A double-blind, placebo-controlled phase 1/2a trial of the genetically attenuated malaria vaccine PfSPZ-GA1
Meta Roestenberg, Jona Walk, Saskia C. van der Boor, Marijke C. C. Langenberg, Marie-Astrid Hoogerwerf, Jacqueline J. Janse, Mikhael D. Manurung, Xi Zen Yap, Amanda Fabra-García, Jan Pieter R. Koopman, Pauline Meij, Els Wessels, Karina Teelen, Youri M. van Waardenburg, Marga van de Vegte‐Bolmer, Geert Jan van Gemert, Leo G. Visser, André van der Ven, Quirijn de Mast, K C Natasha, Yonas Abebe, Tooba Murshedkar, Peter F. Billingsley, Thomas L. Richie, B. Kim Lee Sim, Chris J. Janse, Stephen L. Hoffman, Shahid M. Khan, Robert W. Sauerwein
Abstract
= 13), or normal saline placebo at 8-week intervals, followed by exposure to mosquito bite controlled human malaria infection (CHMI). After CHMI, 3 of 25 volunteers from both PfSPZ-GA1 groups were sterilely protected, and the remaining 17 of 22 showed a patency ≥9 days (median patency in controls, 7 days; range, 7 to 9). All volunteers in the PfSPZ Vaccine control group developed parasitemia (median patency, 9 days; range, 7 to 12). Immunized groups exhibited a significant, dose-related increase in anti-Pf circumsporozoite protein (CSP) antibodies and Pf-specific interferon-γ (IFN-γ)-producing T cells. Although no definite conclusion can be drawn on the potential strength of protective efficacy of PfSPZ-GA1 Vaccine, the favorable safety profile and induced immune responses by PfSPZ-GA1 Vaccine warrant further clinical evaluation.