Immunization with Plasmodium falciparum (Pf) sporozoites under chemoprophylaxis (PfSPZ-CVac) is the most efficacious approach to malaria vaccination. Implementation is hampered by a complex chemoprophylaxis regimen and missing evidence for efficacy against heterologous infection. We report the results of a double-blinded, randomized, placebo-controlled trial of a simplified, condensed immunization regimen in malaria-naive volunteers (EudraCT-Nr: 2018-004523-36). Participants are immunized by direct venous inoculation of 1.1 × 10 5 aseptic, purified, cryopreserved PfSPZ (PfSPZ Challenge) of the PfNF54 strain or normal saline (placebo) on days 1, 6 and 29, with simultaneous oral administration of 10 mg/kg chloroquine base. Primary endpoints are vaccine efficacy tested by controlled human malaria infection (CHMI) using the highly divergent, heterologous strain Pf7G8 and safety. Twelve weeks following immunization, 10/13 participants in the vaccine group are sterilely protected against heterologous CHMI, while (5/5) participants receiving placebo develop parasitemia (risk difference: 77%, p = 0.004, Boschloo’s test). Immunization is well tolerated with self-limiting grade 1–2 headaches, pyrexia and fatigue that diminish with each vaccination. Immunization induces 18-fold higher anti-Pf circumsporozoite protein (PfCSP) antibody levels in protected than in unprotected vaccinees (p = 0.028). In addition anti-PfMSP2 antibodies are strongly protection-associated by protein microarray assessment. This PfSPZ-CVac regimen is highly efficacious, simple, safe, well tolerated and highly immunogenic. In this placebo-controlled trial, 10/13 malaria naïve subjects immunized with a simplified regimen of chemoattenuated P. falciparum sporozoites, PfSPZ-CVac, show sterile protection from heterologous malaria challenge. Immunization was well tolerated and induced high levels of anti-PfCSP antibodies.
【저자키워드】 Translational research, Phase I trials, malaria, 【초록키워드】 antibodies, Efficacy, Vaccine, vaccination, Chloroquine, fatigue, antibody, Infection, risk, immunization, Randomized, Protein, challenge, placebo-controlled trial, Microarray, Placebo, Heterologous, Evidence, administration, Plasmodium falciparum, Safe, regimen, Headaches, Endpoint, double-blinded, complex, participant, immunogenic, P. falciparum, Pyrexia, Volunteer, approach, venous, immunized, vaccinee, tested, develop, addition, receiving, induce, the vaccine, purified, circumsporozoite protein, naïve subject, 【제목키워드】 Vaccine, randomized trial, regimen,