Nov 13 - 17, 2016


Ally Olotu1 , Vicente Urbano2 , Ali Hamad1 , Mwajuma Chemba1 , Elizabeth Nyakarungu1 , Martin Eka2 , Esther Eburi3 , Dianna Hergott4 , Carl D. Maas5 , Mitoha Ondo’o Ayekaba5 , Diosdado Nsue Milang2 , Matilde Riloha Rivas2 , Hassan Abuleil6 , Oscar Embon6 , Chris Schwabe7 , Luis Segura3 , Claudia Daubenberger8 , Marcel Tanner8 , Thomas Richie9 , Peter F. Billingsley9 , B. Kim Lee Sim9 , Salim Abdulla1 , Stephen L. Hoffman9

1 Ifakara Health Institute, Bagamoyo, United Republic of Tanzania, 2 Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea, 3 Medical Care Development International, Malabo, Equatorial Guinea, 4 Medical Care Development International, Silver Spring, MD, United States, 5 Marathon EG Production Ltd., Malabo, Equatorial Guinea, 6 La Paz Medical Center, Malabo, Malabo, Equatorial Guinea, 7 Medical Care Development International, Silver Spring, MD, United States, 8 Swiss Tropical and Public Health Institute, Basel, Switzerland, 9 Sanaria, Rockville, MD, United States

PfSPZ Vaccine is a candidate pre-erythrocytic malaria vaccine composed of radiation-attenuated, aseptic, purified, cryopreserved Plasmodium falciparum (Pf) sporozoites (SPZ). In clinical trials in the U.S. and Africa, PfSPZ Vaccine administered by direct venous inoculation (DVI) provides durable protection against heterologous strains and heterogeneous populations of Pf. Trials in young children are underway. A robust malaria control program has substantially reduced the malaria burden on Bioko Island, Equatorial Guinea (EG). With an eye toward eventual elimination of malaria on Bioko, a malaria vaccine initiative was established to evaluate the potential utility of PfSPZ Vaccine, resulting in the first ever clinical trial in EG. This first trial was a phase 1, randomized, double blind placebocontrolled trial to assess the tolerability, safety, and immunogenicity of PfSPZ Vaccine administered by DVI in young, healthy 18-35 year olds. A sentinel group of three volunteers received an initial PfSPZ Vaccine dose of 1.35x105 PfSPZ and a second dose of 2.7x105 PfSPZ was given two weeks later. Following review by the safety monitoring committee, 30 volunteers were randomized to receive three doses of either 2.7x105 PfSPZ or normal saline placebo at 0, 8 and 16 weeks. Adverse events (AEs) were solicited for 7 days after each vaccination. There was enhanced surveillance and reporting for unsolicited AEs for 28 days after each vaccination. Monitoring for severe adverse events was done throughout the 40-week study period. Blood samples for safety monitoring of hematological, renal and hepatic functions were taken at baseline, 2, 7, 14 and 28 days after each vaccination and monthly after the last dose for six months. Blood samples for antibody and cellular immunology endpoints were taken at baseline and 1 month after the last vaccination. The results of safety, tolerability and immunogenicity will be presented, including a comparison of the immunological response to the same dose of PfSPZ in EG and Tanzania.