A two-part, phase 2 trial evaluating the safety and tolerability of onetime subcutaneous (SC) or intravenous (IV) administration of monoclonal antibody (MAb) L9LS in healthy Malian adults and one-time SC administration of L9LS in healthy Malian children, as well as its protective efficacy against naturally occurring Plasmodium falciparum (Pf) infection over a 7-month malaria season in healthy Malian children 6-10 years of age.~The first part of the study is an age de-escalation and dose-escalation study for safety and tolerability. Adult subjects in the dose-escalation study will be assigned in open-label fashion to 1 of 3 L9LS dose arms. Dosing will begin in the lowest dose arm. Once all subjects in that arm reach day 7 post-administration, if no safety concerns have arisen, dosing will begin at the next dose level. Once all subjects in that arm reach day 7 post-administration, if no safety concerns have arisen, dosing will begin at the highest dose level. Once all adult subjects reach day 7 post-administration, if no safety concerns have arisen, 18 subjects aged 6-10 years will be randomized 1:1 to L9LS or placebo in double-blind fashion. Once all 18 subjects reach day 7 post-administration, if no safety concerns have arisen, an additional 18 subjects aged 6-10 years will be randomized 1:1 to L9LS versus placebo. Randomization of subjects aged 6-10 years in each L9LS dose arm will be weight-stratified and enrollment will be weight de-escalated. Adult subjects will be followed for safety to assess adverse events (AEs) at study visits 1, 3, 7, 14, 21, and 28 days after administration, and once every month thereafter through 28 weeks. Subjects aged 6-10 years will be followed at study visits 1, 3, 7, 14, 21, and 28 days after administration, and once every 2 weeks thereafter through 28 weeks. Primary study assessments include physical examination and blood collection for identification of Pf infection and other research laboratory evaluations. After the last subject in the pediatric L9LS dose arm reaches day 7 safety follow-up, an interim safety evaluation will be performed before enrollment begins for the efficacy part of the study. Data from the 36 subjects aged 6-10 years enrolled in the dose-escalation study will be included in a secondary analysis to determine the relationship between L9LS concentration and the risk of Pf infection.~The second part of the study is a weight-stratified, randomized, double-blind, placebo-controlled trial to assess safety and protective efficacy of L9LS versus placebo administered SC in children 6-10 years of age. In this part of the study, subjects will be randomized to L9LS or placebo. Randomization of subjects in each arm will be weight-stratified. Subjects in the efficacy study will receive the study agent prior to the malaria season and be followed at study visits 1, 3, 7, 14, 21, and 28 days later, and once every 2 weeks thereafter through 28 weeks. Primary study assessments include physical examination and blood collection for identification of Pf infection and other research laboratory evaluations.
The purpose of this study is to evaluate the safety and tolerability of onetime subcutaneous (SC) or intravenous (IV) administration of monoclonal antibody (MAb) L9LS in healthy Malian adults and one-time SC administration of L9LS in healthy Malian children, as well as its protective efficacy against naturally occurring Plasmodium falciparum (Pf) infection over a 7-month malaria season in healthy Malian children 6-10 years of age.