MalariaPhase 2NCT07208760
L9LS-R21 Interaction
A Phase 2 study testing Single dose of 1800 mg L9LS SC (12mL) and Single dose of 225 mg L9LS SC (1.5mL) in people with Malaria, run by National Institute of Allergy and Infectious Diseases (NIAID) at 1 site in Mali.
Trial summary
This is a randomized, double-blind, placebo-controlled trial in 2 parts evaluating the effect of 1-time administration of the monoclonal antibody (MAb) L9LS to healthy Malian participants on the immunogenicity of subsequent administration of the R21/Matrix-M™ vaccine. Read more about this study
- Who is it for?
- Ages 5 months to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Malaria
- What is being tested?
- Single dose of 1800 mg L9LS SC (12mL) and Single dose of 225 mg L9LS SC (1.5mL)
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 0 participants
- Where
- 1 siteMali
- Study dates
- Mar 2026to Mar 2029
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 5 months to 50 years
- All sexes
- Healthy volunteers accepted
- Child, Adult
Who may be able to join
- Part 1: Healthy Adults
- Individuals must meet all of the following criteria to be eligible for study participation:
- Male aged ≥18 and ≤50 years weighing ≥50.0 and ≤100.0 kg or female aged ≥18 and ≤50 years weighing ≥45.0 and ≤90.0 kg.
- Able to provide proof of identity to the satisfaction of the study clinician completing the enrollment process.
- In good general health and without clinically significant medical history.
- Able to provide informed consent.
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- Willing to have blood samples and data stored for future research.
- Resides in or near Sotuba, Mali, and available for the duration of the study.
- Females of childbearing potential must be willing to use reliable contraception from 21 days prior to study day 0 through the final study visit as described below.
- Reliable methods of birth control include 1 of the following: confirmed pharmacologic contraceptives via parenteral delivery or intrauterine or implantable device.
- Nonchildbearing women will be required to report date of last menstrual period, history of surgical sterility (i.e., tubal ligation, hysterectomy) or premature ovarian insufficiency, and will have serum pregnancy test performed per protocol.
- Part 2: Healthy Infants
- Individuals must meet all of the following criteria to be eligible for study participation:
- Aged ≥5 and ≤12 months at enrollment.
- Born at ≥37 weeks gestation (at term).
- Parent and/or guardian able to provide proof of identity to the satisfaction of the study clinician completing the enrollment process.
- In good general health and without clinically significant medical history.
- Parent and/or guardian able to provide informed consent.
- Willing to have blood samples and data stored for future research.
- Resides in or near Sotuba, Mali, and available for the duration of the study.
Who cannot join
- Part 1: Healthy Adults
- Individuals meeting any of the following criteria will be excluded from study participation:
- Pregnancy, as determined by a positive urine or serum beta-human choriogonadotropin test (if female).
- Currently breastfeeding.
- Behavioral, cognitive, or psychiatric disease that in the opinion of the investigator affects the ability of the prospective participant to understand and comply with the study protocol.
- Study comprehension examination score of <80% correct or per investigator discretion.
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- Hemoglobin, WBC, absolute neutrophil, or platelet count outside the local laboratory-defined limits of normal. Individuals may be included at the investigator's discretion for "not clinically significant" values.
- ALT or creatinine (Cr) level above the local laboratory-defined upper limit of normal. Individuals may be included at the investigator's discretion for "not clinically significant" values.
- Infection with HIV virus.
- Known or documented sickle cell disease by history. (Note: Known sickle cell trait is NOT exclusionary.)
- Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, endocrine, rheumatologic, autoimmune, hematological, oncologic, or renal disease by history, physical examination, and/or laboratory studies.
- Receipt of any investigational product within the past 30 days.
- Participation or planned participation in an interventional trial with an investigational product until the last required protocol visit. (Note: Past, current, or planned participation in observational studies is NOT exclusionary; participation in the placebo arm of the Mali adult CIS43LS MAb trial [ClinicalTrials.gov Identifier: NCT04329104] or L9LS MAb trials [NCT05816330] is NOT exclusionary.)
- Medical, occupational, or family problems as a result of alcohol or illicit drug use during the past 12 months.
- History of a severe allergic reaction or anaphylaxis, including history of generalized urticaria and angioedema from prior allergic reactions.
- Hypersensitivity to the active substances or to any of the excipients included in the vaccines.
- Hypersensitivity to hepatitis B vaccines.
