Tafenoquine Drug Levels in Small Children

NCT07835321 | Not Yet Recruiting Phase 2 DMC FDA Drug

• 2 other identifiers: MAL24006U01AI195203
• Study Type: interventional
• Target: 20
• Locations: 2 countries
• Sites: 2

Brief Summary

This study is an open label, single arm, pharmacokinetic trial. A total of 20 participants (children ≤12kg and \>28 days old) will be enrolled. Enrollment will be competitive between Thailand and Vietnam study sites (each site will enroll as many patients that are eligible until the sample size is reached). Tafenoquine will be given concomitantly with the schizonticidal agent, chloroquine, on the day of enrolment. The participant will be admitted to hospital for observation and until the malaria smear is negative for asexual parasites on 2 consecutive days or until the schizonticidal treatment is completed, which will be approximately 3-7 days. All treatment doses will be supervised. Follow up will continue on days 7, 14, 21, and 28 then every month until month 4. Parent/guardian of participants will be instructed to follow up in between visits if participants are feeling unwell. Participants who are lost to follow up (any missed visit), who require drug re-administration after vomiting, or where at least 3 pharmacokinetic samples are not successfully drawn, will be replaced. Participants being replaced will continue in the study for safety assessments and to ensure the treatment of recurrences. The total blood drawn for this study will be 3.76 mL if the participant has no recurrences.

Conditions

Plasmodium Vivax Malaria; Vivax Malaria

Keywords

Plasmodium vivax; Tafenoquine; Radical cure; Antimalarial therapy; 8-aminoquinoline; Pediatric malaria; Infant malaria; Pharmacokinetics; Pediatrics

Outcome Measures

Primary Outcomes (3)

• Tafenoquine blood concentration-time curve area under the curve from time zero to infinity (AUC[0-∞])

  The area under the tafenoquine concentration-time curve from time zero to infinity (AUC\[0-∞\]) will be estimated from the concentration-time data.

  days 1, 7, 28 and month 4

• Maximum observed tafenoquine blood concentration (Cmax)

  Maximum observed blood concentration (Cmax) will be estimated from the concentration-time data.

  days 1, 7, 28 and month 4

• Terminal elimination half-life of tafenoquine (t½)

  Terminal elimination half-life (t½) will be estimated from the concentration-time data.

  days 1, 7, 28 and month 4

Secondary Outcomes (3)

• Number of adverse events and serious adverse events

  up to month 4

• Methaemoglobin levels measured by oximetry

  day 7

• CYP2D6 genotype and associated phenotype as defined by the Clinical Pharmacogenetics Implementation Consortium (CPIC)

  up to month 4

Study Arms (1)

Tafenoquine Plus Chloroquine

EXPERIMENTAL

Participants with Plasmodium vivax malaria will receive oral chloroquine and tafenoquine under direct observation. Chloroquine tablets (250 mg) will be administered at a total dose of 25 mg/kg base divided over 3 days (Days 0, 1, and 2) as schizonticidal treatment. Tafenoquine will be administered as a single oral dose for radical cure according to body weight: 25 mg for participants weighing \<5 kg, 50 mg for participants weighing ≥5 kg to \<10 kg, and 100 mg for participants weighing ≥10 kg to 12 kg. Participants will be followed for safety, efficacy, pharmacokinetics, and recurrence of P. vivax malaria for 4 months.

Drug: Chloroquine; Drug: Tafenoquine

Interventions

Chloroquine DRUG

Oral chloroquine tablets (250 mg). Total dose of 25 mg/kg base divided over 3 days (Days 0, 1, and 2).

Tafenoquine Plus Chloroquine

Tafenoquine DRUG

Single oral dose administered according to body weight: 25 mg for \<5 kg; 50 mg for ≥5 kg to \<10 kg; 100 mg for ≥10 kg to 12 kg.

Tafenoquine Plus Chloroquine

Eligibility Criteria

• Age: 28 Days+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• P. vivax mono-infection as diagnosed by RDT or microscopy
• Quantitative G6PD activity ≥70%
• Age \>28 days old and weight ≤12kg
• The parent/guardian can understand the study instructions and provide written informed consent
• Willing to return with the participant for 4 months to follow up

You may not qualify if:

• Hb \< 8 g/dL
• Severe malaria
• Blood transfusion in the last 3 months
• Any previous history of severe anaemia or haemolysis
• If age is \<6 months old today: gestational age at birth \<37wk or birth weight \<2.5kg
• Use of tafenoquine within the last 4 months
• History of allergic response to an 8-aminoquinoline or the nationally recommended schizonticide (e.g., chloroquine, artemether-lumefantrine)
• Use of drugs that are substrates of organic cation transporter-2 (OCT2) or multidrug and toxin extrusion (MATE) transporters, and drugs that affect chloroquine metabolism
• Presence of any condition which in the judgement of the investigator would place the participant at undue risk or interfere with the results of the study (e.g. chronic disease, failure to thrive, severe malnutrition)

Sponsors & Collaborators

• University of Oxford: lead
• National Institute of Allergy and Infectious Diseases (NIAID): collaborator

Study Sites (2)

Shoklo Malaria Research Unit (SMRU)

Mae Ramat, Changwat Tak, 63140, Thailand

Location

Oxford University Clinical Research Unit (OUCRU)

Bình Phước, Vietnam

Location

MeSH Terms

Conditions

Malaria, Vivax

Interventions

Chloroquine; tafenoquine

Condition Hierarchy (Ancestors)

Malaria; Protozoan Infections; Parasitic Diseases; Infections; Mosquito-Borne Diseases; Vector Borne Diseases

Intervention Hierarchy (Ancestors)

Aminoquinolines; Quinolines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Heterocyclic Compounds

Study Officials

• Cindy Chu, MD, PhD

  Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Fa Ngum Road, Vientiane, LAO PDR

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Cindy Chu, MD, PhD

CONTACT

+856 (0) 21 250 752; cindy@tropmedres.ac

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Masking Details: This is an open-label study. Investigators, study staff, participants, and parents/guardians are aware of the treatment administered. All drug administrations are directly observed by study staff.
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: All enrolled participants with Plasmodium vivax malaria receive the study treatment regimen (tafenoquine with chloroquine) and are followed prospectively to assess safety, efficacy, pharmacokinetics, and recurrence outcomes over 4 months.

Study Record Dates

• First Submitted: August 28, 2026
• First Posted: September 22, 2026
• Study Start: September 1, 2026
• Primary Completion (Estimated): December 1, 2029
• Study Completion (Estimated): April 1, 2030
• Last Updated: September 22, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will share

Locations

TH (1); VN (1)