Clinical Trial of the PfSPZ Vaccine

Plasmodium Falciparum Clinical Trial

Official title: A Phase 1/2a Trial of the PfSPZ Vaccine Administered Subcutaneously or Intradermally to Malaria-Naïve Adult Volunteers

Status Completed

Clinical Trial Summary

The purpose of this study is to determine the safety and tolerability of a non-replicating, metabolically active Plasmodium falciparum sporozoite (PfSPZ) vaccine in malaria-naïve healthy volunteers following multiple-dose subcutaneous (SC) or intradermal (ID) administration.

In addition, the investigators wish to evaluate PfSPZ vaccine-mediated protection against P. falciparum challenge in the following 4 groups (see below) and compare protective efficacy of the PfSPZ vaccine when given by SC v ID administration in all these groups:

• Group 1: 4 doses of 7,500 PfSPZ/immunization,

• Group 2: 4 doses of 30,000 PfSPZ/immunization,

• Group 3: 4 doses of 135,000 PfSPZ/immunization

• Group 4: 4 or 6 doses of 135,000 PfSPZ/immunization.

If > 80% protective efficacy is not achieved in Groups 1, 2, or 3, volunteers in Group 4 will receive a fifth and sixth dose.

Clinical Trial Description

The first clinical trial of the Pf SPZ vaccine is a Phase 1 trial in non-immune healthy adult volunteers. Sanaria is the Sponsor and PATH MVI is funding the trial. The study will be conducted as a collaborative effort between Sanaria, PATH MVI, the NMRC Malaria Program (U.S. Military Malaria Vaccine Program), and the Center for Vaccine Development at the University of Maryland at Baltimore (CVD-UMB). The study will take place at the NMRC Malaria Program Clinical Trials Center on the campus of the National Naval Medical Center in Bethesda, MD and at the CVD and/or General Clinical Research Center, UMB. The study is designed to evaluate the safety, tolerability, immunogenicity and protective efficacy of successively higher doses of the vaccine administered by the subcutaneous (SC) or intradermal (ID) route.

There will be 4 groups of volunteers with each group comprised of a subset of volunteers who receive the vaccine by the SC route and a subset who receive the vaccine by the ID route.

Groups 1-3: The first 3 groups will receive 3 ascending doses of vaccine administered as 4 SC or ID injections separated by 4 week intervals (7,500 PfSPZ/dose, 30,000 PfSPZ/dose, and 135,000 PfSPZ/dose respectively). Each of these groups will be challenged a minimum of 3 weeks after the final dose by exposure to A. stephensi mosquitoes infected with P. falciparum sporozoites. All 3 groups will be followed for safety until 48 weeks after the first immunization.

Group 4: Group 4 will start a minimum of 3 weeks after the first immunization of Group 3. If there is > 80% efficacy in one or more of the subsets of Groups 1, 2, or 3 (SC or ID), Group 4 volunteers will receive 4 immunizations (just like Group 3) but will not have experimental challenge; they will simply be followed for safety for 12 months after the first immunization. The FDA has requested that we follow a group of volunteers receiving the highest dose (135 PfSPZ/immunization) without challenge at 3 weeks. However, if there is NOT > 80% efficacy in one of more subsets of Groups 1, 2, or 3, after a 6 month observation period, Group 4 volunteers will receive two additional monthly immunizations (Immunizations #5 and #6) followed by challenge at approximately 3 weeks after the sixth immunization. All volunteers in Group 4 will be followed for safety until 52 weeks after the first immunization. ;

Study Design

Allocation: Non-Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Prevention

Related Conditions & MeSH terms

• Plasmodium Falciparum

• NCT number: NCT01001650
• Study type: Interventional
• Source: Sanaria Inc.
• Status: Completed
• Phase: Phase 1
• Start date: April 2009
• Completion date: September 2010