- Severe asthma (defined as asthma that is unstable or required emergent care, urgent care, hospitalization, or intubation during the past 2 years, or that has required the use of oral or parenteral corticosteroids at any time during the past 2 years).
- Pre-existing autoimmune or antibody-mediated diseases including but not limited to: systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, Sjögren's syndrome, or autoimmune thrombocytopenia.
- Salivary gland disorder diagnosed by a doctor (e.g., parotitis, sialadenitis, sialolithiasis, salivary gland tumors).
- Known immunodeficiency syndrome.
- Known asplenia or functional asplenia.
- Use of chronic (≥14 days) oral or IV corticosteroids (excluding topical or nasal) at immunosuppressive doses (i.e., prednisone >10 mg/day) or immunosuppressive drugs within 30 days of day 0.
- Receipt of a live vaccine within the past 4 weeks or a killed vaccine within the past 2 weeks prior to study agent administration.
- Receipt of immunoglobulins and/or blood products within the past 6 months.
- Previous receipt of an investigational malaria vaccine or MAb in the last 5 years.
- Other condition(s) that, in the opinion of the investigator, would jeopardize the safety or rights of an individual participating in the trial, interfere with the evaluation of the study objectives, or render the participant unable to comply with the protocol.
- Part 2: Healthy Infants
- Individuals meeting any of the following criteria will be excluded from study participation:
- Body weight <5.5 kg.
- Behavioral, cognitive, or psychiatric disease in the parent and/or guardian that in the opinion of the investigator affects the ability of the parent and/or guardian to understand and comply with the study protocol.
- Any fever (≥ 37.5°C, regardless of route) or acute illness within 7 days prior to randomization.
- Clinically significant congenital anomaly or documented or suspected serious medical illness (e.g., history of epilepsy), serious congenital anomaly, or immediate life-threatening condition in the infant that may interfere with the ability to complete study requirements, as judged by the examining clinician.
- Prior history of a suspected or actual acute medically life-threatening event.
- Receipt of any blood products, monoclonal or polyclonal antibody/immunoglobulin (e.g., hepatitis B immune globulin, IV immunoglobulin), or anticipated use during the study.
- Any suspected or actual life-threatening acute or chronic illnesses known in the mother during her pregnancy.
- Parent or guardian study comprehension examination score of <80% correct or per investigator discretion.
- Hemoglobin, WBC, absolute neutrophil, or platelet count outside the local laboratory-defined limits of normal. Individuals may be included at the investigator's discretion for "not clinically significant" values.
- ALT or Cr level above the local laboratory-defined upper limit of normal. Individuals may be included at the investigator's discretion for "not clinically significant" values.
- Mother and/or infant infected with HIV.
- Sickle cell disease by testing. (Note: Known sickle cell trait is NOT exclusionary.)
- Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, endocrine, rheumatologic, autoimmune, hematological, oncologic, or renal disease by history, physical examination, and/or laboratory studies.
- Receipt of any investigational product within the past 30 days.
- Participation or planned participation in an interventional trial with an investigational product until the last required protocol visit. (Note: Past, current, or planned participation in observational studies is NOT exclusionary.)
- History of a severe allergic reaction or anaphylaxis, including history of generalized urticaria and angioedema from prior allergic reactions.
- Hypersensitivity to the active substances or to any of the excipients included in the vaccines.
- Hypersensitivity to hepatitis B vaccines.
- Salivary gland disorder diagnosed by a doctor (e.g., parotitis, sialadenitis, sialolithiasis, salivary gland tumors).
- Pre-existing autoimmune or antibody-mediated diseases including but not limited to systemic lupus erythematosus or autoimmune thrombocytopenia.
- Known immunodeficiency syndrome.
- Known asplenia or functional asplenia.
- Use of chronic (≥14 days) oral or IV corticosteroids (excluding topical or nasal) at immunosuppressive doses (i.e., prednisone >10 mg/day) or immunosuppressive drugs within 30 days of day 0.
- Previous receipt of the R21/Matrix-MTM or RTS,S/AS01 vaccine.
- Receipt of a live or killed vaccine within the past 1 week prior to study agent administration.
- Previous receipt of an investigational malaria vaccine or MAb.
- Previous receipt of L9LS MAb by the mother.
- Clinical signs of malnutrition.
