Colombia approves single-dose medicine to prevent relapse of P. vivax malaria
The Colombian regulatory authority, INVIMA, approved tafenoquine 150mg tablets, a single-dose medicine to prevent relapse of Plasmodium vivax (P. vivax) malaria, on July 29th 2022. The drug is indicated for patients aged 16 years and older who are receiving chloroquine for acute P. vivax blood-stage infection.
The current liver-stage treatment for P. vivax malaria in Colombia is to take primaquine daily for 14 days. A single-dose of tafenoquine would reduce the length of the liver stage treatment to one day, facilitating patient compliance which could ultimately result in more patients being effectively treated.
Along with this new antimalarial drug, a new point-of-care, quantitative, glucose-6-phosphate dehydrogenase (G6PD) test has been developed. This test is used to screen P. vivax malaria patients to determine if they have normal G6PD enzyme activity. The G6PD enzyme helps protect red blood cells from damage and premature destruction. Only patients who are confirmed to have normal levels of the G6PD enzyme can be treated with tafenoquine.
Malaria in Colombia
Together with Venezuela and Brazil, Colombia, accounted for more than 80% of all estimated malaria cases in the Americas in 20201. In Colombia, malaria mainly affects where access to health services is limited. Afro-Colombians and indigenous populations are disproportionately affected. P. vivax malaria is distributed across the country, from the Amazon region bordering Peru and Brazil to the lowland areas near Venezuela, to the Andean region in Antioquia. The Pacific region is predominately affected by P. falciparum malaria, but there are some areas in this region with a high prevalence of P. vivax.
Colombia is the third country in Latin America to grant regulatory approval for tafenoquine 150mg tablets, after Brazil (2019) and Peru (2021). Tafenoquine has also been approved in the USA, Australia and Thailand for adults aged 16 years and older who are receiving chloroquine for acute P. vivax blood-stage infection.
Evidence generation in Colombia
Medicines for Malaria Venture (MMV) and PATH are collaborating on an initiative, known as the Partnership for Vivax Elimination (PAVE), 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. PAVE, in close collaboration with Colombia’s Ministry of Health, has been undertaking efforts on evidence generation for new malaria treatments and technologies, which include:
- Pilot Educational Programme (PEP): the programme aims to evaluate the effectiveness of training community health workers and other health personnel in diagnosing G6PD deficiency using the STANDARD G6PD test from SD Biosensor. Before taking tafenoquine or primaquine, patients should be tested for G6PD deficiency.
- Health Economic Assessments (HEA): a Cost Effectiveness Analysis (CEA) and a Budget Impact Assessment (BIA) for introducing combinations of radical cure with and without G6PD testing is underway with a Colombian research institution, Universidad de Antioquia.
The results of both initiatives are expected to be available in early 2023, providing evidence for the Ministry of Health to support decision making on P. vivax malaria diagnosis and treatment.
Further information on tafenoquine and G6PD testing
Tafenoquine for prevention of relapse of P. vivax malaria was developed through a partnership between 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 STANDARDTM G6PD test device, a point-of-care, quantitative test, designed to operate in climates where malaria is prevalent. Registration of single-dose tafenoquine by the Colombian national regulator means that the country has the option to introduce the treatment into its treatment guidelines as and when WHO treatment guidelines recommend its use.