Clinical Trial for the Development of a Safe Malaria Challenge Model That Can be Reproduced in Humans

NCT00935623 | Completed Phase 1

• 2 other identifiers: WRAIR 1518HSRRB A-15209
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this study is to demonstrate that volunteers can be safely and reproducibly infected with Plasmodium vivax (P. vivax) by the bites of experimentally infected Anopheles dirus (An. dirus) mosquitoes carrying P. vivax sporozoites in their salivary glands.

Conditions

Plasmodium Vivax Malaria

Keywords

Malaria, Plasmodium vivax

Outcome Measures

Primary Outcomes (1)

• Detection of erythrocytic stage P. vivax parasites by blood smear in volunteers during the 28 day period post challenge via the bites of five P. vivax-infected mosquitoes; Occurrence and intensity of solicited and unsolicited symptoms post challenge

  28 days post challenge

Secondary Outcomes (1)

• Parasitologic and clinical infections in challenge volunteers will be characterized by descriptive analysis of prepatent and patent periods, incubation period and time to resolution of signs and symptoms, and timing and number of relapses.

  Cross-sectional

Study Arms (2)

Cohort 1

EXPERIMENTAL

The first cohort will be challenged with 5 bites from P. vivax-infected mosquitoes each carrying at least a grade 2 sporozoite infection (\>10 sporozoites in salivary gland).

Biological: Malaria Challenge

Cohort 2

EXPERIMENTAL

If the first cohort has less than 100% infectivity rate, the second cohort will be challenged with up to 10 grade 2 infective bites to ensure 100% infectivity rate.

Biological: Malaria Challenge

Interventions

Malaria Challenge BIOLOGICAL

Malaria challenge

Cohort 1; Cohort 2

Eligibility Criteria

• Age: 18 Years - 55 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy adults (male or non-pregnant, non-lactating female) 18 to 55 years of age;
• Able to provide free and willing written informed consent to participate;
• A score at least 80% correct on a 10 question Assessment of Understanding;
• No plans to travel to a malaria endemic area during the course of the study;
• Duffy positive phenotype;
• Normal (non-deficient) G6PD phenotype (range : 4.6 to 13.5 u/gm hemoglobin);
• Free of significant health problems as established by medical history and clinical examination completed prior to the study;
• Available to participate and reachable by phone for duration of study (approximately 9 months starting from screening).
• Only subjects with no or low cardiac risk factors according to the Gaziano study and a normal EKG will be included in the study

You may not qualify if:

• Pregnant or nursing at screening or plans to become pregnant or nurse from the time of enrollment until 6 months after sporozoite challenge;
• Duffy negative phenotype;
• G6PD deficiency or have any hemoglobinopathy by history;
• Past infection with any species of malaria (as demonstrated by a positive thick smear) in the last 5 years;
• History of receipt of treatment or prophylaxis for malaria during the previous 6 months;
• History of receipt of malaria vaccine within the previous 5 years;
• History of receipt of malaria challenge (being bitten by experimentally infected mosquitoes) within the previous 5 years;
• Plans to travel to malarious areas during the study period;
• History of psoriasis (given its interaction with chloroquine);
• Use of any investigational or non-registered drug or vaccine within 30 days preceding the challenge or planned use during the study period;
• Use or planned use of any drugs with significant anti-malarial activity, such as doxycycline, clindamycin, azithromycin, during the study period (volunteers can withhold the use of these medications during the study period, at the minimum starting from 4 weeks before the challenge until 4 weeks after becoming parasitemic);
• Any confirmed or suspected immunosuppressive or immunodeficient condition, including HIV infection and history of splenectomy;
• Administration of chronic (defined as more than 14 days) immunosuppressants or other immune-modifying drugs within six months of challenge;
• For corticosteroids, this is defined as prednisone, or equivalent, 0.5 mg/kg/day;
• Inhaled and topical steroids are allowed;

Sponsors & Collaborators

• U.S. Army Medical Research and Development Command: lead
• United States Department of Defense: collaborator
• Walter Reed Army Institute of Research (WRAIR): collaborator

Study Sites (1)

WRAIR Clinical Trials Center

Silver Spring, Maryland, 20910, United States

Location

MeSH Terms

Conditions

Malaria, Vivax

Condition Hierarchy (Ancestors)

Malaria; Protozoan Infections; Parasitic Diseases; Infections; Mosquito-Borne Diseases; Vector Borne Diseases

Study Officials

• Ilin Chuang, MD, MPH

  US Military Malaria Vaccine Program, Naval Medical Research Center

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: SINGLE GROUP
• Sponsor Type: FED
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 7, 2009
• First Posted: July 9, 2009
• Study Start: April 21, 2009
• Primary Completion: June 1, 2011
• Study Completion: September 1, 2011
• Last Updated: August 16, 2018

Record last verified: 2018-08

Locations

US (1)