- Other condition(s) that, in the opinion of the investigator, might jeopardize the safety or rights of an individual participating in the trial, interfere with the evaluation of the study objectives, or render the participant unable to comply with the protocol.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Phase 2, Randomized, Double-Blind, Placebo-Controlled Trial to Evaluate the Effect of L9LS on R21/Matrix-M™ Vaccine Immunogenicity
This is a randomized, double-blind, placebo-controlled trial in 2 parts evaluating the effect of 1-time administration of the monoclonal antibody (MAb) L9LS to healthy Malian participants on the immunogenicity of subsequent administration of the R21/Matrix-M™ vaccine. L9LS will be administered subcutaneously (SC) for adults and infants. The study will assess how the timing of L9LS administration impacts immunogenicity following subsequent intramuscular (IM) R21/Matrix-M™ vaccination. Twenty-four adult participants and 333 infant participants will be enrolled.
Read the detailed description
In Part 1, 24 adult participants will be randomized 1:1 to receive 1800 mg of L9LS or normal saline placebo at enrollment, followed by the R21/Matrix-M™ 3-dose initial vaccine series starting on day 7. Adult participants will be followed at study visits 7 days after L9LS administration and 7 days after each R21/Matrix-M™ vaccination. If no significant safety concerns arise through 7 days after administration of the first R21/Matrix-M™ vaccine (day 14) per an interim safety review, the study will proceed to Part 2. There will also be study visits 28 and 84 days following the last R21/Matrix-M™ vaccine to assess immune responses.
In Part 2, 333 infant participants will be randomized into 1 of 3 cohorts, each with an L9LS arm and a placebo arm (2:1). The individual cohorts will differ in the timing of the R21/Matrix-M™ 3-dose initial vaccine series (7 days, 2 months, and 4 months between L9LS and first R21/Matrix-M™ respectively). Infant participants will be followed at study visits 7 days after L9LS administration and 7 days after each R21/Matrix-M™ vaccination, after which they will continue to be followed every 28 days through the fourth (booster) dose of the R21/Matrix-M™ vaccine. There will also be study visits 28 and 84 days following the last R21/Matrix-M™ vaccine to assess immune responses. Primary study assessments include medical history, physical examination, and blood collection to assess antibody responses to the R21/Matrix-M™ vaccine, L9LS pharmacokinetics (PK), anti-drug antibody (ADA) assessments, identification of Plasmodium falciparum (Pf) infection by microscopic examination of thick blood smears and reverse transcription polymerase chain reaction (RT-PCR), and other research laboratory evaluations.
- Conditions
- Malaria
- Being tested
- Single dose of 1800 mg L9LS SC (12mL), Placebo 12 mL SC, Single dose of 225 mg L9LS SC (1.5mL), Placebo 1.5 mL SC
- Medical subject headings
- Malaria
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Single dose of 1800 mg L9LS SC (12mL)Drug
A human monoclonal antibody to protect against Plasmodium falciparum.
Placebo 12 mL SCOther
Normal saline.
Single dose of 225 mg L9LS SC (1.5mL)Drug
A human monoclonal antibody to protect against Plasmodium falciparum.
Placebo 1.5 mL SCOther
Normal saline.
| Study group | Role | What they receive |
|---|---|---|
| L9LS in Healthy Malian Adult with R21/Matrix-M™ starting 7 days after | Experimental | L9LS with R21/Matrix-M™ series starting 7 days after. Receives: Drug: Single dose of 1800 mg L9LS SC (12mL) |
| Placebo in Healthy Malian Adult with R21/Matrix-M™ starting 7 days after | Placebo comparator | Placebo with R21/Matrix-M™ series starting 7 days after. Receives: Other: Placebo 12 mL SC |
| L9LS in Healthy Malian Infant with R21/Matrix-M™ starting 7 days after | Experimental | L9LS with R21/Matrix-M™ series starting 7 days after. Receives: Drug: Single dose of 225 mg L9LS SC (1.5mL) |
| Placebo in Healthy Malian Infant with R21/Matrix-M™ starting 7 days after | Placebo comparator | Placebo with R21/Matrix-M™ series starting 7 days after. Receives: Other: Placebo 1.5 mL SC |
| L9LS in Healthy Malian Infant with R21/Matrix-M™ starting 56 days after | Experimental | L9LS with R21/Matrix-M™ series starting 56 days after. Receives: Drug: Single dose of 225 mg L9LS SC (1.5mL) |
| Placebo in Healthy Malian Infant with R21/Matrix-M™ starting 56 days after | Placebo comparator | Placebo with R21/Matrix-M™ series starting 56 days after. Receives: Other: Placebo 1.5 mL SC |
| L9LS in Healthy Malian Infant with R21/Matrix-M™ starting 112 days after | Experimental | L9LS with R21/Matrix-M™ series starting 112 days after. Receives: Drug: Single dose of 225 mg L9LS SC (1.5mL) |
| Placebo in Healthy Malian Infant with R21/Matrix-M™ starting 112 days after | Placebo comparator | Placebo with R21/Matrix-M™ series starting 112 days after. Receives: Other: Placebo 1.5 mL SC |
What is being measured
The primary outcome is the main question the study is designed to answer.
