Study of Controlled Human Malaria Infections to Evaluate Protection After Intravenous or Intramuscular Administration of PfSPZ Vaccine in Malaria-Naive Adults

Malaria Clinical Trial

Official title: VRC 314: A Phase 1, Open-Label, Clinical Trial With Experimental Controlled Human Malaria Infections (CHMI) to Evaluate Safety and Durability of Protection Following Intravenous and Intramuscular Administration of PFSPZ Vaccine in Malaria-Naive Adults

Status Completed

Clinical Trial Summary

Background:

• People bitten by mosquitoes carrying weakened malaria parasites could fight off the disease if later exposed to normal malaria parasites. Scientists have discovered how to make the weakened parasites, which can be injected by the PfSPZ vaccine. Researchers want to see if people who receive the vaccine get malaria after being bitten in a controlled setting (a controlled human malaria infection, CHMI).

Objective:

• To see if the PfSPZ malaria vaccine is safe and prevents malaria in a controlled setting.

Eligibility:

• Healthy adults 18 45 years old.

Design:

• Participants will be screened with medical history, physical exam, blood and lab tests, and EKG.

• Participants will be split into 8 groups, to be in the study for 3 12 months.

• Participants will receive 3 5 vaccinations, injected by a needle in an arm vein or muscle.

• Participants will keep a health diary and be contacted by phone.

• For CHMI, a cup with mosquitoes carrying malaria is applied to participants arm for 5 minutes. Five mosquitoes at a time are used, until 5 have bitten. Some groups will be exposed to malaria more than once.

• After CHMI, participants will visit the clinic very frequently (including daily visits for 12 days) for 28 days.

• Blood will be drawn at most visits, from 1 to 20 tubes. Physical exam and medical history may also be repeated

• Participants who develop malaria will be treated immediately at the clinic. Standard treatment takes 72 hours. Malaria symptoms may last up to 3 days.

Clinical Trial Description

VRC 314 is designed as an open-label evaluation of the safety, tolerability, immunogenicity and protective efficacy of PfSPZ Vaccine. This vaccine administered at 1.35 times 10(5) PfSPZ per injection by the IV route on a schedule of 5 vaccinations was previously shown to confer protection in all vaccinated subjects against CHMI performed shortly after last vaccination; however there was limited durability of protection in a small number of protected subjects who were rechallenged several months later. This study is designed to substantiate the initial results with the IV vaccination route for protection against CHMI. Based on the potential importance of dose and schedule in optimizing sustained immunity with this vaccine, an increase in PfSPZ IV dosage on schedules of 3 to 5 vaccinations will be evaluated for protection against CHMI conducted early (about 3 weeks) and late (about 24 weeks) after completion of vaccinations. To assess if a higher dose given by another route confers protection, one group will receive PfSPZ IM, with half of the amount administered in each arm on a schedule with 4 vaccination.

The primary objectives of the study are related to the safety and tolerability of vaccinations by the IV and IM routes of administration and protection against Plasmodium falciparum (Pf) challenge performed via a well-established CHMI procedure early (2-4 weeks) after completing schedules of 3 to 5 vaccinations. The secondary objective is related to the durability of protection at 20-26 weeks after the last vaccination and exploratory objectives are related to the immunogenicity of the PfSPZ Vaccine and identifying potential immune correlates of protection. ;

Related Conditions & MeSH terms

• Malaria

• NCT number: NCT02015091
• Study type: Interventional
• Source: National Institutes of Health Clinical Center (CC)
• Status: Completed
• Phase: Phase 1
• Start date: December 12, 2013
• Completion date: September 8, 2016