Study finds tafenoquine a cost-effective treatment option for malaria

A new study led by the Menzies School of Health Research has provided more information on the cost-effectiveness of a new malaria drug, tafenoquine, to treat vivax malaria.

The researchers used data from an annual vivax malaria report from Brazil and projected the impact over a 10-year period. They compared different types of drugs to compare costs and impact on disease, including reducing malaria transmission. This is particularly important because vivax malaria can remain undetectable in the liver and reactivate weeks or months after the initial infection.

Primaquine and tafenoquine are the two drugs available to treat the liver stage of vivax malaria. Published in PLOS Medicine, the study found tafenoquine to be a cost-effective option compared to seven days of primaquine treatment. This is despite the requirement to test for glucose-6-phosphate dehydrogenase (G6PD) deficiency before tafenoquine is prescribed. G6PD testing before primaquine treatment is also recommended by the World Health Organization as best practice.

Researchers analyzed the use of G6PD screening and one dose of tafenoquine compared to a seven-day course of low-dose primaquine without G6PD screening. Until recently, the latter was the standard practice for treating the hepatic stage of vivax malaria in Brazil.

Current data suggest that only 62% to 86% of vivax malaria patients in Brazil complete their seven-day course of primaquine. Therefore, when looking at cost-effectiveness, researchers also looked at different scenarios in which patients completed their primaquine treatment.

They used an economic valuation model coupled with a disease transmission model to estimate and map their results. They looked at three primaquine treatment scenarios (patients completing 30%, 67%, or 90% of the seven-day course). The researchers found that tafenoquine was the most cost-effective treatment compared to all three primaquine treatment completion rates.

Incomplete treatment of vivax malaria can lead to future illness from parasites that remain dormant in the liver. This can lead to further loss of productivity and greater economic impacts of the disease.

The researchers’ findings support the use of tafenoquine after G6PD screening in Brazil and highlight that it would be particularly cost-effective in areas where people are less likely to stick to a primaquine treatment plan. The study also suggests that tafenoquine would be even more cost-effective when this treatment becomes available for children.

Vivax malaria is one of the most common forms of malaria. Finding clinically effective and cost-effective ways to combat this disease is essential to achieving malaria elimination.

The use of the G6PD test and tafenoquine was recently adopted as part of Brazil’s national treatment policy for adults. These important findings may also help other countries search for cost-effective treatments for malaria.

Associate Professor Angela Devine says: “Malaria causes a significant economic burden in endemic countries. Therefore, understanding the cost-effectiveness of malaria treatments is essential to help decision-makers set treatment priorities and allocate resources.

“Treatment that is both clinically effective and cost-effective helps limit healthcare costs, increases productivity and contributes to greater economic development.

“These results are important in the role of malaria elimination. They take into account both the economic impact of treatment and the impact of treatment in stopping the spread of this disease.”