For the first time in almost 70 years, Brazil has achieved the registration, by Anvisa, of a new drug for the treatment of vivax malaria", that was how the researcher in Public Health at Fiocruz Rondônia and the Center for Research in Tropical Medicine (Cepem), Dhélio Batista Pereira, reported the most recent achievement in the fight against a disease that affects about 7.5 million people worldwide, according to data from the World Health Organization (WHO). The registration of tafenoquine was accepted by the National Health Surveillance Agency (Anvisa) last week (29) and, according to the researcher, studies conducted prove that the new substance shortens treatment time, which contributes to better adherence to the drug.

Unlike what has been happening with the use of primaquine, a drug used for more than 60 years, administered daily for a period of up to 14 days, "tafenoquine can be applied in a single dose, since it has action that reaches more than 20 days, presenting chances of radical cure, because it acts directly on the hepatic form of vivax malaria (the hypnozoites), avoiding the so-called relapses, which is the return of the disease, causing a new cycle of malaria in the patient, with infection of the bloodstream," explains the specialist in tropical medicine.

With the approval by Anvisa, Brazil became the first malaria endemic country to regulate tafenoquine as drug to be made available to the general population by the Ministry of Health, through the Unified Health System (SUS). The use of tafenoquine was first released in July 2018 by the U.S. Food and Drug Administration, and in September of the same year by the Australian Therapeutic Goods Administration.

These regulatory approvals were based on efficacy and safety data from a comprehensive global clinical development program for the radical cure of malaria caused by Plasmodium vívax, conducted in nine countries with endemic cases of the disease, including Brazil.

Tafenoquine studies began with the U.S. Army at least 30 years ago. But in the last ten years, a partnership between the non-governmental organization Medicines for Malaria Venture (MMV) and the British pharmaceutical company GlaxoSmithKline, with support from the Bill and Melinda Gates Foundation, has made possible the clinical phase of the studies carried out in Peru, India, Vietnam, Ethiopia, and Brazil, in the cities of Porto Velho/RO and Manaus/AM.

Viability studies

The next step will be a study by the Ministry of Health, in partnership with other institutions, to evaluate the implementation of the use of the new drug in malaria patients in Brazil. Dhélio Pereira explains that "the main objective is to evaluate the inclusion of the G6PD enzyme activity test in the body and the choice of treatment, since about 5% of the population in the country has a deficiency of this enzyme activity to some degree. Thus, "if the test points to normality, the patient can take taphenoquine, if the enzyme activity is moderate or mild, he can be medicated with primaquine, but if the enzyme deficiency is high, the patient can be medicated with primaquine, on a monitored and weekly basis," the researcher points out, stating that the deficit of this enzyme can cause serious side effects to the patient, if it is not identified. The idea is to offer differentiated care after the diagnosis of malaria, and guide professionals who work in the public health network regarding the new treatment model. The final survey can guide states and municipalities in effective actions for the diagnosis and treatment of malaria.