In a report published Wednesday in Nature, (Sterile protection against human malaria by chemoattenuated PfSPZ vaccine) investigators from the University of Tübingen reported all nine subjects (100%) immunized with three doses of Sanaria® PfSPZ-CVac malaria vaccine in a recently completed clinical trial were protected against Plasmodium falciparum malaria when exposed to the disease 10 weeks after their last vaccine dose. Professor Peter Kremsner, MD, Director of the Institute of Tropical Medicine at the University, led the clinical team.
PfSPZ-CVac was administered to the nine subjects three times over eight weeks; the research demonstrated the three doses were also safe and effective when administered over just 10 days. Scientists at the Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), U.S. National Institutes of Health (NIH) found that assays of the subjects’ cellular immunity correlated with vaccine-induced protection. A team from Antigen Discovery Inc. that studied the antibody responses of the nine protected individuals, identified 22 malaria parasite proteins that could be the targets of protective immune responses.
Sanaria founder and CEO, Stephen L. Hoffman, MD said, “We are extremely encouraged by these findings. Clinical trials of PfSPZ-CVac underway in Germany, the U.S., and Equatorial Guinea, and soon to start in Mali, Ghana, the U.S., and Gabon will lead to an optimized vaccination regimen that we expect to move rapidly into phase 3 clinical trials and licensure. The ability to complete an immunization regimen in 10 days will facilitate the use of PfSPZ-CVac in mass vaccination programs to eliminate the malaria parasite and to prevent malaria in travelers.”
PfSPZ-CVac is composed of live, purified malaria parasites and the antimalarial drug chloroquine. Volunteers in the clinical trial received three 0.5 mL injections of the vaccine by rapid direct venous inoculation. Ten weeks after their last immunization, all nine subjects who received the highest dose of malaria parasites were protected against the injection of live malaria parasites.
The clinical trial included 42 adult volunteers, 21-45 years old. Twenty-seven volunteers received PfSPZ-CVac at varying doses to evaluate alternative dosage regimens. There was no difference in adverse events between volunteers who received the vaccine and those who received the saltwater placebo. They were enrolled, vaccinated and assessed under the direction of Benjamin Mordmüller, MD at the Institute of Tropical Medicine, University of Tübingen.
The German Center for Infection Research funded the current trial with additional support from Sanaria. Sanaria receives research support and funding from NIAID, which supported vaccine manufacture for this trial, and multiple other institutions in the United States, Europe, and Africa, most of which participate in the International PfSPZ Consortium and will continue its fund-raising efforts to expand its research and clinical programs.
According to the World Health Organization, African children are hardest hit by malaria. The WHO estimates that in 2015 malaria caused 214M clinical episodes and 438,000 deaths worldwide; others have estimated up to 730,500 malaria deaths in 2015. This enormous morbidity and mortality occurs despite investment of billions of dollars in malaria control efforts. Malaria is also a concern for tourists, diplomats, business travelers, aid workers, industrial workers, and military personnel worldwide.
Professor Ogobara Doumbo, MD, PhD, Director of the Bamako Malaria Research Training Center at the University of Bamako, Mali, said, “Those of us in countries where people’s lives are devastated by malaria have been waiting for a highly effective malaria vaccine for decades. We are excited about these new results with PfSPZ-CVac in Germany, and are proud to be able to initiate the first field trials of PfSPZ-based vaccines in Mali, West Africa in collaboration with our colleagues from the Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH and the University of Maryland School of Medicine.”
Professor of Tropical Medicine and Travel Medicine, Martin Grobusch MD, PhD, Director of the Center of Tropical Medicine at the University of Amsterdam’s Academic Medical Center, a clinic that cares for more than 16,000 travelers annually, said, “Travelers continue to be at high risk of acquiring malaria. A vaccine like PfSPZ-CVac that provides complete protective immunity for 10 weeks and can be administered in less than two weeks will be an ideal tool for the prevention of malaria in the traveling population.”