Last updated on December 2016

Safety Tolerability and Immunogenicity of PfSPZ Vaccine in an Age De-escalation Trial in Equatorial Guinea.


Brief description of study

This trial will evaluate the safety, tolerability, and immunogenicity of PfSPZ Vaccine in healthy Equatoguinean adults, adolescents, children and infants who receive doses of 0.9x10^6, 1.8x10^6 or 2.7x10^6 PfSPZ Vaccine via direct venous inoculation (DVI) compared with control groups receiving normal saline (NS) placebo by DVI. In addition, the study will also assess a second PfSPZ-based vaccination approach known as PfSPZ-CVac- the administration of non-irradiated, infectious PfSPZ (PfSPZ Challenge) (1x10^5 PfSPZ) under anti-malarial chemoprophylaxis (chloroquine) in younger adults ages 18 to 35 years for safety, tolerability, immunogenicity and efficacy against controlled human malaria infection (CHMI).

Detailed Study Description

EGSPZV2 is a single center, double-blind, placebo-controlled trial. The study is to take place at the Baney Temporary Research Facility (BTRF) located in Baney City. One hundred and thirty-five healthy male and female; adults, adolescents, children and infant volunteers, aged from 6 months to 65 years who live in the Baney district and Malabo city on Bioko Island will be enrolled based on pre-defined inclusion and exclusion criteria implemented according to international ethical standards. The trial will consist of seven groups (Group 1a: younger adults, ages 18-35; Group 2: older adults, ages 36-65; Group 3: adolescents, ages 11-17; Group 4: older children, ages 6-10; Group 5: younger children, ages 1-5; Groups 6a/b: infants, ages 6 months - 11 months) of volunteers. Vaccination will begin in Group 1a (younger adults), with three doses of 2.7x10^6 PfSPZ Vaccine given eight weeks apart by DVI. An eighth group (Group 1b: younger adults, ages 18- 35), will be uniquely immunized with the comparator vaccine PfSPZ Challenge given under chloroquine prophylaxis (PfSPZ-CVac approach), rather than with PfSPZ Vaccine. A single PfSPZ-CVac younger adult group (group 1b) is included to provide a direct comparison with PfSPZ Vaccine (group 1a) for the ability to protect against CHMI. Each of the first two groups (1a and 1b) will have 20 participants receiving either PfSPZ Vaccine or PfSPZ Challenge and 6 participants receiving NS placebo by DVI, with treatment allocation randomized and double-blind. Volunteers in Group 1b will receive vaccinations 8 weeks after the initial vaccination of Group 1a. Volunteers in Group 1 (younger adults) will receive CHMI between 10 and 14 weeks post last vaccination (with a window of +/- 7 days on each side) and will be followed for 8 weeks following CHMI. Group 2 (older adults) will receive three doses of 2.7x10^6 PfSPZ Vaccine. Group 2 will consist of 12 participants receiving PfSPZ Vaccine and 4 participants receiving NS placebo by DVI, given eight weeks apart. Group 3, 4, 5 and 6b will each have 12 participants receiving three doses of 1.8x10^6 PfSPZ Vaccine and 4 participants receiving NS, also given eight weeks apart. Group 6a will consist of 3 volunteers who will receive a single dose of 9.0 x10^5 PfSPZ Vaccine. Sequential age groups will be staggered to allow assessment of safety and tolerability before further age de-escalation. To assure safety, vaccinations will start in younger adults and will progress to younger and older age groups using staggered start dates at approximately weekly intervals. Age escalation and initial age de-escalation will take place at the same time, hence Group 2 and 3 will be vaccinated at the same time. Progressively younger age groups will then be immunized. The decision to proceed with each of these steps will be made by the study team after a review of safety data from the previously vaccinated group(s). Three Safety Monitoring Committee (SMC) meetings are scheduled to review data prior to initiating the younger children and infant groups.

Clinical Study Identifier: NCT02859350

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Ally Olotu, MD

La Paz Medical Center
Malabo, Equatorial Guinea
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