# Moving towards high-dose primaquine or single-dose tafenoquine for Plasmodium vivax treatment in Cambodia: a meeting report from dissemination of results of the EFFORT trial to stakeholders

## TL;DR

Cambodia is exploring new treatments for Plasmodium vivax malaria to improve elimination efforts.

## Contribution

The study evaluates high-dose primaquine and single-dose tafenoquine as alternatives to current treatment regimens.

## Key findings

- High-dose primaquine and single-dose tafenoquine showed potential as more effective treatments for P. vivax.
- The 14-day low-dose primaquine regimen faces challenges due to poor adherence and suboptimal efficacy.
- The EFFORT trial results are being disseminated to inform policy changes in Cambodia.

## Abstract

Cambodia has targeted malaria elimination by 2025. As the malaria burden has decreased in Cambodia, transmission has become more focal, and Plasmodium vivax has become the predominant species. The recurrent nature of P. vivax, due to its dormant liver stages causing relapses, is the main obstacle to malaria elimination in Cambodia. In 2021, Cambodia’s National Center for Parasitology, Entomology and Malaria Control (CNM) rolled out low-dose 14-day primaquine (total dose 3.5 mg/kg) supported by point-of-care quantitative testing for glucose-6-phosphate dehydrogenase deficiency. However, this treatment is limited by poor adherence to its prolonged duration and suboptimal efficacy of the low total dose. The EFFORT clinical trial was conducted in four malaria-endemic countries, including Cambodia, to assess the safety and effectiveness of a 7-day unsupervised high-dose course of primaquine (7 mg/kg total dose) and single dose tafenoquine (300 mg) compared to 14-day unsupervised low-dose primaquine for the treatment of patients presenting with P. vivax malaria. In addition, data were collected on the feasibility and cost-effectiveness of these treatment options. CNM organized the national dissemination of the EFFORT study results on March 27, 2025, to inform key stakeholders and discuss the implications of the study findings for policy and practice in Cambodia.