Tafenoquine: WHO awards prequalification to single-dose medicine for P. vivax malaria

Tafenoquine, co-administered with chloroquine, is now also included in WHO’s updated Guidelines for malaria, in South America.

The WHO prequalification and updated guidelines include both adults and children aged 2 years and older, weighing at least 10 kg. A single-dose medicine provides an opportunity to overcome challenges with adherence to the existing longer, one-two week regimen of the standard of care, which can be a challenge for patients with relapsing malaria whose symptoms improve shortly after treatment initiation.

P. vivax is the dominant malaria parasite in most countries outside of sub-Saharan Africa, prevalent in most tropical and sub-tropical areas in the world, with children under five and migrant populations at particular risk. Among these vulnerable groups, infants and children carry a disproportionate burden, being highly vulnerable to severe disease, recurrence and anaemia. The complex lifecycle of the P. vivax parasite includes a blood stage and an undetectable dormant liver stage, which can reactivate, causing repeated episodes of malaria following a single infectious bite of a mosquito carrying this parasite.

Thomas Breuer, Chief Global Health Officer, GSK, said, “WHO prequalification of tafenoquine opens new possibilities to positively impact and protect more lives; lives of children and vulnerable populations who continue to bear the burden of this devastating disease. Inclusion of tafenoquine in the updated Guidelines for malaria is an equally important step forward in efforts to eliminate this preventable and treatable disease. Making treatments simpler for people to take is an ambition of ours across much of our Global Health pipeline and portfolio. Alongside our partners, we remain committed to enabling affordable and equitable access to this new single-dose treatment option for those in need in malaria-endemic countries.”

Martin Fitchet, Chief Executive Officer, MMV, said, “Today marks a historic milestone in the fight against malaria. The WHO's prequalification of tafenoquine and its inclusion in the updated Guidelines for malaria is a groundbreaking advancement on the road to elimination, which will transform lives by providing a well-tolerated, effective, and single-dose cure to prevent malaria relapses in some of the world’s most vulnerable communities. This achievement is a testament to the power of innovation and collaboration in global health, to bring us closer to our vision of a malaria-free world.”

Tafenoquine, an 8-aminoquinoline antimalarial drug targeting the liver-stage of P. vivax malaria, is recommended as an alternative to primaquine (3.5 mg/kg total dose) for preventing malaria relapses in children over the age of two in South America. A single dose of tafenoquine administered to P. vivax patients who receive chloroquine treatment provides what is known as radical cure: the treatment of both the blood- and liver-stages of the disease. Tafenoquine, like all 8-aminoquinolines, has the potential to cause haemolytic anaemia in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency, therefore G6PD testing must be performed before prescribing. This is possible with the ‘STANDARD’ G6PD test, developed in collaboration between SD Biosensor and PATH, which provides a measure of a patient’s G6PD enzyme activity levels in two minutes based on a drop of blood from a finger-prick.

WHO prequalification of medicines is crucial as it ensures that the medicine meets standards of quality, safety and efficacy, and is suitable for the target population. The prequalification programme has played a vital role in improving the access to life-saving medications used by millions in low- and middle-income countries.

The WHO Guidelines for malaria are regularly reviewed and updated by the world’s leading malaria experts under WHO’s convening. This update includes a first recommendation for tafenoquine (150mg tablets and 50mg dispersible tablets) with chloroquine in South America.

WHO prequalification and Guideline inclusion follows the launch of tafenoquine in Brazil and Thailand in June this year. Approvals for tafenoquine have been granted in Australia, Brazil, Colombia, Ethiopia, Guyana, Myanmar, Pakistan, Peru, the Philippines, Thailand, Vietnam and the United States, and the drug is undergoing marketing authorisation evaluation in a number of other countries where P. vivax is endemic.