Part 1: Incidence and severity of hypersensitivity reactions
Measured: Occurring within 7 days after the administration of the first dose of the R21/Matrix-M™ vaccine.
Part 2: Total IgG anti-NANP antibody titers
Measured by ECLIA, using the Meso Scale Discovery (MSD) LLC-based automation platform
Measured: 28 days after the third R21/Matrix-M™ vaccination
Secondary outcomes (8)
Part 1a: Incidence and severity of local and systemic AEs
Measured: Occurring within 7 days after the administration of L9LS and within 7 days after administration of each dose of R21/Matrix-M™.
Part 1b: Incidence and severity of laboratory abnormalities
Measured: Occurring within 7 days after the administration of study agent.
Part 2a: Incidence and severity of local and systemic AEs
Measured: Occurring within 7 days after the administration of L9LS and within 7 days after administration of each dose of R21/Matrix-M™.
Part 2b: Incidence and severity of laboratory abnormalities
Measured: Occurring within 7 days after the administration of study agent.
Part 2c: Incidence and severity of hypersensitivity reactions
Measured: Occurring within 7 days after the administration of each dose of R21/Matrix-M™ vaccine.
Part 2d: Total IgG anti-NANP antibody titers
Measured by ECLIA, using the Meso Scale Discovery (MSD) LLC-based automation platform
Measured: 84 days after the third R21/Matrix-M™ vaccination.
Part 2e: Detection of Anti-Drug Antibodies (ADAs) to L9LS
Measured by 3-tier MSD assay
Measured: Through study completion, an average of 2 years.
Part 2f: Serum concentrations of L9LS
Measured with an L9LS anti-idiotype antibody and a MSD LLC-based automation platform
Measured: Up to 18 months.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Oct 2025
- Study startMar 2026 (estimated)
- Primary completionMar 2028 (estimated)
- Study completionMar 2029 (estimated)
Why it stopped: After careful review of R21 interaction data that recently became available from a previous L9LS infant study, the study team has made the decision to not move forward with this protocol.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for MalariaStudies of the same condition, open and under way.
- More trials run by National Institute of Allergy and Infectious Diseases (NIAID)The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
- Collaborators
- National Institutes of Health (NIH), Malaria Research and Training Center, Bamako, Mali, Faculté de Médecine Pharmacie d'Odontostomatologie (FMOS), University of Sciences, Techniques, and Technologies of Bamako (USTTB), University of Washington, Indiana University
- Responsible party
- Sponsor
- Investigators
- Bickey H Chang, MD, MHA, Principal investigator, LIG/NIAID/NIHKassoum Kayentao, MD, MPH, PhD, Principal investigator, MRTC/FMOS/USTTB
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07208760
- Sponsor's protocol ID
- 2025/183/CE/USTTB
- Status last verified
- Apr 2026
- First submitted
- 17 Sep 2025
- Last updated
- 9 Apr 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 9 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2, Randomized, Double-Blind, Placebo-Controlled Trial to Evaluate the Effect of L9LS on R21/Matrix-M™ Vaccine Immunogenicity
- ClinicalTrials.gov ID
- NCT07208760
- Acronym / sponsor ID
- 2025/183/CE/USTTB
- Conditions
- Malaria
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- WithdrawnReason stopped: After careful review of R21 interaction data that recently became available from a previous L9LS infant study, the study team has made the decision to not move forward with this protocol.
