Single-dose Malaria Medicine Prevents Relapse

GSK plc and Medicines for Malaria Venture today announced that the first single-dose of tafenoquine, co-administered with chloroquine for a radical cure, for the prevention of relapse of Plasmodium vivax (P. vivax) malaria, has now been launched in Thailand and Brazil.

In response to the ongoing public health emergency, the government of Brazil accelerated the introduction of tafenoquine in March 2024. The rollout of this new testing and treatment option has begun within the public health system.

In Brazil, malaria cases in indigenous population villages are predicted to reach over 51,000 in 2024. Relapses also increase the disease burden and the potential for onward transmission, ultimately impeding global efforts to eliminate malaria.

Dr. Marcus Lacerda, Tropical Medicine Foundation Dr. Heitor Vieira Dourado and Principal Investigator for the Tafenoquine Rollout STudy, said in a press release on July 5, 2024, “The launch of tafenoquine in Brazil marks a significant step forward in our country’s mission to eliminate malaria by 2035."

Tafenoquine is an 8-aminoquinoline, antimalarial drug targeting the liver-stage of P. vivax malaria. Tafenoquine, like all 8-aminoquinolines, has the potential to cause acute hemolytic anemia in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency.

Therefore, a G6PD test must be performed before prescribing.

When combined with chloroquine for the blood-stage infection, tafenoquine provides what is known as a radical cure: the treatment of both the disease's blood- and liver stages.

P. vivax is the dominant malaria parasite in most countries outside of sub-Saharan Africa.

Approvals for tafenoquine have been granted in the U.S. (ARAKODA™), Australia, Brazil, Ethiopia, Guyana, Peru, Thailand, Colombia, and the Philippines, and the drug is undergoing marketing authorization evaluation in several other countries where P. vivax is endemic.

According to the Centers for Disease Control and Prevention, about 2,000 malaria cases are diagnosed in the United States annually, mostly in travelers.  However, in 2023, seven locally acquired malaria cases were reported in the Sarasota, Florida, area. 

In Africa, two malaria prevention vaccines have been authorized.

The World Health Organization (WHO) recommends Mosquirix™ and R21 / Matrix-M™ vaccines. The WHO estimates the annual global demand for malaria vaccines is about 40–60 million doses by 2026.

R21/Matrix-M includes Novavax AB saponin-based Matrix-M adjuvant and is licensed to and manufactured by the Serum Institute of India Private Ltd.

Neither malaria vaccine is available in the United States in 2024.