An antibody drug called CIS43LS prevents malaria infection by interrupting the lifecycle of the Plasmodium falciparum parasite. The antibody binds to and neutralizes sporozoites, the stage of the parasite transmitted from mosquitos to humans. Credit: NIH
An estimated 241 million cases of malaria occurred worldwide in 2020, according to the World Health Organization , resulting in an estimated 627,000 deaths, mostly in children in sub-Saharan Africa. These cases included more than 11 million pregnant women in Africa, resulting in an estimated 819,000 newborns with low birthweight and thus at increased risk for illness and death.
The Phase 2 NIAID-USTTB trial evaluated the safety and efficacy of a one-time, intravenous infusion of a monoclonal antibody called CIS43LS. This antibody was previously shown to neutralize the sporozoites of P. falciparum in the skin and blood before they could infect liver cells. Researchers led by Robert A. Seder, M.D.
The second part of the trial assessed the efficacy of two different doses of CIS43LS compared to a placebo. Three hundred and thirty participants were assigned at random to receive either 10 mg/kg of the antibody, 40 mg/kg, or a placebo by intravenous infusion. No one knew who was assigned to which group until the end of the trial. The study team followed these individuals for 24 weeks, testing their blood for P. falciparum weekly for the first 28 days and every two weeks thereafter.