- Enrolment
- 0 participants (actual)
- Lead sponsor
- National Institute of Allergy and Infectious Diseases (NIAID)US National Institutes of Health
- Collaborators
- National Institutes of Health (NIH), Malaria Research and Training Center, Bamako, Mali, Faculté de Médecine Pharmacie d'Odontostomatologie (FMOS), University of Sciences, Techniques, and Technologies of Bamako (USTTB), University of Washington, Indiana University
- Study start
- Mar 2026 (estimated)
- Primary completion
- Mar 2028 (estimated)
- Study completion
- Mar 2029 (estimated)
- First posted
- 6 Oct 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a randomized, double-blind, placebo-controlled trial in 2 parts evaluating the effect of 1-time administration of the monoclonal antibody (MAb) L9LS to healthy Malian participants on the immunogenicity of subsequent administration of the R21/Matrix-M™ vaccine. L9LS will be administered subcutaneously (SC) for adults and infants. The study will assess how the timing of L9LS administration impacts immunogenicity following subsequent intramuscular (IM) R21/Matrix-M™ vaccination. Twenty-four adult participants and 333 infant participants will be enrolled.
Detailed description
In Part 1, 24 adult participants will be randomized 1:1 to receive 1800 mg of L9LS or normal saline placebo at enrollment, followed by the R21/Matrix-M™ 3-dose initial vaccine series starting on day 7. Adult participants will be followed at study visits 7 days after L9LS administration and 7 days after each R21/Matrix-M™ vaccination. If no significant safety concerns arise through 7 days after administration of the first R21/Matrix-M™ vaccine (day 14) per an interim safety review, the study will proceed to Part 2. There will also be study visits 28 and 84 days following the last R21/Matrix-M™ vaccine to assess immune responses.
In Part 2, 333 infant participants will be randomized into 1 of 3 cohorts, each with an L9LS arm and a placebo arm (2:1). The individual cohorts will differ in the timing of the R21/Matrix-M™ 3-dose initial vaccine series (7 days, 2 months, and 4 months between L9LS and first R21/Matrix-M™ respectively). Infant participants will be followed at study visits 7 days after L9LS administration and 7 days after each R21/Matrix-M™ vaccination, after which they will continue to be followed every 28 days through the fourth (booster) dose of the R21/Matrix-M™ vaccine. There will also be study visits 28 and 84 days following the last R21/Matrix-M™ vaccine to assess immune responses. Primary study assessments include medical history, physical examination, and blood collection to assess antibody responses to the R21/Matrix-M™ vaccine, L9LS pharmacokinetics (PK), anti-drug antibody (ADA) assessments, identification of Plasmodium falciparum (Pf) infection by microscopic examination of thick blood smears and reverse transcription polymerase chain reaction (RT-PCR), and other research laboratory evaluations.
Study design
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 8
| Arm | Type | Receives |
|---|---|---|
| L9LS in Healthy Malian Adult with R21/Matrix-M™ starting 7 days after | Experimental | Drug: Single dose of 1800 mg L9LS SC (12mL)L9LS with R21/Matrix-M™ series starting 7 days after. |
| Placebo in Healthy Malian Adult with R21/Matrix-M™ starting 7 days after | Placebo comparator | Other: Placebo 12 mL SCPlacebo with R21/Matrix-M™ series starting 7 days after. |
| L9LS in Healthy Malian Infant with R21/Matrix-M™ starting 7 days after | Experimental | Drug: Single dose of 225 mg L9LS SC (1.5mL)L9LS with R21/Matrix-M™ series starting 7 days after. |
| Placebo in Healthy Malian Infant with R21/Matrix-M™ starting 7 days after | Placebo comparator | Other: Placebo 1.5 mL SCPlacebo with R21/Matrix-M™ series starting 7 days after. |
| L9LS in Healthy Malian Infant with R21/Matrix-M™ starting 56 days after | Experimental | Drug: Single dose of 225 mg L9LS SC (1.5mL)L9LS with R21/Matrix-M™ series starting 56 days after. |
| Placebo in Healthy Malian Infant with R21/Matrix-M™ starting 56 days after | Placebo comparator | Other: Placebo 1.5 mL SCPlacebo with R21/Matrix-M™ series starting 56 days after. |
| L9LS in Healthy Malian Infant with R21/Matrix-M™ starting 112 days after | Experimental | Drug: Single dose of 225 mg L9LS SC (1.5mL)L9LS with R21/Matrix-M™ series starting 112 days after. |
| Placebo in Healthy Malian Infant with R21/Matrix-M™ starting 112 days after | Placebo comparator | Other: Placebo 1.5 mL SCPlacebo with R21/Matrix-M™ series starting 112 days after. |
Who may qualify
- Ages
- 5 months to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
Key inclusion criteria (20 listed)
- Part 1: Healthy Adults
- Individuals must meet all of the following criteria to be eligible for study participation:
- Male aged ≥18 and ≤50 years weighing ≥50.0 and ≤100.0 kg or female aged ≥18 and ≤50 years weighing ≥45.0 and ≤90.0 kg.
