FIELD TRIALS OF AN ASEXUAL BLOOD-STAGE MALARIA VACCINE - STUDIES OF THE SYNTHETIC PEPTIDE POLYMER SPF66 IN THAILAND AND THE ANALYTIC PLAN FOR A PHASE IIB EFFICACY STUDY

Several years ago the Walter Reed Army Institute of Research (WRAIR) i nitiated an independent analysis of the candidate malaria blood stage vaccine SPf66. WRAIR contracted for the synthesis and formulation of S Pf66 in United States Food and Drug Administration (FDA) inspected lab oratories within the U.S., and in 1992, filed an Investigational New D rug (IND) application with the FDA. Preclinical studies indicated that the vaccine could be synthesized to meet its release specifications, and when adjuvanted with alum, was essentially equivalent to Colombian produced SPf66 in regards to immunogenicity in preclinical studies of rodents and primates, and in human volunteers in Phase I studies. The goal of these efforts was ultimately to conduct a Phase IIb field tri al to determine the safety and efficacy of SPf66 produced under curren t Good Manufacturing Practices (cGMP). Such a trial is currently under way in a malaria endemic refugee camp along the Thai-Burmese border. W ere we briefly describe the study and present the formal analytic plan that tvas submitted to regulatory authorities in the United States fo r analysis of the study results. We believe such independent confirmat ory studies are an essential part of the vaccine development process a nd, are required to provide important data regarding the safety and ef ficacy of candidate vaccines in diverse geographical regions, and as a means to assess their role in the context of broader malaria control programmes.