Immunization with different numbers of Plasmodium falciparum infected mosquito-bites under chloroquine prophylaxis

Completed

• Conditions: Plasmodium falciparum; 10037072; Malaria

• Registration Number: NL-OMON36588
• Lead Sponsor: niversitair Medisch Centrum Sint Radboud

Brief Summary

Not available

Detailed Description

Not available

Study Timeline

• Last Update Posted: 6 May 2024

Recruitment & Eligibility

• Status: Completed
• Sex: Not specified
• Target Recruitment: 30

Inclusion Criteria

1. Age > 18 and < 35 years healthy volunteers (males or females)
2. General good health based on history and clinical examination
3. Negative pregnancy test
4. Use of adequate contraception for females
5. All volunteers have to sign the informed consent form following proper understanding of the meaning and procedures of the study
6. Volunteer agrees to inform the general practitioner and agrees to sign a request for medical information concerning contra-indications for participation in the study
7. Willingness to undergo a P. falciparum sporozoite challenge
8. For volunteers not living in Leiden: agreement to stay in a hotel room close to the trial center during a part of the study (Day 5 after challenge till 3 days after treatment)
9. Reachable by mobile phone during the whole study period
10. Availability to attend all study visits
11. Agreement to refrain from blood donation to Sanquin or for other purposes, during the course of the study
12. Willingness to undergo an HIV, hepatitis B and C test
13. Negative urine toxicology screening test at screening visit and day before challenge
14. Willingness to take a prophylactic regime of chloroquine and curative regimen of Malarone

Exclusion Criteria

1. History of malaria
2. Plans to travel to malaria endemic areas during the study period
3. Previous participation in any malaria vaccine study and/or positive serology for Pf
4. Symptoms, physical signs and laboratory values suggestive of systemic disorders which could interfere with the interpretation of the study results or compromise the health of the volunteers
5. History of diabetes mellitus or cancer (except basal cell carcinoma of the skin)
6. History of arrhythmias or prolonged QT-interval
7. Positive family history in 1st and 2nd degree relatives for cardiac disease < 50 years old
8. An estimated, ten year risk of fatal cardiovascular disease of >=5%, as estimated by the Systematic Coronary Risk Evaluation (SCORE) system
9. Clinically significant abnormalities in electrocardiogram (ECG) at screening
10. Body Mass Index (BMI) below 18 or above 30 kg/m2
11. Any clinically significant deviation from the normal range in biochemistry or hematology blood tests or in urine analysis
12. Positive HIV, HBV or HCV tests
13. Participation in any other clinical study within 30 days prior to the onset of the study
14. Enrollment in any other clinical study during the study period
15. Pregnant or lactating women
16. Volunteers unable to give written informed consent
17. Volunteers unable to be closely followed for social, geographic or psychological reasons
18. Previous history of drug or alcohol abuse interfering with normal social function during a period of one year prior to enrolment in the study
19. A history of psychiatric disease
20. Known hypersensitivity to Malarone® or chloroquine
21. The use of chronic immunosuppressive drugs, antibiotics, or other immune modifying drugs within three months of study onset (inhaled and topical corticosteroids are allowed) and during the study period
22. Contra-indications to Malarone® or chloroquine including treatment taken by the volunteer that interferes with Malarone® or chloroquine
23. Any confirmed or suspected immunosuppressive or immunodeficient condition, including asplenia
24. Co-workers of the departments of Medical Microbiology, Parasitology, or Internal Medicine of the Leiden University medical Centre
25. A history of sickle cell anemia, sickle cell trait, thalassemia, thalassemia trait or G6PD deficiency

Study & Design

• Study Type: Interventional
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
<p>Primary study endpoint: Duration of prepatent period as measured by microscopy<br /><br>Other main study endpoints:<br /><br>• Parasitemia and kinetics of parasitemia as measured by PCR<br /><br>• Frequency of signs or symptoms in study groups </p><br>

Secondary Outcome Measures

Name	Time	Method
<p>• Antibody production between groups 1, 2, 3 and 4<br /><br>• Cellular immune response between groups 1, 2, 3 and 4<br /><br>• Cytokine profile in groups 1, 2, 3 and 4</p><br>