New single-dose medicine to prevent relapse of P. vivax malaria just approved in Peru
On January 5th, the Peruvian regulatory authority, DIGEMID, approved tafenoquine, 150 mg tablets as the first single-dose medicine to prevent relapse of Plasmodium vivax (P. vivax) malaria for patients aged 16 years and older who are receiving chloroquine for acute P. vivax blood-stage infection. P. vivax is the predominant type of malaria in the American continent, representing over 80% of confirmed cases in Peru in 2019. Peru is the second country in Latin America to grant regulatory approval for this medication. The drug was approved by The National Health Surveillance Agency or ANVISA (Agência Nacional de Vigilância Sanitária) in Brazil in October 2019.
The drug is the first new treatment for P. vivax malaria to be developed in over 70 years, representing an important milestone in the fight against this illness. Furthermore, as a single-dose medicine, tafenoquine could support Peru's malaria elimination goals by shortening treatment duration and thereby improving patient adherence.
The achievement is a result of successful clinical studies, which involved the Universidad Peruana Cayetano Heredia, whose researchers are working closely with the Ministry of Health (MINSA) to explore the use of the drug in the Peruvian Health System. In addition to Brazil and Peru, tafenoquine has also been approved in the USA, Australia and Thailand.
Primaquine, the current recommended treatment for the prevention of relapse, needs to be taken for a minimum of 7 days. Adherence to this dosing regime is a challenge, with an estimated 38% of P. vivax malaria patients in Peru not completing the full course of treatment . Patient follow-up can be difficult, particularly in remote areas of the Amazon basin, where malaria is most prevalent.
Along with this new antimalarial drug, a new point-of-care, semi-quantitative, rapid diagnostic tool has been developed. This tool, the glucose-6-phosphate dehydrogenase (G6PD) enzyme test, is used to screen P. vivax malaria patients to determine if they have normal G6PD enzyme activity. Only patients who are confirmed to have normal levels of the G6PD enzyme can be safely treated with tafenoquine.
About malaria in Peru
Peru has made substantial progress in fighting malaria, resulting in a 50% reduction in cases between 2018 and 2019 . The country’s success is largely attributed to the investment and efforts under MINSA’s “Malaria Zero Plan”, which coordinates the country’s policies and activities, and establishes national malaria elimination goals. An updated version of this Plan is expected to be launched in 2021.
P. vivax malaria relapses are a big concern for the malaria community, and a focus of the Peruvian “Malaria Zero Plan”. If adopted in Peru and in other endemic countries in the Americas, tafenoquine has the potential to improve treatment compliance and cure, resulting in fewer malaria cases.
In Latin America, P. vivax malaria cases are concentrated in Peru, Brazil, Colombia and Venezuela. According to the World Health Organization (WHO), 91% of all malaria cases and 92% of all P. vivax cases in the region were registered in these four countries in 2019. These nations accounted for over 650,000 cases in 2019 alone, of which 77% were P. vivax cases.
Both tafenoquine and the STANDARD G6PDTM test will be introduced for the first time in the Brazilian Amazon, as part of a feasibility study that is starting in 2021. This study will help authorities determine how best to use these new tools in real-world, endemic country conditions.
Access to tafenoquine in Peru
Tafenoquine for prevention of relapse of P. vivax malaria was developed through a partnership between Medicines for Malaria Venture (MMV) and GlaxoSmithKline (GSK), as a not-for-profit initiative. MMV has also been working with GSK to ensure broad and equitable access to the drug in malaria-endemic countries. PATH, a global health nonprofit organization, has supported the development of the point-of-care, quantitative, rapid STANDARD G6PDTM test device, which is designed to operate in tropical climates where malaria is prevalent. Both MMV and PATH are collaborating on an initiative, known as VivAccess, to support countries in the elimination of P. vivax malaria through the adoption of new and existing tools to prevent disease relapse, and to improve malaria treatment options. VivAccess is supported with funding from the Bill & Melinda Gates Foundation and has global reach, including other malaria-endemic countries such as Brazil, Cambodia, Colombia, Ethiopia, India, Lao PDR, Myanmar, Thailand, and Vietnam.