NCT05400655

Anti-malaria MAb in Kenyan Children

Safety and Efficacy of L9LS, a Human Monoclonal Antibody Against Plasmodium Falciparum, in an Age De-Escalation, Dose-Escalation Trial and a Randomized, Placebo-Controlled, Double-Blind Trial of Children in Western Kenya

• Status: Completed
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 912 (actual)
• Sponsor: National Institute of Allergy and Infectious Diseases (NIAID) · NIH
• Sex: All
• Age: 5 Months – 10 Years
• Healthy volunteers: Accepted

Summary

The purpose of this study is to evaluate the safety and tolerability of one-time subcutaneous (SC) administration of monoclonal antibody (MAb) L9LS in healthy Kenyan children aged 5 months to 10 years, as well as the protective efficacy of one or two doses of L9LS against naturally occurring Plasmodium falciparum (Pf) infection among Kenyan children aged 5 to 59 months at enrollment, in a setting of perennial high transmission.

Detailed description

A two-part, phase 2 trial evaluating the safety and tolerability of one-time subcutaneous (SC) administration of monoclonal antibody (MAb) L9LS in healthy Kenyan children aged 5 months to 10 years, as well as the protective efficacy of one or two doses of L9LS against naturally occurring Plasmodium falciparum (Pf) infection among Kenyan children aged 5 to 59 months at enrollment, in a setting of perennial high transmission. Part 1 includes part 1a and part 1b and is an age de-escalation and dose-escalation study. In part 1a, in a stepwise fashion, children aged 5-10 years will receive 5 mg/kg of L9LS or placebo and be followed for 3 months to assess tolerability and safety. If acceptable tolerability and safety profiles are met at 1-week post-injection, the 5 mg/kg dose of L9LS or placebo will be administered to children aged 5-59 months while enrolling another cohort of children aged 5-10 years at a dose of 10 mg/kg of L9LS or placebo. If after 1 week, the 10 mg/kg dose is found to be safe in children aged 5-10 years and the 5 mg/kg dose is found to be safe in children aged 5-59 months, a 20 mg/kg dose of L9LS or placebo will be administered to children aged 5-10 years and a 10 mg/kg dose of L9LS or placebo to children aged 5-59 months. Finally, if these doses are found safe after 1 week, a 20 mg/kg dose of L9LS or placebo will be administered to children aged 5-59 months. Should tolerability and safety of all doses be acceptable in children aged 5-59 months, part 2 of the trial will begin. Part 1b of the study was added later and will include two additional dose escalation cohorts of children aged 5 to 71 months and will test 30 mg/kg L9LS and 40 mg/kg L9LS. Dosing in part 1 of the study will be weight-based and all doses will be administered SC in a double-blinded fashion. 12 participants in each age-dose group will be enrolled in a 3:1 ratio of L9LS to placebo, and all participants will be followed for a total of 3 months. Part 2 is the efficacy study. Children 5-59 months of age will be randomized to receive a 10-20 mg/kg dose of L9LS or placebo by SC administration. There will be two L9LS cohorts, one 5-17 months of age and another 18-59 months of age, which will constitute one L9LS arm. A placebo arm will be composed of children 5-59 months of age. They will be followed over 12 months with monthly blood smear microscopy and polymerase chain reaction (PCR) and twice-monthly symptomatology and careseeking behavior questionnaires. Dosing will be based on three weight bands; all doses will be administered SC with fixed doses of 75 mg L9LS, 150 mg L9LS, or 225 Mg L9LS, resulting in a range of 10-20 mg/kg in a double-blinded fashion. Blood will be drawn to assess antibody titers at baseline, and at three additional time points over 12 months to establish pharmacokinetics (PK). Participants in the L9LS arm will be randomized 1:1 at baseline to receive either a second L9LS injection or a placebo injection to evaluate the additional efficacy of a second dose administered 6 months after the first dose. (Those in the placebo arm will receive a second injection of placebo.) Participants will be followed for an additional 6 months after the second injection with monthly blood smear microscopy and PCR, and a blood draw at month 11 to assess L9LS PK.

Conditions

• Plasmodium Falciparum Infection
• Malaria

Interventions

Type	Name	Description
DRUG	L9LS	Administered subcutaneously.
OTHER	Placebo	Normal saline administered subcutaneously.

Timeline

• Start date: 2022-09-14
• Primary completion: 2024-06-02
• Completion: 2024-06-02
• First posted: 2022-06-01
• Last updated: 2025-10-16
• Results posted: 2025-10-16

Locations

1 site across 1 country: Kenya

Regulatory

• FDA-regulated drug study