Initiation date: 2011
End date: 2012
Past project identifier: NCT01397227
Partner trial identifier: MAL-V-A001
Official title: A Phase I/IIa, Double-blind, Randomized, Placebo-controlled, Dose-escalation Clinical Study Evaluating Safety, Tolerability and Immunogenicity of Two Dose Levels of Recombinant Adenoviral Serotype Ad35 and Serotype Ad26 Vectors Expressing the Malaria Plasmodium Falciparum Circumsporozoite Antigen Administered as Heterologous Prime-boost Regimen, and Assessing Protective Efficacy of the Higher Dose in a Malaria Challenge Model in Unblinded Conditions
Project description: A Study to Assess the Immunogenicity, Tolerability and Safety of a Malaria Vaccine and Also Its Protective Efficacy in a Malaria Challenge Model *
The purpose of this study, conducted in malaria-naïve adults living in the United States, was to assess the safety, tolerability, and immunogenicity of two dose levels (1x10^10 and 5x10^10 virus particles [vp]) of the adenovirus serotype (Ad) Ad35.CS.01/Ad26.CS.01 prime-boost malaria candidate vaccine, followed by an evaluation of the protective efficacy of the higher dose level in an experimental malaria challenge.
The study was designed with two objectives:
  1. Assess the safety and reactogenicity of Ad35.CS.01/Ad26.CS.01 in malaria-naïve adults by monitoring for occurrence of solicited signs and symptoms, occurrence of unsolicited symptoms, and the occurrence of serious adverse events during the study period.

  2. Quantify humoral immune response via antibody titer, and evaluate experimental human malaria infection as a reliable and reproducible model in assessing malaria vaccine candidates.

Enrollment: 36

Outcomes/Next steps: Findings were presented at the 2012 Annual Meeting of the American Society of Tropical Medicine and Hygiene (ASTMH).

Ad35.CS.01/Ad26.CS.01 was found to be well-tolerated, with low systemic reactogenicity in subjects. Although the vaccine was immunogenic, it demonstrated suboptimal efficacy after challenge. However, the experimental human malaria infection model induced highly reproducible infection in all subjects, thereby demonstrating its potential as a useful tool in assessing malaria vaccine candidates.

Based on the outcomes of this study, the PATH Malaria Vaccine Initiative did not make further investments.

View detailed study record on


This project was made possible in part through support provided by the Infectious Disease Division, Bureau for Global Health, US Agency for International Development, under the terms of Cooperative Agreement No. GHS-A-00-04-00016-00. The opinions expressed herein are those of the author(s) and do not necessarily reflect the views of the US Agency for International Development. The vaccines were manufactured by Crucell Holland BV, Leiden, Netherlands under a Division of Microbiology and Infectious Diseases-supported contract N01-AI05421, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD.
*Source:; date accessed November 3, 2016.