Monoclonal antibody safely prevents malaria infection in adults
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One dose of a monoclonal antibody safely protected healthy adults from malaria infection during the 6-month malaria season in Mali, according to data published in The New England Journal of Medicine and presented at a medical conference.
“We need to expand the arsenal of available interventions to prevent malaria infection and accelerate efforts to eliminate the disease,” National Institute of Allergy and Infectious Diseases Director Anthony S. Fauci, MD, said in a press release.
“These study results suggest that a monoclonal antibody could potentially complement other measures to protect travelers and vulnerable groups such as infants, children, and pregnant women from seasonal malaria and help eliminate malaria from defined geographical areas,” Fauci said.
Researchers presented findings from the phase 2 NIAID-USTTB trial at the American Society of Tropical Medicine & Hygiene annual meeting in Seattle. The trial evaluated the safety and efficacy of a one-time, IV infusion of a monoclonal antibody called CIS43LS given to 369 healthy, nonpregnant adults, aged 18 to 55 years from the West African country of Mali.
According to the study, the first part of the trial assessed the safety of three different doses of CIS43LS — 5 mg, 10 mg and 40 mg per kg of body weight — given intravenously in six participants per dose level. The researchers followed participants for 24 weeks, during which time they found that the treatment was safe and well tolerated.
The second part of the trial assessed the efficacy of two different doses of CIS43LS compared with a placebo. In total, 330 participants were randomly assigned in a 1:1:1 ratio to receive either the 10 mg/kg or 40 mg/kg dose or a placebo by IV infusion. The researchers again followed participants for 24 weeks, testing their blood for Plasmodium falciparum weekly for the first 28 days and then every 2 weeks after that.
Over the 24-week study period, the testing detected P. falciparum infections in 35.5% of participants who received 10 mg/kg CIS43LS, 18.2% who received 40 mg/kg of CIS43LS and 78.2% who received placebo. The researchers calculated the efficacy of a 40 mg/kg dose of CIS43LS at 6 months to be 88.2% (adjusted 95% CI, 79.3%-93.3%) and the efficacy of a 10 mg/kg dose to be 75% (adjusted 95% CI, 61%-84%) compared with placebo.
“These first field results demonstrating that a monoclonal antibody safely provides high-level protection against intense malaria transmission in healthy adults pave the way for further studies to determine if such an intervention can prevent malaria infection in infants, children, and pregnant women,” Robert Seder, MD, chief medical officer and associate director of the NIAID Vaccine Research Center, said in the press release. “We hope monoclonal antibodies will transform malaria prevention in endemic regions.”
Seder and colleagues are testing a second, more potent antimalarial monoclonal antibody that is administered subcutaneously in smaller doses. It has shown promise in adults in early-stage testing and is being assessed in two phase 2 trials in infants, children and adults in Mali and Kenya, the NIH said.
There have been recent advancements in malaria prevention for children, including the roll out of the first ever WHO-recommended malaria vaccine and promising findings from another malaria vaccine that had an efficacy of more than 75% in a phase 2b trial.
References:
Kayentao K, et al. N Engl J Med. 2022;doi:10.1056/NEJMoa2206966.
Kayentao K, et al. Testing the safety and efficacy of anti-malaria monoclonal antibodies in African adults and children. Presented at: American Society of Tropical Medicine & Hygiene Annual Meeting; Oct. 30-Nov. 3, 2022; Seattle.
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