Operational feasibility of Plasmodium vivax radical cure with tafenoquine or primaquine following point-of-care, quantitative glucose-6-phosphate dehydrogenase testing in the Brazilian Amazon:a real-life retrospective analysis

14 Feb 2024
Marcelo Brito, Rosilene Rufatto, Felipe Murta, Vanderson Sampaio, Patrícia Balieiro, Djane Baía-Silva, Vanessa Castro, Brenda Alves, Aline Alencar, Stephan Duparc, Penny Grewal Daumerie, Isabelle Borghini-Fuhrer, Elodie Jambert, Cássio Peterka, Francisco Edilson Lima Jr, Leonardo Carvalho Maia, Catherine Lucena Cruz, Bruna Maciele, Mariana Vasconcelos, Myrna Machado, Elder Augusto Figueira, Antônio Alcirley Balieiro, Alexandre Menezes, Roberta Ataídes, Dhelio Batista Pereira†, Marcus Lacerda†

Abstract

Background

To achieve malaria elimination, Brazil must implement Plasmodium vivax radical cure. We aimed to investigate the operational feasibility of point-of-care, quantitative, glucose-6-phosphate dehydrogenase (G6PD) testing followed by chloroquine plus tafenoquine or primaquine.

Methods

This non-interventional, observational study was done at 43 health facilities in Manaus (Amazonas State) and Porto Velho (Rondônia State), Brazil, implementing a new P.vivax treatment algorithm incorporating point-of-care quantitative G6PD testing to identify G6PD status and single-dose tafenoquine (G6PD normal, aged ≥16 years, and not pregnant or breastfeeding) or primaquine (intermediate or normal G6PD, aged ≥6 months, not pregnant, or breastfeeding >1 month). Following training of health-care providers, we collated routine patient records from the malaria epidemiological surveillance system (SIVEP-Malaria) retrospectively for all consenting patients aged at least 6 months with parasitologically confirmed P.vivax malaria mono-infection or P.vivax plus P.falciparum mixed infection, presenting between Sept 9, 2021, and Aug 31, 2022. The primary endpoint was the proportion of patients aged at least 16 years with P.vivax mono-infection treated or not treated appropriately with tafenoquine in accordance with their G6PD status. The trial is registered with ClinicalTrials.gov, NCT05096702, and is completed.

Findings

Of 6075 patients enrolled, 6026 (99·2%) had P.vivax mono-infection, 2685 (44·6%) of whom were administered tafenoquine. G6PD status was identified in 2685 (100%) of 2685 patients treated with tafenoquine. The proportion of patients aged at least 16 years with P.vivax mono-infection who were treated or not treated appropriately with tafenoquine in accordance with their G6PD status was 99·7% (95% CI 99·4–99·8; 4664/4680).

Interpretation

Quantitative G6PD testing before tafenoquine administration was operationally feasible, with high adherence to the treatment algorithm, supporting deployment throughout the Brazilian health system.