- Able to provide proof of identity to the satisfaction of the study clinician completing the enrollment process.
- In good general health and without clinically significant medical history.
Key exclusion criteria (58 listed)
- Part 1: Healthy Adults
- Individuals meeting any of the following criteria will be excluded from study participation:
- Pregnancy, as determined by a positive urine or serum beta-human choriogonadotropin test (if female).
- Currently breastfeeding.
- Behavioral, cognitive, or psychiatric disease that in the opinion of the investigator affects the ability of the prospective participant to understand and comply with the study protocol.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Single dose of 1800 mg L9LS SC (12mL)A human monoclonal antibody to protect against Plasmodium falciparum. | Drug | L9LS in Healthy Malian Adult with R21/Matrix-M™ starting 7 days after |
| Placebo 12 mL SCNormal saline. | Other | Placebo in Healthy Malian Adult with R21/Matrix-M™ starting 7 days after |
| Single dose of 225 mg L9LS SC (1.5mL)A human monoclonal antibody to protect against Plasmodium falciparum. | Drug | L9LS in Healthy Malian Infant with R21/Matrix-M™ starting 112 days after, L9LS in Healthy Malian Infant with R21/Matrix-M™ starting 56 days after, L9LS in Healthy Malian Infant with R21/Matrix-M™ starting 7 days after |
| Placebo 1.5 mL SCNormal saline. | Other | Placebo in Healthy Malian Infant with R21/Matrix-M™ starting 112 days after, Placebo in Healthy Malian Infant with R21/Matrix-M™ starting 56 days after, Placebo in Healthy Malian Infant with R21/Matrix-M™ starting 7 days after |
Primary outcome
Part 1: Incidence and severity of hypersensitivity reactions
Time frame: Occurring within 7 days after the administration of the first dose of the R21/Matrix-M™ vaccine.
Part 2: Total IgG anti-NANP antibody titers
Time frame: 28 days after the third R21/Matrix-M™ vaccination
Measured by ECLIA, using the Meso Scale Discovery (MSD) LLC-based automation platform
8 secondary outcomes
Part 1a: Incidence and severity of local and systemic AEs
Time frame: Occurring within 7 days after the administration of L9LS and within 7 days after administration of each dose of R21/Matrix-M™.
Part 1b: Incidence and severity of laboratory abnormalities
Time frame: Occurring within 7 days after the administration of study agent.
Part 2a: Incidence and severity of local and systemic AEs
Time frame: Occurring within 7 days after the administration of L9LS and within 7 days after administration of each dose of R21/Matrix-M™.
Part 2b: Incidence and severity of laboratory abnormalities
Time frame: Occurring within 7 days after the administration of study agent.
Part 2c: Incidence and severity of hypersensitivity reactions
Time frame: Occurring within 7 days after the administration of each dose of R21/Matrix-M™ vaccine.
Part 2d: Total IgG anti-NANP antibody titers
Time frame: 84 days after the third R21/Matrix-M™ vaccination.
Part 2e: Detection of Anti-Drug Antibodies (ADAs) to L9LS
Time frame: Through study completion, an average of 2 years.
Part 2f: Serum concentrations of L9LS
Time frame: Up to 18 months.
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Apr 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Bickey H Chang, MD, MHA principal investigator
LIG/NIAID/NIH
Kassoum Kayentao, MD, MPH, PhD principal investigator
MRTC/FMOS/USTTB
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Single dose of 1800 mg L9LS SC (12mL) and Single dose of 225 mg L9LS SC (1.5mL) in people with Malaria, run by National Institute of Allergy and Infectious Diseases (NIAID) at 1 site in Mali.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 20 inclusion and 58 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: withdrawn, as of the sponsor's last update on 9 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Mali. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study was withdrawn before enrolling participants, so there are no results.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Part 1: Incidence and severity of hypersensitivity reactions (time frame: Occurring within 7 days after the administration of the first dose of the R21/Matrix-M™ vaccine.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Apr 2026.