Improving single-dose tafenoquine to prevent relapses of vivax malaria

Optimizing the dose of tafenoquine for the radical cure of Plasmodium vivax malaria in Southeast Asia

NIH-funded research University of Oxford · NIH-11176136

This project aims to find the best single-dose amount of tafenoquine to prevent relapses of Plasmodium vivax malaria in people in Southeast Asia, including children and adults.

Quick facts

Grant typeU01 cooperative agreement
Study typeNIH-funded research
Funding institutionUniversity of Oxford NIH-funded
Lab location1 site (Oxford, United Kingdom)
Project IDNIH-11176136 on NIH RePORTER

What this research studies

Relapsing Plasmodium vivax malaria causes much of the illness in Southeast Asia, and the currently recommended single dose of tafenoquine often fails to stop repeat infections. The team will re-analyze individual participant data from past large trials and conduct dose-finding work in the region to test higher weight-based tafenoquine doses (up to about 14 mg/kg) that have been tolerated before. Everyone will be tested for G6PD activity because tafenoquine can cause dangerous anemia in people with G6PD deficiency, and the research focuses on people with adequate G6PD levels. Participants will be followed for months after treatment to see whether higher doses safely reduce the chance of relapse.

Who could benefit from this research

Good fit: Adults and children in Southeast Asia diagnosed with P. vivax malaria who have normal or near-normal G6PD enzyme activity and are not pregnant would be ideal candidates.

Not a fit: People with G6PD deficiency, pregnant or breastfeeding women, and those with other contraindications to tafenoquine likely would not be eligible or benefit.

Why it matters

Potential benefit: If successful, a single, higher tafenoquine dose could prevent most relapses of vivax malaria, lowering illness, clinic visits, and transmission in affected communities.

How similar studies have performed: Large phase 3 trials showed the current 300 mg dose often failed to prevent relapse, but pooled analyses and prior safety data indicate higher weight-based doses may be more effective and have been tolerated in people with sufficient G6PD activity.

Where this research is happening

Oxford, United Kingdom

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.