Single-dose tafenoquine appears to prevent malaria relapse

The studies show that tafenoquine reduces the risk of Plasmodium vivax recurrence in patients with quantitatively confirmed normal glucose-6-phosphate dehydrogenase (G6PD) activity, Nicholas J. White, FRS, wrote in an accompanying editorial.

But the need for this test and current prescribing restrictions will “limit the potential deployment of tafenoquine, at least in the immediate future,” he said. He praised the developers of tafenoquine “for persevering with this potentially valuable antimalarial drug, despite the difficulties,” but cautioned that it’s too soon to conclude that tafenoquine can be used safely and routinely on a large scale “and thus fulfill its promise as a radical improvement in the treatment of malaria.”

Currently, tafenoquine may not be used during pregnancy, lactation, or in patients younger than 16 years, Dr. White noted. Tafenoquine, like primaquine, causes dose-dependent hemolysis in patients with G6PD deficiency, but unlike primaquine, it is given as a single large dose. Hence, pretreatment quantitative G6PD testing is necessary. Point-of-care quantitative G6PD tests have been developed but await extensive field testing, Dr. White said.

Dr. White is with Mahidol University, Bangkok, Thailand, and University of Oxford, England. He reported having no financial disclosures. These comments are from his accompanying editorial ( N Engl J Med. 2019;380:285-6 ).