-challenge | 1 |
Time to parasitemia by blood smear method after the P falciparum challenge. Time to parasitemia is defined as the time from CHMI to a first positive malaria parasite result. Parasitemia was defined as the presence of 2 unambiguous malaria parasites on a single smear. Beginning on Day 1 after their challenge, subjects were seen and evaluated daily by a study investigator and blood was drawn for determination of parasitemia by qPCR. Beginning on Day 5 and through Day 19 after their challenge, blood from these daily draws was utilized to generate blood smears to evaluate the development of malaria infection. In addition to smears, subjects were also evaluated for the presence of parasitemia via qPCR. In addition to smears, subjects were also evaluated for the presence of parasitemia via qPCR. However, only blood smears were used for diagnosis during this trial and evaluation of treatment success.
| days | Infective Controls |
|---|---|
| Diagnostic Efficacy; Time to Parasitemia by Blood Smear Method After the P Falciparum Challenge | 11.6 ± 1.00 |
Time to parasitemia by qPCR method after the P falciparum challenge. Time to parasitemia is defined as the time from CHMI to a first positive malaria parasite result. Parasitemia was defined as the presence of 2 unambiguous malaria parasites on a single smear. On Day 0, subjects were evaluated by qPCR once prior to challenge, to establish a baseline. Beginning on Day 1 through Day 19 after their challenge, subjects were seen and evaluated daily by a study investigator and blood was drawn for determination of parasitemia by qPCR. Beginning on Day 5 and going through Day 19 after their challenge, blood from these daily draws was utilized to generate blood smears to evaluate the development of malaria infection. In addition to smears, subjects were also evaluated for the presence of parasitemia via qPCR. However, only blood smears were used for diagnosis during this trial and evaluation of treatment success.
| days | Infective Controls |
|---|---|
| Diagnostic Efficacy; Time to Parasitemia (Days) by qPCR Method After the P Falciparum Challenge | 7.3 ± 0.65 |
Time to Clearance was determined for all subjects for both smear and qPCR. Time to Clearance was defined as the time (in Days) from malaria diagnosis to confirmed clearance of parasitemia. Confirmed clearance of parasitemia by malaria smear was defined as the observation of 3 sequential negative (no parasites observed) daily smears. Confirmed clearance of parasitemia by qPCR was defined as 2 sequential daily (approximately 24 hours apart) negative qPCR assay results. For clarity, the day of the final test in each sequence (smear, PCR) was used as the day of confirmed clearance for calculation purposes.
| days | Infective Controls |
|---|---|
| Blood smear Method | 1.2 ± 0.39 |
| qPCR method | 3.0 ± 0.60 |
Collected over Day 1 through Day 35. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Infective Controls | 0/12 (0%) | 0/12 (0%) | 12/12 (100%) |
| Event | Infective Controls |
|---|---|
| MalariaInfections and infestations | 12/12 |
| Administration site pruritusGeneral disorders | 8/12 |
| HeadacheNervous system disorders | 4/12 |
| FatigueGeneral disorders | 2/12 |
| PyrexiaGeneral disorders | 2/12 |
| DiarrheaGastrointestinal disorders | 2/12 |
| TachycardiaCardiac disorders | 2/12 |
| Administration site erythemaGeneral disorders | 1/12 |
| MyalgiaMusculoskeletal and connective tissue disorders | 1/12 |
| Oropharyngeal painRespiratory, thoracic and mediastinal disorders | 1/12 |
Healthy, malaria-naïve adults (males and non-pregnant, non-lactating females), aged 18 to 50 years old (inclusive) were recruited from the Washington/ Baltimore DC metropolitan area to participate in this Controlled Human Malaria Infection (CHMI) study. Up to 12 subjects were enrolled (defined as having undergone malaria challenge) into this trial. All 12 subjects were challenged with the new lot of female Anopheles mosquitoes infected with Plasmodium falciparum strain NF54 (clone 3D7), lot 1887
| Age, Customized(years) | Infective Controls |
|---|---|
| Age | 28.7 ± 7.73 |
| Sex: Female, Male(Participants) | Infective Controls |
|---|---|
| Female | 5 |
| Male | 7 |
| Ethnicity (NIH/OMB)(Participants) | Infective Controls |
|---|---|
| Hispanic or Latino | 3 |
| Not Hispanic or Latino | 9 |
| Unknown or Not Reported | 0 |
| Race (NIH/OMB)(Participants) | Infective Controls |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 1 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 3 |
| White | 7 |
| More than one race | 1 |
| Unknown or Not Reported | 0 |
| Region of Enrollment(participants) | Infective Controls |
|---|---|
| United States | 12 |
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U.S. Army Medical Research and Development Command