Tafenoquine approved by US FDA for radical cure of vivax malaria

July 30, 2018

On 20 July 2018, GlaxoSmithKline (GSK) and Medicines for Malaria Venture (MMV) announced that The United States Food and Drug Administration (FDA) have approved tafenoquine (Krintafel) to prevent malaria relapses caused by the parasite Plasmodium vivax. Whilst infection with P. vivax is less likely to kill its host than P. falciparum, the vivax parasite is insidious as it can lay dormant in the liver for months on end, causing relapses of the disease. “Radical cure” of vivax involves treatment with a drug targeting the dormant liver forms of the parasite given in combination with currently available anti-malarials like chloroquine or artemisinin-based combination therapies (ACT). Importantly, tafenoquine can be taken in a single dose, unlike the currently prescribed treatment for vivax malaria relapses, primaquine, which requires 14 days of treatment. Approval of tafenoquine represents a huge leap forward in the quest to eliminate malaria, particularly in South East Asia, where vivax is prevalent. Interestingly, tafenoquine was first synthesised by scientists at the Walter Reed Army Institute of Research in the United States in 1978, and in 2008 GSK entered into a collaboration with not-for-profit drug research partnership MMV to develop tafenoquine as an anti-relapse treatment for P. vivax. ACREME Investigator Professor Ric Price told the BBC that “The ability to get rid of the parasite in the liver with a single dose of tafenoquine is a phenomenal achievement and represents one of the most significant advances in malaria treatment in the last 60 years.” Similar to primaquine, tafenoquine can cause the breakdown of red blood cells in individuals deficient in the enzyme G6PD. For this reason it will be necessary to test patients for this enzyme deficiency prior to treatment with tafenoquine.